import datetime

from django.db import models
from django.contrib.auth.models import User
from taggit.managers import TaggableManager


class PostManager(models.Manager):
    def get_visible(self):
        return self.get_query_set().filter(publish_at__lte=datetime.datetime.now(), active=True)


class TimeStampedActivate(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    modified = models.DateTimeField(auto_now=True)
    active = models.BooleanField(
        default=False,
        help_text="Controls whether or not this item is live."
        )

    class Meta:
        abstract = True
class Blog(TimeStampedActivate):
    """
        A blog belonging to a user.
        Blogs have multiple posts and one use can have multiple blogs.

        ### TESTS

        >>> b = Blog()
        >>> b.name = "Foo Blog"
        >>> b.user = User.objects.create(username='foo', password='test')
        >>> b.slug = 'foo-blog'
        >>> b.save()
        >>> print b
        Foo Blog
        >>> print b.user.username
        foo
        >>> print b.slug
        foo-blog
    """
    name = models.CharField(
        max_length=255,
        help_text="Name of your blog. Upto 255 characters"
        )
    slug = models.SlugField()
    description = models.TextField(
        blank=True,
        help_text="Describe your blog."
        )
    user = models.ForeignKey(User, related_name='blog')

    def __unicode__(self):
        return self.name

class Post(TimeStampedActivate):
    """
    A post that belongs to a blog

    ### TESTS

    >>> b = Blog.objects.get(id=1)
    >>> p = Post()
    >>> p.title = "A test post"
    >>> p.blog = b
    >>> p.body = "This here is the body."
    >>> p.slug = 'a-test-post'
    >>> p.save()
    >>> print p.blog.name
    Foo Blog
    >>> print p.active
    False

    """

    title = models.CharField(
        max_length=255,
        help_text="Title of the post, upto 255 characters long."
        )

    slug = models.SlugField()
    excerpt = models.TextField(
        blank=True,
        help_text="A small teaser of your content."
        )

    body = models.TextField(
        blank=False,
        help_text="The main content of your post."
        )
    publish_at = models.DateTimeField(
        default=datetime.datetime.now(),
        help_text="Date and time post should become visible."
        )
    tags = TaggableManager()

    blog = models.ForeignKey(Blog, related_name="posts")
    objects = PostManager()

    def __unicode__(self):
        return self.title


    class Meta:
        ordering = ['-publish_at', '-modified', '-created']