from __future__ import annotations

from typing import Optional


class VADService:
    def __init__(self) -> None:
        self._model = None
        self._iterator = None
        self._ready = False
        self._attempted = False
        self._error: Optional[str] = None

    def _ensure_loaded(self) -> None:
        if self._ready or self._attempted:
            return
        self._attempted = True
        try:
            from silero_vad import VADIterator, load_silero_vad

            self._model = load_silero_vad()
            self._iterator = VADIterator(
                self._model,
                threshold=0.5,
                sampling_rate=16000,
                min_silence_duration_ms=300,
                speech_pad_ms=30,
            )
            self._ready = True
        except Exception as exc:  # pragma: no cover
            self._error = str(exc)

    def push_chunk(self, pcm_chunk):
        self._ensure_loaded()
        if self._ready and self._iterator is not None:
            return self._iterator(pcm_chunk)
        return None

    @property
    def health(self) -> dict:
        return {"ready": self._ready, "attempted": self._attempted, "error": self._error}