from fastapi import APIRouter, HTTPException
from pydantic import BaseModel
from fastapi.responses import FileResponse
import os
from pathlib import Path
import uuid
from typing import List
import asyncio
# moviepy is imported lazily inside the conversion function to avoid
# failing module import at application startup when the package is missing.

router = APIRouter(prefix="/convert", tags=["convert"])


@router.get("/list-audio", response_model=List[str])
async def list_audio_files():
    base_dir = Path(__file__).resolve().parent.parent.parent / "data" / "audio"
    if not base_dir.exists():
        return []
    files = [f.name for f in base_dir.iterdir() if f.is_file()]
    return files


class DownloadAudioRequest(BaseModel):
    filename: str


@router.post("/download-audio")
async def download_audio_file(data: DownloadAudioRequest):
    base_dir = Path(__file__).resolve().parent.parent.parent / "data" / "audio"
    src = (base_dir / data.filename).resolve()
    try:
        src.relative_to(base_dir.parent)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid filename")
    if not src.exists():
        raise HTTPException(status_code=404, detail="File not found")
    return FileResponse(str(src), filename=src.name, media_type="audio/mpeg")


# New: convert a video file (located in ./data) to mp3 using bundled imageio-ffmpeg
class VideoToMp3Request(BaseModel):
    filename: str


def _run_moviepy(src: Path, dest: Path):
    from moviepy import VideoFileClip

    clip = VideoFileClip(str(src))
    try:
        if clip.audio is None:
            raise RuntimeError("Source file has no audio stream")
        clip.audio.write_audiofile(str(dest), codec="libmp3lame", bitrate="192k")
    finally:
        clip.close()


@router.post("/video-to-mp3")
async def video_to_mp3(req: VideoToMp3Request):
    # ensure MoviePy is available before doing work, return clear 503 if not
    try:
        import moviepy  # noqa: F401
    except Exception:
        raise HTTPException(status_code=503, detail="moviepy is not installed in the runtime. Rebuild image or install moviepy/imageio-ffmpeg")

    data_dir = Path(__file__).resolve().parent.parent.parent / "data"
    src = (data_dir / req.filename).resolve()
    try:
        src.relative_to(data_dir)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid filename")
    if not src.exists() or not src.is_file():
        raise HTTPException(status_code=404, detail="Source file not found")

    out_dir = data_dir / "audio"
    out_dir.mkdir(parents=True, exist_ok=True)
    dest = out_dir / f"{src.stem}.mp3"

    try:
        # run blocking MoviePy conversion in threadpool to avoid blocking event loop
        await asyncio.get_running_loop().run_in_executor(None, _run_moviepy, src, dest)
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"conversion failed: {e}")

    return FileResponse(str(dest), filename=dest.name, media_type="audio/mpeg")


# Note: this endpoint uses the bundled ffmpeg provided by `imageio-ffmpeg`.