"""Nodes talking to the same outside thing are one neuron, across flows.

That merge is the whole point of the brain graph: a broker topic is a single
physical thing, and two flows sharing one are wired together through it even
though neither canvas can draw the other end.
"""

from pathlib import Path

import pytest

from app.flow.controller import FlowController
from app.flow.messages import DType, MessageSpec
from app.flow.nodes import MqttNode
from app.flow.schemas import FlowDef, NodeDef
from app.flow.store import FlowStore

BROKER = {"broker_host": "mosquitto", "broker_port": 1883, "topic": "sensors/temp"}


def subscriber(node_id: str) -> NodeDef:
    return NodeDef(
        id=node_id,
        type="mqtt",
        params=dict(BROKER),
        provides=[MessageSpec(name="temp", dtype=DType.FLOAT)],
    )


@pytest.fixture
def controller(tmp_path: Path) -> FlowController:
    store = FlowStore(tmp_path / "flows")
    store.write_flow(
        FlowDef(
            name="house",
            nodes=[
                subscriber("sensor"),
                NodeDef(
                    id="scale",
                    type="change",
                    requires=[MessageSpec(name="temp", dtype=DType.FLOAT)],
                    provides=[MessageSpec(name="scaled", dtype=DType.FLOAT)],
                ),
            ],
        )
    )
    store.write_flow(FlowDef(name="shed", nodes=[subscriber("sensor")]))
    return FlowController(store)


def test_two_flows_on_one_topic_are_one_neuron(controller: FlowController):
    graph = controller.brain_graph()

    merged = [node for node in graph.nodes if node.kind == "mqtt"]
    assert len(merged) == 1
    assert merged[0].id == "mqtt:mosquitto:1883/sensors/temp"
    assert merged[0].members == ["house.sensor", "shed.sensor"]
    assert merged[0].flows == ["house", "shed"]


def test_a_node_with_no_outside_thing_stays_its_own(controller: FlowController):
    graph = controller.brain_graph()

    scale = next(node for node in graph.nodes if node.kind == "change")
    assert scale.id == "house.scale"
    assert scale.members == ["house.scale"]


def test_an_edge_carries_the_qualified_message(controller: FlowController):
    graph = controller.brain_graph()

    assert [(edge.source, edge.target, edge.messages) for edge in graph.edges] == [
        ("mqtt:mosquitto:1883/sensors/temp", "house.scale", ["house.temp"])
    ]


def test_a_credential_never_reaches_the_key():
    # Stored params, so a secret is still a reference. Neither its name nor its
    # value belongs in something the browser gets to see.
    key = MqttNode.instance_key({**BROKER, "password": {"$secret": "broker_pw"}})

    assert key == "mosquitto:1883/sensors/temp"