views.py

# Copyright The IETF Trust 2007-2020, All Rights Reserved
# -*- coding: utf-8 -*-


import csv
import datetime
import glob
import io
import itertools
import json
import math
import os
import pytz
import re
import tarfile
import tempfile
import markdown2


from calendar import timegm
from collections import OrderedDict, Counter, deque, defaultdict
from urllib.parse import unquote
from tempfile import mkstemp
from wsgiref.handlers import format_date_time

from django import forms
from django.shortcuts import render, redirect, get_object_or_404
from django.http import (HttpResponse, HttpResponseRedirect, HttpResponseForbidden,
                         HttpResponseNotFound, Http404, HttpResponseBadRequest,
                         JsonResponse)
from django.conf import settings
from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.core.exceptions import ValidationError
from django.core.validators import URLValidator
from django.urls import reverse,reverse_lazy
from django.db.models import F, Min, Max, Q
from django.forms.models import modelform_factory, inlineformset_factory
from django.template import TemplateDoesNotExist
from django.template.loader import render_to_string
from django.utils.encoding import force_str
from django.utils.functional import curry
from django.utils.text import slugify
from django.views.decorators.cache import cache_page
from django.utils.html import format_html
from django.views.decorators.csrf import ensure_csrf_cookie, csrf_exempt
from django.views.generic import RedirectView

import debug                            # pyflakes:ignore

from ietf.doc.fields import SearchableDocumentsField
from ietf.doc.models import Document, State, DocEvent, NewRevisionDocEvent, DocAlias
from ietf.group.models import Group
from ietf.group.utils import can_manage_session_materials, can_manage_some_groups, can_manage_group
from ietf.person.models import Person
from ietf.ietfauth.utils import role_required, has_role, user_is_person
from ietf.mailtrigger.utils import gather_address_lists
from ietf.meeting.models import Meeting, Session, Schedule, FloorPlan, SessionPresentation, TimeSlot, SlideSubmission
from ietf.meeting.models import SessionStatusName, SchedulingEvent, SchedTimeSessAssignment, Room, TimeSlotTypeName
from ietf.meeting.forms import CustomDurationField
from ietf.meeting.helpers import get_areas, get_person_by_email, get_schedule_by_name
from ietf.meeting.helpers import build_all_agenda_slices, get_wg_name_list
from ietf.meeting.helpers import get_all_assignments_from_schedule
from ietf.meeting.helpers import get_modified_from_assignments
from ietf.meeting.helpers import get_wg_list, find_ads_for_meeting
from ietf.meeting.helpers import get_meeting, get_ietf_meeting, get_current_ietf_meeting_num
from ietf.meeting.helpers import get_schedule, schedule_permissions
from ietf.meeting.helpers import preprocess_assignments_for_agenda, read_agenda_file
from ietf.meeting.helpers import filter_keywords_for_session, tag_assignments_with_filter_keywords
from ietf.meeting.helpers import convert_draft_to_pdf, get_earliest_session_date
from ietf.meeting.helpers import can_view_interim_request, can_approve_interim_request
from ietf.meeting.helpers import can_edit_interim_request
from ietf.meeting.helpers import can_request_interim_meeting, get_announcement_initial
from ietf.meeting.helpers import sessions_post_save, is_interim_meeting_approved
from ietf.meeting.helpers import send_interim_cancellation_notice
from ietf.meeting.helpers import send_interim_approval
from ietf.meeting.helpers import send_interim_approval_request
from ietf.meeting.helpers import send_interim_announcement_request
from ietf.meeting.utils import finalize, sort_accept_tuple, condition_slide_order
from ietf.meeting.utils import add_event_info_to_session_qs
from ietf.meeting.utils import session_time_for_sorting
from ietf.meeting.utils import session_requested_by
from ietf.meeting.utils import current_session_status
from ietf.meeting.utils import data_for_meetings_overview
from ietf.meeting.utils import preprocess_constraints_for_meeting_schedule_editor
from ietf.meeting.utils import diff_meeting_schedules, prefetch_schedule_diff_objects
from ietf.meeting.utils import swap_meeting_schedule_timeslot_assignments
from ietf.meeting.utils import preprocess_meeting_important_dates
from ietf.message.utils import infer_message
from ietf.name.models import SlideSubmissionStatusName
from ietf.secr.proceedings.utils import handle_upload_file
from ietf.secr.proceedings.proc_utils import (get_progress_stats, post_process, import_audio_files,
    create_recording)
from ietf.utils.decorators import require_api_key
from ietf.utils.history import find_history_replacements_active_at
from ietf.utils.log import assertion
from ietf.utils.mail import send_mail_message, send_mail_text
from ietf.utils.mime import get_mime_type
from ietf.utils.pipe import pipe
from ietf.utils.pdf import pdf_pages
from ietf.utils.response import permission_denied
from ietf.utils.text import xslugify
from ietf.utils.timezone import date2datetime

from .forms import (InterimMeetingModelForm, InterimAnnounceForm, InterimSessionModelForm,
    InterimCancelForm, InterimSessionInlineFormSet, FileUploadForm, RequestMinutesForm,)


def get_interim_menu_entries(request):
    '''Setup menu entries for interim meeting view tabs'''
    entries = []
    entries.append(("Upcoming", reverse("ietf.meeting.views.upcoming")))
    entries.append(("Pending", reverse("ietf.meeting.views.interim_pending")))
    entries.append(("Announce", reverse("ietf.meeting.views.interim_announce")))
    return entries

def send_interim_change_notice(request, meeting):
    """Sends an email notifying changes to a previously scheduled / announced meeting"""
    group = meeting.session_set.first().group
    form = InterimAnnounceForm(get_announcement_initial(meeting, is_change=True))
    message = form.save(user=request.user)
    message.related_groups.add(group)
    send_mail_message(request, message)

# -------------------------------------------------
# View Functions
# -------------------------------------------------

def materials(request, num=None):
    meeting = get_meeting(num)
    begin_date = meeting.get_submission_start_date()
    cut_off_date = meeting.get_submission_cut_off_date()
    cor_cut_off_date = meeting.get_submission_correction_date()
    now = datetime.date.today()
    old = datetime.datetime.now() - datetime.timedelta(days=1)
    if settings.SERVER_MODE != 'production' and '_testoverride' in request.GET:
        pass
    elif now > cor_cut_off_date:
        if meeting.number.isdigit() and int(meeting.number) > 96:
            return redirect('ietf.meeting.views.proceedings', num=meeting.number)
        else:
            return render(request, "meeting/materials_upload_closed.html", {
                'meeting_num': meeting.number,
                'begin_date': begin_date,
                'cut_off_date': cut_off_date,
                'cor_cut_off_date': cor_cut_off_date
            })

    past_cutoff_date = datetime.date.today() > meeting.get_submission_correction_date()

    schedule = get_schedule(meeting, None)

    sessions  = add_event_info_to_session_qs(Session.objects.filter(
        meeting__number=meeting.number,
        timeslotassignments__schedule__in=[schedule, schedule.base if schedule else None]
    ).distinct().select_related('meeting__schedule', 'group__state', 'group__parent'))

    plenaries = sessions.filter(name__icontains='plenary')
    ietf      = sessions.filter(group__parent__type__slug = 'area').exclude(group__acronym='edu')
    irtf      = sessions.filter(group__parent__acronym = 'irtf')
    training  = sessions.filter(group__acronym__in=['edu','iaoc'], type_id__in=['regular', 'other', ])
    iab       = sessions.filter(group__parent__acronym = 'iab')

    session_pks = [s.pk for ss in [plenaries, ietf, irtf, training, iab] for s in ss]
    other     = sessions.filter(type__in=['regular'], group__type__features__has_meetings=True).exclude(pk__in=session_pks)

    for topic in [plenaries, ietf, training, irtf, iab]:
        for event in topic:
            date_list = []
            for slide_event in event.all_meeting_slides(): date_list.append(slide_event.time)
            for agenda_event in event.all_meeting_agendas(): date_list.append(agenda_event.time)
            if date_list: setattr(event, 'last_update', sorted(date_list, reverse=True)[0])

    for session_list in [plenaries, ietf, training, irtf, iab, other]:
        for session in session_list:
            session.past_cutoff_date = past_cutoff_date
            
    return render(request, "meeting/materials.html", {
        'meeting': meeting,
        'plenaries': plenaries,
        'ietf': ietf,
        'training': training,
        'irtf': irtf,
        'iab': iab,
        'other': other,
        'cut_off_date': cut_off_date,
        'cor_cut_off_date': cor_cut_off_date,
        'submission_started': now > begin_date,
        'old': old,
    })

def current_materials(request):
    today = datetime.date.today()
    meetings = Meeting.objects.exclude(number__startswith='interim-').filter(date__lte=today).order_by('-date')
    if meetings:
        return redirect(materials, meetings[0].number)
    else:
        raise Http404('No such meeting')

@cache_page(1 * 60)
def materials_document(request, document, num=None, ext=None):
    meeting=get_meeting(num,type_in=['ietf','interim'])
    num = meeting.number
    if (re.search(r'^\w+-\d+-.+-\d\d$', document) or
        re.search(r'^\w+-interim-\d+-.+-\d\d-\d\d$', document) or
        re.search(r'^\w+-interim-\d+-.+-sess[a-z]-\d\d$', document) or
        re.search(r'^minutes-interim-\d+-.+-\d\d$', document) or
        re.search(r'^slides-interim-\d+-.+-\d\d$', document)):
        name, rev = document.rsplit('-', 1)
    else:
        name, rev = document, None
    # This view does not allow the use of DocAliases. Right now we are probably only creating one (identity) alias, but that may not hold in the future.
    doc = Document.objects.filter(name=name).first()
    # Handle edge case where the above name, rev splitter misidentifies the end of a document name as a revision mumber
    if not doc:
        if rev:
            name = name + '-' + rev
            rev = None
            doc = get_object_or_404(Document, name=name)
        else:
            raise Http404("No such document")

    if not doc.meeting_related():
        raise Http404("Not a meeting related document")
    if not doc.session_set.filter(meeting__number=num).exists():
        raise Http404("No such document for meeting %s" % num)
    if not rev:
        filename = doc.get_file_name()
    else:
        filename = os.path.join(doc.get_file_path(), document)
    if ext:
        if not filename.endswith(ext):
            name, _ = os.path.splitext(filename)
            filename = name + ext
    else:
        filenames = glob.glob(filename+'.*')
        if filenames:
            filename = filenames[0]
    _, basename = os.path.split(filename)
    if not os.path.exists(filename):
        raise Http404("File not found: %s" % filename)

    old_proceedings_format = meeting.number.isdigit() and int(meeting.number) <= 96

    if settings.MEETING_MATERIALS_SERVE_LOCALLY or old_proceedings_format:
        with io.open(filename, 'rb') as file:
            bytes = file.read()
        
        mtype, chset = get_mime_type(bytes)
        content_type = "%s; charset=%s" % (mtype, chset)

        file_ext = os.path.splitext(filename)
        if len(file_ext) == 2 and file_ext[1] == '.md' and mtype == 'text/plain':
            sorted_accept = sort_accept_tuple(request.META.get('HTTP_ACCEPT'))
            for atype in sorted_accept:
                if atype[0] == 'text/markdown':
                    content_type = content_type.replace('plain', 'markdown', 1)
                    break;
                elif atype[0] == 'text/html':
                    bytes = "<html>\n<head></head>\n<body>\n%s\n</body>\n</html>\n" % markdown2.markdown(bytes)
                    content_type = content_type.replace('plain', 'html', 1)
                    break;
                elif atype[0] == 'text/plain':
                    break;

        response = HttpResponse(bytes, content_type=content_type)
        response['Content-Disposition'] = 'inline; filename="%s"' % basename
        return response
    else:
        return HttpResponseRedirect(redirect_to=doc.get_href(meeting=meeting))

@login_required
def materials_editable_groups(request, num=None):
    meeting = get_meeting(num)
    return render(request, "meeting/materials_editable_groups.html", {
        'meeting_num': meeting.number})

def ascii_alphanumeric(string):
    return re.match(r'^[a-zA-Z0-9]*$', string)

class SaveAsForm(forms.Form):
    savename = forms.CharField(max_length=16)

@role_required('Area Director','Secretariat')
def schedule_create(request, num=None, owner=None, name=None):
    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    schedule = get_schedule_by_name(meeting, person, name)

    if schedule is None:
        # here we have to return some ajax to display an error.
        messages.error("Error: No meeting information for meeting %s owner %s schedule %s available" % (num, owner, name)) # pylint: disable=no-value-for-parameter
        return redirect(edit_schedule, num=num, owner=owner, name=name)

    # authorization was enforced by the @group_require decorator above.

    saveasform = SaveAsForm(request.POST)
    if not saveasform.is_valid():
        messages.info(request, "This name is not valid. Please choose another one.")
        return redirect(edit_schedule, num=num, owner=owner, name=name)

    savedname = saveasform.cleaned_data['savename']

    if not ascii_alphanumeric(savedname):
        messages.info(request, "This name contains illegal characters. Please choose another one.")
        return redirect(edit_schedule, num=num, owner=owner, name=name)

    # create the new schedule, and copy the assignments
    try:
        sched = meeting.schedule_set.get(name=savedname, owner=request.user.person)
        if sched:
            return redirect(edit_schedule, num=meeting.number, owner=sched.owner_email(), name=sched.name)
        else:
            messages.info(request, "Schedule creation failed. Please try again.")
            return redirect(edit_schedule, num=num, owner=owner, name=name)

    except Schedule.DoesNotExist:
        pass

    # must be done
    newschedule = Schedule(name=savedname,
                           owner=request.user.person,
                           meeting=meeting,
                           base=schedule.base,
                           origin=schedule,
                           visible=False,
                           public=False)

    newschedule.save()
    if newschedule is None:
        return HttpResponse(status=500)

    # keep a mapping so that extendedfrom references can be chased.
    mapping = {};
    for ss in schedule.assignments.all():
        # hack to copy the object, creating a new one
        # just reset the key, and save it again.
        oldid = ss.pk
        ss.pk = None
        ss.schedule=newschedule
        ss.save()
        mapping[oldid] = ss.pk
        #print "Copying %u to %u" % (oldid, ss.pk)

    # now fix up any extendedfrom references to new set.
    for ss in newschedule.assignments.all():
        if ss.extendedfrom is not None:
            oldid = ss.extendedfrom.id
            newid = mapping[oldid]
            #print "Fixing %u to %u" % (oldid, newid)
            ss.extendedfrom = newschedule.assignments.get(pk = newid)
            ss.save()


    # now redirect to this new schedule.
    return redirect(edit_schedule, meeting.number, newschedule.owner_email(), newschedule.name)


@role_required('Secretariat')
def edit_timeslots(request, num=None):

    meeting = get_meeting(num)

    time_slices,date_slices,slots = meeting.build_timeslices()

    ts_list = deque()
    rooms = meeting.room_set.order_by("capacity","name","id")
    for room in rooms:
        for day in time_slices:
            for slice in date_slices[day]:
                ts_list.append(room.timeslot_set.filter(time=slice[0],duration=datetime.timedelta(seconds=slice[2])).first())
            

    return render(request, "meeting/timeslot_edit.html",
                                         {"rooms":rooms,
                                          "time_slices":time_slices,
                                          "slot_slices": slots,
                                          "date_slices":date_slices,
                                          "meeting":meeting,
                                          "ts_list":ts_list,
                                      })

class NewScheduleForm(forms.ModelForm):
    class Meta:
        model = Schedule
        fields = ['name', 'visible', 'public', 'notes', 'base']

    def __init__(self, meeting, schedule, new_owner, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.meeting = meeting
        self.schedule = schedule
        self.new_owner = new_owner

        username = new_owner.user.username

        name_suggestion = username
        counter = 2

        existing_names = set(Schedule.objects.filter(meeting=meeting, owner=new_owner).values_list('name', flat=True))
        while name_suggestion in existing_names:
            name_suggestion = username + str(counter)
            counter += 1

        self.fields['name'].initial = name_suggestion
        self.fields['name'].label = "Name of new agenda"

        self.fields['base'].queryset = self.fields['base'].queryset.filter(meeting=meeting)

        if schedule:
            self.fields['visible'].initial = schedule.visible
            self.fields['public'].initial = schedule.public
            self.fields['base'].queryset = self.fields['base'].queryset.exclude(pk=schedule.pk)
            self.fields['base'].initial = schedule.base_id
        else:
            base = Schedule.objects.filter(meeting=meeting, name='base').first()
            if base:
                self.fields['base'].initial = base.pk

    def clean_name(self):
        name = self.cleaned_data.get('name')
        if name and Schedule.objects.filter(meeting=self.meeting, owner=self.new_owner, name=name):
            raise forms.ValidationError("Schedule with this name already exists.")
        return name

@role_required('Area Director','Secretariat')
def new_meeting_schedule(request, num, owner=None, name=None):
    meeting  = get_meeting(num)
    schedule = get_schedule_by_name(meeting, get_person_by_email(owner), name)

    if request.method == 'POST':
        form = NewScheduleForm(meeting, schedule, request.user.person, request.POST)

        if form.is_valid():
            new_schedule = form.save(commit=False)
            new_schedule.meeting = meeting
            new_schedule.owner = request.user.person
            new_schedule.origin = schedule
            new_schedule.save()

            if schedule:
                for assignment in schedule.assignments.all():
                    # clone by resetting primary key
                    assignment.pk = None
                    assignment.schedule = new_schedule
                    assignment.extendedfrom = None
                    assignment.save()

            # now redirect to this new schedule
            return redirect(edit_meeting_schedule, meeting.number, new_schedule.owner_email(), new_schedule.name)
            
    else:
        form = NewScheduleForm(meeting, schedule, request.user.person)

    return render(request, "meeting/new_meeting_schedule.html", {
        'meeting': meeting,
        'schedule': schedule,
        'form': form,
    })


class SwapDaysForm(forms.Form):
    source_day = forms.DateField(required=True)
    target_day = forms.DateField(required=True)

@ensure_csrf_cookie
def edit_meeting_schedule(request, num=None, owner=None, name=None):
    meeting = get_meeting(num)
    if name is None:
        schedule = meeting.schedule
    else:
        schedule = get_schedule_by_name(meeting, get_person_by_email(owner), name)

    if schedule is None:
        raise Http404("No meeting information for meeting %s owner %s schedule %s available" % (num, owner, name))

    can_see, can_edit, secretariat = schedule_permissions(meeting, schedule, request.user)

    if not can_see:
        if request.method == 'POST':
            permission_denied(request, "Can't view this schedule.")

        return render(request, "meeting/private_schedule.html", {
            "schedule":schedule,
            "meeting": meeting,
            "meeting_base_url": request.build_absolute_uri(meeting.base_url()),
            "hide_menu": True
        }, status=403, content_type="text/html")

