from collections.abc import Generator
from dataclasses import dataclass
from pathlib import Path
from types import SimpleNamespace
from typing import Any

import pytest


@pytest.fixture(scope="session", autouse=True)
def db() -> Generator[None, None, None]:
    """The engine holds no database state, so these tests need no database."""
    yield


@dataclass
class FakeTarget:
    name: str
    type: str
    value: Any
    values: list[str] | None = None
    range: list[float] | None = None
    description: str = ""
    unit: str | None = None
    readonly: bool = False


@dataclass
class FakeCall:
    target: str
    value: Any = None
    delay_s: float | None = None
    confidence: float = 1.0


class FakeWren:
    """The model package's surface: ``act`` answers whatever a test sets
    ``answer`` to, and ``load_pack`` returns ``pack``."""

    Target = FakeTarget
    Call = FakeCall
    runtime = SimpleNamespace(MODEL=Path("demo.bin"))

    def __init__(self) -> None:
        self.answer: list[FakeCall] = []
        self.pack: dict[str, Any] = {"meta": {"threshold": 0.9, "targets": []}}
        self.loaded: list[Path] = []
        self.commands: list[str] = []
        self.targets: list[list[FakeTarget]] = []
        self.models: list[Any] = []

    def load_pack(self, path: Path) -> dict[str, Any]:
        self.loaded.append(path)
        return self.pack

    def act(
        self, command: str, targets: list[FakeTarget], *, model: Any = None
    ) -> list[FakeCall]:
        self.commands.append(command)
        self.targets.append(targets)
        self.models.append(model)
        return self.answer


@pytest.fixture
def fake_wren(monkeypatch: pytest.MonkeyPatch) -> FakeWren:
    """Stands in for the optional model package the wren node imports."""
    fake = FakeWren()
    monkeypatch.setattr("fluksio.flow.nodes.wren._wren", lambda: fake)
    return fake