import wave
import threading
import numpy as np


class AudioRecorder:
    def __init__(self, sample_rate: int = 16000, device: str | None = None):
        self.sample_rate = sample_rate
        self.device = device or None
        self._buffer: list[np.ndarray] = []
        self._stream = None
        self.is_recording = False
        self._lock = threading.Lock()

    def _callback(self, indata, frames, time, status):
        if self.is_recording:
            with self._lock:
                self._buffer.append(indata[:, 0].copy().astype(np.int16))

    def start(self):
        import sounddevice as sd
        self._buffer = []
        self.is_recording = True
        self._stream = sd.InputStream(
            samplerate=self.sample_rate,
            channels=1,
            dtype="int16",
            callback=self._callback,
            device=self.device,
        )
        self._stream.start()

    def stop(self):
        self.is_recording = False
        if self._stream:
            self._stream.stop()
            self._stream.close()
            self._stream = None

    def save_wav(self, path: str) -> str:
        with self._lock:
            data = np.concatenate(self._buffer) if self._buffer else np.zeros(0, dtype=np.int16)
        with wave.open(path, "wb") as wf:
            wf.setnchannels(1)
            wf.setsampwidth(2)
            wf.setframerate(self.sample_rate)
            wf.writeframes(data.tobytes())
        return path