"""Optional local Whisper transcription of reference audio."""

import logging
from typing import Optional

logger = logging.getLogger(__name__)


def transcribe_reference_audio(audio_path: str, model_name: str = "base") -> Optional[str]:
    """Transcribe reference audio locally using an optional Whisper backend.

    The current qwen-tts demo does not expose a transcription endpoint, so
    transcription is done client-side when a Whisper package is available.
    Returns None if no backend is installed.
    """
    for backend in ("faster_whisper", "whisper"):
        try:
            if backend == "faster_whisper":
                from faster_whisper import WhisperModel
                model = WhisperModel(model_name, device="cpu", compute_type="int8")
                segments, _ = model.transcribe(audio_path)
                text = " ".join(seg.text.strip() for seg in segments).strip()
            else:
                import whisper
                model = whisper.load_model(model_name)
                result = model.transcribe(audio_path)
                text = (result.get("text") or "").strip()
            if text:
                logger.info("Transcription complete via %s: %s", backend, text)
                return text
        except ImportError:
            continue
        except Exception as exc:
            logger.warning("%s transcription failed: %s", backend, exc)
    logger.warning("No Whisper backend available; transcription skipped.")
    return None


def whisper_backend_available() -> Optional[str]:
    """Return the name of an importable Whisper backend, or None.

    Checks faster_whisper first (preferred), then the openai-whisper
    package, without importing the heavy model code: a bare import probe
    is enough to tell whether the package is installed in the current
    environment. Used by the make_audiocpp_server_json tool to warn when
    neither is present (e.g. the wrong conda environment is active).
    """
    for backend in ("faster_whisper", "whisper"):
        try:
            __import__(backend)
        except ImportError:
            continue
        return backend
    return None