# Copyright The IETF Trust 2007, All Rights Reserved

import datetime
import pytz
import os
import re
from tempfile import mkstemp

from django.http import HttpRequest, Http404
from django.db.models import Max, Q, Prefetch, F
from django.conf import settings
from django.core.cache import cache
from django.utils.cache import get_cache_key
from django.shortcuts import get_object_or_404

import debug                            # pyflakes:ignore

from ietf.doc.models import Document
from ietf.group.models import Group
from ietf.ietfauth.utils import has_role, user_is_person
from ietf.person.models  import Person
from ietf.meeting.models import Meeting
from ietf.utils.history import find_history_active_at, find_history_replacements_active_at
from ietf.utils.pipe import pipe

def find_ads_for_meeting(meeting):
    ads = []
    meeting_time = datetime.datetime.combine(meeting.date, datetime.time(0, 0, 0))

    num = 0
    # get list of ADs which are/were active at the time of the meeting.
    #  (previous [x for x in y] syntax changed to aid debugging)
    for g in Group.objects.filter(type="area").order_by("acronym"):
        history = find_history_active_at(g, meeting_time)
        num = num +1
        if history and history != g:
            #print " history[%u]: %s" % (num, history)
            if history.state_id == "active":
                for x in history.rolehistory_set.filter(name="ad",group__type='area').select_related('group', 'person', 'email'):
                    #print "xh[%u]: %s" % (num, x)
                    ads.append(x)
        else:
            #print " group[%u]: %s" % (num, g)
            if g.state_id == "active":
                for x in g.role_set.filter(name="ad",group__type='area').select_related('group', 'person', 'email'):
                    #print "xg[%u]: %s (#%u)" % (num, x, x.pk)
                    ads.append(x)
    return ads


# get list of all areas, + IRTF + IETF (plenaries).
def get_pseudo_areas():
    return Group.objects.filter(Q(state="active", name="IRTF")|
                                Q(state="active", name="IETF")|
                                Q(state="active", type="area")).order_by('acronym')

# get list of all areas, + IRTF.
def get_areas():
    return Group.objects.filter(Q(state="active",
                                  name="IRTF")|
                                Q(state="active", type="area")).order_by('acronym')

# get list of areas that are referenced.
def get_area_list_from_sessions(assignments, num):
    return assignments.filter(timeslot__type = 'Session',
                                    session__group__parent__isnull = False).order_by(
        'session__group__parent__acronym').distinct().values_list(
        'session__group__parent__acronym',flat=True)

def build_all_agenda_slices(meeting):
    time_slices = []
    date_slices = {}

    for ts in meeting.timeslot_set.filter(type__in=['session',]).order_by('time','name'):
            ymd = ts.time.date()

            if ymd not in date_slices and ts.location != None:
                date_slices[ymd] = []
                time_slices.append(ymd)

            if ymd in date_slices:
                if [ts.time, ts.time+ts.duration] not in date_slices[ymd]:   # only keep unique entries
                    date_slices[ymd].append([ts.time, ts.time+ts.duration])

    time_slices.sort()
    return time_slices,date_slices

def get_all_assignments_from_schedule(schedule):
   ss = schedule.assignments.filter(timeslot__location__isnull = False)
   ss = ss.filter(session__type__slug='session')
   ss = ss.order_by('timeslot__time','timeslot__name')

   return ss

def get_modified_from_assignments(assignments):
    return assignments.aggregate(Max('timeslot__modified'))['timeslot__modified__max']

def get_wg_name_list(assignments):
    return assignments.filter(timeslot__type = 'Session',
                                    session__group__isnull = False,
                                    session__group__parent__isnull = False).order_by(
        'session__group__acronym').distinct().values_list(
        'session__group__acronym',flat=True)

def get_wg_list(assignments):
    wg_name_list = get_wg_name_list(assignments)
    return Group.objects.filter(acronym__in = set(wg_name_list)).order_by('parent__acronym','acronym')


def get_meetings(num=None):
    if num == None:
        meetings = Meeting.objects.filter(type="ietf").order_by("-date")
    else:
        meetings = Meeting.objects.filter(type="ietf", number=num)
    return meetings

def get_meeting(num=None):
    meetings = get_meetings(num)
    if meetings.exists():
        return meetings.first()
    else:
        raise Http404("No such meeting found: %s" % num)

def get_schedule(meeting, name=None):
    if name is None:
        schedule = meeting.agenda
    else:
        schedule = get_object_or_404(meeting.schedule_set, name=name)
    return schedule

def get_schedule_by_id(meeting, schedid):
    if schedid is None:
        schedule = meeting.agenda
    else:
        schedule = get_object_or_404(meeting.schedule_set, id=int(schedid))
    return schedule

