"""Speech-to-text via an OpenAI-compatible /audio/transcriptions endpoint.

Bale voice notes arrive as OGG/Opus which not every provider accepts, so the
audio is first converted to mono 16 kHz MP3 with ffmpeg (installed in the bot
image). Any OpenAI-compatible provider works (OpenAI, GLM, OpenRouter proxies,
self-hosted whisper servers exposing the same contract).
"""
import asyncio
import logging
import subprocess
import tempfile
from pathlib import Path

import httpx

from app.config import Settings

logger = logging.getLogger("bot.stt")

_CONVERT_TIMEOUT = 60
_STT_TIMEOUT = 120


def _to_mp3(raw: bytes, suffix: str) -> bytes:
    """Convert arbitrary audio bytes to mono 16 kHz MP3 using ffmpeg."""
    with tempfile.TemporaryDirectory() as tmp:
        src = Path(tmp) / f"in{suffix or '.ogg'}"
        dst = Path(tmp) / "out.mp3"
        src.write_bytes(raw)
        proc = subprocess.run(
            ["ffmpeg", "-y", "-i", str(src), "-vn", "-ac", "1", "-ar", "16000", "-b:a", "64k", str(dst)],
            capture_output=True,
            timeout=_CONVERT_TIMEOUT,
        )
        if proc.returncode != 0 or not dst.exists():
            raise RuntimeError(f"ffmpeg failed: {proc.stderr[-400:]!r}")
        return dst.read_bytes()


async def transcribe(settings: Settings, audio: bytes, mime_type: str | None = None,
                     filename: str | None = None) -> str:
    """Return the Persian transcript for a voice note (empty string on silence)."""
    if not settings.stt_base_url or not settings.stt_api_key:
        raise RuntimeError("STT provider is not configured (PROCUREMENT_BOT_STT_BASE_URL / _AI_BASE_URL)")

    suffix = Path(filename or "").suffix
    if not suffix and mime_type:
        suffix = {"audio/ogg": ".ogg", "audio/opus": ".ogg", "audio/mpeg": ".mp3",
                  "audio/mp4": ".m4a", "audio/wav": ".wav"}.get(mime_type.split(";")[0].strip(), ".ogg")
    converted = await asyncio.to_thread(_to_mp3, audio, suffix)

    url = f"{settings.stt_base_url.rstrip('/')}/audio/transcriptions"
    async with httpx.AsyncClient(timeout=_STT_TIMEOUT) as client:
        resp = await client.post(
            url,
            headers={"Authorization": f"Bearer {settings.stt_api_key}"},
            files={"file": ("voice.mp3", converted, "audio/mpeg")},
            data={"model": settings.STT_MODEL, "language": settings.STT_LANGUAGE},
        )
    if resp.status_code != 200:
        raise RuntimeError(f"STT provider returned HTTP {resp.status_code}: {resp.text[:300]}")
    return str((resp.json() or {}).get("text") or "").strip()