"""Parent mode: the small set of settings the UI may change, and how they are saved."""

from __future__ import annotations

from collections.abc import AsyncIterator
from pathlib import Path

import httpx2
import pytest

from musicmouse.config import WebConfig, load_config
from musicmouse.services.web.service import build_app
from musicmouse.services.web.settings import to_device_volume, to_percent
from musicmouse.simulator.harness import Simulation, build_simulation
from tests.conftest import VALID_CONFIG, write_config

SETTINGS = {
    "min_volume": 0,
    "max_volume": 60,
    "initial_volume": 40,
    "volume_increment": 5,
    "button_leds_brightness": 0.5,
}

#: A config file with comments, to prove saving does not flatten them.
COMMENTED = """\
# The MusicMouse config.
general:
  library:
    root: music        # where the shelves live
    cache: .cache
  serial_port: "/dev/ttyUSB0"
  alsa_device: simulate     # no sound from the test suite, please
  # Volume, 0..100.
  min_volume: 0
  max_volume: 60
  initial_volume: 40

figures:
  fuchs:
    id: "04a1b2c3d4"
    colors: ["#ff6600", "#ffcc00", "#331100", "wff"]
  eule:
    id: "04b2c3d4e5"
    colors: ["#3355ff", "#66aaff", "#001133", "#ffffff"]
"""


@pytest.fixture
async def sim(config_dir: Path) -> AsyncIterator[Simulation]:
    config = load_config(write_config(config_dir, VALID_CONFIG))
    simulation = await build_simulation(config)
    try:
        yield simulation
    finally:
        await simulation.aclose()


@pytest.fixture
async def client(sim: Simulation, config_dir: Path) -> AsyncIterator[httpx2.AsyncClient]:
    path = config_dir / "config.yml"
    path.write_text(COMMENTED, encoding="utf-8")
    api, hub = build_app(sim.app, WebConfig(), path)
    hub.start()
    transport = httpx2.ASGITransport(app=api)
    try:
        async with httpx2.AsyncClient(transport=transport, base_url="http://mouse") as http:
            yield http
    finally:
        hub.stop()


# ------------------------------------------------------------------------- mapping


def test_full_percent_is_the_configured_ceiling(config_dir: Path) -> None:
    general = load_config(write_config(config_dir, VALID_CONFIG)).general
    assert to_device_volume(100, general) == 60
    assert to_device_volume(0, general) == 0
    assert to_device_volume(50, general) == 30


def test_percent_round_trips(config_dir: Path) -> None:
    general = load_config(write_config(config_dir, VALID_CONFIG)).general
    for percent in (0, 25, 50, 75, 100):
        assert to_percent(to_device_volume(percent, general), general) == percent


def test_a_degenerate_range_reads_as_full(config_dir: Path) -> None:
    """min == max is a legal config; it must not divide by zero."""
    general = load_config(write_config(config_dir, VALID_CONFIG)).general
    general.min_volume = general.max_volume = 40
    assert to_percent(40, general) == 100
    assert to_device_volume(50, general) == 40


# -------------------------------------------------------------------------- reading


async def test_settings_expose_only_the_editable_subset(client: httpx2.AsyncClient) -> None:
    body = (await client.get("/api/settings")).json()
    assert set(body) == set(SETTINGS)
    assert body["max_volume"] == 60


# -------------------------------------------------------------------------- writing


async def test_saving_keeps_the_file_readable_and_commented(
    client: httpx2.AsyncClient, config_dir: Path
) -> None:
    response = await client.put("/api/settings", json={**SETTINGS, "max_volume": 45})
    assert response.status_code == 200

    text = (config_dir / "config.yml").read_text(encoding="utf-8")
    assert "max_volume: 45" in text
    assert "# The MusicMouse config." in text
    assert "# where the shelves live" in text
    assert "# Volume, 0..100." in text
    assert "# no sound from the test suite, please" in text

    # And it still loads.
    reloaded = load_config(config_dir / "config.yml")
    assert reloaded.general.max_volume == 45
    assert set(reloaded.figures) == {"fuchs", "eule"}


async def test_a_new_ceiling_applies_to_the_running_player(
    client: httpx2.AsyncClient, sim: Simulation
) -> None:
    """A parent lowering the ceiling expects the next song to be quieter, not the next boot."""
    await client.post("/api/volume", json={"percent": 100})
    await sim.bus.drain()
    assert sim.player.volume == 60

    response = await client.put(
        "/api/settings", json={**SETTINGS, "max_volume": 30, "initial_volume": 20}
    )
    assert response.status_code == 200
    await sim.bus.drain()

    assert sim.player.volume == 30
    assert (await client.get("/api/state")).json()["volume"] == 100


async def test_an_inverted_range_is_rejected(client: httpx2.AsyncClient) -> None:
    response = await client.put("/api/settings", json={**SETTINGS, "min_volume": 70})
    assert response.status_code == 422
    assert "min_volume" in response.json()["detail"]


async def test_an_initial_volume_outside_the_range_is_rejected(
    client: httpx2.AsyncClient,
) -> None:
    response = await client.put("/api/settings", json={**SETTINGS, "initial_volume": 90})
    assert response.status_code == 422
    assert "initial_volume" in response.json()["detail"]


async def test_out_of_bounds_values_are_rejected_by_the_schema(
    client: httpx2.AsyncClient,
) -> None:
    assert (
        await client.put("/api/settings", json={**SETTINGS, "button_leds_brightness": 5})
    ).status_code == 422
    assert (
        await client.put("/api/settings", json={**SETTINGS, "volume_increment": 0})
    ).status_code == 422


async def test_a_rejected_save_leaves_the_file_alone(
    client: httpx2.AsyncClient, config_dir: Path
) -> None:
    before = (config_dir / "config.yml").read_text(encoding="utf-8")
    await client.put("/api/settings", json={**SETTINGS, "min_volume": 70})
    assert (config_dir / "config.yml").read_text(encoding="utf-8") == before