# -*- coding: utf-8 -*-

import urllib

from uuid import uuid4
from hashlib import md5

from django.db import models
from django.conf import settings
from django.utils import timezone
from django.core.cache import cache
from django.contrib.auth import get_user_model
from django.core.urlresolvers import reverse, NoReverseMatch
from django.utils.translation import ugettext_lazy as _

from html2text import html2text
from haystack.query import SearchQuerySet
from taggit.managers import TaggableManager
from hitcounter.models import HitCounterModelMixin

from .managers import NotSpamManager, MostVotedManager, HighestScore
from .utils import blocks
from .utils.etiquetador import etiquetador


User = get_user_model()


class EmailAddressValidation(models.Model):
    address = models.EmailField(unique=True)
    user = models.ForeignKey(User, null=True,
                             related_name='emails_not_validated')
    validation_key = models.CharField(max_length=32, null=True,
                                      default=lambda: uuid4().hex)
    created = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ('user', 'address')


class EmailAddress(models.Model):
    user = models.ForeignKey(User, null=True, related_name='emails',
                             on_delete=models.SET_NULL)
    address = models.EmailField(unique=True)
    real_name = models.CharField(max_length=64, blank=True, db_index=True)
    md5 = models.CharField(max_length=32, null=True)

    class Meta:
        ordering = ('id', )

    def save(self, *args, **kwargs):
        self.md5 = md5(self.address).hexdigest()
        super(EmailAddress, self).save(*args, **kwargs)

    def get_full_name(self):
        if self.user and self.user.get_full_name():
            return self.user.get_full_name()
        else:
            return self.real_name

    def get_full_name_or_anonymous(self):
        return self.get_full_name() or _('Anonymous')

    def __unicode__(self):
        return '"%s" <%s>' % (self.get_full_name(), self.address)


class MailingList(models.Model):
    name = models.CharField(max_length=80)
    email = models.EmailField()
    description = models.TextField()
    logo = models.FileField(upload_to='list_logo') #TODO
    last_imported_index = models.IntegerField(default=0)

    def get_absolute_url(self):
        params = {
            'list': self.name,
            'type': 'thread',
            'order': 'latest',
        }
        return u'{}?{}'.format(reverse('haystack_search'),
                               urllib.urlencode(params))

    def __unicode__(self):
        return self.name


class MailingListMembership(models.Model):
    user = models.ForeignKey(User)
    mailinglist = models.ForeignKey(MailingList)

    def __unicode__(self):
        return '%s on %s' % (self.user.email, self.mailinglist.name)


class Keyword(models.Model):
    keyword = models.CharField(max_length='128')
    weight = models.IntegerField(default=0)
    thread = models.ForeignKey('Thread')

    class Meta:
        ordering = ('?', ) # random order

    def __unicode__(self):
        return self.keyword


class Thread(models.Model, HitCounterModelMixin):

    subject_token = models.CharField(max_length=512)
    mailinglist = models.ForeignKey(MailingList,
                                    verbose_name=_(u"Mailing List"),
                                    help_text=_(u"The Mailing List where is the thread"))
    latest_message = models.OneToOneField('Message', null=True,
                                                     related_name='+',
                                                     verbose_name=_(u"Latest message"),
                                                     help_text=_(u"Latest message posted"))
    score = models.IntegerField(default=0, verbose_name=_(u"Score"), help_text=_(u"Thread score"))
    spam = models.BooleanField(default=False)

    highest_score = HighestScore()
    all_objects = models.Manager()
    objects = NotSpamManager()
    tags = TaggableManager()

    class Meta:
        verbose_name = _(u"Thread")
        verbose_name_plural = _(u"Threads")
        unique_together = ('subject_token', 'mailinglist')
        ordering = ('-latest_message__received_time', )

    @models.permalink
    def get_absolute_url(self):
        return ('thread_view', [self.mailinglist, self.subject_token])

    def update_keywords(self):
        blocks = MessageBlock.objects.filter(message__thread__pk=self.pk,
                                             is_reply=False)

        self.tags.clear()

        text = u'\n'.join(map(unicode, blocks))
        tags = etiquetador(html2text(text))

        for tag, weight in tags:
            keyword, created = Keyword.objects.get_or_create(thread=self,
                                                             keyword=tag)
            if created or keyword.weight != weight:
                keyword.weight = weight
                keyword.save()

            if weight >= 3:
                self.tags.add(tag)

        # removing old tags not used anylonger
        if tags:
            qs = Keyword.objects.filter(thread=self)
            qs = qs.exclude(keyword__in=zip(*tags)[0])
            qs.delete()

    def get_related(self):
        query_string = u' '.join(self.tags.names())
        if query_string:
            query_set = SearchQuerySet().exclude(django_id=self.pk)
            return query_set.filter(content=query_string, type='thread')

        return tuple()

    def __unicode__(self):
        return '%s - %s (%s)' % (self.id,
                                 self.subject_token,
                                 self.message_set.count())

    def update_score(self):
        """Update the relevance score for this thread.

        The score is calculated with the following variables:

        * vote_weight: 100 - (minus) 1 for each 3 days since
          voted with minimum of 5.
        * replies_weight: 300 - (minus) 1 for each 3 days since
          replied with minimum of 5.
        * page_view_weight: 10.