    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base],
        timeslot__location__isnull=False,
        session__type='regular',
    ).order_by('timeslot__time','timeslot__name')

    assignments_by_session = defaultdict(list)
    for a in assignments:
        assignments_by_session[a.session_id].append(a)

    rooms = meeting.room_set.filter(session_types__slug='regular').distinct().order_by("capacity")

    tombstone_states = ['canceled', 'canceledpa', 'resched']

    sessions = add_event_info_to_session_qs(
        Session.objects.filter(
            meeting=meeting,
            type='regular',
        ).order_by('pk'),
        requested_time=True,
        requested_by=True,
    ).filter(
        Q(current_status__in=['appr', 'schedw', 'scheda', 'sched'])
        | Q(current_status__in=tombstone_states, pk__in={a.session_id for a in assignments})
    ).prefetch_related(
        'resources', 'group', 'group__parent', 'group__type', 'joint_with_groups',
    )

    timeslots_qs = TimeSlot.objects.filter(meeting=meeting, type='regular').prefetch_related('type').order_by('location', 'time', 'name')

    min_duration = min(t.duration for t in timeslots_qs)
    max_duration = max(t.duration for t in timeslots_qs)

    def timedelta_to_css_ems(timedelta):
        # we scale the session and slots a bit according to their
        # length for an added visual clue
        capped_min_d = max(min_duration, datetime.timedelta(minutes=30))
        capped_max_d = min(max_duration, datetime.timedelta(hours=4))
        capped_timedelta = min(max(capped_min_d, timedelta), capped_max_d)

        min_d_css_rems = 8
        max_d_css_rems = 10
        # interpolate
        scale = (capped_timedelta - capped_min_d) / (capped_max_d - capped_min_d) if capped_min_d != capped_max_d else 1
        return min_d_css_rems + (max_d_css_rems - min_d_css_rems) * scale

    def prepare_sessions_for_display(sessions):
        # requesters
        requested_by_lookup = {p.pk: p for p in Person.objects.filter(pk__in=set(s.requested_by for s in sessions if s.requested_by))}

        # constraints
        constraints_for_sessions, formatted_constraints_for_sessions, constraint_names = preprocess_constraints_for_meeting_schedule_editor(meeting, sessions)

        sessions_for_group = defaultdict(list)
        for s in sessions:
            sessions_for_group[s.group_id].append(s)

        for s in sessions:
            s.requested_by_person = requested_by_lookup.get(s.requested_by)

            s.scheduling_label = "???"
            if s.group:
                s.scheduling_label = s.group.acronym
            elif s.name:
                s.scheduling_label = s.name

            s.requested_duration_in_hours = round(s.requested_duration.seconds / 60.0 / 60.0, 1)

            session_layout_margin = 0.2
            s.layout_width = timedelta_to_css_ems(s.requested_duration) - 2 * session_layout_margin
            s.parent_acronym = s.group.parent.acronym if s.group and s.group.parent else ""

            # compress the constraints, so similar constraint labels are
            # shared between the conflicting sessions they cover - the JS
            # then simply has to detect violations and show the
            # preprocessed labels
            constrained_sessions_grouped_by_label = defaultdict(set)
            for name_id, ts in itertools.groupby(sorted(constraints_for_sessions.get(s.pk, [])), key=lambda t: t[0]):
                ts = list(ts)
                session_pks = (t[1] for t in ts)
                constraint_name = constraint_names[name_id]
                if "{count}" in constraint_name.formatted_editor_label:
                    for session_pk, grouped_session_pks in itertools.groupby(session_pks):
                        count = sum(1 for i in grouped_session_pks)
                        constrained_sessions_grouped_by_label[format_html(constraint_name.formatted_editor_label, count=count)].add(session_pk)

                else:
                    constrained_sessions_grouped_by_label[constraint_name.formatted_editor_label].update(session_pks)

            s.constrained_sessions = list(constrained_sessions_grouped_by_label.items())
            s.formatted_constraints = formatted_constraints_for_sessions.get(s.pk, {})

            s.other_sessions = [s_other for s_other in sessions_for_group.get(s.group_id) if s != s_other]

            s.readonly = s.current_status in tombstone_states or any(a.schedule_id != schedule.pk for a in assignments_by_session.get(s.pk, []))


    if request.method == 'POST':
        if not can_edit:
            permission_denied(request, "Can't edit this schedule.")

        action = request.POST.get('action')

        # handle ajax requests
        if action == 'assign' and request.POST.get('session', '').isdigit() and request.POST.get('timeslot', '').isdigit():
            session = get_object_or_404(sessions, pk=request.POST['session'])
            timeslot = get_object_or_404(timeslots_qs, pk=request.POST['timeslot'])

            tombstone_session = None

            existing_assignments = SchedTimeSessAssignment.objects.filter(session=session, schedule=schedule)
            if existing_assignments:
                if schedule.pk == meeting.schedule_id and session.current_status == 'sched':
                    old_timeslot = existing_assignments[0].timeslot
                    # clone session and leave it as a tombstone
                    tombstone_session = session
                    tombstone_session.tombstone_for_id = session.pk
                    tombstone_session.pk = None
                    tombstone_session.save()

                    session = None

                    SchedulingEvent.objects.create(
                        session=tombstone_session,
                        status=SessionStatusName.objects.get(slug='resched'),
                        by=request.user.person,
                    )

                    tombstone_session.current_status = 'resched' # rematerialize status for the rendering

                    SchedTimeSessAssignment.objects.create(
                        session=tombstone_session,
                        schedule=schedule,
                        timeslot=old_timeslot,
                    )

                existing_assignments.update(timeslot=timeslot, modified=datetime.datetime.now())
            else:
                SchedTimeSessAssignment.objects.create(
                    session=session,
                    schedule=schedule,
                    timeslot=timeslot,
                )

            r = {'success': True}
            if tombstone_session:
                prepare_sessions_for_display([tombstone_session])
                r['tombstone'] = render_to_string("meeting/edit_meeting_schedule_session.html", {'session': tombstone_session})
            return JsonResponse(r)

        elif action == 'unassign' and request.POST.get('session', '').isdigit():
            session = get_object_or_404(sessions, pk=request.POST['session'])
            SchedTimeSessAssignment.objects.filter(session=session, schedule=schedule).delete()

            return JsonResponse({'success': True})

        elif action == 'swapdays':
            # updating the client side is a bit complicated, so just
            # do a full refresh

            swap_days_form = SwapDaysForm(request.POST)
            if not swap_days_form.is_valid():
                return HttpResponse("Invalid swap: {}".format(swap_days_form.errors), status=400)

            source_day = swap_days_form.cleaned_data['source_day']
            target_day = swap_days_form.cleaned_data['target_day']

            source_timeslots = [ts for ts in timeslots_qs if ts.time.date() == source_day]
            target_timeslots = [ts for ts in timeslots_qs if ts.time.date() == target_day]
            swap_meeting_schedule_timeslot_assignments(schedule, source_timeslots, target_timeslots, target_day - source_day)

            return HttpResponseRedirect(request.get_full_path())

        return HttpResponse("Invalid parameters", status=400)

    # prepare timeslot layout

    timeslots_by_room_and_day = defaultdict(list)
    room_has_timeslots = set()
    for t in timeslots_qs:
        room_has_timeslots.add(t.location_id)
        timeslots_by_room_and_day[(t.location_id, t.time.date())].append(t)

    days = []
    for day in sorted(set(t.time.date() for t in timeslots_qs)):
        room_timeslots = []
        for r in rooms:
            if r.pk not in room_has_timeslots:
                continue

            timeslots = []
            for t in timeslots_by_room_and_day.get((r.pk, day), []):
                t.layout_width = timedelta_to_css_ems(t.end_time() - t.time)
                timeslots.append(t)

            room_timeslots.append((r, timeslots))

        days.append({
            'day': day,
            'room_timeslots': room_timeslots,
        })

    room_labels = [[r for r in rooms if r.pk in room_has_timeslots] for i in range(len(days))]

    # possible timeslot start/ends
    timeslot_groups = defaultdict(set)
    for ts in timeslots_qs:
        ts.start_end_group = "ts-group-{}-{}".format(ts.time.strftime("%Y%m%d-%H%M"), int(ts.duration.total_seconds() / 60))
        timeslot_groups[ts.time.date()].add((ts.time, ts.end_time(), ts.start_end_group))

    # prepare sessions
    prepare_sessions_for_display(sessions)

    for ts in timeslots_qs:
        ts.session_assignments = []
    timeslots_by_pk = {ts.pk: ts for ts in timeslots_qs}

    unassigned_sessions = []
    for s in sessions:
        assigned = False
        for a in assignments_by_session.get(s.pk, []):
            timeslot = timeslots_by_pk.get(a.timeslot_id)
            if timeslot:
                timeslot.session_assignments.append((a, s))
                assigned = True

        if not assigned:
            unassigned_sessions.append(s)

    # group parent colors
    def cubehelix(i, total, hue=1.2, start_angle=0.5):
        # theory in https://arxiv.org/pdf/1108.5083.pdf
        rotations = total // 4
        x = float(i + 1) / (total + 1)
        phi = 2 * math.pi * (start_angle / 3 + rotations * x)
        a = hue * x * (1 - x) / 2.0

        return (
            max(0, min(x + a * (-0.14861 * math.cos(phi) + 1.78277 * math.sin(phi)), 1)),
            max(0, min(x + a * (-0.29227 * math.cos(phi) + -0.90649 * math.sin(phi)), 1)),
            max(0, min(x + a * (1.97294 * math.cos(phi)), 1)),
        )

    session_parents = sorted(set(
        s.group.parent for s in sessions
        if s.group and s.group.parent and (s.group.parent.type_id == 'area' or s.group.parent.acronym == 'irtf')
    ), key=lambda p: p.acronym)
    for i, p in enumerate(session_parents):
        rgb_color = cubehelix(i, len(session_parents))
        p.scheduling_color = "rgb({}, {}, {})".format(*tuple(int(round(x * 255)) for x in rgb_color))
        p.light_scheduling_color = "rgb({}, {}, {})".format(*tuple(int(round((0.9 + 0.1 * x) * 255)) for x in rgb_color))

    return render(request, "meeting/edit_meeting_schedule.html", {
        'meeting': meeting,
        'schedule': schedule,
        'can_edit': can_edit,
        'can_edit_properties': can_edit or secretariat,
        'secretariat': secretariat,
        'days': days,
        'room_labels': room_labels,
        'timeslot_groups': sorted((d, list(sorted(t_groups))) for d, t_groups in timeslot_groups.items()),
        'unassigned_sessions': unassigned_sessions,
        'session_parents': session_parents,
        'hide_menu': True,
    })


class RoomNameModelChoiceField(forms.ModelChoiceField):
    def label_from_instance(self, obj):
        return obj.name

class TimeSlotForm(forms.Form):
    day = forms.TypedChoiceField(coerce=lambda t: datetime.datetime.strptime(t, "%Y-%m-%d").date())
    time = forms.TimeField()
    duration = CustomDurationField() # this is just to make 1:30 turn into 1.5 hours instead of 1.5 minutes
    location = RoomNameModelChoiceField(queryset=Room.objects.all(), required=False, empty_label="(No location)")
    show_location = forms.BooleanField(initial=True, required=False)
    type = forms.ModelChoiceField(queryset=TimeSlotTypeName.objects.filter(used=True), empty_label=None, required=False)
    name = forms.CharField(help_text='Name that appears on the agenda', required=False)
    short = forms.CharField(max_length=32,label='Short name', help_text='Abbreviated session name used for material file names', required=False)
    group = forms.ModelChoiceField(queryset=Group.objects.filter(type__in=['ietf', 'team'], state='active'),
        help_text='''Select a group to associate with this session.<br>For example: Tutorials = Education, Code Sprint = Tools Team''',
        required=False)
    agenda_note = forms.CharField(required=False)

    def __init__(self, meeting, schedule, *args, timeslot=None, **kwargs):
        super().__init__(*args,**kwargs)

        self.fields["time"].widget.attrs["placeholder"] = "HH:MM"
        self.fields["duration"].widget.attrs["placeholder"] = "HH:MM"
        self.fields["duration"].initial = ""

        self.fields["day"].choices = [
            ((meeting.date + datetime.timedelta(days=i)).isoformat(), (meeting.date + datetime.timedelta(days=i)).strftime("%a %b %d"))
            for i in range(meeting.days)
        ]

        self.fields['location'].queryset = self.fields['location'].queryset.filter(meeting=meeting)

        self.fields['group'].widget.attrs['data-ietf'] = Group.objects.get(acronym='ietf').pk

        self.active_assignment = None

        if timeslot:
            self.initial = {
                'day': timeslot.time.date(),
                'time': timeslot.time.time(),
                'duration': timeslot.duration,
                'location': timeslot.location_id,
                'show_location': timeslot.show_location,
                'type': timeslot.type_id,
                'name': timeslot.name,
            }

            assignments = sorted(SchedTimeSessAssignment.objects.filter(
                timeslot=timeslot,
                schedule__in=[schedule, schedule.base if schedule else None]
            ).select_related('session', 'session__group'), key=lambda a: 0 if a.schedule_id == schedule.pk else 1)

            if assignments:
                self.active_assignment = assignments[0]

                self.initial['short'] = self.active_assignment.session.short
                self.initial['group'] = self.active_assignment.session.group_id

        if not self.active_assignment or timeslot.type_id != 'regular':
            del self.fields['agenda_note'] # at the moment, the UI only shows this field for regular sessions

        self.timeslot = timeslot

    def clean(self):
        group = self.cleaned_data.get('group')
        ts_type = self.cleaned_data.get('type')
        short = self.cleaned_data.get('short')

        if ts_type:
            if ts_type.slug in ['break', 'reg', 'reserved', 'unavail', 'regular']:
                if ts_type.slug != 'regular':
                    self.cleaned_data['group'] = self.fields['group'].queryset.get(acronym='secretariat')
            else:
                if not group:
                    self.add_error('group', 'When scheduling this type of time slot, a group must be associated')
                if not short:
                    self.add_error('short', 'When scheduling this type of time slot, a short name is required')

            if self.timeslot and self.timeslot.type_id == 'regular' and self.active_assignment and ts_type.pk != self.timeslot.type_id:
                self.add_error('type', "Can't change type on time slots for regular sessions when a session has been assigned")

        if self.active_assignment and self.active_assignment.session.group != self.cleaned_data.get('group') and self.active_assignment.session.materials.exists() and self.timeslot.type_id != 'regular':
            self.add_error('group', "Can't change group after materials have been uploaded")


@role_required('Area Director', 'Secretariat')
def edit_meeting_timeslots_and_misc_sessions(request, num=None, owner=None, name=None):
    meeting = get_meeting(num)
    if name is None:
        schedule = meeting.schedule
    else:
        schedule = get_schedule_by_name(meeting, get_person_by_email(owner), name)

    if schedule is None:
        raise Http404("No meeting information for meeting %s owner %s schedule %s available" % (num, owner, name))

    rooms = list(Room.objects.filter(meeting=meeting).prefetch_related('session_types').order_by('-capacity', 'name'))
    rooms.append(Room(name="(No location)"))

    timeslot_qs = TimeSlot.objects.filter(meeting=meeting).prefetch_related('type').order_by('time')

    can_edit = has_role(request.user, 'Secretariat')

    if request.method == 'GET' and request.GET.get('action') == "edit-timeslot":
        timeslot_pk = request.GET.get('timeslot')
        if not timeslot_pk or not timeslot_pk.isdecimal():
            raise Http404
        timeslot = get_object_or_404(timeslot_qs, pk=timeslot_pk)

        assigned_session = add_event_info_to_session_qs(Session.objects.filter(
            timeslotassignments__schedule__in=[schedule, schedule.base],
            timeslotassignments__timeslot=timeslot,
        )).first()

        timeslot.can_cancel = not assigned_session or assigned_session.current_status not in ['canceled', 'canceled', 'resched']

        return JsonResponse({
            'form': render_to_string("meeting/edit_timeslot_form.html", {
                'timeslot_form_action': 'edit',
                'timeslot_form': TimeSlotForm(meeting, schedule, timeslot=timeslot),
                'timeslot': timeslot,
                'schedule': schedule,
                'meeting': meeting,
                'can_edit': can_edit,
            }, request=request)
        })

    scroll = request.POST.get('scroll')

    def redirect_with_scroll():
        url = request.get_full_path()
        if scroll and scroll.isdecimal():
            url += "#scroll={}".format(scroll)
        return HttpResponseRedirect(url)

    add_timeslot_form = None
    if request.method == 'POST' and request.POST.get('action') == 'add-timeslot' and can_edit:
        add_timeslot_form = TimeSlotForm(meeting, schedule, request.POST)
        if add_timeslot_form.is_valid():
            c = add_timeslot_form.cleaned_data

            timeslot, created = TimeSlot.objects.get_or_create(
                meeting=meeting,
                type=c['type'],
                name=c['name'],
                time=datetime.datetime.combine(c['day'], c['time']),
                duration=c['duration'],
                location=c['location'],
                show_location=c['show_location'],
            )

            if timeslot.type_id != 'regular':
                if not created:
                    Session.objects.filter(timeslotassignments__timeslot=timeslot).delete()

                session = Session.objects.create(
                    meeting=meeting,
                    name=c['name'],
                    short=c['short'],
                    group=c['group'],
                    type=c['type'],
                    agenda_note=c.get('agenda_note') or "",
                )

                SchedulingEvent.objects.create(
                    session=session,
                    status=SessionStatusName.objects.get(slug='sched'),
                    by=request.user.person,
                )

