from django.contrib.auth import get_user_model
from django.db import models
from django.urls import reverse
from itertools import groupby
from slugify import slugify
from textwrap import shorten

from meta.models import ModelMeta
from users.models import Profile

from . import kinds
ENTRY_KINDS = [(k.id, k.id) for k in kinds.all]


class EntryManager(models.Manager):
    def get_queryset(self):
        qs = super(EntryManager, self).get_queryset()
        return qs.select_related('author').prefetch_related('syndications')


class Entry(ModelMeta, models.Model):
    objects = EntryManager()
    kind = models.CharField(
        max_length=30,
        choices=ENTRY_KINDS,
        db_index=True,
        default=ENTRY_KINDS[0][0]
    )

    name = models.CharField(max_length=100, blank=True)
    photo = models.ImageField(blank=True)
    content = models.TextField()

    author = models.ForeignKey(
        get_user_model(),
        related_name='entries',
        on_delete=models.CASCADE,
    )

    published = models.DateTimeField()
    updated = models.DateTimeField()

    _metadata = {
        'description': 'excerpt',
        'image': 'image_url',
        'twitter_creator': 'twitter_creator',
        'og_profile_id': 'og_profile_id',
    }

    @property
    def title(self):
        if self.name:
            return self.name
        return shorten(self.paragraphs[0], width=100, placeholder='…')

    @property
    def excerpt(self):
        try:
            return self.paragraphs[0 if self.name else 1]
        except IndexError:
            return ' '

    @property
    def paragraphs(self):
        lines = self.content.splitlines()
        return [
            "\n".join(para) for k, para in groupby(lines, key=bool) if k
        ]

    @property
    def twitter_creator(self):
        return self.author.twitter_username

    @property
    def og_profile_id(self):
        return self.author.facebook_id

    @property
    def image_url(self):
        return self.photo.url if self.photo else self.author.avatar_url

    def __str__(self):
        return '{0} {1}: {2}'.format(self.kind, self.id, self.title)

    def get_absolute_url(self):
        return self.url

    @property
    def url(self):
        kind = kinds.from_id[self.kind]
        args = [self.id]
        if kind.slug:
            args.append(self.slug)
        return reverse('entries:' + kind.entry, args=args)

    @property
    def slug(self):
        return slugify(self.name)

    class Meta:
        verbose_name_plural = 'entries'
        ordering = ['-published']


class SyndicationManager(models.Manager):
    def get_queryset(self):
        qs = super(SyndicationManager, self).get_queryset()
        return qs.select_related('profile__site')


class Syndication(models.Model):
    objects = SyndicationManager()
    entry = models.ForeignKey(
        Entry,
        related_name='syndications',
        on_delete=models.CASCADE
    )
    profile = models.ForeignKey(Profile, on_delete=models.CASCADE)
    url = models.CharField(max_length=255)

    class Meta:
        ordering = ['profile']