"""Tests for AudioPipeline."""

import struct

from tuimble.audio import FRAME_SIZE, SAMPLE_RATE, AudioPipeline, _apply_gain


def test_default_construction():
    ap = AudioPipeline()
    assert ap._sample_rate == SAMPLE_RATE
    assert ap._frame_size == FRAME_SIZE
    assert ap._input_device is None
    assert ap._output_device is None
    assert ap.capturing is False
    assert ap.deafened is False


def test_custom_construction():
    ap = AudioPipeline(sample_rate=24000, frame_size=480,
                       input_device=1, output_device=2)
    assert ap._sample_rate == 24000
    assert ap._frame_size == 480
    assert ap._input_device == 1
    assert ap._output_device == 2


def test_capturing_toggle():
    ap = AudioPipeline()
    assert ap.capturing is False
    ap.capturing = True
    assert ap.capturing is True
    ap.capturing = False
    assert ap.capturing is False


def test_get_capture_frame_empty():
    ap = AudioPipeline()
    assert ap.get_capture_frame() is None


def test_get_capture_frame_returns_queued():
    ap = AudioPipeline()
    ap._capture_queue.put(b"\x01\x02\x03")
    assert ap.get_capture_frame() == b"\x01\x02\x03"
    assert ap.get_capture_frame() is None


def test_queue_playback_and_callback():
    """Verify playback callback writes PCM directly to output buffer."""
    ap = AudioPipeline()
    frame_bytes = FRAME_SIZE * 2  # 16-bit mono = 2 bytes per sample
    pcm = bytes(range(256)) * (frame_bytes // 256) + bytes(range(frame_bytes % 256))
    assert len(pcm) == frame_bytes

    ap.queue_playback(pcm)

    outdata = bytearray(frame_bytes)
    ap._playback_callback(outdata, FRAME_SIZE, None, None)
    assert bytes(outdata) == pcm


def test_playback_callback_silence_on_empty():
    """Empty queue produces silence."""
    ap = AudioPipeline()
    frame_bytes = FRAME_SIZE * 2
    outdata = bytearray(b"\xff" * frame_bytes)
    ap._playback_callback(outdata, FRAME_SIZE, None, None)
    assert outdata == bytearray(frame_bytes)  # all zeros


def test_playback_callback_short_pcm_pads_silence():
    """PCM shorter than output buffer gets zero-padded."""
    ap = AudioPipeline()
    frame_bytes = FRAME_SIZE * 2
    short_pcm = b"\x42" * 100
    ap.queue_playback(short_pcm)

    outdata = bytearray(frame_bytes)
    ap._playback_callback(outdata, FRAME_SIZE, None, None)
    assert outdata[:100] == bytearray(b"\x42" * 100)
    assert outdata[100:] == bytearray(frame_bytes - 100)


def test_queue_playback_overflow_drops():
    """Full queue drops new data silently."""
    ap = AudioPipeline(frame_size=FRAME_SIZE)
    # Fill the queue
    for i in range(ap._playback_queue.maxsize):
        ap.queue_playback(b"\x00")
    # This should not raise
    ap.queue_playback(b"\xff")
    assert ap._playback_queue.qsize() == ap._playback_queue.maxsize


def test_deafened_toggle():
    ap = AudioPipeline()
    assert ap.deafened is False
    ap.deafened = True
    assert ap.deafened is True
    ap.deafened = False
    assert ap.deafened is False


def test_queue_playback_discards_when_deafened():
    """Incoming PCM is dropped when deafened."""
    ap = AudioPipeline()
    ap.deafened = True
    ap.queue_playback(b"\x42" * 100)
    assert ap._playback_queue.qsize() == 0


def test_playback_callback_silence_when_deafened():
    """Playback callback writes silence when deafened, even with queued data."""
    ap = AudioPipeline()
    frame_bytes = FRAME_SIZE * 2
    # Queue data before deafening
    pcm = b"\x42" * frame_bytes
    ap.queue_playback(pcm)
    ap.deafened = True

    outdata = bytearray(b"\xff" * frame_bytes)
    ap._playback_callback(outdata, FRAME_SIZE, None, None)
    assert outdata == bytearray(frame_bytes)  # all zeros


def test_stop_without_start():
    """Stop on unstarted pipeline should not raise."""
    ap = AudioPipeline()
    ap.stop()


# -- _apply_gain tests -------------------------------------------------------


def test_apply_gain_unity():
    """Gain 1.0 returns identical samples."""
    pcm = struct.pack("<4h", 100, -200, 32767, -32768)
    assert _apply_gain(pcm, 1.0) == pcm


def test_apply_gain_double():
    """Gain 2.0 doubles sample values."""
    pcm = struct.pack("<2h", 100, -100)
    result = struct.unpack("<2h", _apply_gain(pcm, 2.0))
    assert result == (200, -200)


def test_apply_gain_clips():
    """Values exceeding int16 range are clipped."""
    pcm = struct.pack("<2h", 20000, -20000)
    result = struct.unpack("<2h", _apply_gain(pcm, 2.0))
    assert result == (32767, -32768)


def test_apply_gain_zero():
    """Gain 0.0 produces silence."""
    pcm = struct.pack("<2h", 1000, -1000)
    result = struct.unpack("<2h", _apply_gain(pcm, 0.0))
    assert result == (0, 0)


def test_apply_gain_empty():
    """Empty buffer returns empty."""
    assert _apply_gain(b"", 2.0) == b""


# -- gain property tests ------------------------------------------------------


def test_gain_defaults():
    ap = AudioPipeline()
    assert ap.input_gain == 1.0
    assert ap.output_gain == 1.0


def test_gain_clamping():
    ap = AudioPipeline()
    ap.input_gain = 3.0
    assert ap.input_gain == 2.0
    ap.output_gain = -1.0
    assert ap.output_gain == 0.0


def test_capture_callback_applies_input_gain():
    """Input gain is applied to captured PCM."""
    ap = AudioPipeline()
    ap.capturing = True
    ap.input_gain = 0.5
    pcm = struct.pack("<2h", 1000, -1000)
    ap._capture_callback(pcm, 2, None, None)
    frame = ap.get_capture_frame()
    result = struct.unpack("<2h", frame)
    assert result == (500, -500)


def test_playback_callback_applies_output_gain():
    """Output gain is applied during playback."""
    ap = AudioPipeline()
    ap.output_gain = 0.5
    pcm = struct.pack("<2h", 1000, -1000)
    ap.queue_playback(pcm)
    outdata = bytearray(4)
    ap._playback_callback(outdata, 2, None, None)
    result = struct.unpack("<2h", bytes(outdata))
    assert result == (500, -500)