# seems this belongs in ietf/person/utils.py?
def get_person_by_email(email):
    # email == None may actually match people who haven't set an email!
    if email is None:
        return None
    return Person.objects.filter(email__address=email).distinct().first()

def get_schedule_by_name(meeting, owner, name):
    if owner is not None:
        return meeting.schedule_set.filter(owner = owner, name = name).first()
    else:
        return meeting.schedule_set.filter(name = name).first()

def meeting_updated(meeting):
    meeting_time = datetime.datetime(*(meeting.date.timetuple()[:7]))
    ts = max(meeting.timeslot_set.aggregate(Max('modified'))["modified__max"] or meeting_time,
             meeting.session_set.aggregate(Max('modified'))["modified__max"] or meeting_time)
    tz = pytz.timezone(settings.PRODUCTION_TIMEZONE)
    ts = tz.localize(ts)
    return ts

def preprocess_assignments_for_agenda(assignments_queryset, meeting):
    # prefetch some stuff to prevent a myriad of small, inefficient queries
    assignments_queryset = assignments_queryset.select_related(
        "timeslot", "timeslot__location", "timeslot__type",
        "session",
        "session__group", "session__group__charter", "session__group__charter__group",
    ).prefetch_related(
        Prefetch("session__materials",
                 queryset=Document.objects.exclude(states__type=F("type"),states__slug='deleted').select_related("group").order_by("order"),
                 to_attr="prefetched_active_materials",
             ),
        "timeslot__meeting",
    )

    assignments = list(assignments_queryset) # make sure we're set in stone

    meeting_time = datetime.datetime.combine(meeting.date, datetime.time())

    # replace groups with historic counterparts
    for a in assignments:
        if a.session:
            a.session.historic_group = None

    groups = [a.session.group for a in assignments if a.session and a.session.group]
    group_replacements = find_history_replacements_active_at(groups, meeting_time)

    for a in assignments:
        if a.session and a.session.group:
            a.session.historic_group = group_replacements.get(a.session.group_id)

    # replace group parents with historic counterparts
    for a in assignments:
        if a.session and a.session.historic_group:
            a.session.historic_group.historic_parent = None

    parents = Group.objects.filter(pk__in=set(a.session.historic_group.parent_id for a in assignments if a.session and a.session.historic_group and a.session.historic_group.parent_id))
    parent_replacements = find_history_replacements_active_at(parents, meeting_time)

    for a in assignments:
        if a.session and a.session.historic_group and a.session.historic_group.parent_id:
            a.session.historic_group.historic_parent = parent_replacements.get(a.session.historic_group.parent_id)

    return assignments

def read_agenda_file(num, doc):
    # XXXX FIXME: the path fragment in the code below should be moved to
    # settings.py.  The *_PATH settings should be generalized to format()
    # style python format, something like this:
    #  DOC_PATH_FORMAT = { "agenda": "/foo/bar/agenda-{meeting.number}/agenda-{meeting-number}-{doc.group}*", }
    path = os.path.join(settings.AGENDA_PATH, "%s/agenda/%s" % (num, doc.external_url))
    if os.path.exists(path):
        with open(path) as f:
            return f.read()
    else:
        return None

def convert_draft_to_pdf(doc_name):
    inpath = os.path.join(settings.IDSUBMIT_REPOSITORY_PATH, doc_name + ".txt")
    outpath = os.path.join(settings.INTERNET_DRAFT_PDF_PATH, doc_name + ".pdf")

    try:
        infile = open(inpath, "r")
    except IOError:
        return

    t,tempname = mkstemp()
    os.close(t)
    tempfile = open(tempname, "w")

    pageend = 0;
    newpage = 0;
    formfeed = 0;
    for line in infile:
        line = re.sub("\r","",line)
        line = re.sub("[ \t]+$","",line)
        if re.search("\[?[Pp]age [0-9ivx]+\]?[ \t]*$",line):
            pageend=1
            tempfile.write(line)
            continue
        if re.search("^[ \t]*\f",line):
            formfeed=1
            tempfile.write(line)
            continue
        if re.search("^ *INTERNET.DRAFT.+[0-9]+ *$",line) or re.search("^ *Internet.Draft.+[0-9]+ *$",line) or re.search("^draft-[-a-z0-9_.]+.*[0-9][0-9][0-9][0-9]$",line) or re.search("^RFC.+[0-9]+$",line):
            newpage=1
        if re.search("^[ \t]*$",line) and pageend and not newpage:
            continue
        if pageend and newpage and not formfeed:
            tempfile.write("\f")
        pageend=0
        formfeed=0
        newpage=0
        tempfile.write(line)

    infile.close()
    tempfile.close()
    t,psname = mkstemp()
    os.close(t)
    pipe("enscript --margins 76::76: -B -q -p "+psname + " " +tempname)
    os.unlink(tempname)
    pipe("ps2pdf "+psname+" "+outpath)
    os.unlink(psname)

def agenda_permissions(meeting, schedule, user):
    # do this in positive logic.
    cansee = False
    canedit = False
    secretariat = False

    if has_role(user, 'Secretariat'):
        cansee = True
        secretariat = True
        # NOTE: secretariat is not superuser for edit!
    elif schedule.public:
        cansee = True
    elif schedule.visible and has_role(user, ['Area Director', 'IAB Chair', 'IRTF Chair']):
        cansee = True

    if user_is_person(user, schedule.owner):
        cansee = True
        canedit = True

    return cansee, canedit, secretariat

def session_constraint_expire(request,session):
    from django.core.urlresolvers import reverse
    from ajax import session_constraints
    path = reverse(session_constraints, args=[session.meeting.number, session.pk])
    temp_request = HttpRequest()
    temp_request.path = path
    temp_request.META['HTTP_HOST'] = request.META['HTTP_HOST']
    key = get_cache_key(temp_request)
    if key is not None and cache.has_key(key):
        cache.delete(key)