                SchedTimeSessAssignment.objects.create(
                    timeslot=timeslot,
                    session=session,
                    schedule=schedule
                )

            return redirect_with_scroll()

    edit_timeslot_form = None
    if request.method == 'POST' and request.POST.get('action') == 'edit-timeslot' and can_edit:
        timeslot_pk = request.POST.get('timeslot')
        if not timeslot_pk or not timeslot_pk.isdecimal():
            raise Http404

        timeslot = get_object_or_404(TimeSlot, pk=timeslot_pk)

        edit_timeslot_form = TimeSlotForm(meeting, schedule, request.POST, timeslot=timeslot)
        if edit_timeslot_form.is_valid() and edit_timeslot_form.active_assignment.schedule_id == schedule.pk:

            c = edit_timeslot_form.cleaned_data

            timeslot.type = c['type']
            timeslot.name = c['name']
            timeslot.time = datetime.datetime.combine(c['day'], c['time'])
            timeslot.duration = c['duration']
            timeslot.location = c['location']
            timeslot.show_location = c['show_location']
            timeslot.save()

            session = Session.objects.filter(
                timeslotassignments__schedule__in=[schedule, schedule.base if schedule else None],
                timeslotassignments__timeslot=timeslot,
            ).select_related('group').first()

            if session:
                if timeslot.type_id != 'regular':
                    session.name = c['name']
                    session.short = c['short']
                    session.group = c['group']
                    session.type = c['type']
                session.agenda_note = c.get('agenda_note') or ""
                session.save()

            return redirect_with_scroll()

    if request.method == 'POST' and request.POST.get('action') == 'cancel-timeslot' and can_edit:
        timeslot_pk = request.POST.get('timeslot')
        if not timeslot_pk or not timeslot_pk.isdecimal():
            raise Http404

        timeslot = get_object_or_404(TimeSlot, pk=timeslot_pk)
        if timeslot.type_id != 'break':
            sessions = add_event_info_to_session_qs(
                Session.objects.filter(timeslotassignments__schedule=schedule, timeslotassignments__timeslot=timeslot),
            ).exclude(current_status__in=['canceled', 'resched'])
            for session in sessions:
                SchedulingEvent.objects.create(
                    session=session,
                    status=SessionStatusName.objects.get(slug='canceled'),
                    by=request.user.person,
                )

        return redirect_with_scroll()

    if request.method == 'POST' and request.POST.get('action') == 'delete-timeslot' and can_edit:
        timeslot_pk = request.POST.get('timeslot')
        if not timeslot_pk or not timeslot_pk.isdecimal():
            raise Http404

        timeslot = get_object_or_404(TimeSlot, pk=timeslot_pk)

        if timeslot.type_id != 'regular':
            for session in Session.objects.filter(timeslotassignments__schedule=schedule, timeslotassignments__timeslot=timeslot):
                for doc in session.materials.all():
                    doc.set_state(State.objects.get(type=doc.type_id, slug='deleted'))
                    e = DocEvent(doc=doc, rev=doc.rev, by=request.user.person, type='deleted')
                    e.desc = "Deleted meeting session"
                    e.save()

                session.delete()

        timeslot.delete()

        return redirect_with_scroll()
    
    sessions_by_pk = {
        s.pk: s for s in
        add_event_info_to_session_qs(
            Session.objects.filter(
                meeting=meeting,
            ).order_by('pk'),
            requested_time=True,
            requested_by=True,
        ).filter(
            current_status__in=['appr', 'schedw', 'scheda', 'sched', 'canceled', 'canceledpa', 'resched']
        ).prefetch_related(
            'group', 'group', 'group__type',
        )
    }

    assignments_by_timeslot = defaultdict(list)
    for a in SchedTimeSessAssignment.objects.filter(schedule__in=[schedule, schedule.base]):
        assignments_by_timeslot[a.timeslot_id].append(a)

    days = [meeting.date + datetime.timedelta(days=i) for i in range(meeting.days)]

    timeslots_by_day_and_room = defaultdict(list)
    for t in timeslot_qs:
        timeslots_by_day_and_room[(t.time.date(), t.location_id)].append(t)

    min_time = min([t.time.time() for t in timeslot_qs] + [datetime.time(8)])
    max_time = max([t.end_time().time() for t in timeslot_qs] + [datetime.time(22)])
    min_max_delta = datetime.datetime.combine(meeting.date, max_time) - datetime.datetime.combine(meeting.date, min_time)

    day_grid = []
    for d in days:
        room_timeslots = []
        for r in rooms:
            ts = []
            for t in timeslots_by_day_and_room.get((d, r.pk), []):
                # FIXME: the database (as of 2020) contains spurious
                # regular time slots in rooms not intended for regular
                # sessions - once those are gone, this filter can go
                # away
                if t.type_id == 'regular' and not any(t.slug == 'regular' for t in r.session_types.all()):
                    continue

                t.assigned_sessions = []
                for a in assignments_by_timeslot.get(t.pk, []):
                    s = sessions_by_pk.get(a.session_id)
                    if s:
                        t.assigned_sessions.append(s)

                t.left_offset = 100.0 * (t.time - datetime.datetime.combine(t.time.date(), min_time)) / min_max_delta
                t.layout_width = min(100.0 * t.duration / min_max_delta, 100 - t.left_offset)
                ts.append(t)

            room_timeslots.append((r, ts))

        day_grid.append({
            'day': d,
            'room_timeslots': room_timeslots
        })

    return render(request, "meeting/edit_meeting_timeslots_and_misc_sessions.html", {
        'meeting': meeting,
        'schedule': schedule,
        'can_edit': can_edit,
        'day_grid': day_grid,
        'empty_timeslot_form': TimeSlotForm(meeting, schedule),
        'add_timeslot_form': add_timeslot_form,
        'edit_timeslot_form': edit_timeslot_form,
        'scroll': scroll,
        'hide_menu': True,
    })


##############################################################################
#@role_required('Area Director','Secretariat')
# disable the above security for now, check it below.
@ensure_csrf_cookie
def edit_schedule(request, num=None, owner=None, name=None):

    if request.method == 'POST':
        return schedule_create(request, num, owner, name)

    user     = request.user
    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    if name is None:
        schedule = meeting.schedule
    else:
        schedule = get_schedule_by_name(meeting, person, name)
    if schedule is None:
        raise Http404("No meeting information for meeting %s owner %s schedule %s available" % (num, owner, name))

    meeting_base_url = request.build_absolute_uri(meeting.base_url())
    site_base_url = request.build_absolute_uri('/')[:-1] # skip the trailing slash

    rooms = meeting.room_set.filter(session_types__slug='regular').distinct().order_by("capacity")
    saveas = SaveAsForm()
    saveasurl=reverse(edit_schedule,
                      args=[meeting.number, schedule.owner_email(), schedule.name])

    can_see, can_edit,secretariat = schedule_permissions(meeting, schedule, user)

    if not can_see:
        return render(request, "meeting/private_schedule.html",
                                             {"schedule":schedule,
                                              "meeting": meeting,
                                              "meeting_base_url":meeting_base_url,
                                              "hide_menu": True
                                          }, status=403, content_type="text/html")

    assignments = get_all_assignments_from_schedule(schedule)

    # get_modified_from needs the query set, not the list
    modified = get_modified_from_assignments(assignments)

    area_list = get_areas()
    wg_name_list = get_wg_name_list(assignments)
    wg_list = get_wg_list(wg_name_list)
    ads = find_ads_for_meeting(meeting)
    for ad in ads:
        # set the default to avoid needing extra arguments in templates
        # django 1.3+
        ad.default_hostscheme = site_base_url

    time_slices,date_slices = build_all_agenda_slices(meeting)

    return render(request, "meeting/landscape_edit.html",
                                         {"schedule":schedule,
                                          "saveas": saveas,
                                          "saveasurl": saveasurl,
                                          "meeting_base_url": meeting_base_url,
                                          "site_base_url": site_base_url,
                                          "rooms":rooms,
                                          "time_slices":time_slices,
                                          "date_slices":date_slices,
                                          "modified": modified,
                                          "meeting":meeting,
                                          "area_list": area_list,
                                          "area_directors" : ads,
                                          "wg_list": wg_list ,
                                          "assignments": assignments,
                                          "show_inline": set(["txt","htm","html"]),
                                          "hide_menu": True,
                                          "can_edit_properties": can_edit or secretariat,
                                      })


class SchedulePropertiesForm(forms.ModelForm):
    class Meta:
        model = Schedule
        fields = ['name', 'notes', 'visible', 'public', 'base']

    def __init__(self, meeting, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.fields['base'].queryset = self.fields['base'].queryset.filter(meeting=meeting)
        if self.instance.pk is not None:
            self.fields['base'].queryset = self.fields['base'].queryset.exclude(pk=self.instance.pk)

@role_required('Area Director','Secretariat')
def edit_schedule_properties(request, num, owner, name):
    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    schedule = get_schedule_by_name(meeting, person, name)
    if schedule is None:
        raise Http404("No agenda information for meeting %s owner %s schedule %s available" % (num, owner, name))

    can_see, can_edit, secretariat = schedule_permissions(meeting, schedule, request.user)

    can_edit_properties = can_edit or secretariat

    if not can_edit_properties:
        permission_denied(request, "You may not edit this schedule.")

    if request.method == 'POST':
        form = SchedulePropertiesForm(meeting, instance=schedule, data=request.POST)
        if form.is_valid():
           form.save()
           if request.GET.get('next'):
               return HttpResponseRedirect(request.GET.get('next'))
           return redirect('ietf.meeting.views.edit_schedule', num=num, owner=owner, name=name)
    else:
        form = SchedulePropertiesForm(meeting, instance=schedule)

    return render(request, "meeting/properties_edit.html", {
        "schedule": schedule,
        "form": form,
        "meeting": meeting,
    })


nat_sort_re = re.compile('([0-9]+)')
def natural_sort_key(s): # from https://stackoverflow.com/questions/4836710/is-there-a-built-in-function-for-string-natural-sort
    return [int(text) if text.isdecimal() else text.lower() for text in nat_sort_re.split(s)]

@role_required('Area Director','Secretariat')
def list_schedules(request, num):
    meeting = get_meeting(num)

    schedules = Schedule.objects.filter(
        meeting=meeting
    ).prefetch_related('owner', 'assignments', 'origin', 'origin__assignments', 'base').order_by('owner', '-name', '-public').distinct()
    if not has_role(request.user, 'Secretariat'):
        schedules = schedules.filter(Q(visible=True) | Q(owner=request.user.person))

    official_schedules = []
    own_schedules = []
    other_public_schedules = []
    other_private_schedules = []

    is_secretariat = has_role(request.user, 'Secretariat')

    for s in schedules:
        s.can_edit_properties = is_secretariat or user_is_person(request.user, s.owner)

        if s.origin:
            s.changes_from_origin = len(diff_meeting_schedules(s.origin, s))

        if s in [meeting.schedule, meeting.schedule.base if meeting.schedule else None]:
            official_schedules.append(s)
        elif user_is_person(request.user, s.owner):
            own_schedules.append(s)
        elif s.public:
            other_public_schedules.append(s)
        else:
            other_private_schedules.append(s)

    schedule_groups = [
        (official_schedules, False, "Official Agenda"),
        (own_schedules, True, "Own Draft Agendas"),
        (other_public_schedules, False, "Other Draft Agendas"),
        (other_private_schedules, False, "Other Private Draft Agendas"),
    ]

    schedule_groups = [(sorted(l, reverse=True, key=lambda s: natural_sort_key(s.name)), own, *t) for l, own, *t in schedule_groups if l or own]

    return render(request, "meeting/schedule_list.html", {
        'meeting': meeting,
        'schedule_groups': schedule_groups,
    })

class DiffSchedulesForm(forms.Form):
    from_schedule = forms.ChoiceField()
    to_schedule = forms.ChoiceField()

    def __init__(self, meeting, user, *args, **kwargs):
        super().__init__(*args, **kwargs)

        qs = Schedule.objects.filter(meeting=meeting).prefetch_related('owner').order_by('-public').distinct()

        if not has_role(user, 'Secretariat'):
            qs = qs.filter(Q(visible=True) | Q(owner__user=user))

        sorted_schedules = sorted(qs, reverse=True, key=lambda s: natural_sort_key(s.name))

        schedule_choices = [(schedule.name, "{} ({})".format(schedule.name, schedule.owner)) for schedule in sorted_schedules]

        self.fields['from_schedule'].choices = schedule_choices
        self.fields['to_schedule'].choices = schedule_choices

@role_required('Area Director','Secretariat')
def diff_schedules(request, num):
    meeting = get_meeting(num)

    diffs = None
    from_schedule = None
    to_schedule = None

    if 'from_schedule' in request.GET:
        form = DiffSchedulesForm(meeting, request.user, request.GET)
        if form.is_valid():
            from_schedule = get_object_or_404(Schedule, name=form.cleaned_data['from_schedule'], meeting=meeting)
            to_schedule = get_object_or_404(Schedule, name=form.cleaned_data['to_schedule'], meeting=meeting)
            raw_diffs = diff_meeting_schedules(from_schedule, to_schedule)

            diffs = prefetch_schedule_diff_objects(raw_diffs)
            for d in diffs:
                s = d['session']
                s.session_label = s.short_name
                if s.requested_duration:
                    s.session_label = "{} ({}h)".format(s.session_label, round(s.requested_duration.seconds / 60.0 / 60.0, 1))
    else:
        form = DiffSchedulesForm(meeting, request.user)

    return render(request, "meeting/diff_schedules.html", {
        'meeting': meeting,
        'form': form,
        'diffs': diffs,
        'from_schedule': from_schedule,
        'to_schedule': to_schedule,
    })


@ensure_csrf_cookie
def agenda(request, num=None, name=None, base=None, ext=None, owner=None, utc=""):
    base = base if base else 'agenda'
    ext = ext if ext else '.html'
    mimetype = {
        ".html":"text/html; charset=%s"%settings.DEFAULT_CHARSET,
        ".txt": "text/plain; charset=%s"%settings.DEFAULT_CHARSET,
        ".csv": "text/csv; charset=%s"%settings.DEFAULT_CHARSET,
    }

    # We do not have the appropriate data in the datatracker for IETF 64 and earlier.
    # So that we're not producing misleading pages...
    
    assert num is None or num.isdigit()

    meeting = get_ietf_meeting(num)
    if not meeting or (meeting.number.isdigit() and int(meeting.number) <= 64 and (not meeting.schedule or not meeting.schedule.assignments.exists())):
        if ext == '.html' or (meeting and meeting.number.isdigit() and 0 < int(meeting.number) <= 64):
            return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s' % num )
        else:
            raise Http404("No such meeting")

    if name is None:
        schedule = get_schedule(meeting, name)
    else:
        person   = get_person_by_email(owner)
        schedule = get_schedule_by_name(meeting, person, name)

    if schedule == None:
        base = base.replace("-utc", "")
        return render(request, "meeting/no-"+base+ext, {'meeting':meeting }, content_type=mimetype[ext])

    updated = meeting.updated()
    filtered_assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base],
        timeslot__type__private=False,
    )
    filtered_assignments = preprocess_assignments_for_agenda(filtered_assignments, meeting)
    tag_assignments_with_filter_keywords(filtered_assignments)

    if ext == ".csv":
        return agenda_csv(schedule, filtered_assignments)

    # extract groups hierarchy, it's a little bit complicated because
    # we can be dealing with historic groups
    seen = set()
    groups = [a.session.historic_group for a in filtered_assignments
              if a.session
              and a.session.historic_group
              and a.session.historic_group.type_id in ('wg', 'rg', 'ag', 'rag', 'iab', 'program')
              and a.session.historic_group.historic_parent]
    group_parents = []
    for g in groups:
        if g.historic_parent.acronym not in seen:
            group_parents.append(g.historic_parent)
            seen.add(g.historic_parent.acronym)

    seen = set()
    for p in group_parents:
        p.group_list = []
        for g in groups:
            if g.acronym not in seen and g.historic_parent.acronym == p.acronym:
                p.group_list.append(g)
                seen.add(g.acronym)

        p.group_list.sort(key=lambda g: g.acronym)

    # Groups gathered and processed. Now arrange for the filter UI.
    #
    # The agenda_filter template expects a list of categorized header buttons, each
    # with a list of children. Make two categories: the IETF areas and the other parent groups.
    # We also pass a list of 'extra' buttons - currently Office Hours and miscellaneous filters.
    # All but the last of these are additionally used by the agenda.html template to make
    # a list of filtered ical buttons. The last group is ignored for this. 
    area_group_filters = []
    other_group_filters = []
    extra_filters = []
    
    for p in group_parents:
        new_filter = dict(
            label=p.acronym.upper(),
            keyword=p.acronym.lower(),
            children=[
                dict(
                    label=g.acronym,
                    keyword=g.acronym.lower(),
                    is_bof=g.is_bof(),
                ) for g in p.group_list
            ]
        )
        if p.type.slug == 'area':
            area_group_filters.append(new_filter)
        else:
            other_group_filters.append(new_filter)

    office_hours_labels = set()
    for a in filtered_assignments:
        suffix = ' office hours'
        if a.session.name.lower().endswith(suffix):
            office_hours_labels.add(a.session.name[:-len(suffix)].strip())

    if len(office_hours_labels) > 0:
        # keyword needs to match what's tagged in filter_keywords_for_session() 
        extra_filters.append(dict(
            label='Office Hours',
            keyword='officehours',
            children=[
                dict(
                    label=label,
                    keyword=label.lower().replace(' ', '')+'officehours',
                    is_bof=False,
                ) for label in office_hours_labels
            ]
        ))

