from django.contrib.postgres.fields import JSONField
from django.core.urlresolvers import reverse
from django.db import models
from django.dispatch import receiver
from django.utils import timezone

from misago.conf import settings

from misago.threads import threadtypes
from misago.threads.checksums import update_post_checksum, is_post_valid


class Post(models.Model):
    category = models.ForeignKey('misago_categories.Category')
    thread = models.ForeignKey('misago_threads.Thread')
    poster = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
    )
    poster_name = models.CharField(max_length=255)
    poster_ip = models.GenericIPAddressField()
    original = models.TextField()
    parsed = models.TextField()
    checksum = models.CharField(max_length=64, default='-')
    mentions = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name="mention_set")

    has_attachments = models.BooleanField(default=False)
    attachments_cache = JSONField(null=True, blank=True)

    posted_on = models.DateTimeField()
    updated_on = models.DateTimeField()

    edits = models.PositiveIntegerField(default=0)
    last_editor = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
        related_name='+',
    )
    last_editor_name = models.CharField(max_length=255, null=True, blank=True)
    last_editor_slug = models.SlugField(max_length=255, null=True, blank=True)

    hidden_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
        related_name='+',
    )
    hidden_by_name = models.CharField(max_length=255, null=True, blank=True)
    hidden_by_slug = models.SlugField(max_length=255, null=True, blank=True)
    hidden_on = models.DateTimeField(default=timezone.now)

    has_reports = models.BooleanField(default=False)
    has_open_reports = models.BooleanField(default=False)
    is_unapproved = models.BooleanField(default=False, db_index=True)
    is_hidden = models.BooleanField(default=False)
    is_protected = models.BooleanField(default=False)

    is_event = models.BooleanField(default=False)
    event_type = models.CharField(max_length=255, null=True, blank=True)
    event_context = JSONField(null=True, blank=True)

    def __unicode__(self):
        return '%s...' % self.original[10:].strip()

    def delete(self, *args, **kwargs):
        from misago.threads.signals import delete_post
        delete_post.send(sender=self)

        super(Post, self).delete(*args, **kwargs)

    def merge(self, other_post):
        if self.thread_id != other_post.thread_id:
            message = "only posts belonging to same thread can be merged"
            raise ValueError(message)

        message = "posts made by different authors can't be merged"
        if self.poster_id and other_post.poster_id:
            if self.poster_id != other_post.poster_id:
                raise ValueError(message)
        else:
            raise ValueError(message)

        if self.pk == other_post.pk:
            raise ValueError("post can't be merged with itself")

        other_post.original = '%s\n\n%s' % (other_post.original, self.original)
        other_post.parsed = '%s\n%s' % (other_post.parsed, self.parsed)
        update_post_checksum(other_post)

        from misago.threads.signals import merge_post
        merge_post.send(sender=self, other_thread=other_post)

    def move(self, new_thread):
        from misago.threads.signals import move_post

        self.category = new_thread.category
        self.thread = new_thread
        move_post.send(sender=self)

    @property
    def thread_type(self):
        return self.category.thread_type

    def get_absolute_url(self):
        return self.thread_type.get_post_absolute_url(self)

    @property
    def short(self):
        if self.is_valid:
            if len(self.original) > 150:
                return '%s...' % self.original[:150].strip()
            else:
                return self.original
        else:
            return ''

    @property
    def is_valid(self):
        return is_post_valid(self)