import json
from unittest.mock import patch, MagicMock

import pytest


@pytest.fixture
def state_path(tmp_path, monkeypatch):
    import pipewire
    p = tmp_path / "pipewire-modules.json"
    monkeypatch.setattr(pipewire, "STATE_PATH", p)
    return p


def test_save_devices_persists_selection(state_path):
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    data = json.loads(state_path.read_text())
    assert data["mic"] == "mic-src"
    assert data["monitor"] == "monitor-src"


def test_save_devices_does_not_load_modules(state_path):
    import pipewire
    with patch("subprocess.check_output") as run:
        pipewire.save_devices("mic-src", "monitor-src")
    run.assert_not_called()


def test_load_devices_returns_none_without_state(state_path):
    import pipewire
    assert pipewire.load_devices() is None


def test_load_devices_returns_none_on_incomplete_state(state_path):
    import pipewire
    state_path.write_text(json.dumps({"mic": "mic-src"}))
    assert pipewire.load_devices() is None


def test_load_devices_roundtrip(state_path):
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    assert pipewire.load_devices() == {"mic": "mic-src", "monitor": "monitor-src"}


def test_setup_without_configured_devices_does_nothing(state_path):
    import pipewire
    with patch("subprocess.check_output") as run:
        assert pipewire.setup() == []
    run.assert_not_called()


def test_setup_loads_sink_and_two_loopbacks(state_path):
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    with patch.object(pipewire, "is_loaded", side_effect=[False, True]), \
         patch("subprocess.check_output", side_effect=[b"11\n", b"12\n", b"13\n"]) as run:
        ids = pipewire.setup()
    assert ids == [11, 12, 13]
    cmds = [c.args[0] for c in run.call_args_list]
    assert cmds[0][:3] == ["pactl", "load-module", "module-null-sink"]
    assert cmds[1][:3] == ["pactl", "load-module", "module-loopback"]
    assert cmds[2][:3] == ["pactl", "load-module", "module-loopback"]


def test_setup_uses_configured_sources(state_path):
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    with patch.object(pipewire, "is_loaded", side_effect=[False, True]), \
         patch("subprocess.check_output", side_effect=[b"11\n", b"12\n", b"13\n"]) as run:
        pipewire.setup()
    cmds = [c.args[0] for c in run.call_args_list]
    assert "source=mic-src" in cmds[1]
    assert "source=monitor-src" in cmds[2]


def test_setup_applies_large_loopback_latency(state_path):
    """A small buffer would put the loopbacks on the graph's realtime deadline."""
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    with patch.object(pipewire, "is_loaded", side_effect=[False, True]), \
         patch("subprocess.check_output", side_effect=[b"11\n", b"12\n", b"13\n"]) as run:
        pipewire.setup()
    expected = f"latency_msec={pipewire.LOOPBACK_LATENCY_MSEC}"
    for cmd in [c.args[0] for c in run.call_args_list][1:]:
        assert expected in cmd
    assert pipewire.LOOPBACK_LATENCY_MSEC >= 100


def test_setup_is_noop_when_already_loaded(state_path):
    import pipewire
    pipewire.save_devices("mic-src", "monitor-src")
    with patch.object(pipewire, "is_loaded", return_value=True), \
         patch("subprocess.check_output") as run:
        assert pipewire.setup() == []
    run.assert_not_called()


def test_teardown_unloads_chain_modules_highest_id_first():
    import pipewire
    listing = (
        b"7\tmodule-something\tunrelated\n"
        b"11\tmodule-null-sink\tsink_name=transkriptor-combined\n"
        b"12\tmodule-loopback\tsource=mic-src sink=transkriptor-combined\n"
        b"13\tmodule-loopback\tsource=monitor-src sink=transkriptor-combined\n"
    )
    with patch("subprocess.check_output", return_value=listing), \
         patch("subprocess.run") as run:
        pipewire.teardown()
    unloaded = [c.args[0][-1] for c in run.call_args_list]
    assert unloaded == ["13", "12", "11"]


def test_teardown_ignores_unrelated_modules():
    import pipewire
    listing = b"7\tmodule-something\tunrelated\n"
    with patch("subprocess.check_output", return_value=listing), \
         patch("subprocess.run") as run:
        pipewire.teardown()
    run.assert_not_called()


def test_teardown_survives_pactl_failure():
    import pipewire
    import subprocess as sp
    with patch("subprocess.check_output", side_effect=sp.SubprocessError("boom")):
        pipewire.teardown()  # must not raise


def test_setup_survives_pactl_failure(state_path):
    import pipewire
    import subprocess as sp
    pipewire.save_devices("mic-src", "monitor-src")
    with patch.object(pipewire, "is_loaded", return_value=False), \
         patch("subprocess.check_output", side_effect=sp.SubprocessError("boom")):
        assert pipewire.setup() == []


def test_is_loaded_detects_sink():
    import pipewire
    with patch("subprocess.check_output", return_value=b"42\ttranskriptor-combined.monitor\n"):
        assert pipewire.is_loaded() is True
    with patch("subprocess.check_output", return_value=b"42\tsomething-else.monitor\n"):
        assert pipewire.is_loaded() is False