    # Keywords that should appear in 'non-area' column
    non_area_labels = [
        'BoF', 'EDU', 'Hackathon', 'IEPG', 'IESG', 'IETF', 'Plenary', 'Secretariat', 'Tools',
    ]
    # Remove any unused non-area keywords
    non_area_filters = [
        dict(label=label, keyword=label.lower(), is_bof=False) 
        for label in non_area_labels if any([
            label.lower() in assignment.filter_keywords 
            for assignment in filtered_assignments
        ])
    ]
    if len(non_area_filters) > 0:
        extra_filters.append(dict(
            label=None,
            keyword=None,
            children=non_area_filters,
        ))

    area_group_filters.sort(key=lambda p:p['label'])
    other_group_filters.sort(key=lambda p:p['label'])
    filter_categories = [category 
                         for category in [area_group_filters, other_group_filters, extra_filters]
                         if len(category) > 0]

    is_current_meeting = (num is None) or (num == get_current_ietf_meeting_num())
    
    rendered_page = render(request, "meeting/"+base+ext, {
        "schedule": schedule,
        "filtered_assignments": filtered_assignments,
        "updated": updated,
        "filter_categories": filter_categories,
        "non_area_keywords": [label.lower() for label in non_area_labels],
        "now": datetime.datetime.now(),
        "is_current_meeting": is_current_meeting,
        "use_codimd": True if meeting.date>=settings.MEETING_USES_CODIMD_DATE else False,
        "cache_time": 150 if is_current_meeting else 3600,
    }, content_type=mimetype[ext])

    return rendered_page

def agenda_csv(schedule, filtered_assignments):
    response = HttpResponse(content_type="text/csv; charset=%s"%settings.DEFAULT_CHARSET)
    writer = csv.writer(response, delimiter=str(','), quoting=csv.QUOTE_ALL)

    headings = ["Date", "Start", "End", "Session", "Room", "Area", "Acronym", "Type", "Description", "Session ID", "Agenda", "Slides"]

    def write_row(row):
        encoded_row = [v.encode('utf-8') if isinstance(v, str) else v for v in row]

        while len(encoded_row) < len(headings):
            encoded_row.append(None) # produce empty entries at the end as necessary

        writer.writerow(encoded_row)

    def agenda_field(item):
        agenda_doc = item.session.agenda()
        if agenda_doc:
            return "http://www.ietf.org/proceedings/{schedule.meeting.number}/agenda/{agenda.uploaded_filename}".format(schedule=schedule, agenda=agenda_doc)
        else:
            return ""

    def slides_field(item):
        return "|".join("http://www.ietf.org/proceedings/{schedule.meeting.number}/slides/{slide.uploaded_filename}".format(schedule=schedule, slide=slide) for slide in item.session.slides())

    write_row(headings)

    for item in filtered_assignments:
        row = []
        row.append(item.timeslot.time.strftime("%Y-%m-%d"))
        row.append(item.timeslot.time.strftime("%H%M"))
        row.append(item.timeslot.end_time().strftime("%H%M"))

        if item.timeslot.type_id == "break":
            row.append(item.timeslot.type.name)
            row.append(schedule.meeting.break_area)
            row.append("")
            row.append("")
            row.append("")
            row.append(item.timeslot.name)
            row.append("b{}".format(item.timeslot.pk))
        elif item.timeslot.type_id == "reg":
            row.append(item.timeslot.type.name)
            row.append(schedule.meeting.reg_area)
            row.append("")
            row.append("")
            row.append("")
            row.append(item.timeslot.name)
            row.append("r{}".format(item.timeslot.pk))
        elif item.timeslot.type_id == "other":
            row.append("None")
            row.append(item.timeslot.location.name if item.timeslot.location else "")
            row.append("")
            row.append(item.session.historic_group.acronym)
            row.append(item.session.historic_group.historic_parent.acronym.upper() if item.session.historic_group.historic_parent else "")
            row.append(item.session.name)
            row.append(item.session.pk)
        elif item.timeslot.type_id == "plenary":
            row.append(item.session.name)
            row.append(item.timeslot.location.name if item.timeslot.location else "")
            row.append("")
            row.append(item.session.historic_group.acronym if item.session.historic_group else "")
            row.append("")
            row.append(item.session.name)
            row.append(item.session.pk)
            row.append(agenda_field(item))
            row.append(slides_field(item))
        elif item.timeslot.type_id == 'regular':
            row.append(item.timeslot.name)
            row.append(item.timeslot.location.name if item.timeslot.location else "")
            row.append(item.session.historic_group.historic_parent.acronym.upper() if item.session.historic_group.historic_parent else "")
            row.append(item.session.historic_group.acronym if item.session.historic_group else "")
            row.append("BOF" if item.session.historic_group.state_id in ("bof", "bof-conc") else item.session.historic_group.type.name)
            row.append(item.session.historic_group.name if item.session.historic_group else "")
            row.append(item.session.pk)
            row.append(agenda_field(item))
            row.append(slides_field(item))

        if len(row) > 3:
            write_row(row)

    return response

@role_required('Area Director','Secretariat','IAB')
def agenda_by_room(request, num=None, name=None, owner=None):
    meeting = get_meeting(num) 
    if name is None:
        schedule = get_schedule(meeting)
    else:
        person   = get_person_by_email(owner)
        schedule = get_schedule_by_name(meeting, person, name)

    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base if schedule else None]
    ).prefetch_related('timeslot', 'timeslot__location', 'session', 'session__group', 'session__group__parent')

    ss_by_day = OrderedDict()
    for day in assignments.dates('timeslot__time','day'):
        ss_by_day[day]=[]
    for ss in assignments.order_by('timeslot__location__functional_name','timeslot__location__name','timeslot__time'):
        day = ss.timeslot.time.date()
        ss_by_day[day].append(ss)
    return render(request,"meeting/agenda_by_room.html",{"meeting":meeting,"schedule":schedule,"ss_by_day":ss_by_day})

@role_required('Area Director','Secretariat','IAB')
def agenda_by_type(request, num=None, type=None, name=None, owner=None):
    meeting = get_meeting(num) 
    if name is None:
        schedule = get_schedule(meeting)
    else:
        person   = get_person_by_email(owner)
        schedule = get_schedule_by_name(meeting, person, name)
    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base if schedule else None]
    ).prefetch_related(
        'timeslot', 'timeslot__location', 'session', 'session__group', 'session__group__parent'
    ).order_by('session__type__slug','timeslot__time','session__group__acronym')

    if type:
        assignments = assignments.filter(session__type__slug=type)
    return render(request,"meeting/agenda_by_type.html",{"meeting":meeting,"schedule":schedule,"assignments":assignments})

@role_required('Area Director','Secretariat','IAB')
def agenda_by_type_ics(request,num=None,type=None):
    meeting = get_meeting(num) 
    schedule = get_schedule(meeting)
    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base if schedule else None]
    ).prefetch_related(
        'timeslot', 'timeslot__location', 'session', 'session__group', 'session__group__parent'
    ).order_by('session__type__slug','timeslot__time')
    if type:
        assignments = assignments.filter(session__type__slug=type)
    updated = meeting.updated()
    return render(request,"meeting/agenda.ics",{"schedule":schedule,"updated":updated,"assignments":assignments},content_type="text/calendar")

def session_draft_list(num, acronym):
    try:
        agendas = Document.objects.filter(type="agenda",
                                         session__meeting__number=num,
                                         session__group__acronym=acronym,
                                         states=State.objects.get(type="agenda", slug="active")).distinct()
    except Document.DoesNotExist:
        raise Http404

    drafts = set()
    for agenda in agendas:
        content, _ = read_agenda_file(num, agenda)
        if content:
            drafts.update(re.findall(b'(draft-[-a-z0-9]*)', content))

    result = []
    for draft in drafts:
        draft = force_str(draft)
        try:
            if re.search('-[0-9]{2}$', draft):
                doc_name = draft
            else:
                doc = Document.objects.get(name=draft)
                doc_name = draft + "-" + doc.rev

            if doc_name not in result:
                result.append(doc_name)
        except Document.DoesNotExist:
            pass

    for sp in SessionPresentation.objects.filter(session__meeting__number=num, session__group__acronym=acronym, document__type='draft'):
        doc_name = sp.document.name + "-" + sp.document.rev
        if doc_name not in result:
            result.append(doc_name)

    return sorted(result)

def session_draft_tarfile(request, num, acronym):
    drafts = session_draft_list(num, acronym);

    response = HttpResponse(content_type='application/octet-stream')
    response['Content-Disposition'] = 'attachment; filename=%s-drafts.tgz'%(acronym)
    tarstream = tarfile.open('','w:gz',response)
    mfh, mfn = mkstemp()
    os.close(mfh)
    manifest = io.open(mfn, "w")

    for doc_name in drafts:
        pdf_path = os.path.join(settings.INTERNET_DRAFT_PDF_PATH, doc_name + ".pdf")

        if not os.path.exists(pdf_path):
            convert_draft_to_pdf(doc_name)

        if os.path.exists(pdf_path):
            try:
                tarstream.add(pdf_path, str(doc_name + ".pdf"))
                manifest.write("Included:  "+pdf_path+"\n")
            except Exception as e:
                manifest.write(("Failed (%s): "%e)+pdf_path+"\n")
        else:
            manifest.write("Not found: "+pdf_path+"\n")

    manifest.close()
    tarstream.add(mfn, "manifest.txt")
    tarstream.close()
    os.unlink(mfn)
    return response

def session_draft_pdf(request, num, acronym):
    drafts = session_draft_list(num, acronym);
    curr_page = 1
    pmh, pmn = mkstemp()
    os.close(pmh)
    pdfmarks = io.open(pmn, "w")
    pdf_list = ""

    for draft in drafts:
        pdf_path = os.path.join(settings.INTERNET_DRAFT_PDF_PATH, draft + ".pdf")
        if not os.path.exists(pdf_path):
            convert_draft_to_pdf(draft)

        if os.path.exists(pdf_path):
            pages = pdf_pages(pdf_path)
            pdfmarks.write("[/Page "+str(curr_page)+" /View [/XYZ 0 792 1.0] /Title (" + draft + ") /OUT pdfmark\n")
            pdf_list = pdf_list + " " + pdf_path
            curr_page = curr_page + pages

    pdfmarks.close()
    pdfh, pdfn = mkstemp()
    os.close(pdfh)
    gs = settings.GHOSTSCRIPT_COMMAND
    code, out, err = pipe(gs + " -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=" + pdfn + " " + pdf_list + " " + pmn)
    assertion('code == 0')

    pdf = io.open(pdfn,"rb")
    pdf_contents = pdf.read()
    pdf.close()

    os.unlink(pmn)
    os.unlink(pdfn)
    return HttpResponse(pdf_contents, content_type="application/pdf")

def week_view(request, num=None, name=None, owner=None):
    meeting = get_meeting(num)

    if name is None:
        schedule = get_schedule(meeting)
    else:
        person   = get_person_by_email(owner)
        schedule = get_schedule_by_name(meeting, person, name)

    if not schedule:
        raise Http404

    filtered_assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base],
        timeslot__type__private=False,
    )
    # Only show assignments from the traditional meeting "week" (Sat-Fri). 
    # We'll determine this using the saturday before the first scheduled regular session.
    first_regular_session = meeting.schedule.qs_assignments_with_sessions.filter(session__type_id='regular').order_by('timeslot__time').first()
    first_regular_session_time = first_regular_session.timeslot.time if first_regular_session else date2datetime(meeting.date)
    saturday_before = first_regular_session_time.replace(hour=0, minute=0, second=0, microsecond=0) - datetime.timedelta(days=(first_regular_session_time.weekday() - 5)%7)
#    saturday_after = saturday_before + datetime.timedelta(days=7)
#    filtered_assignments = filtered_assignments.filter(timeslot__time__gte=saturday_before,timeslot__time__lt=saturday_after)
    filtered_assignments = preprocess_assignments_for_agenda(filtered_assignments, meeting)
    tag_assignments_with_filter_keywords(filtered_assignments)

    items = []
    for a in filtered_assignments:
        # we don't HTML escape any of these as the week-view code is using createTextNode
        item = {
            "key": str(a.timeslot.pk),
            "day": (a.timeslot.time - saturday_before).days - 1,
            "time": a.timeslot.time.strftime("%H%M") + "-" + a.timeslot.end_time().strftime("%H%M"),
            "duration": a.timeslot.duration.seconds,
            "time_id": a.timeslot.time.strftime("%m%d%H%M"),
            "dayname": "{weekday}, {month} {day_of_month}, {year}".format(
                weekday=a.timeslot.time.strftime("%A").upper(),
                month=a.timeslot.time.strftime("%B"),
                day_of_month=a.timeslot.time.strftime("%d").lstrip("0"),
                year=a.timeslot.time.strftime("%Y"),
            ),
            "type": a.timeslot.type.name,
            "filter_keywords": ",".join(a.filter_keywords),
        }

        if a.session:
            if a.session.historic_group:
                item["group"] = a.session.historic_group.acronym

            if a.session.name:
                item["name"] = a.session.name
            elif a.timeslot.type_id == "break":
                item["name"] = a.timeslot.name
                item["area"] = a.timeslot.type_id
                item["group"] = a.timeslot.type_id
            elif a.session.historic_group:
                item["name"] = a.session.historic_group.name
                if a.session.historic_group.state_id == "bof":
                    item["name"] += " BOF"

                item["state"] = a.session.historic_group.state.name
                if a.session.historic_group.historic_parent:
                    item["area"] = a.session.historic_group.historic_parent.acronym

            if a.timeslot.show_location:
                item["room"] = a.timeslot.get_location()

            if a.session and a.session.agenda():
                item["agenda"] = a.session.agenda().get_href()

            if a.session.current_status == 'canceled':
                item["name"] = "CANCELLED - " + item["name"]

        items.append(item)

    return render(request, "meeting/week-view.html", {
        "items": json.dumps(items),
    })

@role_required('Area Director','Secretariat','IAB')
def room_view(request, num=None, name=None, owner=None):
    meeting = get_meeting(num)

    rooms = meeting.room_set.order_by('functional_name','name')
    if not rooms.exists():
        return HttpResponse("No rooms defined yet")

    if name is None:
        schedule = get_schedule(meeting)
    else:
        person   = get_person_by_email(owner)
        schedule = get_schedule_by_name(meeting, person, name)

    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base if schedule else None]
    ).prefetch_related(
        'timeslot', 'timeslot__location', 'session', 'session__group', 'session__group__parent'
    )
    unavailable = meeting.timeslot_set.filter(type__slug='unavail')
    if not (assignments.exists() or unavailable.exists()):
        return HttpResponse("No sessions/timeslots available yet")

    earliest = None
    latest = None

    if assignments:
        earliest = assignments.aggregate(Min('timeslot__time'))['timeslot__time__min']
        latest =  assignments.aggregate(Max('timeslot__time'))['timeslot__time__max']
        
    if unavailable:
        earliest_unavailable = unavailable.aggregate(Min('time'))['time__min']
        if not earliest or ( earliest_unavailable and earliest_unavailable < earliest ):
            earliest = earliest_unavailable
        latest_unavailable = unavailable.aggregate(Max('time'))['time__max']
        if not latest or ( latest_unavailable and latest_unavailable > latest ):
            latest = latest_unavailable

    if not (earliest and latest):
        raise Http404

    base_time = earliest
    base_day = datetime.datetime(base_time.year,base_time.month,base_time.day)

    day = base_day
    days = []
    while day <= latest :
        days.append(day)
        day += datetime.timedelta(days=1)

    unavailable = list(unavailable)
    for t in unavailable:
        t.delta_from_beginning = (t.time - base_time).total_seconds()
        t.day = (t.time-base_day).days

    assignments = list(assignments)
    for ss in assignments:
        ss.delta_from_beginning = (ss.timeslot.time - base_time).total_seconds()
        ss.day = (ss.timeslot.time-base_day).days

    template = "meeting/room-view.html"
    return render(request, template,{"meeting":meeting,"schedule":schedule,"unavailable":unavailable,"assignments":assignments,"rooms":rooms,"days":days})

def ical_session_status(assignment):
    if assignment.session.current_status == 'canceled':
        return "CANCELLED"
    elif assignment.session.current_status == 'resched':
        t = "RESCHEDULED"
        if assignment.session.tombstone_for_id is not None:
            other_assignment = SchedTimeSessAssignment.objects.filter(schedule=assignment.schedule_id, session=assignment.session.tombstone_for_id).first()
            if other_assignment:
                t = "RESCHEDULED TO {}-{}".format(
                    other_assignment.timeslot.time.strftime("%A %H:%M").upper(),
                    other_assignment.timeslot.end_time().strftime("%H:%M")
                )
        return t
    else:
        return "CONFIRMED"

def parse_agenda_filter_params(querydict):
    """Parse agenda filter parameters from a request"""
    if len(querydict) == 0:
        return None

    # Parse group filters from GET parameters. The keys in this dict define the
    # allowed querystring parameters.
    filt_params = {'show': set(), 'hide': set(), 'showtypes': set(), 'hidetypes': set()}

    for key, value in querydict.items():
        if key not in filt_params:
            raise ValueError('Unrecognized parameter "%s"' % key)
        if value is None:
            return ValueError(
                'Parameter "%s" is not assigned a value (use "key=" for an empty value)' % key
            )
        vals = unquote(value).lower().split(',')
        vals = [v.strip() for v in vals]
        filt_params[key] = set([v for v in vals if len(v) > 0])  # remove empty strings

    return filt_params


def should_include_assignment(filter_params, assignment):
    """Decide whether to include an assignment

    When filtering by wg, uses historic_group if available as an attribute
    on the session, otherwise falls back to using group.
    """
    shown = len(set(filter_params['show']).intersection(assignment.filter_keywords)) > 0
    hidden = len(set(filter_params['hide']).intersection(assignment.filter_keywords)) > 0
    return shown and not hidden

def agenda_ical(request, num=None, name=None, acronym=None, session_id=None):
    """Agenda ical view

    By default, all agenda items will be shown. A filter can be specified in 
    the querystring. It has the format
    
      ?show=...&hide=...&showtypes=...&hidetypes=...

    where any of the parameters can be omitted. The right-hand side of each
    '=' is a comma separated list, which can be empty. If none of the filter
    parameters are specified, no filtering will be applied, even if the query
    string is not empty.

    The show and hide parameters each take a list of working group (wg) acronyms.    
    The showtypes and hidetypes parameters take a list of session types. 

