"""A node's settings are arguments of its function, like its ports.

What distinguishes them is where the value comes from: a port carries whatever
the graph last published, a setting is a constant stored with the flow. Both
arrive by name, so one name cannot mean both.
"""

from pathlib import Path

import pytest

from fluksio.flow.controller import FlowController
from fluksio.flow.messages import DType, MessageSpec
from fluksio.flow.pipeline import Pipeline
from fluksio.flow.schemas import FlowDef, NodeDef
from fluksio.flow.state import MemoryState
from fluksio.flow.store import FlowStore

SOURCE = "def process(reading, factor):\n    return {'scaled': reading * factor}\n"


def a_flow(**params: object) -> FlowDef:
    return FlowDef(
        name="house",
        nodes=[
            NodeDef(
                id="scale",
                params=dict(params),
                requires=[MessageSpec(name="reading", dtype=DType.FLOAT)],
                provides=[MessageSpec(name="scaled", dtype=DType.FLOAT)],
            )
        ],
    )


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


def test_a_setting_reaches_the_function_as_a_keyword_argument(store: FlowStore):
    store.write_flow(a_flow(factor=3))
    store.write_node_source("house", "scale", SOURCE)
    controller = FlowController(store)

    nodes, _loaded, _initial, _inputs = controller._build_flows(
        [(store.read_flow("house"), False)]
    )
    pipeline = Pipeline(nodes=nodes, state=MemoryState())
    pipeline.run({"house.reading": 2.0})

    assert pipeline.values()["house.scaled"]["value"] == 6.0


def test_a_setting_named_after_a_port_is_refused(store: FlowStore):
    store.write_draft(a_flow(reading=3), 0)
    store.write_node_source("house", "scale", SOURCE, draft=True)
    controller = FlowController(store)

    preview = controller.preview("house")

    assert [node.status for node in preview.nodes] == ["error"]
    assert "both an input and a setting" in (preview.nodes[0].error or "")