import os
import uuid
from fastapi import FastAPI, Request, Form
from fastapi.templating import Jinja2Templates
from fastapi.responses import HTMLResponse, FileResponse
from fastapi.concurrency import run_in_threadpool
import yt_dlp

app = FastAPI()
templates = Jinja2Templates(directory="templates")

# Use /tmp/downloads which is writable in most environments like Hugging Face Spaces
DOWNLOAD_FOLDER = "/tmp/downloads"
os.makedirs(DOWNLOAD_FOLDER, exist_ok=True)

def download_video(url: str, output_path: str):
    ydl_opts = {
        'outtmpl': output_path,  # File output template (unique_id.ext)
        'format': 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best',  # Download best quality
        'merge_output_format': 'mp4',  # Merge into MP4
        'quiet': True,
        'no_warnings': True,
    }
    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        ydl.download([url])

@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    return templates.TemplateResponse("index.html", {"request": request})

@app.post("/download", response_class=HTMLResponse)
async def download(request: Request, video_url: str = Form(...)):
    unique_id = uuid.uuid4().hex
    # The file will be saved as <unique_id>.<ext>
    output_template = os.path.join(DOWNLOAD_FOLDER, f"{unique_id}.%(ext)s")
    try:
        # Offload the blocking download function to a thread
        await run_in_threadpool(download_video, video_url, output_template)
        downloaded_file = None
        # Locate the downloaded file
        for file in os.listdir(DOWNLOAD_FOLDER):
            if file.startswith(unique_id):
                downloaded_file = file
                break
        if not downloaded_file:
            raise Exception("Failed to download video.")
        download_link = f"/download_file/{downloaded_file}"
        return templates.TemplateResponse("result.html", {"request": request, "download_link": download_link})
    except Exception as e:
        return templates.TemplateResponse("index.html", {"request": request, "error": str(e)})

@app.get("/download_file/{filename}", response_class=FileResponse)
async def get_file(filename: str):
    file_path = os.path.join(DOWNLOAD_FOLDER, filename)
    if os.path.exists(file_path):
        return FileResponse(file_path, media_type='video/mp4', filename=filename)
    return HTMLResponse("File not found", status_code=404)