"""Simulated BPM: sequence switching timing and beat regularity."""

import asyncio
import os
import sys
import time
from typing import List

PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
SRC_PATH = os.path.join(PROJECT_ROOT, "src")
if SRC_PATH not in sys.path:
    sys.path.insert(0, SRC_PATH)

from util import sequence_playback as sp  # noqa: E402
from util.audio_detector import AudioBeatDetector, set_shared_beat_detector  # noqa: E402


class _FakeSettings:
    def __init__(self, **values):
        self._values = values

    def get(self, key, default=None):
        return self._values.get(key, default)


def _install_simulated_bpm(monkeypatch, bpm: float, *, sequence_switch_wait: str = "beat"):
    monkeypatch.setattr(
        "settings.get_settings",
        lambda: _FakeSettings(
            audio_simulated_bpm=bpm,
            sequence_switch_wait=sequence_switch_wait,
        ),
    )
    det = AudioBeatDetector()
    set_shared_beat_detector(det)
    monkeypatch.setattr(
        "util.audio_detector.shared_beat_detector_timing_sequences", lambda: False
    )


def _beat_timestamps(seconds: float) -> List[float]:
    async def collect():
        sp.stop()
        sp.clear_pending_play()
        set_shared_beat_detector(None)
        sp._beat_consumer_started = False
        sp._background_beat_task = None
        sp.ensure_beat_consumer_started()

        stamps: List[float] = []
        last = sp.simulated_beat_tick()
        deadline = time.monotonic() + seconds
        while time.monotonic() < deadline:
            tick = sp.simulated_beat_tick()
            if tick != last:
                stamps.append(time.monotonic())
                last = tick
            await asyncio.sleep(0.005)
        sp.stop()
        return stamps

    return asyncio.run(collect())


def _intervals(stamps: List[float]) -> List[float]:
    return [stamps[i + 1] - stamps[i] for i in range(len(stamps) - 1)]


def test_effective_switch_wait_is_beat_when_audio_off_even_if_saved_downbeat(monkeypatch):
    _install_simulated_bpm(monkeypatch, 60.0, sequence_switch_wait="downbeat")
    assert sp.effective_sequence_switch_wait() == "beat"
    set_shared_beat_detector(None)


def test_e2e_switch_on_next_beat_while_mic_running_sim_clocks(monkeypatch):
    """End-to-end: audio running flag set, sim BPM ticks, switch on next beat not downbeat."""
    bpm = 120.0
    _install_simulated_bpm(monkeypatch, bpm, sequence_switch_wait="downbeat")
    det = AudioBeatDetector()
    set_shared_beat_detector(det)
    with det._lock:
        det._running = True
        det._status["running"] = True

    sp.stop()
    sp.clear_pending_play()
    sp._beat_consumer_started = False
    sp._background_beat_task = None
    sp._sim_beat_counter = 0
    sp._last_thread_beat_phase = {"bar_beat": 1, "is_downbeat": True}

    switch_events: List[tuple] = []

    async def track_start(_z, seq_id, _p, _opts, **_kwargs):
        phase = sp._beat_phase_from_sources()
        switch_events.append((time.monotonic(), str(seq_id), int(phase.get("bar_beat") or 0)))

    monkeypatch.setattr(sp, "_start_immediate", track_start)

    async def run():
        sp.ensure_beat_consumer_started()
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "1",
            }
        sp._mark_simulated_beat_phase()
        sp._mark_simulated_beat_phase()
        assert sp._beat_phase_from_sources()["bar_beat"] == 2

        t_queue = time.monotonic()
        sp._queue_pending_start(
            "z1", "2", "1", None, sp.effective_sequence_switch_wait(), bpm=bpm
        )
        assert sp.pending_play_status()["wait_for"] == "beat"

        beat_interval = 60.0 / bpm
        for _ in range(6):
            if not sp.pending_play_status()["pending"]:
                break
            sp._mark_simulated_beat_phase()
            sp.push_thread_beat()
            await asyncio.sleep(0.05)
        return t_queue, switch_events, beat_interval