    Hiding (by wg or type) takes priority over showing.
    """
    meeting = get_meeting(num, type_in=None)
    schedule = get_schedule(meeting, name)
    updated = meeting.updated()

    if schedule is None and acronym is None and session_id is None:
        raise Http404

    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[schedule, schedule.base],
        timeslot__type__private=False,
    )
    assignments = preprocess_assignments_for_agenda(assignments, meeting)
    tag_assignments_with_filter_keywords(assignments)

    try:
        filt_params = parse_agenda_filter_params(request.GET)
    except ValueError as e:
        return HttpResponseBadRequest(str(e))

    if filt_params is not None:
        # Apply the filter
        assignments = [a for a in assignments if should_include_assignment(filt_params, a)]

    if acronym:
        assignments = [ a for a in assignments if a.session.historic_group and a.session.historic_group.acronym == acronym ]
    elif session_id:
        assignments = [ a for a in assignments if a.session_id == int(session_id) ]

    for a in assignments:
        if a.session:
            a.session.ical_status = ical_session_status(a)

    return render(request, "meeting/agenda.ics", {
        "schedule": schedule,
        "assignments": assignments,
        "updated": updated
    }, content_type="text/calendar")

@cache_page(15 * 60)
def agenda_json(request, num=None):
    meeting = get_meeting(num, type_in=['ietf','interim'])

    sessions = []
    locations = set()
    parent_acronyms = set()
    assignments = SchedTimeSessAssignment.objects.filter(
        schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None],
        timeslot__type__private=False,
    ).exclude(
        session__type__in=['break', 'reg']
    )
    # Update the assignments with historic information, i.e., valid at the
    # time of the meeting
    assignments = preprocess_assignments_for_agenda(assignments, meeting, extra_prefetches=[
        "session__materials__docevent_set",
        "session__sessionpresentation_set",
        "timeslot__meeting"
    ])
    for asgn in assignments:
        sessdict = dict()
        sessdict['objtype'] = 'session'
        sessdict['id'] = asgn.pk
        sessdict['is_bof'] = False
        if asgn.session.historic_group:
            sessdict['group'] = {
                    "acronym": asgn.session.historic_group.acronym,
                    "name": asgn.session.historic_group.name,
                    "type": asgn.session.historic_group.type_id,
                    "state": asgn.session.historic_group.state_id,
                }
            if asgn.session.historic_group.is_bof():
                sessdict['is_bof'] = True
            if asgn.session.historic_group.type_id in ['wg','rg', 'ag', 'rag'] or asgn.session.historic_group.acronym in ['iesg',]: # TODO: should that first list be groupfeatures driven?
                if asgn.session.historic_group.historic_parent:
                    sessdict['group']['parent'] = asgn.session.historic_group.historic_parent.acronym
                    parent_acronyms.add(asgn.session.historic_group.historic_parent.acronym)
        if asgn.session.name:
            sessdict['name'] = asgn.session.name
        else:
            sessdict['name'] = asgn.session.historic_group.name
        if asgn.session.short:
            sessdict['short'] = asgn.session.short
        if asgn.session.agenda_note:
            sessdict['agenda_note'] = asgn.session.agenda_note
        if asgn.session.remote_instructions:
            sessdict['remote_instructions'] = asgn.session.remote_instructions
        utc_start = asgn.timeslot.utc_start_time()
        if utc_start:
            sessdict['start'] = utc_start.strftime("%Y-%m-%dT%H:%M:%SZ")
        sessdict['duration'] = str(asgn.timeslot.duration)
        sessdict['location'] = asgn.room_name
        if asgn.timeslot.location:      # Some socials have an assignment but no location
            locations.add(asgn.timeslot.location)
        if asgn.session.agenda():
            sessdict['agenda'] = asgn.session.agenda().get_href()

        if asgn.session.minutes():
            sessdict['minutes'] = asgn.session.minutes().get_href()
        if asgn.session.slides():
            sessdict['presentations'] = []
            presentations = SessionPresentation.objects.filter(session=asgn.session, document__type__slug='slides')
            for pres in presentations:
                sessdict['presentations'].append(
                    {
                        'name':     pres.document.name,
                        'title':    pres.document.title,
                        'order':    pres.order,
                        'rev':      pres.rev,
                        'resource_uri': '/api/v1/meeting/sessionpresentation/%s/'%pres.id,
                    })
        sessdict['session_res_uri'] = '/api/v1/meeting/session/%s/'%asgn.session.id
        sessdict['session_id'] = asgn.session.id
        modified = asgn.session.modified
        for doc in asgn.session.materials.all():
            rev_docevent = doc.latest_event(NewRevisionDocEvent,'new_revision')
            modified = max(modified, (rev_docevent and rev_docevent.time) or modified)
        sessdict['modified'] = modified
        sessdict['status'] = asgn.session.current_status
        sessions.append(sessdict)

    rooms = []
    for room in locations:
        roomdict = dict()
        roomdict['id'] = room.pk
        roomdict['objtype'] = 'location'
        roomdict['name'] = room.name
        if room.floorplan:
            roomdict['level_name'] = room.floorplan.name
            roomdict['level_sort'] = room.floorplan.order
        if room.x1 is not None:
            roomdict['x'] = (room.x1+room.x2)/2.0
            roomdict['y'] = (room.y1+room.y2)/2.0
        roomdict['modified'] = room.modified
        if room.floorplan and room.floorplan.image:
            roomdict['map'] = room.floorplan.image.url
            roomdict['modified'] = max(room.modified, room.floorplan.modified)
        rooms.append(roomdict)

    parents = []
    for parent in Group.objects.filter(acronym__in=parent_acronyms):
        parentdict = dict()
        parentdict['id'] = parent.pk
        parentdict['objtype'] = 'parent'
        parentdict['name'] = parent.acronym
        parentdict['description'] = parent.name
        parentdict['modified'] = parent.time
        parents.append(parentdict)

    meetinfo = []
    meetinfo.extend(sessions)
    meetinfo.extend(rooms)
    meetinfo.extend(parents)
    meetinfo.sort(key=lambda x: x['modified'],reverse=True)
    last_modified = meetinfo and meetinfo[0]['modified']

    tz = pytz.timezone(settings.PRODUCTION_TIMEZONE)

    for obj in meetinfo:
        obj['modified'] = tz.localize(obj['modified']).astimezone(pytz.utc).strftime('%Y-%m-%dT%H:%M:%SZ')

    data = {"%s"%num: meetinfo}

    response = HttpResponse(json.dumps(data, indent=2, sort_keys=True), content_type='application/json;charset=%s'%settings.DEFAULT_CHARSET)
    if last_modified:
        last_modified = tz.localize(last_modified).astimezone(pytz.utc)
        response['Last-Modified'] = format_date_time(timegm(last_modified.timetuple()))
    return response

def meeting_requests(request, num=None):
    meeting = get_meeting(num)
    sessions = add_event_info_to_session_qs(
        Session.objects.filter(
            meeting__number=meeting.number,
            type__slug='regular',
            group__parent__isnull=False
        ),
        requested_by=True,
    ).exclude(
        requested_by=0
    ).order_by(
        "group__parent__acronym", "current_status", "group__acronym"
    ).prefetch_related(
        "group","group__ad_role__person"
    )

    status_names = {n.slug: n.name for n in SessionStatusName.objects.all()}
    session_requesters = {p.pk: p for p in Person.objects.filter(pk__in=[s.requested_by for s in sessions if s.requested_by is not None])}

    for s in sessions:
        s.current_status_name = status_names.get(s.current_status, s.current_status)
        s.requested_by_person = session_requesters.get(s.requested_by)

    groups_not_meeting = Group.objects.filter(state='Active',type__in=['wg','rg','ag','rag','bof','program']).exclude(acronym__in = [session.group.acronym for session in sessions]).order_by("parent__acronym","acronym").prefetch_related("parent")

    return render(request, "meeting/requests.html",
        {"meeting": meeting, "sessions":sessions,
         "groups_not_meeting": groups_not_meeting})

def get_sessions(num, acronym):
    meeting = get_meeting(num=num,type_in=None)
    sessions = Session.objects.filter(meeting=meeting,group__acronym=acronym,type__in=['regular','plenary','other'])

    if not sessions:
        sessions = Session.objects.filter(meeting=meeting,short=acronym,type__in=['regular','plenary','other']) 

    sessions = add_event_info_to_session_qs(sessions)

    return sorted(sessions, key=lambda s: session_time_for_sorting(s, use_meeting_date=False))

def session_details(request, num, acronym):
    meeting = get_meeting(num=num,type_in=None)
    sessions = get_sessions(num, acronym)

    if not sessions:
        raise Http404

    # Find the time of the meeting, so that we can look back historically 
    # for what the group was called at the time. 
    meeting_time = datetime.datetime.combine(meeting.date, datetime.time()) 

    groups = list(set([ s.group for s in sessions ]))
    group_replacements = find_history_replacements_active_at(groups, meeting_time) 

    status_names = {n.slug: n.name for n in SessionStatusName.objects.all()}
    for session in sessions:

        session.historic_group = None 
        if session.group: 
            session.historic_group = group_replacements.get(session.group_id) 
            if session.historic_group: 
                session.historic_group.historic_parent = None 

        session.type_counter = Counter()
        ss = session.timeslotassignments.filter(schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None]).order_by('timeslot__time')
        if ss:
            if meeting.type_id == 'interim' and not (meeting.city or meeting.country):
                session.times = [ x.timeslot.utc_start_time() for x in ss ]                
            else:
                session.times = [ x.timeslot.local_start_time() for x in ss ]
            session.cancelled = session.current_status == 'canceled'
            session.status = ''
        elif meeting.type_id=='interim':
            session.times = [ meeting.date ]
            session.cancelled = session.current_status == 'canceled'
            session.status = ''
        else:
            session.times = []
            session.cancelled = session.current_status == 'canceled'
            session.status = status_names.get(session.current_status, session.current_status)

        session.filtered_artifacts = list(session.sessionpresentation_set.filter(document__type__slug__in=['agenda','minutes','bluesheets']))
        session.filtered_artifacts.sort(key=lambda d:['agenda','minutes','bluesheets'].index(d.document.type.slug))
        session.filtered_slides    = session.sessionpresentation_set.filter(document__type__slug='slides').order_by('order')
        session.filtered_drafts    = session.sessionpresentation_set.filter(document__type__slug='draft')
        # TODO FIXME Deleted materials shouldn't be in the sessionpresentation_set
        for qs in [session.filtered_artifacts,session.filtered_slides,session.filtered_drafts]:
            qs = [p for p in qs if p.document.get_state_slug(p.document.type_id)!='deleted']
            session.type_counter.update([p.document.type.slug for p in qs])

        session.order_number = session.order_in_meeting()

    # we somewhat arbitrarily use the group of the last session we get from
    # get_sessions() above when checking can_manage_session_materials()
    can_manage = can_manage_session_materials(request.user, session.group, session)
    can_view_request = can_view_interim_request(meeting, request.user)

    scheduled_sessions = [s for s in sessions if s.current_status == 'sched']
    unscheduled_sessions = [s for s in sessions if s.current_status != 'sched']

    pending_suggestions = None
    if request.user.is_authenticated:
        if can_manage:
            pending_suggestions = session.slidesubmission_set.filter(status__slug='pending')
        else:
            pending_suggestions = session.slidesubmission_set.filter(status__slug='pending', submitter=request.user.person)

    return render(request, "meeting/session_details.html",
                  { 'scheduled_sessions':scheduled_sessions ,
                    'unscheduled_sessions':unscheduled_sessions , 
                    'pending_suggestions' : pending_suggestions,
                    'meeting' :meeting ,
                    'acronym' :acronym,
                    'is_materials_manager' : session.group.has_role(request.user, session.group.features.matman_roles),
                    'can_manage_materials' : can_manage,
                    'can_view_request': can_view_request,
                    'thisweek': datetime.date.today()-datetime.timedelta(days=7),
                    'now': datetime.datetime.now(),
                    'use_codimd': True if meeting.date>=settings.MEETING_USES_CODIMD_DATE else False,
                  })

class SessionDraftsForm(forms.Form):
    drafts = SearchableDocumentsField(required=False)

    def __init__(self, *args, **kwargs):
        self.already_linked = kwargs.pop('already_linked')
        super(self.__class__, self).__init__(*args, **kwargs)

    def clean(self):
        selected = self.cleaned_data['drafts']
        problems = set(selected).intersection(set(self.already_linked)) 
        if problems:
           raise forms.ValidationError("Already linked: %s" % ', '.join([d.name for d in problems]))
        return self.cleaned_data

def add_session_drafts(request, session_id, num):
    # num is redundant, but we're dragging it along an artifact of where we are in the current URL structure
    session = get_object_or_404(Session,pk=session_id)
    if not session.can_manage_materials(request.user):
        raise Http404
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        raise Http404

    already_linked = [sp.document for sp in session.sessionpresentation_set.filter(document__type_id='draft')]

    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    if request.method == 'POST':
        form = SessionDraftsForm(request.POST,already_linked=already_linked)
        if form.is_valid():
            for draft in form.cleaned_data['drafts']:
                session.sessionpresentation_set.create(document=draft,rev=None)
                c = DocEvent(type="added_comment", doc=draft, rev=draft.rev, by=request.user.person)
                c.desc = "Added to session: %s" % session
                c.save()
            return redirect('ietf.meeting.views.session_details', num=session.meeting.number, acronym=session.group.acronym)
    else:
        form = SessionDraftsForm(already_linked=already_linked)

    return render(request, "meeting/add_session_drafts.html",
                  { 'session': session,
                    'session_number': session_number,
                    'already_linked': session.sessionpresentation_set.filter(document__type_id='draft'),
                    'form': form,
                  })


class UploadBlueSheetForm(FileUploadForm):

    def __init__(self, *args, **kwargs):
        kwargs['doc_type'] = 'bluesheets'
        super(UploadBlueSheetForm, self).__init__(*args, **kwargs )


def upload_session_bluesheets(request, session_id, num):
    # num is redundant, but we're dragging it along an artifact of where we are in the current URL structure
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload bluesheets for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    if session.meeting.type.slug == 'ietf' and not has_role(request.user, 'Secretariat'):
        permission_denied(request, 'Restricted to role Secretariat')
        
    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    if request.method == 'POST':
        form = UploadBlueSheetForm(request.POST,request.FILES)
        if form.is_valid():
            file = request.FILES['file']

            ota = session.official_timeslotassignment()
            sess_time = ota and ota.timeslot.time
            if not sess_time:
                return HttpResponse("Cannot receive uploads for an unscheduled session.  Please check the session ID.", status=410, content_type="text/plain")


            save_error = save_bluesheet(request, session, file, encoding=form.file_encoding[file.name])
            if save_error:
                form.add_error(None, save_error)
            else:
                return redirect('ietf.meeting.views.session_details',num=num,acronym=session.group.acronym)
    else: 
        form = UploadBlueSheetForm()

    bluesheet_sp = session.sessionpresentation_set.filter(document__type='bluesheets').first()

    return render(request, "meeting/upload_session_bluesheets.html", 
                  {'session': session,
                   'session_number': session_number,
                   'bluesheet_sp' : bluesheet_sp,
                   'form': form,
                  })


def save_bluesheet(request, session, file, encoding='utf-8'):
    bluesheet_sp = session.sessionpresentation_set.filter(document__type='bluesheets').first()
    _, ext = os.path.splitext(file.name)

    if bluesheet_sp:
        doc = bluesheet_sp.document
        doc.rev = '%02d' % (int(doc.rev)+1)
        bluesheet_sp.rev = doc.rev
        bluesheet_sp.save()
    else:
        ota = session.official_timeslotassignment()
        sess_time = ota and ota.timeslot.time

        if session.meeting.type_id=='ietf':
            name = 'bluesheets-%s-%s-%s' % (session.meeting.number, 
                                            session.group.acronym, 
                                            sess_time.strftime("%Y%m%d%H%M"))
            title = 'Bluesheets IETF%s: %s : %s' % (session.meeting.number, 
                                                    session.group.acronym, 
                                                    sess_time.strftime("%a %H:%M"))
        else:
            name = 'bluesheets-%s-%s' % (session.meeting.number, sess_time.strftime("%Y%m%d%H%M"))
            title = 'Bluesheets %s: %s' % (session.meeting.number, sess_time.strftime("%a %H:%M"))
        doc = Document.objects.create(
                  name = name,
                  type_id = 'bluesheets',
                  title = title,
                  group = session.group,
                  rev = '00',
              )
        doc.states.add(State.objects.get(type_id='bluesheets',slug='active'))
        DocAlias.objects.create(name=doc.name).docs.add(doc)
        session.sessionpresentation_set.create(document=doc,rev='00')
    filename = '%s-%s%s'% ( doc.name, doc.rev, ext)
    doc.uploaded_filename = filename
    e = NewRevisionDocEvent.objects.create(doc=doc, rev=doc.rev, by=request.user.person, type='new_revision', desc='New revision available: %s'%doc.rev)
    save_error = handle_upload_file(file, filename, session.meeting, 'bluesheets', request=request, encoding=encoding)
    if not save_error:
        doc.save_with_history([e])
    return save_error

class UploadMinutesForm(FileUploadForm):
    apply_to_all = forms.BooleanField(label='Apply to all group sessions at this meeting',initial=True,required=False)

    def __init__(self, show_apply_to_all_checkbox, *args, **kwargs):
        kwargs['doc_type'] = 'minutes'
        super(UploadMinutesForm, self).__init__(*args, **kwargs )
        if not show_apply_to_all_checkbox:
            self.fields.pop('apply_to_all')


def upload_session_minutes(request, session_id, num):
    # num is redundant, but we're dragging it along an artifact of where we are in the current URL structure
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload minutes for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    show_apply_to_all_checkbox = len(sessions) > 1 if session.type_id == 'regular' else False
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    minutes_sp = session.sessionpresentation_set.filter(document__type='minutes').first()
    
    if request.method == 'POST':
        form = UploadMinutesForm(show_apply_to_all_checkbox,request.POST,request.FILES)
        if form.is_valid():
            file = request.FILES['file']
            _, ext = os.path.splitext(file.name)
            apply_to_all = session.type_id == 'regular'
            if show_apply_to_all_checkbox:
                apply_to_all = form.cleaned_data['apply_to_all']
            if minutes_sp:
                doc = minutes_sp.document
                doc.rev = '%02d' % (int(doc.rev)+1)
                minutes_sp.rev = doc.rev
                minutes_sp.save()
            else:
                ota = session.official_timeslotassignment()
                sess_time = ota and ota.timeslot.time
                if not sess_time:
                    return HttpResponse("Cannot receive uploads for an unscheduled session.  Please check the session ID.", status=410, content_type="text/plain")
                if session.meeting.type_id=='ietf':
                    name = 'minutes-%s-%s' % (session.meeting.number, 
                                                 session.group.acronym) 
                    title = 'Minutes IETF%s: %s' % (session.meeting.number, 
                                                         session.group.acronym) 
                    if not apply_to_all:
                        name += '-%s' % (sess_time.strftime("%Y%m%d%H%M"),)
                        title += ': %s' % (sess_time.strftime("%a %H:%M"),)
                else:
                    name = 'minutes-%s-%s' % (session.meeting.number, sess_time.strftime("%Y%m%d%H%M"))
                    title = 'Minutes %s: %s' % (session.meeting.number, sess_time.strftime("%a %H:%M"))
                if Document.objects.filter(name=name).exists():
                    doc = Document.objects.get(name=name)
                    doc.rev = '%02d' % (int(doc.rev)+1)
                else:
                    doc = Document.objects.create(
                              name = name,
                              type_id = 'minutes',
                              title = title,
                              group = session.group,
                              rev = '00',
                          )
                    DocAlias.objects.create(name=doc.name).docs.add(doc)
                doc.states.add(State.objects.get(type_id='minutes',slug='active'))
                if session.sessionpresentation_set.filter(document=doc).exists():
                    sp = session.sessionpresentation_set.get(document=doc)
                    sp.rev = doc.rev
                    sp.save()
                else:
                    session.sessionpresentation_set.create(document=doc,rev=doc.rev)
            if apply_to_all:
                for other_session in sessions:
                    if other_session != session:
                        other_session.sessionpresentation_set.filter(document__type='minutes').delete()
                        other_session.sessionpresentation_set.create(document=doc,rev=doc.rev)
            filename = '%s-%s%s'% ( doc.name, doc.rev, ext)
            doc.uploaded_filename = filename
            e = NewRevisionDocEvent.objects.create(doc=doc, by=request.user.person, type='new_revision', desc='New revision available: %s'%doc.rev, rev=doc.rev)
            # The way this function builds the filename it will never trigger the file delete in handle_file_upload.
            save_error = handle_upload_file(file, filename, session.meeting, 'minutes', request=request, encoding=form.file_encoding[file.name])
            if save_error:
                form.add_error(None, save_error)
            else:
                doc.save_with_history([e])
                return redirect('ietf.meeting.views.session_details',num=num,acronym=session.group.acronym)
    else: 
        form = UploadMinutesForm(show_apply_to_all_checkbox)

    return render(request, "meeting/upload_session_minutes.html", 
                  {'session': session,
                   'session_number': session_number,
                   'minutes_sp' : minutes_sp,
                   'form': form,
                  })


class UploadAgendaForm(FileUploadForm):
    apply_to_all = forms.BooleanField(label='Apply to all group sessions at this meeting',initial=True,required=False)

