main.py

from fastapi import FastAPI, HTTPException, Response
from fastapi.responses import JSONResponse
from pydantic import BaseModel
from audio_separator.separator import Separator
import ffmpeg
from datetime import datetime
import logging
import os
import uuid
from youtube_transcript_api import YouTubeTranscriptApi
import asyncio
from fastapi.concurrency import run_in_threadpool
from concurrent.futures import ThreadPoolExecutor

app = FastAPI()
tmp_directory = "tmp"
separator = Separator(output_dir=tmp_directory, log_level=logging.INFO)
logging.getLogger().setLevel(logging.INFO)
separator.load_model("UVR-MDX-NET-Inst_Main.onnx")

extractionExecuter = ThreadPoolExecutor(max_workers=8)
ffmpegExecuter = ThreadPoolExecutor(max_workers=8)


class IsolationRequest(BaseModel):
    url: str
    start_time: float
    duration_seconds: float


@app.post("/isolate")
async def isolate_voice(request: IsolationRequest):
    media_url = request.url
    start_seconds = request.start_time
    duration_seconds = request.duration_seconds
    try:
        extracted_audio_path = f"{tmp_directory}/{uuid.uuid4()}.wav"

        # TODO switch to CUDA
        await extract_audio(
            media_url, start_seconds, duration_seconds, extracted_audio_path
        )

        (
            primary_stem_output_path,
            secondary_stem_output_path,
        ) = await asyncio.get_event_loop().run_in_executor(
            extractionExecuter,
            separator.separate,
            extracted_audio_path,
        )

        with open(f"{tmp_directory}/{primary_stem_output_path}", "rb") as f:
            isolated_audio_data = f.read()

    except Exception as e:
        logging.error(f"An error occurred: {str(e)}")
        raise HTTPException(
            status_code=500, detail="An error occurred during vocal isolation"
        )

    finally:
        try:
            os.remove(extracted_audio_path)
            os.remove(f"{tmp_directory}/{primary_stem_output_path}")
            os.remove(f"{tmp_directory}/{secondary_stem_output_path}")
        except OSError as e:
            logging.warning(
                f"Error occurred while cleaning up temporary files: {str(e)}"
            )

    return Response(content=isolated_audio_data, media_type="audio/wav")


async def extract_audio(
    media_url: str, start_seconds: float, duration_seconds: float, output_path: str
):
    start_time = datetime.now()
    await asyncio.get_event_loop().run_in_executor(
        ffmpegExecuter,  # Uses the default executor
        lambda: ffmpeg.input(media_url, ss=start_seconds)
        .output(output_path, format="wav", t=duration_seconds)
        .global_args("-loglevel", "error", "-hide_banner")
        .global_args("-nostats")
        .run(),
    )

    end_time = datetime.now()
    logging.info(
        f"Audio extraction took {(end_time - start_time).total_seconds()} seconds"
    )


def scrape_subtitles(video_id, translate_to, translate_from):
    transcript_list = YouTubeTranscriptApi.list_transcripts(
        video_id,
    )

    # see if translation already exists
    try:
        return transcript_list.find_transcript([translate_to]).fetch()
    except:
        pass

    # find transcription in video language
    try:
        return (
            transcript_list.find_transcript([translate_from])
            .translate(translate_to)
            .fetch()
        )

    except:
        pass

    # search for any other translatable languages
    for transcript in transcript_list:
        try:
            return transcript.translate(translate_to).fetch()
        except:
            continue

    return None


def format_language_code(lang: str) -> str:
    mapping = {
        "he": "iw",
        "zh": "zh-Hans",
        "zh-TW": "zh-Hant",
    }
    return mapping.get(lang, lang.split("-")[0])


class SubtitleRequest(BaseModel):
    video_id: str
    translate_to: str
    translate_from: str


@app.post("/subtitles")
async def get_subtitles(request: SubtitleRequest):
    try:
        subtitles = await run_in_threadpool(
            scrape_subtitles,
            request.video_id,
            format_language_code(request.translate_to),
            format_language_code(request.translate_from),
        )
        if subtitles is None:
            return Response("Not available", 400)
        return JSONResponse(subtitles, 200)
    except Exception as e:
        logging.warn(e)
        raise HTTPException(
            status_code=500, detail="An error occurred while getting subtitles"
        )


# if __name__ == "__main__":
#     import uvicorn

#     uvicorn.run(app, host="0.0.0.0", port=8000)