# Copyright The IETF Trust 2007, All Rights Reserved

import datetime
import os
import re
import tarfile
import urllib
from tempfile import mkstemp
from collections import OrderedDict
import csv
import json

import debug                            # pyflakes:ignore

from django import forms
from django.shortcuts import render, redirect
from django.http import HttpResponse, HttpResponseRedirect, HttpResponseForbidden, Http404
from django.contrib import messages
from django.core.urlresolvers import reverse
from django.db.models import Min, Max
from django.conf import settings
from django.forms.models import modelform_factory
from django.forms import ModelForm
from django.views.decorators.csrf import ensure_csrf_cookie

from ietf.doc.models import Document, State
from ietf.group.models import Group
from ietf.ietfauth.utils import role_required, has_role
from ietf.meeting.models import Meeting, Session, Schedule, Room
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_schedule, agenda_permissions, meeting_updated, get_meetings
from ietf.meeting.helpers import preprocess_assignments_for_agenda, read_agenda_file
from ietf.meeting.helpers import convert_draft_to_pdf
from ietf.utils.pipe import pipe
from ietf.utils.pdf import pdf_pages

def materials(request, meeting_num=None):
    meeting = get_meeting(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()
    if settings.SERVER_MODE != 'production' and '_testoverride' in request.REQUEST:
        pass
    elif now > cor_cut_off_date:
        return render(request, "meeting/materials_upload_closed.html", {
            'meeting_num': meeting_num,
            'begin_date': begin_date,
            'cut_off_date': cut_off_date,
            'cor_cut_off_date': cor_cut_off_date
        })

    #sessions  = Session.objects.filter(meeting__number=meeting_num, timeslot__isnull=False)
    schedule = get_schedule(meeting, None)
    sessions  = Session.objects.filter(meeting__number=meeting_num, timeslotassignments__schedule=schedule).select_related()
    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'])
    iab       = sessions.filter(group__parent__acronym = 'iab')

    cache_version = Document.objects.filter(session__meeting__number=meeting_num).aggregate(Max('time'))["time__max"]
    return render(request, "meeting/materials.html", {
        'meeting_num': meeting_num,
        'plenaries': plenaries, 'ietf': ietf, 'training': training, 'irtf': irtf, 'iab': iab,
        'cut_off_date': cut_off_date,
        'cor_cut_off_date': cor_cut_off_date,
        'submission_started': now > begin_date,
        'cache_version': cache_version,
    })

def current_materials(request):
    meetings = Meeting.objects.exclude(number__startswith='interim-').order_by('-number')
    if meetings:
        return redirect(materials, meetings[0].number)
    else:
        raise Http404

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 agenda_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))
        return redirect(edit_agenda, 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_agenda, 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_agenda, 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_agenda, meeting.number, sched.name)
        else:
            messages.info(request, "Agenda creation failed. Please try again.")
            return redirect(edit_agenda, num=num, owner=owner, name=name)

    except Schedule.DoesNotExist:
        pass

    # must be done
    newschedule = Schedule(name=savedname,
                           owner=request.user.person,
                           meeting=meeting,
                           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_agenda, meeting.number, newschedule.owner_email(), newschedule.name)


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

    meeting = get_meeting(num)
    timeslots = meeting.timeslot_set.exclude(location=None).select_related("location", "type")

    time_slices,date_slices,slots = meeting.build_timeslices()

    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.order_by("capacity")

    # this import locate here to break cyclic loop.
    from ietf.meeting.ajax import timeslot_roomsurl, AddRoomForm, timeslot_slotsurl, AddSlotForm
    roomsurl  = reverse(timeslot_roomsurl, args=[meeting.number])
    adddayurl = reverse(timeslot_slotsurl, args=[meeting.number])

    return render(request, "meeting/timeslot_edit.html",
                                         {"timeslots": timeslots,
                                          "meeting_base_url": meeting_base_url,
                                          "site_base_url": site_base_url,
                                          "rooms":rooms,
                                          "addroom":  AddRoomForm(),
                                          "roomsurl": roomsurl,
                                          "addday":   AddSlotForm(),
                                          "adddayurl":adddayurl,
                                          "time_slices":time_slices,
                                          "slot_slices": slots,
                                          "date_slices":date_slices,
                                          "meeting":meeting,
                                          "hide_menu": True,
                                      })

class RoomForm(ModelForm):
    class Meta:
        model = Room
        exclude = ('meeting',)