    def __init__(self, show_apply_to_all_checkbox, *args, **kwargs):
        kwargs['doc_type'] = 'agenda'
        super(UploadAgendaForm, self).__init__(*args, **kwargs )
        if not show_apply_to_all_checkbox:
            self.fields.pop('apply_to_all')

def upload_session_agenda(request, session_id, num):
    # num is redundant, but we're dragging it along an artifact of where we are in the current URL structure
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload an agenda for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    show_apply_to_all_checkbox = len(sessions) > 1 if session.type_id == 'regular' else False
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    agenda_sp = session.sessionpresentation_set.filter(document__type='agenda').first()
    
    if request.method == 'POST':
        form = UploadAgendaForm(show_apply_to_all_checkbox,request.POST,request.FILES)
        if form.is_valid():
            file = request.FILES['file']
            _, ext = os.path.splitext(file.name)
            apply_to_all = session.type_id == 'regular'
            if show_apply_to_all_checkbox:
                apply_to_all = form.cleaned_data['apply_to_all']
            if agenda_sp:
                doc = agenda_sp.document
                doc.rev = '%02d' % (int(doc.rev)+1)
                agenda_sp.rev = doc.rev
                agenda_sp.save()
            else:
                ota = session.official_timeslotassignment()
                sess_time = ota and ota.timeslot.time
                if not sess_time:
                    return HttpResponse("Cannot receive uploads for an unscheduled session.  Please check the session ID.", status=410, content_type="text/plain")
                if session.meeting.type_id=='ietf':
                    name = 'agenda-%s-%s' % (session.meeting.number, 
                                                 session.group.acronym) 
                    title = 'Agenda IETF%s: %s' % (session.meeting.number, 
                                                         session.group.acronym) 
                    if not apply_to_all:
                        name += '-%s' % (session.docname_token(),)
                        if sess_time:
                            title += ': %s' % (sess_time.strftime("%a %H:%M"),)
                else:
                    name = 'agenda-%s-%s' % (session.meeting.number, session.docname_token())
                    title = 'Agenda %s' % (session.meeting.number, )
                    if sess_time:
                        title += ': %s' % (sess_time.strftime("%a %H:%M"),)
                if Document.objects.filter(name=name).exists():
                    doc = Document.objects.get(name=name)
                    doc.rev = '%02d' % (int(doc.rev)+1)
                else:
                    doc = Document.objects.create(
                              name = name,
                              type_id = 'agenda',
                              title = title,
                              group = session.group,
                              rev = '00',
                          )
                    DocAlias.objects.create(name=doc.name).docs.add(doc)
                doc.states.add(State.objects.get(type_id='agenda',slug='active'))
            if session.sessionpresentation_set.filter(document=doc).exists():
                sp = session.sessionpresentation_set.get(document=doc)
                sp.rev = doc.rev
                sp.save()
            else:
                session.sessionpresentation_set.create(document=doc,rev=doc.rev)
            if apply_to_all:
                for other_session in sessions:
                    if other_session != session:
                        other_session.sessionpresentation_set.filter(document__type='agenda').delete()
                        other_session.sessionpresentation_set.create(document=doc,rev=doc.rev)
            filename = '%s-%s%s'% ( doc.name, doc.rev, ext)
            doc.uploaded_filename = filename
            e = NewRevisionDocEvent.objects.create(doc=doc,by=request.user.person,type='new_revision',desc='New revision available: %s'%doc.rev,rev=doc.rev)
            # The way this function builds the filename it will never trigger the file delete in handle_file_upload.
            save_error = handle_upload_file(file, filename, session.meeting, 'agenda', request=request, encoding=form.file_encoding[file.name])
            if save_error:
                form.add_error(None, save_error)
            else:
                doc.save_with_history([e])
                return redirect('ietf.meeting.views.session_details',num=num,acronym=session.group.acronym)
    else: 
        form = UploadAgendaForm(show_apply_to_all_checkbox, initial={'apply_to_all':session.type_id=='regular'})

    return render(request, "meeting/upload_session_agenda.html", 
                  {'session': session,
                   'session_number': session_number,
                   'agenda_sp' : agenda_sp,
                   'form': form,
                  })


class UploadSlidesForm(FileUploadForm):
    title = forms.CharField(max_length=255)
    apply_to_all = forms.BooleanField(label='Apply to all group sessions at this meeting',initial=False,required=False)

    def __init__(self, session, show_apply_to_all_checkbox, *args, **kwargs):
        self.session = session
        kwargs['doc_type'] = 'slides'
        super(UploadSlidesForm, self).__init__(*args, **kwargs )
        if not show_apply_to_all_checkbox:
            self.fields.pop('apply_to_all')

    def clean_title(self):
        title = self.cleaned_data['title']
        # The current tables only handles Unicode BMP:
        if ord(max(title)) > 0xffff:
            raise forms.ValidationError("The title contains characters outside the Unicode BMP, which is not currently supported")
        if self.session.meeting.type_id=='interim':
            if re.search(r'-\d{2}$', title):
                raise forms.ValidationError("Interim slides currently may not have a title that ends with something that looks like a revision number (-nn)")
        return title

def upload_session_slides(request, session_id, num, name):
    # num is redundant, but we're dragging it along an artifact of where we are in the current URL structure
    session = get_object_or_404(Session,pk=session_id)
    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload slides for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    show_apply_to_all_checkbox = len(sessions) > 1 if session.type_id == 'regular' else False
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    slides = None
    slides_sp = None
    if name:
        slides = Document.objects.filter(name=name).first()
        if not (slides and slides.type_id=='slides'):
            raise Http404
        slides_sp = session.sessionpresentation_set.filter(document=slides).first()
    
    if request.method == 'POST':
        form = UploadSlidesForm(session, show_apply_to_all_checkbox,request.POST,request.FILES)
        if form.is_valid():
            file = request.FILES['file']
            _, ext = os.path.splitext(file.name)
            apply_to_all = session.type_id == 'regular'
            if show_apply_to_all_checkbox:
                apply_to_all = form.cleaned_data['apply_to_all']
            if slides_sp:
                doc = slides_sp.document
                doc.rev = '%02d' % (int(doc.rev)+1)
                doc.title = form.cleaned_data['title']
                slides_sp.rev = doc.rev
                slides_sp.save()
            else:
                title = form.cleaned_data['title']
                if session.meeting.type_id=='ietf':
                    name = 'slides-%s-%s' % (session.meeting.number, 
                                             session.group.acronym) 
                    if not apply_to_all:
                        name += '-%s' % (session.docname_token(),)
                else:
                    name = 'slides-%s-%s' % (session.meeting.number, session.docname_token())
                name = name + '-' + slugify(title).replace('_', '-')[:128]
                if Document.objects.filter(name=name).exists():
                   doc = Document.objects.get(name=name)
                   doc.rev = '%02d' % (int(doc.rev)+1)
                   doc.title = form.cleaned_data['title']
                else:
                    doc = Document.objects.create(
                              name = name,
                              type_id = 'slides',
                              title = title,
                              group = session.group,
                              rev = '00',
                          )
                    DocAlias.objects.create(name=doc.name).docs.add(doc)
                doc.states.add(State.objects.get(type_id='slides',slug='active'))
                doc.states.add(State.objects.get(type_id='reuse_policy',slug='single'))
            if session.sessionpresentation_set.filter(document=doc).exists():
                sp = session.sessionpresentation_set.get(document=doc)
                sp.rev = doc.rev
                sp.save()
            else:
                max_order = session.sessionpresentation_set.filter(document__type='slides').aggregate(Max('order'))['order__max'] or 0
                session.sessionpresentation_set.create(document=doc,rev=doc.rev,order=max_order+1)
            if apply_to_all:
                for other_session in sessions:
                    if other_session != session and not other_session.sessionpresentation_set.filter(document=doc).exists():
                        max_order = other_session.sessionpresentation_set.filter(document__type='slides').aggregate(Max('order'))['order__max'] or 0
                        other_session.sessionpresentation_set.create(document=doc,rev=doc.rev,order=max_order+1)
            filename = '%s-%s%s'% ( doc.name, doc.rev, ext)
            doc.uploaded_filename = filename
            e = NewRevisionDocEvent.objects.create(doc=doc,by=request.user.person,type='new_revision',desc='New revision available: %s'%doc.rev,rev=doc.rev)
            # The way this function builds the filename it will never trigger the file delete in handle_file_upload.
            save_error = handle_upload_file(file, filename, session.meeting, 'slides', request=request, encoding=form.file_encoding[file.name])
            if save_error:
                form.add_error(None, save_error)
            else:
                doc.save_with_history([e])
                post_process(doc)
                return redirect('ietf.meeting.views.session_details',num=num,acronym=session.group.acronym)
    else: 
        initial = {}
        if slides:
            initial = {'title':slides.title}
        form = UploadSlidesForm(session, show_apply_to_all_checkbox, initial=initial)

    return render(request, "meeting/upload_session_slides.html", 
                  {'session': session,
                   'session_number': session_number,
                   'slides_sp' : slides_sp,
                   'form': form,
                  })
@login_required
def propose_session_slides(request, session_id, num):
    session = get_object_or_404(Session,pk=session_id)
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    session_number = None
    sessions = get_sessions(session.meeting.number,session.group.acronym)
    show_apply_to_all_checkbox = len(sessions) > 1 if session.type_id == 'regular' else False
    if len(sessions) > 1:
       session_number = 1 + sessions.index(session)

    
    if request.method == 'POST':
        form = UploadSlidesForm(session, show_apply_to_all_checkbox,request.POST,request.FILES)
        if form.is_valid():
            file = request.FILES['file']
            _, ext = os.path.splitext(file.name)
            apply_to_all = session.type_id == 'regular'
            if show_apply_to_all_checkbox:
                apply_to_all = form.cleaned_data['apply_to_all']
            title = form.cleaned_data['title']

            submission = SlideSubmission.objects.create(session = session, title = title, filename = '', apply_to_all = apply_to_all, submitter=request.user.person)

            if session.meeting.type_id=='ietf':
                name = 'slides-%s-%s' % (session.meeting.number, 
                                         session.group.acronym) 
                if not apply_to_all:
                    name += '-%s' % (session.docname_token(),)
            else:
                name = 'slides-%s-%s' % (session.meeting.number, session.docname_token())
            name = name + '-' + slugify(title).replace('_', '-')[:128]
            filename = '%s-ss%d%s'% (name, submission.id, ext)
            destination = io.open(os.path.join(settings.SLIDE_STAGING_PATH, filename),'wb+')
            for chunk in file.chunks():
                destination.write(chunk)
            destination.close()

            submission.filename = filename
            submission.save()

            (to, cc) = gather_address_lists('slides_proposed', group=session.group).as_strings() 
            msg_txt = render_to_string("meeting/slides_proposed.txt", {
                    "to": to,
                    "cc": cc,
                    "submission": submission,
                    "settings": settings,
                 })
            msg = infer_message(msg_txt)
            msg.by = request.user.person
            msg.save()
            send_mail_message(request, msg)
            return redirect('ietf.meeting.views.session_details',num=num,acronym=session.group.acronym)
    else: 
        initial = {}
        form = UploadSlidesForm(session, show_apply_to_all_checkbox, initial=initial)

    return render(request, "meeting/propose_session_slides.html", 
                  {'session': session,
                   'session_number': session_number,
                   'form': form,
                  })

def remove_sessionpresentation(request, session_id, num, name):
    sp = get_object_or_404(SessionPresentation,session_id=session_id,document__name=name)
    session = sp.session
    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to manage materials for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")
    if request.method == 'POST':
        session.sessionpresentation_set.filter(pk=sp.pk).delete()
        c = DocEvent(type="added_comment", doc=sp.document, rev=sp.document.rev, by=request.user.person)
        c.desc = "Removed from session: %s" % (session)
        c.save()
        return redirect('ietf.meeting.views.session_details', num=session.meeting.number, acronym=session.group.acronym)

    return render(request,'meeting/remove_sessionpresentation.html', {'sp': sp })

def ajax_add_slides_to_session(request, session_id, num):
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload slides for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    if request.method != 'POST' or not request.POST:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'No data submitted or not POST' }),content_type='application/json')

    order_str = request.POST.get('order', None)    
    try:
        order = int(order_str)
    except (ValueError, TypeError):
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied order is not valid' }),content_type='application/json')
    if order < 1 or order > session.sessionpresentation_set.filter(document__type_id='slides').count() + 1 :
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied order is not valid' }),content_type='application/json')

    name = request.POST.get('name', None)
    doc = Document.objects.filter(name=name).first()
    if not doc:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied name is not valid' }),content_type='application/json')

    if not session.sessionpresentation_set.filter(document=doc).exists():
        condition_slide_order(session)
        session.sessionpresentation_set.filter(document__type_id='slides', order__gte=order).update(order=F('order')+1)
        session.sessionpresentation_set.create(document=doc,rev=doc.rev,order=order)
        DocEvent.objects.create(type="added_comment", doc=doc, rev=doc.rev, by=request.user.person, desc="Added to session: %s" % session)

    return HttpResponse(json.dumps({'success':True}), content_type='application/json')


def ajax_remove_slides_from_session(request, session_id, num):
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload slides for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    if request.method != 'POST' or not request.POST:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'No data submitted or not POST' }),content_type='application/json')  

    oldIndex_str = request.POST.get('oldIndex', None)
    try:
        oldIndex = int(oldIndex_str)
    except (ValueError, TypeError):
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')
    if oldIndex < 1 or oldIndex > session.sessionpresentation_set.filter(document__type_id='slides').count() :
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')

    name = request.POST.get('name', None)
    doc = Document.objects.filter(name=name).first()
    if not doc:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied name is not valid' }),content_type='application/json')

    condition_slide_order(session)
    affected_presentations = session.sessionpresentation_set.filter(document=doc).first()
    if affected_presentations:
        if affected_presentations.order == oldIndex:
            affected_presentations.delete()
            session.sessionpresentation_set.filter(document__type_id='slides', order__gt=oldIndex).update(order=F('order')-1)    
            DocEvent.objects.create(type="added_comment", doc=doc, rev=doc.rev, by=request.user.person, desc="Removed from session: %s" % session)
            return HttpResponse(json.dumps({'success':True}), content_type='application/json')
        else:
            return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Name does not match index' }),content_type='application/json')
    else:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'SessionPresentation not found' }),content_type='application/json')


def ajax_reorder_slides_in_session(request, session_id, num):
    session = get_object_or_404(Session,pk=session_id)

    if not session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to upload slides for this session.")
    if session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")

    if request.method != 'POST' or not request.POST:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'No data submitted or not POST' }),content_type='application/json')  

    num_slides_in_session = session.sessionpresentation_set.filter(document__type_id='slides').count()
    oldIndex_str = request.POST.get('oldIndex', None)
    try:
        oldIndex = int(oldIndex_str)
    except (ValueError, TypeError):
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')
    if oldIndex < 1 or oldIndex > num_slides_in_session :
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')

    newIndex_str = request.POST.get('newIndex', None)
    try:
        newIndex = int(newIndex_str)
    except (ValueError, TypeError):
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')
    if newIndex < 1 or newIndex > num_slides_in_session :
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')

    if newIndex == oldIndex:
        return HttpResponse(json.dumps({ 'success' : False, 'error' : 'Supplied index is not valid' }),content_type='application/json')

    condition_slide_order(session)
    sp = session.sessionpresentation_set.get(order=oldIndex)
    if oldIndex < newIndex:
        session.sessionpresentation_set.filter(order__gt=oldIndex, order__lte=newIndex).update(order=F('order')-1)
    else:
        session.sessionpresentation_set.filter(order__gte=newIndex, order__lt=oldIndex).update(order=F('order')+1)
    sp.order = newIndex
    sp.save()

    return HttpResponse(json.dumps({'success':True}), content_type='application/json')


@role_required('Secretariat')
def make_schedule_official(request, num, owner, name):

    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    schedule = get_schedule_by_name(meeting, person, name)

    if schedule is None:
        raise Http404

    if request.method == 'POST':
        if not (schedule.public and schedule.visible):
            schedule.public = True
            schedule.visible = True
            schedule.save()
        if schedule.base and not (schedule.base.public and schedule.base.visible):
            schedule.base.public = True
            schedule.base.visible = True
            schedule.base.save()
        meeting.schedule = schedule
        meeting.save()
        return HttpResponseRedirect(reverse('ietf.meeting.views.list_schedules',kwargs={'num':num}))

    if not schedule.public:
        messages.warning(request,"This schedule will be made public as it is made official.")
    if not schedule.visible:
        messages.warning(request,"This schedule will be made visible as it is made official.")
    if schedule.base:
        if not schedule.base.public:
            messages.warning(request,"The base schedule will be made public as it is made official.")
        if not schedule.base.visible:
            messages.warning(request,"The base schedule will be made visible as it is made official.")

    return render(request, "meeting/make_schedule_official.html",
                  { 'schedule' : schedule,
                    'meeting' : meeting,
                  }
                 )
    

@role_required('Secretariat','Area Director')
def delete_schedule(request, num, owner, name):

    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    schedule = get_schedule_by_name(meeting, person, name)

    # FIXME: we ought to put these checks in a function and only show
    # the delete button if the checks pass
    if schedule == meeting.schedule:
        permission_denied(request, 'You may not delete the official schedule for %s'%meeting)

    if Schedule.objects.filter(base=schedule).exists():
        return HttpResponseForbidden('You may not delete a schedule serving as the base for other schedules')

    if not ( has_role(request.user, 'Secretariat') or person.user == request.user ):
        permission_denied(request, "You may not delete other user's schedules")

    if request.method == 'POST':
        # remove schedule from origin tree
        replacement_origin = schedule.origin
        Schedule.objects.filter(origin=schedule).update(origin=replacement_origin)

        schedule.delete()
        return HttpResponseRedirect(reverse('ietf.meeting.views.list_schedules',kwargs={'num':num}))

    return render(request, "meeting/delete_schedule.html",
                  { 'schedule' : schedule,
                    'meeting' : meeting,
                  }
                 )
  
