from fastapi import FastAPI, HTTPException, Query
from youtube_transcript_api import YouTubeTranscriptApi, TranscriptsDisabled, NoTranscriptFound
from urllib.parse import urlparse, parse_qs

app = FastAPI()

def extract_video_id(youtube_url: str) -> str:
    try:
        parsed_url = urlparse(youtube_url)
        video_id = parse_qs(parsed_url.query).get("v", [None])[0]
        if not video_id:
            raise ValueError("Invalid YouTube URL.")
        return video_id
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid YouTube URL format.")

@app.get("/transcript")
def get_transcript(youtube_url: str = Query(..., description="Full YouTube video URL")):
    video_id = extract_video_id(youtube_url)
    try:
        transcript = YouTubeTranscriptApi.get_transcript(video_id)
        text_only = " ".join([entry["text"] for entry in transcript])
        return {
            "video_id": video_id,
            "transcript": text_only
        }
    except TranscriptsDisabled:
        raise HTTPException(status_code=404, detail="Transcripts are disabled for this video.")
    except NoTranscriptFound:
        raise HTTPException(status_code=404, detail="No transcript found for this video.")
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))