"""
30. Object pagination

Django provides a framework for paginating a list of objects in a few lines
of code. This is often useful for dividing search results or long lists of
objects into easily readable pages.
"""

from django.db import models

class Article(models.Model):
    headline = models.CharField(maxlength=100, default='Default headline')
    pub_date = models.DateTimeField()

    def __str__(self):
        return self.headline

__test__ = {'API_TESTS':"""
# prepare a list of objects for pagination
>>> from datetime import datetime
>>> for x in range(1, 10):
...     a = Article(headline='Article %s' % x, pub_date=datetime(2005, 7, 29))
...     a.save()

# create a basic paginator, 5 articles per page
>>> from django.core.paginator import ObjectPaginator, InvalidPage
>>> paginator = ObjectPaginator(Article.objects.all(), 5)

# the paginator knows how many hits and pages it contains
>>> paginator.hits
9

>>> paginator.pages
2

# get the first page (zero-based)
>>> paginator.get_page(0)
[<Article: Article 1>, <Article: Article 2>, <Article: Article 3>, <Article: Article 4>, <Article: Article 5>]

# get the second page
>>> paginator.get_page(1)
[<Article: Article 6>, <Article: Article 7>, <Article: Article 8>, <Article: Article 9>]

# does the first page have a next or previous page?
>>> paginator.has_next_page(0)
True

>>> paginator.has_previous_page(0)
False

# check the second page
>>> paginator.has_next_page(1)
False

>>> paginator.has_previous_page(1)
True

>>> paginator.first_on_page(0)
1
>>> paginator.first_on_page(1)
6
>>> paginator.last_on_page(0)
5
>>> paginator.last_on_page(1)
9

# Add a few more records to test out the orphans feature.
>>> for x in range(10, 13):
...     Article(headline="Article %s" % x, pub_date=datetime(2006, 10, 6)).save()

# With orphans set to 3 and 10 items per page, we should get all 12 items on a single page:
>>> paginator = ObjectPaginator(Article.objects.all(), 10, orphans=3)
>>> paginator.pages
1

# With orphans only set to 1, we should get two pages:
>>> paginator = ObjectPaginator(Article.objects.all(), 10, orphans=1)
>>> paginator.pages
2
"""}