from __future__ import annotations

import logging

logger = logging.getLogger(__name__)

SUPPORTED_AUDIO_FORMATS = frozenset({
    "aac", "aiff", "alac", "amr", "caf", "flac",
    "m4a", "mp3", "oga", "wav", "webm", "wma",
})

NATIVE_OPUS_EXTS = frozenset({".opus", ".ogg"})

FFMPEG_OPUS_CMD = (
    "ffmpeg -i {input_path} -vn -ar 48000 -ac 1 -c:a libopus -b:a 64k {output_path}"
)


def is_native_opus(filename: str) -> bool:
    ext = filename.rsplit(".", 1)[-1].lower() if "." in filename else ""
    return f".{ext}" in NATIVE_OPUS_EXTS


def requires_transcoding(filename: str) -> bool:
    ext = filename.rsplit(".", 1)[-1].lower() if "." in filename else ""
    return ext in SUPPORTED_AUDIO_FORMATS and not is_native_opus(filename)


def build_transcode_command(input_path: str, output_path: str) -> str:
    return FFMPEG_OPUS_CMD.format(input_path=input_path, output_path=output_path)


async def transcode_to_opus(
    input_path: str,
    output_path: str,
    max_duration_secs: int = 300,
) -> dict:
    import asyncio

    if not requires_transcoding(input_path):
        return {"success": True, "path": input_path, "transcoded": False}

    cmd = build_transcode_command(input_path, output_path)

    try:
        proc = await asyncio.create_subprocess_shell(
            cmd,
            stdout=asyncio.subprocess.PIPE,
            stderr=asyncio.subprocess.PIPE,
        )
        stdout, stderr = await asyncio.wait_for(
            proc.communicate(), timeout=max_duration_secs + 10
        )

        if proc.returncode == 0:
            return {"success": True, "path": output_path, "transcoded": True}
        else:
            error_msg = stderr.decode("utf-8", errors="replace")[:500]
            logger.error("FFmpeg transcoding failed: %s", error_msg)
            return {"success": False, "error": error_msg, "path": None, "transcoded": False}
    except asyncio.TimeoutError:
        return {"success": False, "error": "Transcoding timed out", "path": None, "transcoded": False}
    except FileNotFoundError:
        return {"success": False, "error": "ffmpeg not found in PATH", "path": None, "transcoded": False}
    except Exception:
        logger.exception("Voice transcoding error")
        return {"success": False, "error": "Internal error during transcoding", "path": None, "transcoded": False}