"""Exact pinned local-audio preparation fragment with its direct dependencies."""

import os
from pathlib import Path
import shutil
import subprocess
from typing import Optional


LOCAL_NATIVE_AUDIO_FORMATS = {".wav", ".aiff", ".aif"}
logger = __import__("logging").getLogger(__name__)


def _find_ffmpeg_binary() -> Optional[str]:
    return shutil.which("ffmpeg")


def windows_hide_flags() -> int:
    return 0


def _prepare_local_audio(file_path: str, work_dir: str) -> tuple[Optional[str], Optional[str]]:
    """Normalize audio for local CLI STT when needed."""
    audio_path = Path(file_path)
    if audio_path.suffix.lower() in LOCAL_NATIVE_AUDIO_FORMATS:
        return file_path, None

    ffmpeg = _find_ffmpeg_binary()
    if not ffmpeg:
        return None, "Local STT fallback requires ffmpeg for non-WAV inputs, but ffmpeg was not found"

    converted_path = os.path.join(work_dir, f"{audio_path.stem}.wav")
    command = [ffmpeg, "-y", "-i", file_path, converted_path]

    try:
        subprocess.run(command, check=True, capture_output=True, text=True, timeout=300, stdin=subprocess.DEVNULL, creationflags=windows_hide_flags())
        return converted_path, None
    except subprocess.TimeoutExpired:
        logger.error("ffmpeg conversion timed out for %s", file_path)
        return None, "Audio conversion for local STT timed out"
    except subprocess.CalledProcessError as e:
        details = e.stderr.strip() or e.stdout.strip() or str(e)
        logger.error("ffmpeg conversion failed for %s: %s", file_path, details)
        return None, f"Failed to convert audio for local STT: {details}"