# app/main.py
import uuid
import time
import shutil
import asyncio
from pathlib import Path

import aiofiles
from fastapi import FastAPI, Request, UploadFile, File, HTTPException, Depends
from fastapi.responses import JSONResponse, HTMLResponse, FileResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates

from . import utils

# --- App Setup ---
app = FastAPI(title="Triflix Simple Uploader")
app.mount("/static", StaticFiles(directory="app/static"), name="static")
templates = Jinja2Templates(directory="app/templates")

# Ensure base upload directory exists on startup
utils.UPLOAD_ROOT.mkdir(parents=True, exist_ok=True)

# --- Background Cleanup Task ---
async def cleanup_expired_uploads():
    """Periodically scans for and removes expired uploads."""
    while True:
        await asyncio.sleep(60 * 10)  # Run every 10 minutes
        now = time.time()
        for upload_dir in utils.UPLOAD_ROOT.iterdir():
            if not upload_dir.is_dir():
                continue
            try:
                meta = utils.load_meta(upload_dir.name)
                # Expire after 1 hour (3600 seconds)
                if meta.get("created_at_ts", 0) < now - 3600:
                    print(f"Cleaning up expired upload: {upload_dir.name}")
                    shutil.rmtree(upload_dir, ignore_errors=True)
            except Exception as e:
                print(f"Error during cleanup of {upload_dir.name}: {e}")

@app.on_event("startup")
async def on_startup():
    asyncio.create_task(cleanup_expired_uploads())

# --- Dependency ---
def get_request_ip(request: Request):
    return request.client.host

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

@app.post("/upload", status_code=201)
async def create_upload(file: UploadFile = File(...), ip: str = Depends(get_request_ip)):
    if not utils.enforce_rate_limit(ip, limit=5, per_seconds=60):
        raise HTTPException(status_code=429, detail="Upload limit exceeded.")

    upload_id = uuid.uuid4().hex
    upload_dir = utils.get_upload_dir(upload_id)
    upload_dir.mkdir()
    
    file_path = upload_dir / file.filename
    
    # Stream the file to disk asynchronously
    try:
        async with aiofiles.open(file_path, "wb") as f:
            while content := await file.read(1024 * 1024):  # Read in 1MB chunks
                await f.write(content)
    except Exception as e:
        # Clean up if upload fails
        shutil.rmtree(upload_dir, ignore_errors=True)
        raise HTTPException(status_code=500, detail=f"Failed to write file to disk: {e}")
    
    file_size = file_path.stat().st_size
    now = time.time()

    meta = {
        "upload_id": upload_id,
        "filename": file.filename,
        "size_bytes": file_size,
        "created_at_ts": now,
        "owner_ip": ip,
        "file_path": str(file_path)
    }
    utils.save_meta(upload_id, meta)
    
    return {
        "upload_id": upload_id,
        "filename": file.filename,
        "size_bytes": file_size,
        "download_url": f"/download/{upload_id}",
    }

@app.get("/download/{upload_id}")
async def download_file(upload_id: str):
    try:
        meta = utils.load_meta(upload_id)
        file_path = Path(meta["file_path"])
        
        if not file_path.exists():
            raise HTTPException(status_code=404, detail="File not found on server.")
        
        return FileResponse(
            path=file_path,
            filename=meta["filename"],
            media_type="application/octet-stream"
        )
    except FileNotFoundError:
        raise HTTPException(status_code=404, detail="Upload session not found.")