import os
import sys
import logging
import asyncio
from pathlib import Path
from typing import Optional, Tuple

logger = logging.getLogger("AGYVoiceTranscriber")

_whisper_model = None

def get_whisper_model():
    """Lazy loader for singleton WhisperModel instance."""
    global _whisper_model
    if _whisper_model is None:
        try:
            from faster_whisper import WhisperModel
            logger.info("Initializing faster-whisper model (base, int8)...")
            _whisper_model = WhisperModel("base", device="cpu", compute_type="int8")
            logger.info("faster-whisper model initialized successfully.")
        except Exception as e:
            logger.error(f"Failed to load faster-whisper model: {e}", exc_info=True)
            _whisper_model = None
    return _whisper_model

def _transcribe_sync(audio_path: str, language: Optional[str] = None) -> Tuple[bool, str, str]:
    model = get_whisper_model()
    if model is None:
        return False, "", "unknown"

    try:
        # Default to Persian (fa) unless explicitly specified otherwise
        lang = language if (language and language not in ("auto", "none")) else "fa"
        segments, info = model.transcribe(
            audio_path,
            beam_size=5,
            language=lang,
            vad_filter=True,
            initial_prompt="گفتگوی محاوره‌ای و رسمی به زبان فارسی",
        )
        texts = [seg.text.strip() for seg in segments if seg.text.strip()]
        full_text = " ".join(texts).strip()
        detected_lang = getattr(info, "language", "unknown")
        return True, full_text, detected_lang
    except Exception as e:
        logger.error(f"Error transcribing audio {audio_path}: {e}", exc_info=True)
        return False, str(e), "unknown"

async def transcribe_audio_file(audio_path: str, language: Optional[str] = None) -> Tuple[bool, str, str]:
    """
    Asynchronously transcribes audio file (OGG, MP3, WAV, M4A, etc.) to text.
    Returns: (success, transcribed_text, detected_language)
    """
    return await asyncio.to_thread(_transcribe_sync, audio_path, language)