    t_queue, events, beat_interval = asyncio.run(run())
    assert len(events) == 1, f"expected one switch, got {events}"
    _t, seq_id, bar_beat = events[0]
    assert seq_id == "2"
    assert bar_beat == 3, f"expected switch on next beat (bar 3), got bar {bar_beat}"
    assert _t - t_queue < beat_interval * 1.1, (
        f"switch took too long ({_t - t_queue:.2f}s) for {bpm} BPM"
    )
    sp.stop()
    with det._lock:
        det._running = False
        det._status["running"] = False
    set_shared_beat_detector(None)


def test_simulated_beat_intervals_steady_at_60_bpm(monkeypatch):
    bpm = 60.0
    _install_simulated_bpm(monkeypatch, bpm)
    expected = 60.0 / bpm
    stamps = _beat_timestamps(seconds=5.5)
    assert len(stamps) >= 4, f"expected several beats, got {len(stamps)}"
    for gap in _intervals(stamps):
        assert abs(gap - expected) < 0.12, f"beat gap {gap:.3f}s expected ~{expected:.3f}s"
    set_shared_beat_detector(None)


def test_simulated_switch_consumes_on_upbeat_not_only_downbeat(monkeypatch):
    """With downbeat saved but audio off, switch must happen on the next beat (e.g. bar 3), not bar 1."""
    _install_simulated_bpm(monkeypatch, 120.0, sequence_switch_wait="downbeat")
    assert sp.effective_sequence_switch_wait() == "beat"
    sp.stop()
    sp.clear_pending_play()
    sp._sim_beat_counter = 0
    sp._last_thread_beat_phase = {"bar_beat": 1, "is_downbeat": True}

    consumed_bar_beats: List[int] = []

    async def fake_start(_z, _s, _p, _opts, **_kwargs):
        phase = sp._beat_phase_from_sources()
        consumed_bar_beats.append(int(phase.get("bar_beat") or 0))
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "2",
            }

    monkeypatch.setattr("util.sequence_playback._start_immediate", fake_start)

    async def run():
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "1",
            }
        sp._mark_simulated_beat_phase()
        sp._mark_simulated_beat_phase()
        assert sp._beat_phase_from_sources()["bar_beat"] == 2

        wait_for = sp.effective_sequence_switch_wait()
        assert wait_for == "beat"
        sp._queue_pending_start("z1", "2", "1", None, wait_for, bpm=120.0)
        assert sp.pending_play_status()["wait_for"] == "beat"

        for _ in range(6):
            if not sp.pending_play_status()["pending"]:
                break
            sp._mark_simulated_beat_phase()
            phase = sp._beat_phase_from_sources()
            is_down = bool(phase.get("is_downbeat"))
            await sp._try_consume_pending_play(is_downbeat=is_down)
        return consumed_bar_beats

    consumed = asyncio.run(run())
    assert consumed == [3], f"expected switch on bar beat 3 (next beat), got {consumed}"
    sp.stop()
    set_shared_beat_detector(None)


def test_simulated_switch_waits_for_downbeat_only_when_pending_downbeat(monkeypatch):
    """Control: downbeat pending with live audio must skip upbeats."""
    monkeypatch.setattr(
        "settings.get_settings",
        lambda: _FakeSettings(
            audio_simulated_bpm=120,
            sequence_switch_wait="downbeat",
        ),
    )
    det = AudioBeatDetector()
    set_shared_beat_detector(det)
    with det._lock:
        det._running = True
        det._status["running"] = True
    sp.stop()
    sp.clear_pending_play()
    sp._sim_beat_counter = 0
    sp._last_thread_beat_phase = {"bar_beat": 1, "is_downbeat": True}

    consumed_bar_beats: List[int] = []

