import os
import re
import urllib
import math

from django.conf import settings

from ietf.utils import markup_txt
from ietf.doc.models import DocAlias, RelatedDocument, BallotType, DocReminder
from ietf.doc.models import DocEvent, BallotDocEvent, NewRevisionDocEvent, StateDocEvent
from ietf.name.models import DocReminderTypeName, DocRelationshipName
from ietf.group.models import Role
from ietf.ietfauth.utils import has_role
from ietf.person.models import Person
from ietf.utils import draft

def get_state_types(doc):
    res = []

    if not doc:
        return res
    
    res.append(doc.type_id)

    if doc.type_id == "draft":
        if doc.stream_id and doc.stream_id != "legacy":
            res.append("draft-stream-%s" % doc.stream_id)

        res.append("draft-iesg")
        res.append("draft-iana-review")
        res.append("draft-iana-action")
        res.append("draft-rfceditor")
        
    return res

def get_tags_for_stream_id(stream_id):
    if stream_id == "ietf":
        return ["w-expert", "w-extern", "w-merge", "need-aut", "w-refdoc", "w-refing", "rev-wg", "rev-wglc", "rev-ad", "rev-iesg", "sheph-u", "no-adopt", "other"]
    elif stream_id == "iab":
        return ["need-ed", "w-part", "w-review", "need-rev", "sh-f-up"]
    elif stream_id == "irtf":
        return ["need-ed", "need-sh", "w-dep", "need-rev", "iesg-com"]
    elif stream_id == "ise":
        return ["w-dep", "w-review", "need-rev", "iesg-com"]
    else:
        return []

def can_adopt_draft(user, doc):
    if not user.is_authenticated():
        return False

    if has_role(user, "Secretariat"):
        return True

    return (doc.stream_id in (None, "ietf", "irtf")
            and doc.group.type_id == "individ"
            and Role.objects.filter(name__in=("chair", "delegate", "secr"),
                                    group__type__in=("wg", "rg"),
                                    group__state="active",
                                    person__user=user).exists())

def needed_ballot_positions(doc, active_positions):
    '''Returns text answering the question "what does this document
    need to pass?".  The return value is only useful if the document
    is currently in IESG evaluation.'''
    yes = [p for p in active_positions if p and p.pos_id == "yes"]
    noobj = [p for p in active_positions if p and p.pos_id == "noobj"]
    blocking = [p for p in active_positions if p and p.pos.blocking]
    recuse = [p for p in active_positions if p and p.pos_id == "recuse"]

    answer = []
    if len(yes) < 1:
        answer.append("Needs a YES.")
    if blocking:
        if len(blocking) == 1:
            answer.append("Has a %s." % blocking[0].pos.name.upper())
        else:
            if blocking[0].pos.name.upper().endswith('S'):
                answer.append("Has %d %ses." % (len(blocking), blocking[0].pos.name.upper()))
            else:
                answer.append("Has %d %ss." % (len(blocking), blocking[0].pos.name.upper()))
    needed = 1
    if doc.type_id == "draft" and doc.intended_std_level_id in ("bcp", "ps", "ds", "std"):
        # For standards-track, need positions from 2/3 of the
        # non-recused current IESG.
        active = len(Person.objects.filter(role__name="ad", 
            role__group__state="active").distinct())
        needed = int(math.ceil((active - len(recuse)) * 2.0/3.0))
    else:
        if len(yes) < 1:
            return " ".join(answer)

    have = len(yes) + len(noobj)
    if have < needed:
        more = needed - have
        if more == 1:
            answer.append("Needs one more YES or NO OBJECTION position to pass.")
        else:
            answer.append("Needs %d more YES or NO OBJECTION positions to pass." % more)
    else:
        if blocking:
            answer.append("Has enough positions to pass once %s positions are resolved." % blocking[0].pos.name.upper())
        else:
            answer.append("Has enough positions to pass.")