# -------------------------------------------------
# Interim Views
# -------------------------------------------------


def ajax_get_utc(request):
    '''Ajax view that takes arguments time, timezone, date and returns UTC data'''
    time = request.GET.get('time')
    timezone = request.GET.get('timezone')
    date = request.GET.get('date')
    time_re = re.compile(r'^\d{2}:\d{2}$')
    # validate input
    if not time_re.match(time) or not date:
        return HttpResponse(json.dumps({'error': True}),
                            content_type='application/json')
    hour, minute = time.split(':')
    if not (int(hour) <= 23 and int(minute) <= 59):
        return HttpResponse(json.dumps({'error': True}),
                            content_type='application/json')
    year, month, day = date.split('-')
    dt = datetime.datetime(int(year), int(month), int(day), int(hour), int(minute))
    tz = pytz.timezone(timezone)
    aware_dt = tz.localize(dt, is_dst=None)
    utc_dt = aware_dt.astimezone(pytz.utc)
    utc = utc_dt.strftime('%H:%M')
    # calculate utc day offset
    naive_utc_dt = utc_dt.replace(tzinfo=None)
    utc_day_offset = (naive_utc_dt.date() - dt.date()).days
    html = "<span>{utc} UTC</span>".format(utc=utc)
    if utc_day_offset != 0:
        html = html + "<span class='day-offset'> {0:+d} Day</span>".format(utc_day_offset)
    context_data = {'timezone': timezone, 
                    'time': time, 
                    'utc': utc, 
                    'utc_day_offset': utc_day_offset,
                    'html': html}
    return HttpResponse(json.dumps(context_data),
                        content_type='application/json')


def interim_announce(request):
    '''View which shows interim meeting requests awaiting announcement'''
    meetings = data_for_meetings_overview(Meeting.objects.filter(type='interim').order_by('date'), interim_status='scheda')
    menu_entries = get_interim_menu_entries(request)
    selected_menu_entry = 'announce'

    return render(request, "meeting/interim_announce.html", {
        'menu_entries': menu_entries,
        'selected_menu_entry': selected_menu_entry,
        'meetings': meetings})


@role_required('Secretariat',)
def interim_send_announcement(request, number):
    '''View for sending the announcement of a new interim meeting'''
    meeting = get_object_or_404(Meeting, number=number)
    group = meeting.session_set.first().group

    if request.method == 'POST':
        form = InterimAnnounceForm(request.POST,
                                   initial=get_announcement_initial(meeting))
        if form.is_valid():
            message = form.save(user=request.user)
            message.related_groups.add(group)
            for session in meeting.session_set.all():
                SchedulingEvent.objects.create(
                    session=session,
                    status=SessionStatusName.objects.get(slug='sched'),
                    by=request.user.person,
                )
            send_mail_message(request, message)
            messages.success(request, 'Interim meeting announcement sent')
            return redirect(interim_announce)

    form = InterimAnnounceForm(initial=get_announcement_initial(meeting))

    return render(request, "meeting/interim_send_announcement.html", {
        'meeting': meeting,
        'form': form})


@role_required('Secretariat',)
def interim_skip_announcement(request, number):
    '''View to change status of interim meeting to Scheduled without
    first announcing.  Only applicable to IRTF groups.
    '''
    meeting = get_object_or_404(Meeting, number=number)

    if request.method == 'POST':
        for session in meeting.session_set.all():
            SchedulingEvent.objects.create(
                session=session,
                status=SessionStatusName.objects.get(slug='sched'),
                by=request.user.person,
            )
        messages.success(request, 'Interim meeting scheduled.  No announcement sent.')
        return redirect(interim_announce)

    return render(request, "meeting/interim_skip_announce.html", {
        'meeting': meeting})


def interim_pending(request):

    '''View which shows interim meeting requests pending approval'''
    meetings = data_for_meetings_overview(Meeting.objects.filter(type='interim').order_by('date'), interim_status='apprw')

    menu_entries = get_interim_menu_entries(request)
    selected_menu_entry = 'pending'

    for meeting in meetings:
        if can_approve_interim_request(meeting, request.user):
            meeting.can_approve = True

    return render(request, "meeting/interim_pending.html", {
        'menu_entries': menu_entries,
        'selected_menu_entry': selected_menu_entry,
        'meetings': meetings})


@login_required
def interim_request(request):

    if not can_manage_some_groups(request.user):
        permission_denied(request, "You don't have permission to request any interims")

    '''View for requesting an interim meeting'''
    SessionFormset = inlineformset_factory(
        Meeting,
        Session,
        form=InterimSessionModelForm,
        formset=InterimSessionInlineFormSet,
        can_delete=False, extra=2)

    if request.method == 'POST':
        form = InterimMeetingModelForm(request, data=request.POST)
        formset = SessionFormset(instance=Meeting(), data=request.POST)
        if form.is_valid() and formset.is_valid():
            group = form.cleaned_data.get('group')
            is_approved = form.cleaned_data.get('approved', False)
            is_virtual = form.is_virtual()
            meeting_type = form.cleaned_data.get('meeting_type')

            requires_approval = not ( is_approved or ( is_virtual and not settings.VIRTUAL_INTERIMS_REQUIRE_APPROVAL ))

            # pre create meeting
            if meeting_type in ('single', 'multi-day'):
                meeting = form.save(date=get_earliest_session_date(formset))

                # need to use curry here to pass custom variable to form init
                SessionFormset.form.__init__ = curry(
                    InterimSessionModelForm.__init__,
                    user=request.user,
                    group=group,
                    requires_approval=requires_approval)
                formset = SessionFormset(instance=meeting, data=request.POST)
                formset.is_valid()
                formset.save()
                sessions_post_save(request, formset)

                if requires_approval:
                    send_interim_approval_request(meetings=[meeting])
                else:
                    send_interim_approval(request.user, meeting=meeting)
                    if not has_role(request.user, 'Secretariat'):
                        send_interim_announcement_request(meeting=meeting)

            # series require special handling, each session gets it's own
            # meeting object we won't see this on edit because series are
            # subsequently dealt with individually
            elif meeting_type == 'series':
                series = []
                SessionFormset.form.__init__ = curry(
                    InterimSessionModelForm.__init__,
                    user=request.user,
                    group=group,
                    requires_approval=requires_approval)
                formset = SessionFormset(instance=Meeting(), data=request.POST)
                formset.is_valid()  # re-validate
                for session_form in formset.forms:
                    if not session_form.has_changed():
                        continue
                    # create meeting
                    form = InterimMeetingModelForm(request, data=request.POST)
                    form.is_valid()
                    meeting = form.save(date=session_form.cleaned_data['date'])
                    # create save session
                    session = session_form.save(commit=False)
                    session.meeting = meeting
                    session.save()
                    series.append(meeting)
                    sessions_post_save(request, [session_form])

                if requires_approval:
                    send_interim_approval_request(meetings=series)
                else:
                    send_interim_approval(request.user, meeting=meeting)
                    if not has_role(request.user, 'Secretariat'):
                        send_interim_announcement_request(meeting=meeting)

            messages.success(request, 'Interim meeting request submitted')
            return redirect(upcoming)

    else:
        initial = {'meeting_type': 'single', 'group': request.GET.get('group', '')}
        form = InterimMeetingModelForm(request=request, 
                                       initial=initial)
        formset = SessionFormset()

    return render(request, "meeting/interim_request.html", {
        "form": form,
        "formset": formset})


@login_required
def interim_request_cancel(request, number):
    '''View for cancelling an interim meeting request'''
    meeting = get_object_or_404(Meeting, number=number)
    first_session = meeting.session_set.first()
    group = first_session.group
    if not can_manage_group(request.user, group):
        permission_denied(request, "You do not have permissions to cancel this meeting request")
    session_status = current_session_status(first_session)

    if request.method == 'POST':
        form = InterimCancelForm(request.POST)
        if form.is_valid():
            if 'comments' in form.changed_data:
                meeting.session_set.update(agenda_note=form.cleaned_data.get('comments'))

            was_scheduled = session_status.slug == 'sched'

            result_status = SessionStatusName.objects.get(slug='canceled' if was_scheduled else 'canceledpa')
            for session in meeting.session_set.all():
                SchedulingEvent.objects.create(
                    session=session,
                    status=result_status,
                    by=request.user.person,
                )

            if was_scheduled:
                send_interim_cancellation_notice(meeting)

            messages.success(request, 'Interim meeting cancelled')
            return redirect(upcoming)
    else:
        form = InterimCancelForm(initial={'group': group.acronym, 'date': meeting.date})

    return render(request, "meeting/interim_request_cancel.html", {
        "form": form,
        "meeting": meeting,
        "session_status": session_status,
    })


@login_required
def interim_request_details(request, number):
    '''View details of an interim meeting request'''
    meeting = get_object_or_404(Meeting, number=number)
    group = meeting.session_set.first().group
    if not can_manage_group(request.user, group):
        permission_denied(request, "You do not have permissions to manage this meeting request")
    sessions = meeting.session_set.all()
    can_edit = can_edit_interim_request(meeting, request.user)
    can_approve = can_approve_interim_request(meeting, request.user)

    if request.method == 'POST':
        if request.POST.get('approve') and can_approve_interim_request(meeting, request.user):
            for session in meeting.session_set.all():
                SchedulingEvent.objects.create(
                    session=session,
                    status=SessionStatusName.objects.get(slug='scheda'),
                    by=request.user.person,
                )
            messages.success(request, 'Interim meeting approved')
            if has_role(request.user, 'Secretariat'):
                return redirect(interim_send_announcement, number=number)
            else:
                send_interim_announcement_request(meeting)
                return redirect(interim_pending)
        if request.POST.get('disapprove') and can_approve_interim_request(meeting, request.user):
            for session in meeting.session_set.all():
                SchedulingEvent.objects.create(
                    session=session,
                    status=SessionStatusName.objects.get(slug='disappr'),
                    by=request.user.person,
                )
            messages.success(request, 'Interim meeting disapproved')
            return redirect(interim_pending)

    first_session = sessions.first()
    assignments = SchedTimeSessAssignment.objects.filter(schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None])

    return render(request, "meeting/interim_request_details.html", {
        "meeting": meeting,
        "sessions": sessions,
        "assignments": assignments,
        "group": first_session.group,
        "requester": session_requested_by(first_session),
        "session_status": current_session_status(first_session),
        "can_edit": can_edit,
        "can_approve": can_approve})


@login_required
def interim_request_edit(request, number):
    '''Edit details of an interim meeting reqeust'''
    meeting = get_object_or_404(Meeting, number=number)
    if not can_edit_interim_request(meeting, request.user):
        permission_denied(request, "You do not have permissions to edit this meeting request")

    SessionFormset = inlineformset_factory(
        Meeting,
        Session,
        form=InterimSessionModelForm,
        can_delete=False,
        extra=1)

    if request.method == 'POST':
        form = InterimMeetingModelForm(request=request, instance=meeting,
                                       data=request.POST)
        group = Group.objects.get(pk=form.data['group'])
        is_approved = is_interim_meeting_approved(meeting)

        SessionFormset.form.__init__ = curry(
            InterimSessionModelForm.__init__,
            user=request.user,
            group=group,
            requires_approval= not is_approved)

        formset = SessionFormset(instance=meeting, data=request.POST)

        if form.is_valid() and formset.is_valid():
            meeting = form.save(date=get_earliest_session_date(formset))
            formset.save()
            sessions_post_save(request, formset)

            message = 'Interim meeting request saved'
            meeting_is_scheduled = add_event_info_to_session_qs(meeting.session_set).filter(current_status='sched').exists()
            if (form.has_changed() or formset.has_changed()) and meeting_is_scheduled:
                send_interim_change_notice(request, meeting)
                message = message + ' and change announcement sent'
            messages.success(request, message)
            return redirect(interim_request_details, number=number)

    else:
        form = InterimMeetingModelForm(request=request, instance=meeting)
        formset = SessionFormset(instance=meeting)

    return render(request, "meeting/interim_request_edit.html", {
        "meeting": meeting,
        "form": form,
        "formset": formset})

@cache_page(60*60)
def past(request):
    '''List of past meetings'''
    today = datetime.datetime.today()

    meetings = data_for_meetings_overview(Meeting.objects.filter(date__lte=today).order_by('-date'))

    return render(request, 'meeting/past.html', {
                  'meetings': meetings,
                  })

def upcoming(request):
    '''List of upcoming meetings'''
    today = datetime.date.today()

    # Get ietf meetings starting 7 days ago, and interim meetings starting today
    ietf_meetings = Meeting.objects.filter(type_id='ietf', date__gte=today-datetime.timedelta(days=7))
    for m in ietf_meetings:
        m.end = m.date+datetime.timedelta(days=m.days)

    interim_sessions = add_event_info_to_session_qs(
        Session.objects.filter(
            meeting__type_id='interim', 
            timeslotassignments__schedule=F('meeting__schedule'),
            timeslotassignments__timeslot__time__gte=today
        )
    ).filter(current_status__in=('sched','canceled'))

    # get groups for group UI display - same algorithm as in agenda(), but
    # using group / parent instead of historic_group / historic_parent
    groups = [s.group for s in interim_sessions
              if s.group
              and s.group.type_id in ('wg', 'rg', 'ag', 'rag', 'iab', 'program')
              and s.group.parent]
    group_parents = {g.parent for g in groups if g.parent}
    seen = set()
    for p in group_parents:
        p.group_list = []
        for g in groups:
            if g.acronym not in seen and g.parent.acronym == p.acronym:
                p.group_list.append(g)
                seen.add(g.acronym)

    # only one category
    filter_categories = [[
        dict(
            label=p.acronym, 
            keyword=p.acronym.lower(),
            children=[dict(
                label=g.acronym,
                keyword=g.acronym.lower(),
                is_bof=g.is_bof(),
            ) for g in p.group_list]
        ) for p in group_parents
    ]]
    
    for session in interim_sessions:
        session.historic_group = session.group
        session.filter_keywords = filter_keywords_for_session(session)

    entries = list(ietf_meetings)
    entries.extend(list(interim_sessions))
    entries.sort(key = lambda o: pytz.utc.localize(datetime.datetime.combine(o.date, datetime.datetime.min.time())) if isinstance(o,Meeting) else o.official_timeslotassignment().timeslot.utc_start_time())
    
    # add menu entries
    menu_entries = get_interim_menu_entries(request)
    selected_menu_entry = 'upcoming'

    # add menu actions
    actions = []
    if can_request_interim_meeting(request.user):
        actions.append(dict(
            label='Request new interim meeting',
            url=reverse('ietf.meeting.views.interim_request'),
            append_filter=False)
        )
    actions.append(dict(
        label='Download as .ics',
        url=reverse('ietf.meeting.views.upcoming_ical'),
        append_filter=True)
    )
    actions.append(dict(
        label='Subscribe with webcal',
        url='webcal://'+request.get_host()+reverse('ietf.meeting.views.upcoming_ical'),
        append_filter=True)
    )

    return render(request, 'meeting/upcoming.html', {
                  'entries': entries,
                  'filter_categories': filter_categories,
                  'menu_actions': actions,
                  'menu_entries': menu_entries,
                  'selected_menu_entry': selected_menu_entry,
                  'now': datetime.datetime.now(),
                  'use_codimd': True if datetime.date.today()>=settings.MEETING_USES_CODIMD_DATE else False,
                  })


def upcoming_ical(request):
    """Return Upcoming meetings in iCalendar file

    Filters by wg name and session type.
    """
    try:
        filter_params = parse_agenda_filter_params(request.GET)
    except ValueError as e:
        return HttpResponseBadRequest(str(e))
        
    today = datetime.date.today()

    # get meetings starting 7 days ago -- we'll filter out sessions in the past further down
    meetings = data_for_meetings_overview(Meeting.objects.filter(date__gte=today-datetime.timedelta(days=7)).prefetch_related('schedule').order_by('date'))

    assignments = list(SchedTimeSessAssignment.objects.filter(
        schedule__in=[m.schedule_id for m in meetings] + [m.schedule.base_id for m in meetings if m.schedule],
        session__in=[s.pk for m in meetings for s in m.sessions if m.type_id != 'ietf'],
        timeslot__time__gte=today,
    ).order_by(
        'schedule__meeting__date', 'session__type', 'timeslot__time'
    ).select_related(
        'session__group', 'session__group__parent', 'timeslot', 'schedule', 'schedule__meeting'
    ).distinct())

    tag_assignments_with_filter_keywords(assignments)

    # apply filters
    if filter_params is not None:
        assignments = [a for a in assignments if should_include_assignment(filter_params, a)]

    # we already collected sessions with current_status, so reuse those
    sessions = {s.pk: s for m in meetings for s in m.sessions}
    for a in assignments:
        if a.session_id is not None:
            a.session = sessions.get(a.session_id) or a.session
            a.session.ical_status = ical_session_status(a)

    # handle IETFs separately
    ietfs = [m for m in meetings if m.type_id == 'ietf']
    preprocess_meeting_important_dates(ietfs)

    # icalendar response file should have '\r\n' line endings per RFC5545
    response = render_to_string('meeting/upcoming.ics', {
        'vtimezones': ''.join(sorted(list({meeting.vtimezone() for meeting in meetings if meeting.vtimezone()}))),
        'assignments': assignments,
        'ietfs': ietfs,
    }, request=request)
    response = re.sub("\r(?!\n)|(?<!\r)\n", "\r\n", response)

    response = HttpResponse(response, content_type='text/calendar')
    response['Content-Disposition'] = 'attachment; filename="upcoming.ics"'
    return response
    

def upcoming_json(request):
    '''Return Upcoming meetings in json format'''
    today = datetime.date.today()

    # get meetings starting 7 days ago -- we'll filter out sessions in the past further down
    meetings = data_for_meetings_overview(Meeting.objects.filter(date__gte=today-datetime.timedelta(days=7)).order_by('date'))

    data = {}
    for m in meetings:
        data[m.number] = {
            'date':  m.date.strftime("%Y-%m-%d"),
        }

    response = HttpResponse(json.dumps(data, indent=2, sort_keys=False), content_type='application/json;charset=%s'%settings.DEFAULT_CHARSET)
    return response

def floor_plan(request, num=None, floor=None, ):
    meeting = get_meeting(num)
    schedule = meeting.schedule
    floors = FloorPlan.objects.filter(meeting=meeting).order_by('order')
    if floor:
        floors = [ f for f in floors if xslugify(f.name) == floor ]
    for floor in floors:
        try:
            floor.image.width
        except FileNotFoundError:
            raise Http404('Missing floorplan image for %s' % floor)
    return render(request, 'meeting/floor-plan.html', {
            "meeting": meeting,
            "schedule": schedule,
            "number": num,
            "floors": floors,
        })

def proceedings(request, num=None):

    meeting = get_meeting(num)

    if (meeting.number.isdigit() and int(meeting.number) <= 64) or not meeting.schedule or not meeting.schedule.assignments.exists():
            return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s' % num )

    begin_date = meeting.get_submission_start_date()
    cut_off_date = meeting.get_submission_cut_off_date()
    cor_cut_off_date = meeting.get_submission_correction_date()
    now = datetime.date.today()

    schedule = get_schedule(meeting, None)
    sessions  = add_event_info_to_session_qs(
        Session.objects.filter(meeting__number=meeting.number)
    ).filter(
        Q(timeslotassignments__schedule__in=[schedule, schedule.base if schedule else None]) | Q(current_status='notmeet')
    ).select_related().order_by('-current_status')
    plenaries = sessions.filter(name__icontains='plenary').exclude(current_status='notmeet')
    ietf      = sessions.filter(group__parent__type__slug = 'area').exclude(group__acronym='edu')
    irtf      = sessions.filter(group__parent__acronym = 'irtf')
    training  = sessions.filter(group__acronym__in=['edu','iaoc'], type_id__in=['regular', 'other', ]).exclude(current_status='notmeet')
    iab       = sessions.filter(group__parent__acronym = 'iab').exclude(current_status='notmeet')

    cache_version = Document.objects.filter(session__meeting__number=meeting.number).aggregate(Max('time'))["time__max"]

    ietf_areas = []
    for area, sessions in itertools.groupby(sorted(ietf, key=lambda s: (s.group.parent.acronym, s.group.acronym)), key=lambda s: s.group.parent):
        sessions = list(sessions)
        meeting_groups = set(s.group_id for s in sessions if s.current_status != 'notmeet')
        meeting_sessions = []
        not_meeting_sessions = []
        for s in sessions:
            if s.current_status == 'notmeet' and s.group_id not in meeting_groups:
                not_meeting_sessions.append(s)
            else:
                meeting_sessions.append(s)
        ietf_areas.append((area, meeting_sessions, not_meeting_sessions))

    return render(request, "meeting/proceedings.html", {
        'meeting': meeting,
        'plenaries': plenaries, 'ietf': ietf, 'training': training, 'irtf': irtf, 'iab': iab,
        'ietf_areas': ietf_areas,
        'cut_off_date': cut_off_date,
        'cor_cut_off_date': cor_cut_off_date,
        'submission_started': now > begin_date,
        'cache_version': cache_version,
    })