    async def fake_start(_z, _s, _p, _opts, **_kwargs):
        phase = sp._beat_phase_from_sources()
        consumed_bar_beats.append(int(phase.get("bar_beat") or 0))

    monkeypatch.setattr("util.sequence_playback._start_immediate", fake_start)

    async def run():
        sp._queue_pending_start("z1", "2", "1", None, "downbeat", bpm=120.0)
        for _ in range(6):
            if not sp.pending_play_status()["pending"]:
                break
            sp._mark_simulated_beat_phase()
            phase = sp._beat_phase_from_sources()
            await sp._try_consume_pending_play(
                is_downbeat=bool(phase.get("is_downbeat"))
            )
        return consumed_bar_beats

    consumed = asyncio.run(run())
    assert consumed == [1], f"downbeat pending should wait for bar 1, got {consumed}"
    sp.stop()
    with det._lock:
        det._running = False
        det._status["running"] = False
    set_shared_beat_detector(None)


def test_pending_switch_freezes_current_sequence(monkeypatch):
    """While waiting for the next beat, the running sequence must not advance."""
    _install_simulated_bpm(monkeypatch, 120.0)
    sp.stop()
    sp.clear_pending_play()
    sp._beat_consumer_started = False
    sp._background_beat_task = None
    sp.ensure_beat_consumer_started()

    ctx = {
        "lanes": [[{"preset_id": "1", "beats": 99}]],
        "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
        "num_lanes": 1,
        "loop": True,
        "sequence_loop_beat": 0,
        "sequence_id": "1",
    }
    with sp._beat_run_lock:
        sp._beat_run = ctx

    async def fake_start(_z, _s, _p, _opts, **_kwargs):
        return None

    monkeypatch.setattr("util.sequence_playback._start_immediate", fake_start)

    async def run():
        sp._queue_pending_start(
            "z1", "2", "1", None, sp.effective_sequence_switch_wait(), bpm=120.0
        )
        assert ctx.get("_pending_switch") is True
        await asyncio.sleep(2.5)
        return int(ctx.get("lane_states", [{}])[0].get("beatCount", 0))

    beat_count = asyncio.run(run())
    assert beat_count == 0, f"sequence should freeze while pending, got {beat_count}"
    sp.stop()
    set_shared_beat_detector(None)


def test_pending_switch_drains_piled_beats_after_slow_start(monkeypatch):
    """Beats queued during a slow handoff must not advance the new sequence twice."""
    _install_simulated_bpm(monkeypatch, 120.0)
    sp.stop()
    sp.clear_pending_play()

    async def slow_start(_z, _s, _p, _opts, **_kwargs):
        sp.push_thread_beat()
        sp.push_thread_beat()
        await asyncio.sleep(0.05)
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "2",
            }

    monkeypatch.setattr("util.sequence_playback._start_immediate", slow_start)

    async def run():
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "1",
            }
        sp._queue_pending_start("z1", "2", "1", None, "beat", bpm=120.0)
        assert await sp._try_consume_pending_play(is_downbeat=False) is True
        piled = 0
        while True:
            try:
                sp._thread_beat_queue.get_nowait()
                piled += 1
            except Exception:
                break
        assert piled == 0, f"piled beats should be drained, found {piled}"
        await sp.process_active_beat_advance()
        with sp._beat_run_lock:
            ctx = sp._beat_run
        assert ctx is not None
        return int(ctx["lane_states"][0].get("beatCount", 0))

    beat_count = asyncio.run(run())
    assert beat_count == 1, f"expected single advance after switch, got {beat_count}"
    sp.stop()
    set_shared_beat_detector(None)


def test_handoff_rearm_blocks_immediate_double_advance(monkeypatch):
    """After a switch, piled beats must not advance the new sequence twice in a row."""
    _install_simulated_bpm(monkeypatch, 120.0)
    sp.stop()
    sp.clear_pending_play()

