from django.test import TestCase

from misago.threads.paginator import PostsPaginator


class PostsPaginatorTests(TestCase):
    def test_paginator(self):
        """pages share first and last items with each other"""
        items = [i + 1 for i in range(30)]

        paginator = PostsPaginator(items, 5)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5],
            [5, 6, 7, 8, 9],
            [9, 10, 11, 12, 13],
            [13, 14, 15, 16, 17],
            [17, 18, 19, 20, 21],
            [21, 22, 23, 24, 25],
            [25, 26, 27, 28, 29],
            [29, 30],
        ])

    def test_paginator_orphans(self):
        """paginator handles orphans"""
        items = [i + 1 for i in range(16)]

        paginator = PostsPaginator(items, 8, 6)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5, 6, 7, 8],
            [8, 9, 10, 11, 12, 13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 4, 4)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4],
            [4, 5, 6, 7],
            [7, 8, 9, 10],
            [10, 11, 12, 13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 5, 3)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5],
            [5, 6, 7, 8, 9],
            [9, 10, 11, 12, 13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 6, 2)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5, 6],
            [6, 7, 8, 9, 10, 11],
            [11, 12, 13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 7, 1)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5, 6, 7],
            [7, 8, 9, 10, 11, 12, 13],
            [13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 7, 3)
        self.assertEqual(self.get_paginator_items_list(paginator), [
            [1, 2, 3, 4, 5, 6, 7],
            [7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
        ])

        paginator = PostsPaginator(items, 10, 6)
        self.assertEqual(self.get_paginator_items_list(paginator), [items])

    def test_paginator_overlap(self):
        """test for #732 - assert that page contants don't overlap too much"""
        num_items = 16
        items = [i + 1 for i in range(num_items)]

        per_page = 2
        while per_page < num_items:
            orphans = 0
            while orphans + per_page <= num_items:
                paginator = PostsPaginator(items, per_page, orphans)
                pages = self.get_paginator_items_list(paginator)
                for p, page in enumerate(pages):
                    for c, compared in enumerate(pages):
                        if p == c:
                            continue
                        common_part = set(page) & set(compared)
                        self.assertTrue(
                            len(common_part) < 2, "invalid overlap (page %s and %s): %s" % (
                                p + 1, c + 1, sorted(list(common_part))
                            ))

                orphans += 1
            per_page += 1

    def get_paginator_items_list(self, paginator):
        items_list = []
        for page in paginator.page_range:
            items_list.append(paginator.page(page).object_list)
        return items_list