@role_required('Secretariat')
def edit_roomurl(request, num, roomid):
    meeting = get_meeting(num)

    try:
        room = meeting.room_set.get(pk=roomid)
    except Room.DoesNotExist:
        raise Http404("No room %u for meeting %s" % (roomid, meeting.name))

    if request.POST:
        roomform = RoomForm(request.POST, instance=room)
        new_room = roomform.save(commit=False)
        new_room.meeting = meeting
        new_room.save()
        roomform.save_m2m()
        return HttpResponseRedirect( reverse(edit_timeslots, args=[meeting.number]) )

    roomform = RoomForm(instance=room)
    meeting_base_url = request.build_absolute_uri(meeting.base_url())
    site_base_url = request.build_absolute_uri('/')[:-1] # skip the trailing slash
    return render(request, "meeting/room_edit.html",
                                         {"meeting_base_url": meeting_base_url,
                                          "site_base_url": site_base_url,
                                          "editroom":  roomform,
                                          "meeting":meeting,
                                          "hide_menu": True,
                                      })

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

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

    user     = request.user
    meeting  = get_meeting(num)
    person   = get_person_by_email(owner)
    if name is None:
        schedule = meeting.agenda
    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='session').distinct().order_by("capacity")
    saveas = SaveAsForm()
    saveasurl=reverse(edit_agenda,
                      args=[meeting.number, schedule.owner_email(), schedule.name])

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

    if not can_see:
        return render(request, "meeting/private_agenda.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,
                                      })

##############################################################################
#  show the properties associated with an agenda (visible, public)
#    this page uses ajax POST requests to the API
#
AgendaPropertiesForm = modelform_factory(Schedule, fields=('name','visible', 'public'))

@role_required('Area Director','Secretariat')
@ensure_csrf_cookie
def edit_agenda_properties(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:
        raise Http404("No meeting information for meeting %s owner %s schedule %s available" % (num, owner, name))
    form     = AgendaPropertiesForm(instance=schedule)

    cansee, canedit, secretariat = agenda_permissions(meeting, schedule, request.user)

    if not (canedit or has_role(request.user,'Secretariat')):
        return HttpResponseForbidden("You may not edit this agenda")
    else:
        return render(request, "meeting/properties_edit.html",
                                             {"schedule":schedule,
                                              "form":form,
                                              "meeting":meeting,
                                              "hide_menu": True,
                                          })

##############################################################################
# show list of agendas.
#

@role_required('Area Director','Secretariat')
@ensure_csrf_cookie
def edit_agendas(request, num=None, order=None):

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

    meeting = get_meeting(num)
    user = request.user

    schedules = meeting.schedule_set
    if not has_role(user, 'Secretariat'):
        schedules = schedules.filter(visible = True) | schedules.filter(owner = user.person)

    schedules = schedules.order_by('owner', 'name')

    return render(request, "meeting/agenda_list.html",
                                         {"meeting":   meeting,
                                          "schedules": schedules.all(),
                                          "hide_menu": True,
                                          })

@ensure_csrf_cookie
def agenda(request, num=None, name=None, base=None, ext=None):
    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,
    }

    meetings = get_meetings(num)

    # We do not have the appropriate data in the datatracker for IETF 64 and earlier.
    # So that we're not producing misleading pages...
    if not meetings.exists() or not meetings.first().agenda.assignments.exists():
        if ext == '.html':
            return HttpResponseRedirect( 'https://www.ietf.org/proceedings/%s' % num )
        else:
            raise Http404

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

    updated = meeting_updated(meeting)
    filtered_assignments = schedule.assignments.exclude(timeslot__type__in=['lead','offagenda'])
    filtered_assignments = preprocess_assignments_for_agenda(filtered_assignments, meeting)

    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', 'iab')
              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)

    return render(request, "meeting/"+base+ext, {
        "schedule": schedule,
        "filtered_assignments": filtered_assignments,
        "updated": updated,
        "group_parents": group_parents,
    }, content_type=mimetype[ext])

def agenda_csv(schedule, filtered_assignments):
    response = HttpResponse(content_type="text/csv; charset=%s"%settings.DEFAULT_CHARSET)
    writer = csv.writer(response, delimiter=',', 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, unicode) 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.external_url}".format(schedule=schedule, agenda=agenda_doc)
        else:
            return ""

    def slides_field(item):
        return "|".join("http://www.ietf.org/proceedings/{schedule.meeting.number}/slides/{slide.external_url}".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 == "session":
            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):
    meeting = get_meeting(num) 
    schedule = get_schedule(meeting)
    ss_by_day = OrderedDict()
    for day in schedule.assignments.dates('timeslot__time','day'):
        ss_by_day[day]=[]
    for ss in schedule.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,"ss_by_day":ss_by_day})

