from __future__ import unicode_literals

import copy

from django.contrib.postgres.indexes import GinIndex
from django.contrib.postgres.fields import JSONField
from django.contrib.postgres.search import SearchVector, SearchVectorField
from django.db import models
from django.utils import six, timezone
from django.utils.encoding import python_2_unicode_compatible

from misago.conf import settings
from misago.core.pgutils import PgPartialIndex
from misago.core.utils import parse_iso8601_string
from misago.markup import finalise_markup
from misago.threads.checksums import is_post_valid, update_post_checksum
from misago.threads.filtersearch import filter_search


@python_2_unicode_compatible
class Post(models.Model):
    category = models.ForeignKey(
        'misago_categories.Category',
        on_delete=models.CASCADE,
    )
    thread = models.ForeignKey(
        'misago_threads.Thread',
        on_delete=models.CASCADE,
    )
    poster = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
    )
    poster_name = models.CharField(max_length=255)
    original = models.TextField()
    parsed = models.TextField()
    checksum = models.CharField(max_length=64, default='-')
    mentions = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name="mention_set")

    attachments_cache = JSONField(null=True, blank=True)

    posted_on = models.DateTimeField(db_index=True)
    updated_on = models.DateTimeField()
    hidden_on = models.DateTimeField(default=timezone.now)

    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)

    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, db_index=True)
    event_type = models.CharField(max_length=255, null=True, blank=True)
    event_context = JSONField(null=True, blank=True)

    likes = models.PositiveIntegerField(default=0)
    last_likes = JSONField(null=True, blank=True)

    liked_by = models.ManyToManyField(
        settings.AUTH_USER_MODEL,
        related_name='liked_post_set',
        through='misago_threads.PostLike',
    )

    search_document = models.TextField(null=True, blank=True)
    search_vector = SearchVectorField()

    class Meta:
        indexes = [
            PgPartialIndex(
                fields=['has_open_reports'],
                where={'has_open_reports': True},
            ),
            PgPartialIndex(
                fields=['is_hidden'],
                where={'is_hidden': False},
            ),
            PgPartialIndex(
                fields=['is_event', 'event_type'],
                where={'is_event': True},
            ),
            GinIndex(fields=['search_vector']),
        ]

        index_together = [
            ('thread', 'id'),  # speed up threadview for team members
            ('is_event', 'is_hidden'),
            ('poster', 'posted_on'),
        ]

    def __str__(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.poster_id != other_post.poster_id:
            raise ValueError("post can't be merged with other user's post")
        elif (self.poster_id is None and other_post.poster_id is None and
                self.poster_name != other_post.poster_name):
            raise ValueError("post can't be merged with other user's post")

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

        if self.is_event or other_post.is_event:
            raise ValueError("can't merge events")

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

        other_post.original = six.text_type('\n\n').join((other_post.original, self.original))
        other_post.parsed = six.text_type('\n').join((other_post.parsed, self.parsed))
        update_post_checksum(other_post)

        if self.is_protected:
            other_post.is_protected = True
        if self.is_best_answer:
            self.thread.best_answer = other_post
        if other_post.is_best_answer:
            self.thread.best_answer_is_protected = other_post.is_protected

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

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

        if self.is_best_answer:
            self.thread.clear_best_answer()

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

    @property
    def attachments(self):
        if hasattr(self, '_hydrated_attachments_cache'):
            return self._hydrated_attachments_cache

        self._hydrated_attachments_cache = []
        if self.attachments_cache:
            for attachment in copy.deepcopy(self.attachments_cache):
                attachment['uploaded_on'] = parse_iso8601_string(attachment['uploaded_on'])
                self._hydrated_attachments_cache.append(attachment)

        return self._hydrated_attachments_cache

    @property
    def content(self):
        if not hasattr(self, '_finalised_parsed'):
            self._finalised_parsed = finalise_markup(self.parsed)
        return self._finalised_parsed

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

    def get_api_url(self):
        return self.thread_type.get_post_api_url(self)

    def get_likes_api_url(self):
        return self.thread_type.get_post_likes_api_url(self)

    def get_editor_api_url(self):
        return self.thread_type.get_post_editor_api_url(self)

    def get_edits_api_url(self):
        return self.thread_type.get_post_edits_api_url(self)

    def get_read_api_url(self):
        return self.thread_type.get_post_read_api_url(self)

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

    def set_search_document(self, thread_title=None):
        if thread_title:
            self.search_document = filter_search('\n\n'.join([thread_title, self.original]))
        else:
            self.search_document = filter_search(self.original)

    def update_search_vector(self):
        self.search_vector = SearchVector(
            'search_document',
            config=settings.MISAGO_SEARCH_CONFIG,
        )

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

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

    @property
    def is_first_post(self):
        return self.id == self.thread.first_post_id

    @property
    def is_best_answer(self):
        return self.id == self.thread.best_answer_id