from common_cents.category_tree import build_category_tree


def _by_name(nodes):
    return {n.name: n for n in nodes}


def test_flat_paths():
    nodes = build_category_tree({"Food": 1000, "Travel": 500})
    by_name = _by_name(nodes)
    assert set(by_name) == {"Food", "Travel"}
    assert by_name["Food"].self_total == 1000
    assert by_name["Food"].total() == 1000


def test_nested_paths_roll_up():
    nodes = build_category_tree(
        {"Food": 1000, "Food:Restaurants": 2000, "Food:Restaurants:Sushi": 500}
    )
    food = _by_name(nodes)["Food"]
    assert food.self_total == 1000
    assert food.total() == 3500
    rest = food.children["Restaurants"]
    assert rest.self_total == 2000
    assert rest.total() == 2500


def test_intermediate_ancestors_have_zero_self_total():
    nodes = build_category_tree({"A:B:C": 100})
    a = _by_name(nodes)["A"]
    assert a.self_total == 0
    assert a.total() == 100
    assert a.children["B"].self_total == 0
    assert a.children["B"].children["C"].self_total == 100


def test_prev_totals_separate_from_current():
    nodes = build_category_tree({"Food": 100}, prev_totals={"Food": 200, "Travel": 50})
    by_name = _by_name(nodes)
    assert by_name["Food"].self_total == 100
    assert by_name["Food"].self_prev_total == 200
    # Travel exists only in prev — appears in tree.
    assert by_name["Travel"].self_total == 0
    assert by_name["Travel"].self_prev_total == 50


def test_extra_paths_create_empty_nodes():
    nodes = build_category_tree({}, extra_paths=["Food:Restaurants"])
    food = _by_name(nodes)["Food"]
    assert food.total() == 0
    assert "Restaurants" in food.children


def test_empty_inputs():
    assert build_category_tree({}) == []
    assert build_category_tree({}, {}) == []


def test_blank_segments_skipped():
    """A path like ``::A`` should not create empty-named nodes."""
    nodes = build_category_tree({"::Food": 100})
    by_name = _by_name(nodes)
    assert "" not in by_name
    assert "Food" in by_name