import os
import uuid

from django.core.urlresolvers import reverse
from django.db import models
from django.db.models import Q
from django.utils.translation import ugettext_lazy as _
from django.utils.timezone import now

from django.contrib.auth.models import User
from django.core.exceptions import ObjectDoesNotExist
from django.core.exceptions import ValidationError

import reversion

from markitup.fields import MarkupField

from model_utils.managers import InheritanceManager

from symposion.conference.models import Section
from symposion.speakers.models import Speaker


class ProposalSection(models.Model):
    """
    configuration of proposal submissions for a specific Section.

    a section is available for proposals iff:
      * it is after start (if there is one) and
      * it is before end (if there is one) and
      * closed is NULL or False
    """

    section = models.OneToOneField(Section)

    start = models.DateTimeField(null=True, blank=True)
    end = models.DateTimeField(null=True, blank=True)
    closed = models.NullBooleanField()
    published = models.NullBooleanField()

    @classmethod
    def available(cls):
        return cls._default_manager.filter(
            Q(start__lt=now()) | Q(start=None),
            Q(end__gt=now()) | Q(end=None),
            Q(closed=False) | Q(closed=None),
        )

    def is_available(self):
        if self.closed:
            return False
        if self.start and self.start > now():
            return False
        if self.end and self.end < now():
            return False
        return True

    def __unicode__(self):
        return self.section.name


class ProposalKind(models.Model):
    """
    e.g. talk vs panel vs tutorial vs poster

    Note that if you have different deadlines, reviewers, etc. you'll want
    to distinguish the section as well as the kind.
    """

    section = models.ForeignKey(Section, related_name="proposal_kinds")

    name = models.CharField(_("Name"), max_length=100)
    slug = models.SlugField()

    def __unicode__(self):
        return self.name


class ProposalBase(models.Model):

    objects = InheritanceManager()

    kind = models.ForeignKey(ProposalKind)

    title = models.CharField(max_length=100)
    description = models.TextField(
        _("Brief Description"),
        max_length=400,  # @@@ need to enforce 400 in UI
        help_text=_("If your proposal is accepted this will be made public and printed in the "
                    "program. Should be one paragraph, maximum 400 characters.")
    )
    abstract = MarkupField(
        _("Detailed Abstract"),
        help_text=_("Detailed outline. Will be made public if your proposal is accepted. Edit "
                    "using <a href='http://daringfireball.net/projects/markdown/basics' "
                    "target='_blank'>Markdown</a>.")
    )
    additional_notes = MarkupField(
        blank=True,
        help_text=_("Anything else you'd like the program committee to know when making their "
                    "selection: your past experience, etc. This is not made public. Edit using "
                    "<a href='http://daringfireball.net/projects/markdown/basics' "
                    "target='_blank'>Markdown</a>.")
    )
    submitted = models.DateTimeField(
        default=now,
        editable=False,
    )
    speaker = models.ForeignKey(Speaker, related_name="proposals")

    def additional_speaker_validator(self, a_speaker):
        if a_speaker.speaker.email == self.speaker.email:
            raise ValidationError(_("%s is same as primary speaker.") % a_speaker.speaker.email)
        if a_speaker in [self.additional_speakers]:
            raise ValidationError(_("%s has already been in speakers.") % a_speaker.speaker.email)

    additional_speakers = models.ManyToManyField(Speaker, through="AdditionalSpeaker",
                                                 blank=True, validators=[additional_speaker_validator])
    cancelled = models.BooleanField(default=False)

    def can_edit(self):
        return True

    @property
    def section(self):
        return self.kind.section

    @property
    def speaker_email(self):
        return self.speaker.email

    @property
    def number(self):
        return str(self.pk).zfill(3)

    @property
    def status(self):
        try:
            return self.result.status
        except ObjectDoesNotExist:
            return _('Undecided')

    def speakers(self):
        yield self.speaker
        speakers = self.additional_speakers.exclude(
            additionalspeaker__status=AdditionalSpeaker.SPEAKING_STATUS_DECLINED)
        for speaker in speakers:
            yield speaker

    def notification_email_context(self):
        return {
            "title": self.title,
            "speaker": self.speaker.name,
            "speakers": ', '.join([x.name for x in self.speakers()]),
            "kind": self.kind.name,
        }

reversion.register(ProposalBase)


class AdditionalSpeaker(models.Model):

    SPEAKING_STATUS_PENDING = 1
    SPEAKING_STATUS_ACCEPTED = 2
    SPEAKING_STATUS_DECLINED = 3

    SPEAKING_STATUS = [
        (SPEAKING_STATUS_PENDING, _("Pending")),
        (SPEAKING_STATUS_ACCEPTED, _("Accepted")),
        (SPEAKING_STATUS_DECLINED, _("Declined")),
    ]

    speaker = models.ForeignKey(Speaker)
    proposalbase = models.ForeignKey(ProposalBase)
    status = models.IntegerField(choices=SPEAKING_STATUS, default=SPEAKING_STATUS_PENDING)

    class Meta:
        unique_together = ("speaker", "proposalbase")

    def __unicode__(self):
        if self.status is self.SPEAKING_STATUS_PENDING:
            return _(u"pending speaker (%s)") % self.speaker.email
        elif self.status is self.SPEAKING_STATUS_DECLINED:
            return _(u"declined speaker (%s)") % self.speaker.email
        else:
            return self.speaker.name


def uuid_filename(instance, filename):
    ext = filename.split(".")[-1]
    filename = "%s.%s" % (uuid.uuid4(), ext)
    return os.path.join("document", filename)


class SupportingDocument(models.Model):

    proposal = models.ForeignKey(ProposalBase, related_name="supporting_documents")

    uploaded_by = models.ForeignKey(User)

    created_at = models.DateTimeField(default=now)

    file = models.FileField(upload_to=uuid_filename)
    description = models.CharField(max_length=140)

    def download_url(self):
        return reverse("proposal_document_download",
                       args=[self.pk, os.path.basename(self.file.name).lower()])