@role_required('Area Director','Secretariat','IAB')
def agenda_by_type(request,num=None,type=None):
    meeting = get_meeting(num) 
    schedule = get_schedule(meeting)
    assignments = schedule.assignments.order_by('session__type__slug','timeslot__time')
    if type:
        assignments = assignments.filter(session__type__slug=type)
    return render(request,"meeting/agenda_by_type.html",{"meeting":meeting,"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 = schedule.assignments.order_by('session__type__slug','timeslot__time')
    if type:
        assignments = assignments.filter(session__type__slug=type)
    updated = meeting_updated(meeting)
    return render(request,"meeting/agenda.ics",{"schedule":schedule,"updated":updated,"assignments":assignments},content_type="text/calendar")

def session_agenda(request, num, session):
    d = Document.objects.filter(type="agenda", session__meeting__number=num)
    if session == "plenaryt":
        d = d.filter(session__name__icontains="technical", session__slots__type="plenary")
    elif session == "plenaryw":
        d = d.filter(session__name__icontains="admin", session__slots__type="plenary")
    else:
        d = d.filter(session__group__acronym=session)

    if d:
        agenda = d[0]
        html5_preamble = "<!doctype html><html lang=en><head><meta charset=utf-8><title>%s</title></head><body>"
        html5_postamble = "</body></html>"
        content = read_agenda_file(num, agenda)
        _, ext = os.path.splitext(agenda.external_url)
        ext = ext.lstrip(".").lower()

        if ext == "txt":
            if not content:
                content = "Could not read agenda file '%s'" % agenda.external_url
            return HttpResponse(content, content_type="text/plain; charset=%s"%settings.DEFAULT_CHARSET)
        elif ext == "pdf":
            return HttpResponse(content, content_type="application/pdf")
        else:
            if not content:
                content = "<p>Could not read agenda file '%s'</p>" % agenda.external_url
                agenda = "Error"
            return HttpResponse((html5_preamble % agenda) + content + html5_postamble)

    raise Http404("No agenda for the %s session of IETF %s is available" % (session, num))

def session_draft_list(num, session):
    try:
        agendas = Document.objects.filter(type="agenda",
                                         session__meeting__number=num,
                                         session__group__acronym=session,
                                         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('(draft-[-a-z0-9]*)', content))

    result = []
    for draft in drafts:
        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

    return sorted(result)

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

    response = HttpResponse(content_type='application/octet-stream')
    response['Content-Disposition'] = 'attachment; filename=%s-drafts.tgz'%(session)
    tarstream = tarfile.open('','w:gz',response)
    mfh, mfn = mkstemp()
    os.close(mfh)
    manifest = 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, 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, session):
    drafts = session_draft_list(num, session);
    curr_page = 1
    pmh, pmn = mkstemp()
    os.close(pmh)
    pdfmarks = 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)
    pipe("gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=" + pdfn + " " + pdf_list + " " + pmn)

    pdf = open(pdfn,"r")
    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):
    meeting = get_meeting(num)
    schedule = get_schedule(meeting)

    if not schedule:
        raise Http404

    filtered_assignments = schedule.assignments.exclude(timeslot__type__in=['lead','offagenda'])
    filtered_assignments = preprocess_assignments_for_agenda(filtered_assignments, meeting)
    
    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.strftime("%w"),
            "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
        }

        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_absolute_url()

        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):
    meeting = get_meeting(num)

    rooms = meeting.room_set.order_by('functional_name','name')
    if rooms.count() == 0:
        raise Http404

    assignments = meeting.agenda.assignments.all()
    unavailable = meeting.timeslot_set.filter(type__slug='unavail')
    if (unavailable.count() + assignments.count()) == 0 :
        raise Http404

    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,"unavailable":unavailable,"assignments":assignments,"rooms":rooms,"days":days})

def ical_agenda(request, num=None, name=None, ext=None):
    meeting = get_meeting(num)
    schedule = get_schedule(meeting, name)
    updated = meeting_updated(meeting)

    if schedule is None:
        raise Http404

    q = request.META.get('QUERY_STRING','') or ""
    filter = set(urllib.unquote(q).lower().split(','))
    include = [ i for i in filter if not (i.startswith('-') or i.startswith('~')) ]
    include_types = set(["plenary","other"])
    exclude = []

