import numpy as np

from livesub.audio.segmenter import Segmenter, SegmenterConfig
from livesub.constants import SAMPLE_RATE


def tone(ms: int, amplitude: float = 0.3) -> np.ndarray:
    n = SAMPLE_RATE * ms // 1000
    t = np.arange(n, dtype=np.float32) / SAMPLE_RATE
    return (np.sin(2 * np.pi * 220 * t) * amplitude).astype(np.float32)


def silence(ms: int) -> np.ndarray:
    return np.zeros(SAMPLE_RATE * ms // 1000, dtype=np.float32)


def config(**kw) -> SegmenterConfig:
    base = dict(silence_ms=300, min_segment_ms=200, max_segment_ms=5000,
                partial_interval_ms=0)
    base.update(kw)
    return SegmenterConfig(**base)


def test_speech_then_silence_emits_one_final_segment():
    seg = Segmenter(config())
    out = seg.push(silence(200))
    assert out == []
    out += seg.push(tone(800))
    out += seg.push(silence(600))
    finals = [s for s in out if s.is_final]
    assert len(finals) == 1
    assert 0.7 <= finals[0].duration_s <= 1.8


def test_short_blip_is_discarded():
    seg = Segmenter(config(min_segment_ms=500))
    out = seg.push(tone(60)) + seg.push(silence(600))
    assert out == []


def test_max_length_forces_a_cut():
    seg = Segmenter(config(max_segment_ms=1000))
    out = seg.push(tone(3000))
    assert len([s for s in out if s.is_final]) >= 2


def test_partial_results_are_emitted_while_speaking():
    seg = Segmenter(config(partial_interval_ms=300))
    out = seg.push(tone(1500))
    partials = [s for s in out if not s.is_final]
    assert len(partials) >= 2
    # 중간 결과는 누적된다
    assert partials[-1].duration_s > partials[0].duration_s


def test_flush_returns_pending_speech():
    seg = Segmenter(config())
    assert seg.push(tone(700)) == []  # 아직 침묵이 안 왔으니 확정 없음
    leftover = seg.flush()
    assert leftover is not None and leftover.is_final
    assert seg.flush() is None


def test_continuous_silence_never_emits():
    seg = Segmenter(config())
    for _ in range(10):
        assert seg.push(silence(200)) == []


def test_lead_in_is_prepended():
    """발화 직전 오디오가 붙어 첫 음절이 잘리지 않아야 한다."""
    seg = Segmenter(config(lead_in_ms=200))
    seg.push(silence(400))
    out = seg.push(tone(600)) + seg.push(silence(600))
    finals = [s for s in out if s.is_final]
    assert len(finals) == 1
    # 0.6초 발화 + 최대 0.2초 리드인
    assert finals[0].duration_s > 0.6