import numpy as np
import librosa
from config import SAMPLE_RATE, CHUNK_SIZE


def load_audio_as_int16(audio_path: str) -> np.ndarray:
    """Load file âm thanh, resample về 16kHz, trả về int16."""
    y, _ = librosa.load(audio_path, sr=SAMPLE_RATE)
    return (y * 32767).astype(np.int16)


def iter_chunks(audio_int16: np.ndarray, chunk_size: int = CHUNK_SIZE):
    """Yield từng chunk, tự pad chunk cuối nếu thiếu."""
    for i in range(0, len(audio_int16), chunk_size):
        chunk = audio_int16[i : i + chunk_size]
        if len(chunk) < chunk_size:
            chunk = np.pad(chunk, (0, chunk_size - len(chunk)))
        yield chunk


def make_silence(chunk_size: int = CHUNK_SIZE) -> np.ndarray:
    """Trả về 1 chunk toàn silence (dùng để flush model)."""
    return np.zeros(chunk_size, dtype=np.int16)