    return " ".join(answer)
    
def create_ballot_if_not_open(doc, by, ballot_slug):
    if not doc.ballot_open(ballot_slug):
        e = BallotDocEvent(type="created_ballot", by=by, doc=doc)
        e.ballot_type = BallotType.objects.get(doc_type=doc.type, slug=ballot_slug)
        e.desc = u'Created "%s" ballot' % e.ballot_type.name
        e.save()

def close_ballot(doc, by, ballot_slug):
    if doc.ballot_open(ballot_slug):
        e = BallotDocEvent(type="closed_ballot", doc=doc, by=by)
        e.ballot_type = BallotType.objects.get(doc_type=doc.type,slug=ballot_slug)
        e.desc = 'Closed "%s" ballot' % e.ballot_type.name
        e.save()

def close_open_ballots(doc, by):
    for t in BallotType.objects.filter(doc_type=doc.type_id):
        close_ballot(doc, by, t.slug )

def augment_with_start_time(docs):
    """Add a started_time attribute to each document with the time of
    the first revision."""
    docs = list(docs)

    docs_dict = {}
    for d in docs:
        docs_dict[d.pk] = d
        d.start_time = None

    seen = set()

    for e in DocEvent.objects.filter(type="new_revision", doc__in=docs).order_by('time'):
        if e.doc_id in seen:
            continue

        docs_dict[e.doc_id].start_time = e.time
        seen.add(e.doc_id)

    return docs

def get_chartering_type(doc):
    chartering = ""
    if doc.get_state_slug() not in ("notrev", "approved"):
        if doc.group.state_id in ("proposed", "bof"):
            chartering = "initial"
        elif doc.group.state_id == "active":
            chartering = "rechartering"

    return chartering

def augment_events_with_revision(doc, events):
    """Take a set of events for doc and add a .rev attribute with the
    revision they refer to by checking NewRevisionDocEvents."""

    event_revisions = list(NewRevisionDocEvent.objects.filter(doc=doc).order_by('time', 'id').values('id', 'rev', 'time'))

    if doc.type_id == "draft" and doc.get_state_slug() == "rfc":
        # add fake "RFC" revision
        e = doc.latest_event(type="published_rfc")
        if e:
            event_revisions.append(dict(id=e.id, time=e.time, rev="RFC"))
            event_revisions.sort(key=lambda x: (x["time"], x["id"]))

    for e in sorted(events, key=lambda e: (e.time, e.id), reverse=True):
        while event_revisions and (e.time, e.id) < (event_revisions[-1]["time"], event_revisions[-1]["id"]):
            event_revisions.pop()

        if event_revisions:
            cur_rev = event_revisions[-1]["rev"]
        else:
            cur_rev = "00"

        e.rev = cur_rev

def add_links_in_new_revision_events(doc, events, diff_revisions):
    """Add direct .txt links and diff links to new_revision events."""
    prev = None

    diff_urls = dict(((name, revision), url) for name, revision, time, url in diff_revisions)

    for e in sorted(events, key=lambda e: (e.time, e.id)):
        if not e.type == "new_revision":
            continue

        if not (e.doc.name, e.rev) in diff_urls:
            continue

        full_url = diff_url = diff_urls[(e.doc.name, e.rev)]

        if doc.type_id in "draft": # work around special diff url for drafts
            full_url = "http://tools.ietf.org/id/" + diff_url + ".txt"

        # build links
        links = r'<a href="%s">\1</a>' % full_url
        if prev:
            links += ""

        if prev != None:
            links += ' (<a href="http:%s?url1=%s&url2=%s">diff from previous</a>)' % (settings.RFCDIFF_PREFIX, urllib.quote(prev, safe="~"), urllib.quote(diff_url, safe="~"))

        # replace the bold filename part
        e.desc = re.sub(r"<b>(.+-[0-9][0-9].txt)</b>", links, e.desc)

        prev = diff_url


def get_document_content(key, filename, split=True, markup=True):
    f = None
    try:
        f = open(filename, 'rb')
        raw_content = f.read()
    except IOError:
        error = "Error; cannot read ("+key+")"
        return error
    finally:
        if f:
            f.close()
    if markup:
        return markup_txt.markup(raw_content, split)
    else:
        return raw_content

def add_state_change_event(doc, by, prev_state, new_state, prev_tags=[], new_tags=[], timestamp=None):
    """Add doc event to explain that state change just happened."""
    if prev_state and new_state:
        assert prev_state.type_id == new_state.type_id

    if prev_state == new_state and set(prev_tags) == set(new_tags):
        return None

    def tags_suffix(tags):
        return (u"::" + u"::".join(t.name for t in tags)) if tags else u""

    e = StateDocEvent(doc=doc, by=by)
    e.type = "changed_state"
    e.state_type = (prev_state or new_state).type
    e.state = new_state
    e.desc = "%s changed to <b>%s</b>" % (e.state_type.label, new_state.name + tags_suffix(new_tags))
    if prev_state:
        e.desc += " from %s" % (prev_state.name + tags_suffix(prev_tags))
    if timestamp:
        e.time = timestamp
    e.save()
    return e