    # Process the special flags.
    #   "-wgname" will remove a working group from the output.
    #   "~Type" will add that type to the output.
    #   "-~Type" will remove that type from the output
    # Current types are:
    #   Session, Other (default on), Break, Plenary (default on)
    # Non-Working Group "wg names" include:
    #   edu, ietf, tools, iesg, iab

    for item in filter:
        if len(item) > 2 and item[0] == '-' and item[1] == '~':
            include_types -= set([item[2:]])
        elif len(item) > 1 and item[0] == '-':
            exclude.append(item[1:])
        elif len(item) > 1 and item[0] == '~':
            include_types |= set([item[1:]])

    assignments = schedule.assignments.exclude(timeslot__type__in=['lead','offagenda'])
    assignments = preprocess_assignments_for_agenda(assignments, meeting)

    assignments = [a for a in assignments if
                   (a.timeslot.type_id in include_types
                    or (a.session.historic_group and a.session.historic_group.acronym in include)
                    or (a.session.historic_group and a.session.historic_group.historic_parent and a.session.historic_group.historic_parent.acronym in include))
                   and (not a.session.historic_group or a.session.historic_group.acronym not in exclude)]

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

def meeting_requests(request, num=None):
    meeting = get_meeting(num)
    sessions = Session.objects.filter(meeting__number=meeting.number, type__slug='session', group__parent__isnull = False).exclude(requested_by=0).order_by("group__parent__acronym","status__slug","group__acronym")

    groups_not_meeting = Group.objects.filter(state='Active',type__in=['WG','RG','BOF']).exclude(acronym__in = [session.group.acronym for session in sessions]).order_by("parent__acronym","acronym")

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

def session_details(request, num, acronym, date=None, week_day=None, seq=None):
    meeting = get_meeting(num)
    sessions = Session.objects.filter(meeting=meeting,group__acronym=acronym,type__in=['session','plenary','other'])

    if not sessions:
        sessions = Session.objects.filter(meeting=meeting,short=acronym) 

    if date:
        if len(date)==15:
            start = datetime.datetime.strptime(date,"%Y-%m-%d-%H%M")
            sessions = sessions.filter(timeslotassignments__schedule=meeting.agenda,timeslotassignments__timeslot__time=start)
        else:
            start = datetime.datetime.strptime(date,"%Y-%m-%d").date()
            end = start+datetime.timedelta(days=1)
            sessions = sessions.filter(timeslotassignments__schedule=meeting.agenda,timeslotassignments__timeslot__time__range=(start,end))

    if week_day:
        try:
            dow = ['sun','mon','tue','wed','thu','fri','sat'].index(week_day.lower()[:3]) + 1
        except ValueError:
            raise Http404
        sessions = sessions.filter(timeslotassignments__schedule=meeting.agenda,timeslotassignments__timeslot__time__week_day=dow)
        

    def sort_key(session):
        official_sessions = session.timeslotassignments.filter(schedule=session.meeting.agenda)
        if official_sessions:
            return official_sessions.first().timeslot.time
        else:
            return session.requested

    sessions = sorted(sessions,key=sort_key)

    if seq:
        iseq = int(seq) - 1
        if not iseq in range(0,len(sessions)):
            raise Http404
        else:
            sessions= [sessions[iseq]]

    if not sessions:
        raise Http404

    if len(sessions)==1:
        session = sessions[0]
        scheduled_time = "Not yet scheduled"
        ss = session.timeslotassignments.filter(schedule=meeting.agenda).order_by('timeslot__time')
        if ss:
            scheduled_time = ','.join(x.timeslot.time.strftime("%A %b-%d %H%M") for x in ss)
        # TODO FIXME Deleted materials shouldn't be in the sessionpresentation_set
        filtered_sessionpresentation_set = [p for p in session.sessionpresentation_set.all() if p.document.get_state_slug(p.document.type_id)!='deleted']
        return render(request, "meeting/session_details.html",
                      { 'session':sessions[0] ,
                        'meeting' :meeting ,
                        'acronym' :acronym,
                        'time': scheduled_time,
                        'filtered_sessionpresentation_set': filtered_sessionpresentation_set
                      })
    else:
        return render(request, "meeting/session_list.html",
                      { 'sessions':sessions ,
                        'meeting' :meeting ,
                        'acronym' :acronym,
                      })