"""DiagramDocument tests: add/remove, connect rules, signals, serialization."""
import pytest

from pipeline_editor.model.document import DiagramDocument
from pipeline_editor.model.edge import EdgeModel
from pipeline_editor.model.node_library import default_library


@pytest.fixture
def doc(qapp):
    return DiagramDocument()


@pytest.fixture
def lib():
    return default_library()


def _add(doc, lib, key, x, y):
    node = lib.get(key).instantiate(doc.next_id("n"), x, y)
    return doc.add_node(node)


def test_add_and_signals(doc, lib):
    events = []
    doc.node_added.connect(lambda nid: events.append(("node", nid)))
    doc.edge_added.connect(lambda eid: events.append(("edge", eid)))
    a = _add(doc, lib, "source", 0, 0)
    b = _add(doc, lib, "pump", 200, 0)
    edge = EdgeModel(doc.next_id("e"), a.node_id, "out", b.node_id, "in")
    doc.add_edge(edge)
    assert ("node", a.node_id) in events
    assert ("edge", edge.edge_id) in events
    assert doc.dirty is True


def test_connect_rules(doc, lib):
    a = _add(doc, lib, "source", 0, 0)      # water out
    b = _add(doc, lib, "pump", 200, 0)      # water in
    t = _add(doc, lib, "transformer", 0, 200)  # power ports
    assert doc.can_connect(a.node_id, "out", b.node_id, "in") is True
    assert doc.can_connect(a.node_id, "out", t.node_id, "hv") is False  # water vs power
    assert doc.can_connect(a.node_id, "out", a.node_id, "out") is False  # same port


def test_remove_node_cascades_edges(doc, lib):
    a = _add(doc, lib, "source", 0, 0)
    b = _add(doc, lib, "pump", 200, 0)
    e = doc.add_edge(EdgeModel(doc.next_id("e"), a.node_id, "out", b.node_id, "in"))
    removed = doc.remove_node(a.node_id)
    assert e.edge_id in removed
    assert doc.edge(e.edge_id) is None
    assert doc.node(a.node_id) is None


def test_edge_inherits_relation(doc, lib):
    a = _add(doc, lib, "source", 0, 0)
    b = _add(doc, lib, "pump", 200, 0)
    e = doc.add_edge(EdgeModel(doc.next_id("e"), a.node_id, "out", b.node_id, "in"))
    assert e.relation == "water"


def test_serialization_roundtrip(doc, lib):
    a = _add(doc, lib, "source", 10, 20)
    b = _add(doc, lib, "consumer", 300, 20)
    a.properties.set_value("supply", 200)
    doc.add_edge(EdgeModel(doc.next_id("e"), a.node_id, "out", b.node_id, "in"))
    text = doc.to_json()

    doc2 = DiagramDocument.from_json(text)
    assert list(n.node_id for n in doc2.nodes()) == [a.node_id, b.node_id]
    ra = doc2.node(a.node_id)
    assert ra.x == 10 and ra.properties.value("supply") == 200
    assert sum(1 for _ in doc2.edges()) == 1


def test_clear(doc, lib):
    _add(doc, lib, "source", 0, 0)
    doc.clear()
    assert len(doc) == 0