        * vote_score: sum(vote_weight)
        * replies_score: sum(replies_weight)
        * page_view_score: sum(page_view_weight)

        * score = (vote_score + replies_score + page_view_score) // 10
        with minimum of 0 and maximum of 5000

        """

        if not self.subject_token:
            return

        # Save this pseudo now to avoid calling the
        #   function N times in the loops below
        now = timezone.now()
        days_ago = lambda date: (now - date).days
        get_score = lambda weight, created: \
                                  max(weight - (days_ago(created) // 3), 5)

        vote_score = 0
        replies_score = 0
        for msg in self.message_set.all():
            # Calculate replies_score
            replies_score += get_score(300, msg.received_time)

            # Calculate vote_score
            for vote in msg.vote_set.all():
                vote_score += get_score(100, vote.created)

        # Calculate page_view_score
        page_view_score = self.hits * 10

        self.score = (page_view_score + vote_score + replies_score) // 10
        self.save()


class Vote(models.Model):
    user = models.ForeignKey(User)
    message = models.ForeignKey('Message')
    created = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ('user', 'message')

    def __unicode__(self):
        return 'Vote on %s by %s' % (self.Message.id,
                                     self.user.username)


class Message(models.Model):

    from_address = models.ForeignKey(EmailAddress, db_index=True)
    thread = models.ForeignKey(Thread, null=True, db_index=True)
    # RFC 2822 recommends to use 78 chars + CRLF (so 80 chars) for
    #   the max_length of a subject but most of implementations
    #   goes for 256. We use 512 just in case.
    subject = models.CharField(max_length=512, db_index=True,
                               verbose_name=_(u"Subject"),
                               help_text=_(u"Please enter a message subject"))
    subject_clean = models.CharField(max_length=512, db_index=True)
    body = models.TextField(default='',
                            verbose_name=_(u"Message body"),
                            help_text=_(u"Please enter a message body"))
    received_time = models.DateTimeField(db_index=True)
    message_id = models.CharField(max_length=512)
    spam = models.BooleanField(default=False)

    all_objects = models.Manager()
    objects = NotSpamManager()
    most_voted = MostVotedManager()

    class Meta:
        verbose_name = _(u"Message")
        verbose_name_plural = _(u"Messages")
        unique_together = ('thread', 'message_id')
        ordering = ('received_time', )

    def __unicode__(self):
        return '(%s) %s: %s' % (self.id,
                                self.from_address.get_full_name(),
                                self.subject_clean)

    def update_blocks(self):
        # delete all blocks for that message
        self.blocks.all().delete()

        for i, block in enumerate(blocks.EmailBlockParser(self)):
            MessageBlock.from_emailblock(block, self, i)

    @property
    def mailinglist(self):
        if not self.thread:
            return None

        return self.thread.mailinglist

    def vote_list(self):
        """Return a list of user that voted in this message."""
        return [vote.user for vote in self.vote_set.iterator()]

    def votes_count(self):
        return len(self.vote_list())

    def vote(self, user):
        Vote.objects.create(
            message=self,
            user=user
        )

    def unvote(self, user):
        Vote.objects.get(
            message=self,
            user=user
        ).delete()

    @property
    def url(self):
        """Shortcut to get thread url"""
        return reverse('thread_view', args=[self.mailinglist.name,
                                            self.thread.subject_token])

    @property
    def description(self):
        """Alias to self.body"""
        return self.body

    @property
    def title(self):
        """Alias to self.subject_clean"""
        return self.subject_clean

    @property
    def modified(self):
        """Alias to self.modified"""
        return self.received_time

    @property
    def tag(self):
        if not self.thread:
            return None
        return self.mailinglist.name

    @property
    def author(self):
        return self.fullname

    @property
    def author_url(self):
        if self.from_address.user_id:
            return self.from_address.user.get_absolute_url()
        return None

    # An alias for author
    @property
    def modified_by(self):
        return self.author

    # An alias for author_url
    @property
    def modified_by_url(self):
        return self.author_url

    @property
    def fullname(self):
        return self.from_address.get_full_name()

    @property
    def icon_name(self):
        return u'envelope'

    @property
    def type(self):
        return u'thread'


class MessageBlock(models.Model):
    message = models.ForeignKey(Message, related_name='blocks')
    text = models.TextField()
    is_reply = models.BooleanField()
    order = models.IntegerField()

    def __unicode__(self):
        return self.text

    class Meta:
        ordering = ('order', )

    @classmethod
    def from_emailblock(klass, emailblock, message, order):
        obj = klass.objects.create(text=emailblock.text,
                                   is_reply=emailblock.is_reply,
                                   message=message,
                                   order=order)
        return obj



class MessageMetadata(models.Model):
    Message = models.ForeignKey(Message)
    # Same problem here than on subjects. Read comment above
    #   on Message.subject
    name = models.CharField(max_length=512)
    value = models.TextField()

    def __unicode__(self):
        return 'Email Message Id: %s - %s: %s' % (self.Message.id,
                                                  self.name, self.value)