import pytest

from plesna.graph import Edge, Graph, Node


def test_append_nodess():
    nodeA = Node(name="A")
    nodeB = Node(name="B")

    graph = Graph()
    graph.add_node(nodeA)
    graph.add_node(nodeB)

    assert graph.nodes == {nodeA, nodeB}


def test_append_edges():
    nodeA = Node(name="A")
    nodeB = Node(name="B")
    nodeC = Node(name="C")

    edge1 = Edge(arrow_name="arrow", source=nodeA, target=nodeC)
    edge2 = Edge(arrow_name="arrow", source=nodeB, target=nodeC)

    graph = Graph()
    graph.add_edge(edge1)
    graph.add_edge(edge2)

    assert graph.nodes == {nodeA, nodeB, nodeC}


def test_init_edges_nodes():
    nodeA = Node(name="A")
    nodeB = Node(name="B")
    nodeC = Node(name="C")

    edge1 = Edge(arrow_name="arrow", source=nodeB, target=nodeC)

    graph = Graph()
    graph.add_node(nodeA)
    graph.add_edge(edge1)

    assert graph.nodes == {nodeA, nodeB, nodeC}


@pytest.fixture
def nodes():
    return {
        "A": Node(name="A"),
        "B": Node(name="B"),
        "C": Node(name="C"),
        "D": Node(name="D"),
    }


@pytest.fixture
def dag_edges(nodes):
    return {
        "1": Edge(arrow_name="arrow", source=nodes["A"], target=nodes["C"]),
        "2": Edge(arrow_name="arrow", source=nodes["B"], target=nodes["C"]),
        "3": Edge(arrow_name="arrow", source=nodes["C"], target=nodes["D"]),
    }


@pytest.fixture
def notdag_edges(nodes):
    return {
        "1": Edge(arrow_name="arrow", source=nodes["A"], target=nodes["C"]),
        "2": Edge(arrow_name="arrow", source=nodes["B"], target=nodes["C"]),
        "3": Edge(arrow_name="arrow", source=nodes["C"], target=nodes["D"]),
        "4": Edge(arrow_name="arrow", source=nodes["D"], target=nodes["B"]),
    }


def test_get_edges_from(nodes, dag_edges):
    edges = dag_edges
    graph = Graph(edges=edges.values())
    assert graph.get_edges_from(nodes["A"]) == [edges["1"]]


def test_get_targets_from(nodes, dag_edges):
    edges = dag_edges
    graph = Graph(edges=edges.values())
    assert graph.get_direct_targets_from(nodes["A"]) == set([nodes["C"]])
    assert graph.get_direct_targets_from(nodes["C"]) == set([nodes["D"]])
    assert graph.get_direct_targets_from(nodes["D"]) == set()
    assert graph.get_targets_from(nodes["A"]) == set([nodes["C"], nodes["D"]])


def test_get_sources_from(nodes, dag_edges):
    edges = dag_edges
    graph = Graph(edges=edges.values())
    assert graph.get_direct_sources_from(nodes["A"]) == set()
    assert graph.get_direct_sources_from(nodes["C"]) == set([nodes["A"], nodes["B"]])
    assert graph.get_direct_sources_from(nodes["D"]) == set([nodes["C"]])

    assert graph.get_sources_from(nodes["D"]) == set(
        [nodes["A"], nodes["B"], nodes["C"]]
    )


def test_valid_dage(dag_edges, notdag_edges):
    graph = Graph(edges=dag_edges.values())
    assert graph.is_dag()

    graph = Graph(edges=notdag_edges.values())
    assert not graph.is_dag()