"""Nodes shared across flows: one source, many instances."""

from pathlib import Path

import pytest

from app.flow.messages import MessageSpec
from app.flow.schemas import FlowDef, NodeDef
from app.flow.store import FlowStore, LibExists, LibNotFound

SOURCE = "def process():\n    return {'temp': 1}\n"


@pytest.fixture
def store(tmp_path: Path) -> FlowStore:
    return FlowStore(tmp_path / "flows")


def a_flow(name: str = "heating") -> FlowDef:
    return FlowDef(
        name=name,
        nodes=[NodeDef(id="sensor", provides=[MessageSpec(name="temp")])],
    )


def test_sharing_moves_the_source_and_points_the_node_at_it(store: FlowStore):
    store.write_flow(a_flow())
    store.write_node_source("heating", "sensor", SOURCE)

    store.share_node("heating", "sensor", "read_temp")

    assert store.list_lib() == ["read_temp"]
    assert store.read_lib_source("read_temp") == SOURCE
    node = store.read_flow("heating", draft=True).nodes[0]
    assert node.source_ref == "read_temp"
    # The private copy is gone; the library one is what it runs.
    assert not (store.root / "heating" / "nodes" / "sensor.py").exists()


def test_the_library_is_not_mistaken_for_a_flow(store: FlowStore):
    store.write_flow(a_flow())
    store.write_node_source("heating", "sensor", SOURCE)
    store.share_node("heating", "sensor", "read_temp")

    assert store.list_flows() == ["heating"]
    assert [flow.name for flow in store.read_all()] == ["heating"]


def test_a_second_flow_can_use_the_same_source(store: FlowStore):
    store.write_flow(a_flow())
    store.write_node_source("heating", "sensor", SOURCE)
    store.share_node("heating", "sensor", "read_temp")

    store.write_flow(
        FlowDef(
            name="cooling",
            nodes=[
                NodeDef(
                    id="sensor",
                    source_ref="read_temp",
                    provides=[MessageSpec(name="temp")],
                )
            ],
        )
    )

    assert store.usages("read_temp") == ["cooling.sensor", "heating.sensor"]


def test_a_shared_name_is_not_taken_twice(store: FlowStore):
    store.write_flow(a_flow())
    store.write_node_source("heating", "sensor", SOURCE)
    store.share_node("heating", "sensor", "read_temp")

    store.write_flow(FlowDef(name="cooling", nodes=[NodeDef(id="sensor")]))
    with pytest.raises(LibExists):
        store.share_node("cooling", "sensor", "read_temp")


def test_unsharing_takes_a_private_copy_back(store: FlowStore):
    store.write_flow(a_flow())
    store.write_node_source("heating", "sensor", SOURCE)
    store.share_node("heating", "sensor", "read_temp")

    store.unshare_node("heating", "sensor")

    node = store.read_flow("heating", draft=True).nodes[0]
    assert node.source_ref is None
    assert store.read_node_source("heating", "sensor", draft=True) == SOURCE
    # The library keeps its copy for whoever else is using it.
    assert store.list_lib() == ["read_temp"]


def test_a_missing_shared_source_is_reported(store: FlowStore):
    with pytest.raises(LibNotFound):
        store.read_lib_source("nothing_here")