import os
import asyncio
from telethon.sync import TelegramClient
from telethon.sessions import StringSession
from fastapi import FastAPI, UploadFile, File, HTTPException
from fastapi.responses import FileResponse
import uvicorn
import socks

# Configuration from environment variables
SESSION_STRING = os.environ.get('SESSION_STRING')
API_ID = os.environ.get('API_ID') # You need to get your API_ID from my.telegram.org
API_HASH = os.environ.get('API_HASH') # You need to get your API_HASH from my.telegram.org
PROXY_IP = os.environ.get('PROXY_IP')
PROXY_PORT = os.environ.get('PROXY_PORT')
PROXY_TYPE = os.environ.get('PROXY_TYPE', 'socks5').lower() # Default to socks5

# The Telegram channel you want to upload files to
TARGET_CHANNEL = 'https://t.me/TestNAI01'

# Directory to store uploaded files temporarily
UPLOAD_DIR = "uploads"
os.makedirs(UPLOAD_DIR, exist_ok=True)

app = FastAPI()

def get_proxy():
    """Returns proxy settings if configured."""
    if PROXY_IP and PROXY_PORT:
        proxy_type_map = {
            'socks4': socks.SOCKS4,
            'socks5': socks.SOCKS5,
            'http': socks.HTTP,
        }
        return (proxy_type_map.get(PROXY_TYPE, socks.SOCKS5), PROXY_IP, int(PROXY_PORT))
    return None

async def upload_to_telegram(file_path: str):
    """
    Uploads a file to the specified Telegram channel using a session string.
    """
    if not SESSION_STRING or not API_ID or not API_HASH:
        raise ValueError("SESSION_STRING, API_ID, and API_HASH must be set in environment variables.")

    proxy = get_proxy()

    async with TelegramClient(StringSession(SESSION_STRING), API_ID, API_HASH, proxy=proxy) as client:
        try:
            await client.send_file(TARGET_CHANNEL, file_path)
        except Exception as e:
            raise HTTPException(status_code=500, detail=f"Failed to upload to Telegram: {e}")

@app.post("/v1/upload")
async def upload_file(file: UploadFile = File(...)):
    """
    Receives a file and uploads it to the Telegram channel.
    """
    file_location = os.path.join(UPLOAD_DIR, file.filename)
    with open(file_location, "wb+") as file_object:
        file_object.write(file.file.read())

    try:
        await upload_to_telegram(file_location)
        return {"message": f"File '{file.filename}' uploaded successfully to Telegram."}
    finally:
        # Clean up the local file after uploading
        if os.path.exists(file_location):
            os.remove(file_location)

@app.get("/v1/download/{filename}")
async def download_file(filename: str):
    """
    Serves a file for download.
    Note: This endpoint serves files from the local 'uploads' directory.
    For a production system, you would need a more robust way to retrieve files,
    possibly by storing a mapping of filenames to Telegram message IDs.
    """
    file_path = os.path.join(UPLOAD_DIR, filename)
    if os.path.exists(file_path):
        return FileResponse(file_path)
    raise HTTPException(status_code=404, detail="File not found. This is a simple server; for production, a proper file retrieval from Telegram would be needed.")

if __name__ == "__main__":
    # This block is for local testing without Docker
    # To run with Docker, the CMD in the Dockerfile will be used
    if not all([SESSION_STRING, API_ID, API_HASH]):
        print("Error: SESSION_STRING, API_ID, and API_HASH environment variables must be set.")
    else:
        uvicorn.run(app, host="0.0.0.0", port=8000)