    async def slow_start(_z, _s, _p, _opts, **kwargs):
        sp.push_thread_beat()
        await asyncio.sleep(0.02)
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "2",
                "_anchor_bar_on_pass_start": False,
            }

    monkeypatch.setattr("util.sequence_playback._start_immediate", slow_start)
    monkeypatch.setattr("util.sequence_playback._restart_background_beat_clock", lambda: None)

    async def run():
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "1",
            }
        sp._queue_pending_start("z1", "2", "1", None, "beat", bpm=120.0)
        sp._accept_thread_beat_now()
        assert await sp._try_consume_pending_play(is_downbeat=False) is True
        assert sp._accept_thread_beat_now() is False
        await sp.process_active_beat_advance()
        sp.push_thread_beat()
        assert sp._accept_thread_beat_now() is False
        with sp._beat_run_lock:
            ctx = sp._beat_run
        return int(ctx["lane_states"][0].get("beatCount", 0))

    beat_count = asyncio.run(run())
    assert beat_count == 1, f"handoff should advance once, got {beat_count}"
    sp.stop()
    set_shared_beat_detector(None)


def test_mid_bar_handoff_keeps_bar_phase(monkeypatch):
    """Switching on an upbeat must not snap the bar readout back to 1/4."""
    _install_simulated_bpm(monkeypatch, 120.0)
    sp.stop()
    sp.clear_pending_play()
    sp._sim_beat_counter = 3
    sp._last_thread_beat_phase = {"bar_beat": 3, "is_downbeat": False}

    async def fake_start(_z, _s, _p, _opts, **kwargs):
        with sp._beat_run_lock:
            sp._beat_run = {
                "lanes": [[{"preset_id": "1", "beats": 99}]],
                "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
                "num_lanes": 1,
                "loop": True,
                "sequence_loop_beat": 0,
                "sequence_id": "2",
                "_anchor_bar_on_pass_start": kwargs.get("handoff_is_downbeat", False),
            }

    monkeypatch.setattr("util.sequence_playback._start_immediate", fake_start)
    monkeypatch.setattr("util.sequence_playback._restart_background_beat_clock", lambda: None)

    async def run():
        sp._queue_pending_start("z1", "2", "1", None, "beat", bpm=120.0)
        assert await sp._try_consume_pending_play(is_downbeat=False) is True
        await sp.process_active_beat_advance()
        return sp._sim_beat_counter, sp._last_thread_beat_phase["bar_beat"]

    counter, bar_beat = asyncio.run(run())
    assert counter == 3, f"mid-bar handoff should keep sim counter, got {counter}"
    assert bar_beat == 3, f"mid-bar handoff should keep bar beat, got {bar_beat}"
    sp.stop()
    set_shared_beat_detector(None)


def test_idle_start_is_immediate_not_pending(monkeypatch):
    """First sequence with nothing playing should not wait for the next beat."""
    _install_simulated_bpm(monkeypatch, 60.0)
    sp.stop()
    sp.clear_pending_play()

    class FakeSeq:
        def read(self, _sid):
            return {"profile_id": "1", "lanes": [[{"preset_id": "1", "beats": 1}]]}

    monkeypatch.setitem(sys.modules, "models.sequence", type(sys)("models.sequence"))
    sys.modules["models.sequence"].Sequence = FakeSeq  # type: ignore[attr-defined]

    started = []

    async def fake_start(z, s, p, opts):
        started.append((z, s, p))

    monkeypatch.setattr("util.sequence_playback._start_immediate", fake_start)

    async def run():
        t0 = time.monotonic()
        await sp.start("z1", "1", "1", None)
        return time.monotonic() - t0

    elapsed = asyncio.run(run())
    assert sp.pending_play_status()["pending"] is False
    assert started == [("z1", "1", "1")]
    assert elapsed < 0.05, f"idle start should be immediate, took {elapsed:.3f}s"
    sp.stop()
    set_shared_beat_detector(None)


