from bindery.merge import merge_chapter_lists


def urls(*numbers):
    return [f"c{n}" for n in numbers]


def test_stubbed_chapters_stay_and_new_chapter_goes_last():
    existing = urls(*range(1, 61))
    site = urls(1, 2, 3, 4, *range(46, 62))
    assert merge_chapter_lists(existing, site) == urls(*range(1, 62))


def test_new_chapter_goes_after_its_site_predecessor():
    assert merge_chapter_lists(urls(1, 2, 3), ["c1", "c2", "x", "c3"]) == ["c1", "c2", "x", "c3"]


def test_new_chapter_after_a_gap_goes_before_removed_chapters():
    # The author replaced 2-3 with a new chapter x.
    assert merge_chapter_lists(urls(1, 2, 3, 4), ["c1", "x", "c4"]) == ["c1", "x", "c2", "c3", "c4"]


def test_new_chapter_before_everything_goes_first():
    assert merge_chapter_lists(urls(1, 2), ["p", "c1", "c2"]) == ["p", "c1", "c2"]


def test_failed_chapter_later_lands_in_order():
    # c61 failed last time, c62 was added. The next run adds c61 before c62.
    assert merge_chapter_lists(urls(59, 60, 62), urls(59, 60, 61, 62)) == urls(59, 60, 61, 62)


def test_existing_order_wins_and_duplicates_are_dropped():
    # The site moved b before a. Our order stays, and c is newer than every chapter we have.
    assert merge_chapter_lists(["a", "b", "b"], ["b", "a", "a", "c"]) == ["a", "b", "c"]


def test_new_chapter_after_a_stubbed_tail_goes_last():
    # The site kept 1-5, removed 6-10 and added 11 and 12.
    assert merge_chapter_lists(urls(*range(1, 11)), urls(1, 2, 3, 4, 5, 11, 12)) == urls(*range(1, 13))


def test_new_chapters_after_every_old_chapter_is_gone_go_last():
    assert merge_chapter_lists(urls(1, 2, 3), urls(7, 8)) == urls(1, 2, 3, 7, 8)


def test_empty_lists():
    assert merge_chapter_lists([], urls(1, 2)) == urls(1, 2)
    assert merge_chapter_lists(urls(1), []) == urls(1)


def test_older_copy_fills_the_gap_before_newer_chapters():
    existing = urls(*range(1, 6), *range(50, 61))
    epub = urls(*range(1, 46))
    assert merge_chapter_lists(existing, epub, newest_last=False) == urls(*range(1, 46), *range(50, 61))
    assert merge_chapter_lists(urls(1, 2), urls(1, 2, 3), newest_last=False) == urls(1, 2, 3)