"""Voice transcription helpers for co-creation sessions."""

from __future__ import annotations

from dataclasses import dataclass

from fastapi import HTTPException
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.config import settings
from app.services.provider_router import transcribe_audio


@dataclass(frozen=True)
class VoiceTranscriptionResult:
    """Normalized transcription result for one uploaded voice turn."""

    transcript_text: str
    confidence: float | None = None
    provider: str = "demo"


def _resolve_transcript_hint(transcript_hint: str | None) -> str | None:
    normalized = (transcript_hint or "").strip()
    return normalized or None


async def transcribe_voice_audio(
    *,
    audio_bytes: bytes,
    file_name: str,
    mime_type: str | None,
    transcript_hint: str | None = None,
    db: AsyncSession | None = None,
    user_id: str | None = None,
) -> VoiceTranscriptionResult:
    """Transcribe one uploaded audio turn using configured ASR providers."""

    mode = (settings.voice_transcription_mode or "provider").strip().lower()

    if mode == "disabled":
        raise HTTPException(
            status_code=503,
            detail="当前环境已禁用语音转写，请先使用文本共创模式。",
        )

    hint = _resolve_transcript_hint(transcript_hint)
    provider_name = "openai_asr" if mode == "openai" else mode
    strategy_providers = None if mode == "provider" else [provider_name]
    result = await transcribe_audio(
        audio_bytes=audio_bytes,
        file_name=file_name,
        mime_type=mime_type,
        transcript_hint=hint,
        language=settings.voice_transcription_language,
        provider_names=strategy_providers,
        db=db,
        user_id=user_id,
    )

    return VoiceTranscriptionResult(
        transcript_text=result.transcript_text,
        confidence=result.confidence,
        provider=result.provider,
    )