from __future__ import annotations

from app.change_detection.structured_diff import diff_item_sets


def test_diff_item_sets_detects_additions_and_removals():
    previous = ["https://x.com/a", "https://x.com/b"]
    current = ["https://x.com/b", "https://x.com/c"]
    diff = diff_item_sets(previous, current)
    assert diff.added == ["https://x.com/c"]
    assert diff.removed == ["https://x.com/a"]
    assert diff.has_changes is True


def test_diff_item_sets_no_change_when_identical():
    items = ["https://x.com/a", "https://x.com/b"]
    diff = diff_item_sets(items, list(items))
    assert diff.added == []
    assert diff.removed == []
    assert diff.has_changes is False


def test_diff_item_sets_handles_empty_previous():
    diff = diff_item_sets([], ["https://x.com/a"])
    assert diff.added == ["https://x.com/a"]
    assert diff.removed == []