@role_required('Secretariat')
def finalize_proceedings(request, num=None):

    meeting = get_meeting(num)

    if (meeting.number.isdigit() and int(meeting.number) <= 64) or not meeting.schedule or not meeting.schedule.assignments.exists() or meeting.proceedings_final:
        raise Http404

    if request.method=='POST':
        finalize(meeting)
        return HttpResponseRedirect(reverse('ietf.meeting.views.proceedings',kwargs={'num':meeting.number}))
    
    return render(request, "meeting/finalize.html", {'meeting':meeting,})

def proceedings_acknowledgements(request, num=None):
    '''Display Acknowledgements for meeting'''
    if not (num and num.isdigit()):
        raise Http404
    meeting = get_meeting(num)
    if int(meeting.number) < settings.NEW_PROCEEDINGS_START:
        return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s/acknowledgement.html' % num )
    return render(request, "meeting/proceedings_acknowledgements.html", {
        'meeting': meeting,
    })

def proceedings_attendees(request, num=None):
    '''Display list of meeting attendees'''
    if not (num and num.isdigit()):
        raise Http404
    meeting = get_meeting(num)
    if int(meeting.number) < settings.NEW_PROCEEDINGS_START:
        return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s/attendees.html' % num )
    overview_template = '/meeting/proceedings/%s/attendees.html' % meeting.number
    try:
        template = render_to_string(overview_template, {})
    except TemplateDoesNotExist:
        raise Http404
    return render(request, "meeting/proceedings_attendees.html", {
        'meeting': meeting,
        'template': template,
    })

def proceedings_overview(request, num=None):
    '''Display Overview for given meeting'''
    if not (num and num.isdigit()):
        raise Http404
    meeting = get_meeting(num)
    if int(meeting.number) < settings.NEW_PROCEEDINGS_START:
        return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s/overview.html' % num )
    overview_template = '/meeting/proceedings/%s/overview.rst' % meeting.number
    try:
        template = render_to_string(overview_template, {})
    except TemplateDoesNotExist:
        raise Http404
    return render(request, "meeting/proceedings_overview.html", {
        'meeting': meeting,
        'template': template,
    })

@cache_page( 60 * 60 )
def proceedings_progress_report(request, num=None):
    '''Display Progress Report (stats since last meeting)'''
    if not (num and num.isdigit()):
        raise Http404
    meeting = get_meeting(num)
    if int(meeting.number) < settings.NEW_PROCEEDINGS_START:
        return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s/progress-report.html' % num )
    sdate = meeting.previous_meeting().date
    edate = meeting.date
    context = get_progress_stats(sdate,edate)
    context['meeting'] = meeting
    return render(request, "meeting/proceedings_progress_report.html", context)
    
class OldUploadRedirect(RedirectView):
    def get_redirect_url(self, **kwargs):
        return reverse_lazy('ietf.meeting.views.session_details',kwargs=self.kwargs)

@csrf_exempt
def api_import_recordings(request, number):
    '''REST API to check for recording files and import'''
    if request.method == 'POST':
        meeting = get_meeting(number)
        import_audio_files(meeting)
        return HttpResponse(status=201)
    else:
        return HttpResponse(status=405)

@require_api_key
@role_required('Recording Manager')
@csrf_exempt
def api_set_session_video_url(request):
    def err(code, text):
        return HttpResponse(text, status=code, content_type='text/plain')
    if request.method == 'POST':
        # parameters:
        #   apikey: the poster's personal API key
        #   meeting: '101', or 'interim-2018-quic-02'
        #   group: 'quic' or 'plenary'
        #   item: '1', '2', '3' (the group's first, second, third etc.
        #                           session during the week)
        #   url: The recording url (on YouTube, or whatever)
        user = request.user.person
        for item in ['meeting', 'group', 'item', 'url',]:
            value = request.POST.get(item)
            if not value:
                return err(400, "Missing %s parameter" % item)
        number = request.POST.get('meeting')
        sessions = Session.objects.filter(meeting__number=number)
        if not sessions.exists():
            return err(400, "No sessions found for meeting '%s'" % (number, ))
        acronym = request.POST.get('group')
        sessions = sessions.filter(group__acronym=acronym)
        if not sessions.exists():
            return err(400, "No sessions found in meeting '%s' for group '%s'" % (number, acronym))
        session_times = [ (s.official_timeslotassignment().timeslot.time, s.id, s) for s in sessions if s.official_timeslotassignment() ]
        session_times.sort()
        item = request.POST.get('item')
        if not item.isdigit():
            return err(400, "Expected a numeric value for 'item', found '%s'" % (item, ))
        n = int(item)-1              # change 1-based to 0-based
        try:
            time, __, session = session_times[n]
        except IndexError:
            return err(400, "No item '%s' found in list of sessions for group" % (item, ))
        url = request.POST.get('url')
        try:
            URLValidator()(url)
        except ValidationError:
            return err(400, "Invalid url value: '%s'" % (url, ))
        recordings = [ (r.name, r.title, r) for r in session.recordings() if 'video' in r.title.lower() ]
        if recordings:
            r = recordings[-1][-1]
            if r.external_url != url:
                e = DocEvent.objects.create(doc=r, rev=r.rev, type="added_comment", by=request.user.person,
                    desc="External url changed from %s to %s" % (r.external_url, url))
                r.external_url = url
                r.save_with_history([e])
            else:
                return err(400, "URL is the same")
        else:
            time = session.official_timeslotassignment().timeslot.time
            title = 'Video recording for %s on %s at %s' % (acronym, time.date(), time.time())
            create_recording(session, url, title=title, user=user)
    else:
        return err(405, "Method not allowed")

    return HttpResponse("Done", status=200, content_type='text/plain')


@require_api_key
@role_required('Recording Manager', 'Secretariat')
@csrf_exempt
def api_upload_bluesheet(request):
    def err(code, text):
        return HttpResponse(text, status=code, content_type='text/plain')
    if request.method == 'POST':
        # parameters:
        #   apikey: the poster's personal API key
        #   meeting: number as string, i.e., '101', or 'interim-2018-quic-02'
        #   group: acronym or special, i.e., 'quic' or 'plenary'
        #   item: '1', '2', '3' (the group's first, second, third etc.
        #                           session during the week)
        #   bluesheet: json blob with
        #       [{'name': 'Name', 'affiliation': 'Organization', }, ...]
        for item in ['meeting', 'group', 'item', 'bluesheet',]:
            value = request.POST.get(item)
            if not value:
                return err(400, "Missing %s parameter" % item)
        number = request.POST.get('meeting')
        sessions = Session.objects.filter(meeting__number=number)
        if not sessions.exists():
            return err(400, "No sessions found for meeting '%s'" % (number, ))
        acronym = request.POST.get('group')
        sessions = sessions.filter(group__acronym=acronym)
        if not sessions.exists():
            return err(400, "No sessions found in meeting '%s' for group '%s'" % (number, acronym))
        session_times = [ (s.official_timeslotassignment().timeslot.time, s.id, s) for s in sessions if s.official_timeslotassignment() ]
        session_times.sort()
        item = request.POST.get('item')
        if not item.isdigit():
            return err(400, "Expected a numeric value for 'item', found '%s'" % (item, ))
        n = int(item)-1              # change 1-based to 0-based
        try:
            time, __, session = session_times[n]
        except IndexError:
            return err(400, "No item '%s' found in list of sessions for group" % (item, ))
        bjson = request.POST.get('bluesheet')
        try:
            data = json.loads(bjson)
        except json.decoder.JSONDecodeError:
            return err(400, "Invalid json value: '%s'" % (bjson, ))

        text = render_to_string('meeting/bluesheet.txt', {
                'data': data,
                'session': session,
            })

        fd, name = tempfile.mkstemp(suffix=".txt", text=True)
        os.close(fd)
        with open(name, "w") as file:
            file.write(text)
        with open(name, "br") as file:
            save_err = save_bluesheet(request, session, file)
        if save_err:
            return err(400, save_err)
    else:
        return err(405, "Method not allowed")

    return HttpResponse("Done", status=200, content_type='text/plain')


def important_dates(request, num=None, output_format=None):
    assert num is None or num.isdigit()
    preview_roles = ['Area Director', 'Secretariat', 'IETF Chair', 'IAD', ]

    meeting = get_ietf_meeting(num)
    if not meeting:
        raise Http404
    base_num = int(meeting.number)

    user = request.user
    today = datetime.date.today()
    meetings = []
    if meeting.show_important_dates or meeting.date < today:
        meetings.append(meeting)
    for i in range(1,3):
        future_meeting = get_ietf_meeting(base_num+i)
        if future_meeting and ( future_meeting.show_important_dates
            or (user and user.is_authenticated and has_role(user, preview_roles))):
            meetings.append(future_meeting)

    if output_format == 'ics':
        preprocess_meeting_important_dates(meetings)

        ics = render_to_string('meeting/important_dates.ics', {
            'meetings': meetings,
        }, request=request)
        # icalendar response file should have '\r\n' line endings per RFC5545
        response = HttpResponse(re.sub("\r(?!\n)|(?<!\r)\n", "\r\n", ics), content_type='text/calendar')
        response['Content-Disposition'] = 'attachment; filename="important-dates.ics"'
        return response

    return render(request, 'meeting/important-dates.html', {
        'meetings': meetings
    })

TimeSlotTypeForm = modelform_factory(TimeSlot, fields=('type',))

@role_required('Secretariat')
def edit_timeslot_type(request, num, slot_id):
    timeslot = get_object_or_404(TimeSlot,id=slot_id)
    meeting = get_object_or_404(Meeting,number=num)
    if timeslot.meeting!=meeting:
        raise Http404()
    if request.method=='POST':
        form = TimeSlotTypeForm(instance=timeslot,data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('ietf.meeting.views.edit_timeslots',kwargs={'num':num}))

    else:
        form = TimeSlotTypeForm(instance=timeslot)
        
    sessions = timeslot.sessions.filter(timeslotassignments__schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None])

    return render(request, 'meeting/edit_timeslot_type.html', {'timeslot':timeslot,'form':form,'sessions':sessions})


@role_required('Secretariat')
def request_minutes(request, num=None):
    meeting = get_ietf_meeting(num)
    if request.method=='POST':
        form = RequestMinutesForm(data=request.POST)
        if form.is_valid():
            send_mail_text(request,
                           to=form.cleaned_data.get('to'),
                           frm=request.user.person.email_address(),
                           subject=form.cleaned_data.get('subject'),
                           txt=form.cleaned_data.get('body'),
                           cc=form.cleaned_data.get('cc'),
                          )
            return HttpResponseRedirect(reverse('ietf.meeting.views.materials',kwargs={'num':num}))
    else:
        needs_minutes = set()
        session_qs = add_event_info_to_session_qs(
            Session.objects.filter(
                timeslotassignments__schedule__meeting=meeting,
                timeslotassignments__schedule__meeting__schedule=F('timeslotassignments__schedule'),
                group__type__in=['wg','rg','ag','rag','program'],
            )
        ).filter(~Q(current_status='canceled')).select_related('group', 'group__parent')
        for session in session_qs:
            if not session.all_meeting_minutes():
                group = session.group
                if group.parent and group.parent.type_id in ('area','irtf'):
                    needs_minutes.add(group)
        needs_minutes = list(needs_minutes)
        needs_minutes.sort(key=lambda g: ('zzz' if g.parent.acronym == 'irtf' else g.parent.acronym)+":"+g.acronym)
        body_context = {'meeting':meeting, 
                        'needs_minutes':needs_minutes,
                        'settings':settings,
                       }
        body = render_to_string('meeting/request_minutes.txt', body_context)
        initial = {'to': 'wgchairs@ietf.org',
                   'cc': 'irsg@irtf.org',
                   'subject': 'Request for IETF WG and Bof Session Minutes',
                   'body': body,
                  }
        form = RequestMinutesForm(initial=initial)
    context = {'meeting':meeting, 'form': form}
    return render(request, 'meeting/request_minutes.html', context)

class ApproveSlidesForm(forms.Form):
    title = forms.CharField(max_length=255)
    apply_to_all = forms.BooleanField(label='Apply to all group sessions at this meeting',initial=False,required=False)

    def __init__(self, show_apply_to_all_checkbox, *args, **kwargs):
        super(ApproveSlidesForm, self).__init__(*args, **kwargs )
        if not show_apply_to_all_checkbox:
            self.fields.pop('apply_to_all')
            
@login_required
def approve_proposed_slides(request, slidesubmission_id, num):
    submission = get_object_or_404(SlideSubmission,pk=slidesubmission_id)
    if not submission.session.can_manage_materials(request.user):
        permission_denied(request, "You don't have permission to manage slides for this session.")
    if submission.session.is_material_submission_cutoff() and not has_role(request.user, "Secretariat"):
        permission_denied(request, "The materials cutoff for this session has passed. Contact the secretariat for further action.")   
    
    session_number = None
    sessions = get_sessions(submission.session.meeting.number,submission.session.group.acronym)
    show_apply_to_all_checkbox = len(sessions) > 1 if submission.session.type_id == 'regular' else False
    if len(sessions) > 1:
       session_number = 1 + sessions.index(submission.session)
    name, _ = os.path.splitext(submission.filename)
    name = name[:name.rfind('-ss')]
    existing_doc = Document.objects.filter(name=name).first()
    if request.method == 'POST' and submission.status.slug == 'pending':
        form = ApproveSlidesForm(show_apply_to_all_checkbox, request.POST)
        if form.is_valid():
            apply_to_all = submission.session.type_id == 'regular'
            if show_apply_to_all_checkbox:
                apply_to_all = form.cleaned_data['apply_to_all']
            if request.POST.get('approve'):
                # Ensure that we have a file to approve.  The system gets cranky otherwise.
                if submission.filename is None or submission.filename == '' or not os.path.isfile(submission.staged_filepath()):
                    return HttpResponseNotFound("The slides you attempted to approve could not be found.  Please disapprove and delete them instead.")
                title = form.cleaned_data['title']
                if existing_doc:
                   doc = Document.objects.get(name=name)
                   doc.rev = '%02d' % (int(doc.rev)+1)
                   doc.title = form.cleaned_data['title']
                else:
                    doc = Document.objects.create(
                              name = name,
                              type_id = 'slides',
                              title = title,
                              group = submission.session.group,
                              rev = '00',
                          )
                    DocAlias.objects.create(name=doc.name).docs.add(doc)
                doc.states.add(State.objects.get(type_id='slides',slug='active'))
                doc.states.add(State.objects.get(type_id='reuse_policy',slug='single'))
                if submission.session.sessionpresentation_set.filter(document=doc).exists():
                    sp = submission.session.sessionpresentation_set.get(document=doc)
                    sp.rev = doc.rev
                    sp.save()
                else:
                    max_order = submission.session.sessionpresentation_set.filter(document__type='slides').aggregate(Max('order'))['order__max'] or 0
                    submission.session.sessionpresentation_set.create(document=doc,rev=doc.rev,order=max_order+1)
                if apply_to_all:
                    for other_session in sessions:
                        if other_session != submission.session and not other_session.sessionpresentation_set.filter(document=doc).exists():
                            max_order = other_session.sessionpresentation_set.filter(document__type='slides').aggregate(Max('order'))['order__max'] or 0
                            other_session.sessionpresentation_set.create(document=doc,rev=doc.rev,order=max_order+1)
                sub_name, sub_ext = os.path.splitext(submission.filename)
                target_filename = '%s-%s%s' % (sub_name[:sub_name.rfind('-ss')],doc.rev,sub_ext)
                doc.uploaded_filename = target_filename
                e = NewRevisionDocEvent.objects.create(doc=doc,by=submission.submitter,type='new_revision',desc='New revision available: %s'%doc.rev,rev=doc.rev)
                doc.save_with_history([e])
                path = os.path.join(submission.session.meeting.get_materials_path(),'slides')
                if not os.path.exists(path):
                    os.makedirs(path)
                os.rename(submission.staged_filepath(), os.path.join(path, target_filename))
                post_process(doc)
                acronym = submission.session.group.acronym
                submission.status = SlideSubmissionStatusName.objects.get(slug='approved')
                submission.doc = doc
                submission.save()
                return redirect('ietf.meeting.views.session_details',num=num,acronym=acronym)
            elif request.POST.get('disapprove'):
                # Errors in processing a submit request sometimes result
                # in a SlideSubmission object without a file.  Handle
                # this case and keep processing the 'disapprove' even if
                # the filename doesn't exist.
                try:
                    if submission.filename != None and submission.filename != '':
                        os.unlink(submission.staged_filepath())
                except (FileNotFoundError, IsADirectoryError):
                    pass
                acronym = submission.session.group.acronym
                submission.status = SlideSubmissionStatusName.objects.get(slug='rejected')
                submission.save()
                return redirect('ietf.meeting.views.session_details',num=num,acronym=acronym)
            else:
                pass
    elif not submission.status.slug == 'pending':
        return render(request, "meeting/previously_approved_slides.html",
                      {'submission': submission })
    else:
        initial = {
            'title': submission.title,
            'apply_to_all' : submission.apply_to_all,
        }
        form = ApproveSlidesForm(show_apply_to_all_checkbox, initial=initial )

    return render(request, "meeting/approve_proposed_slides.html", 
                  {'submission': submission,
                   'session_number': session_number,
                   'existing_doc' : existing_doc,
                   'form': form,
                  })