def update_reminder(doc, reminder_type_slug, event, due_date):
    reminder_type = DocReminderTypeName.objects.get(slug=reminder_type_slug)

    try:
        reminder = DocReminder.objects.get(event__doc=doc, type=reminder_type, active=True)
    except DocReminder.DoesNotExist:
        reminder = None

    if due_date:
        # activate/update reminder
        if not reminder:
            reminder = DocReminder(type=reminder_type)

        reminder.event = event
        reminder.due = due_date
        reminder.active = True
        reminder.save()
    else:
        # deactivate reminder
        if reminder:
            reminder.active = False
            reminder.save()

def prettify_std_name(n):
    if re.match(r"(rfc|bcp|fyi|std)[0-9]+", n):
        return n[:3].upper() + " " + n[3:]
    else:
        return n

def nice_consensus(consensus):
    mapping = {
        None: "Unknown",
        True: "Yes",
        False: "No"
        }
    return mapping[consensus]

def update_telechat(request, doc, by, new_telechat_date, new_returning_item=None):
    from ietf.doc.models import TelechatDocEvent
    
    on_agenda = bool(new_telechat_date)

    prev = doc.latest_event(TelechatDocEvent, type="scheduled_for_telechat")
    prev_returning = bool(prev and prev.returning_item)
    prev_telechat = prev.telechat_date if prev else None
    prev_agenda = bool(prev_telechat)
    
    returning_item_changed = bool(new_returning_item != None and new_returning_item != prev_returning)

    if new_returning_item == None:
        returning = prev_returning
    else:
        returning = new_returning_item

    if returning == prev_returning and new_telechat_date == prev_telechat:
        # fully updated, nothing to do
        return

    # auto-update returning item
    if (not returning_item_changed and on_agenda and prev_agenda
        and new_telechat_date != prev_telechat):
        returning = True

    e = TelechatDocEvent()
    e.type = "scheduled_for_telechat"
    e.by = by
    e.doc = doc
    e.returning_item = returning
    e.telechat_date = new_telechat_date
    
    if on_agenda != prev_agenda:
        if on_agenda:
            e.desc = "Placed on agenda for telechat - %s" % (new_telechat_date)
        else:
            e.desc = "Removed from agenda for telechat"
    elif on_agenda and new_telechat_date != prev_telechat:
        e.desc = "Telechat date has been changed to <b>%s</b> from <b>%s</b>" % (
            new_telechat_date, prev_telechat)
    else:
        # we didn't reschedule but flipped returning item bit - let's
        # just explain that
        if returning:
            e.desc = "Set telechat returning item indication"
        else:
            e.desc = "Removed telechat returning item indication"

    e.save()

def rebuild_reference_relations(doc):
    if doc.type.slug != 'draft':
        return None

    if doc.get_state_slug() == 'rfc':
        filename=os.path.join(settings.RFC_PATH,doc.canonical_name()+".txt")
    else:
        filename=os.path.join(settings.INTERNET_DRAFT_PATH,doc.filename_with_rev())

    try:
       refs = draft.Draft(draft._gettext(filename), filename).get_refs()
    except IOError as e:
       return { 'errors': ["%s :%s" %  (e.strerror, filename)] }
    
    doc.relateddocument_set.filter(relationship__slug__in=['refnorm','refinfo','refold','refunk']).delete()

    warnings = []
    errors = []
    unfound = set()
    for ( ref, refType ) in refs.iteritems():
        refdoc = DocAlias.objects.filter( name=ref )
        count = refdoc.count()
        if count == 0:
            unfound.add( "%s" % ref )
            continue
        elif count > 1:
            errors.append("Too many DocAlias objects found for %s"%ref)
        else:
            # Don't add references to ourself
            if doc != refdoc[0].document:
                RelatedDocument.objects.get_or_create( source=doc, target=refdoc[ 0 ], relationship=DocRelationshipName.objects.get( slug='ref%s' % refType ) )
    if unfound:
        warnings.append('There were %d references with no matching DocAlias'%len(unfound))

    ret = {}
    if errors:
        ret['errors']=errors 
    if warnings:
        ret['warnings']=warnings 
    if unfound:
        ret['unfound']=list(unfound) 

    return ret