def test_active_switch_still_queues_pending(monkeypatch):
    _install_simulated_bpm(monkeypatch, 60.0, sequence_switch_wait="downbeat")
    sp.stop()
    with sp._beat_run_lock:
        sp._beat_run = {
            "lanes": [[{"preset_id": "1", "beats": 1}]],
            "lane_states": [{"stepIdx": 0, "beatCount": 0, "done": False}],
            "num_lanes": 1,
            "loop": False,
            "sequence_id": "1",
        }

    class FakeSeq:
        def read(self, _sid):
            return {"profile_id": "1", "lanes": [[{"preset_id": "1", "beats": 1}]]}

    monkeypatch.setitem(sys.modules, "models.sequence", type(sys)("models.sequence"))
    sys.modules["models.sequence"].Sequence = FakeSeq  # type: ignore[attr-defined]
    monkeypatch.setattr("util.sequence_playback._start_immediate", lambda *a, **k: None)

    async def run():
        await sp.start("z1", "2", "1", None)

    asyncio.run(run())
    st = sp.pending_play_status()
    assert st["pending"] is True
    assert st["sequence_id"] == "2"
    assert st["wait_for"] == "beat", f"simulated switch must queue beat, got {st['wait_for']!r}"
    sp.stop()
    set_shared_beat_detector(None)


def test_pending_switch_uses_beat_after_audio_stops(monkeypatch):
    """Queued while live audio was timing (downbeat) must switch on beat once sim clocks."""
    monkeypatch.setattr(
        "settings.get_settings",
        lambda: _FakeSettings(
            audio_simulated_bpm=120,
            sequence_switch_wait="downbeat",
        ),
    )
    det = AudioBeatDetector()
    set_shared_beat_detector(det)
    sp.stop()
    sp.clear_pending_play()
    sp._sim_beat_counter = 0
    sp._last_thread_beat_phase = {"bar_beat": 1, "is_downbeat": True}

    consumed_bar_beats: List[int] = []

    async def fake_start(_z, _s, _p, _opts, **_kwargs):
        phase = sp._beat_phase_from_sources()
        consumed_bar_beats.append(int(phase.get("bar_beat") or 0))

    monkeypatch.setattr(sp, "_start_immediate", fake_start)

    async def run():
        with det._lock:
            det._running = True
            det._status["running"] = True
            det._holdover_active = True
        monkeypatch.setattr(
            "util.audio_detector.shared_beat_detector_timing_sequences", lambda: True
        )
        sp._queue_pending_start("z1", "2", "1", None, "downbeat", bpm=120.0)
        assert sp.pending_play_status()["wait_for"] == "downbeat"

        with det._lock:
            det._running = False
            det._status["running"] = False
            det._holdover_active = False
        monkeypatch.setattr(
            "util.audio_detector.shared_beat_detector_timing_sequences", lambda: False
        )

        sp._mark_simulated_beat_phase()
        sp._mark_simulated_beat_phase()
        for _ in range(4):
            if not sp.pending_play_status()["pending"]:
                break
            sp._mark_simulated_beat_phase()
            phase = sp._beat_phase_from_sources()
            await sp._try_consume_pending_play(
                is_downbeat=bool(phase.get("is_downbeat"))
            )
        return consumed_bar_beats

    consumed = asyncio.run(run())
    assert consumed == [3], (
        f"after audio stop, pending should consume on next beat (bar 3), got {consumed}"
    )
    sp.stop()
    set_shared_beat_detector(None)


def test_audio_status_reports_beat_switch_when_simulated(server):
    """API: audio off + saved downbeat still exposes beat-only switch wait."""
    c = server["client"]
    c.put("/settings", json={"sequence_switch_wait": "downbeat"})
    c.post("/api/audio/stop")

    status = c.get("/api/audio/status").json()["status"]
    assert status.get("bpm_simulated") is True
    assert status.get("sequence_switch_wait") == "beat"
    assert status.get("sequence_switch_wait_saved") == "downbeat"