from fastapi import FastAPI, Request, Query
from fastapi.responses import RedirectResponse
import httpx
import os
from .db import add_user
from dotenv import load_dotenv

load_dotenv()

app = FastAPI()

CLIENT_ID = os.environ.get("SLAKC_CLIENT_ID")
CLIENT_SECRET = os.environ.get("SLAKC_CLIENT_SECRET")
REDIRECT_URI = os.environ.get("SLAKC_REDIRECT_URI")

def validate_user_scopes(granted_scopes: str, required_scopes: list) -> bool:
    if not granted_scopes:
        return False
    granted_set = set(granted_scopes.split(','))
    required_set = set(required_scopes)
    return required_set.issubset(granted_set)

@app.get("/slack/oauth/install")
async def install():
    slack_auth_url = (
        "https://slack.com/oauth/v2/authorize"
        f"?client_id={CLIENT_ID}"
        f"&redirect_uri={REDIRECT_URI}"
        "&scope="
        "&user_scope=channels:write,channels:history,channels:read,chat:write,im:history,users:read"
    )
    return RedirectResponse(slack_auth_url)

@app.get("/slack/oauth/redirect")
async def oauth_redirect(request: Request, code: str = Query(...), state: str = Query(None)):
    async with httpx.AsyncClient() as client:
        response = await client.post("https://slack.com/api/oauth.v2.access", data={
            "client_id": CLIENT_ID,
            "client_secret": CLIENT_SECRET,
            "code": code,
            "redirect_uri": REDIRECT_URI
        })
        data = response.json()

    if not data.get("ok"):
        return {"error": data.get("error", "Unknown error")}

    user_id = data.get("authed_user", {}).get("id")
    access_token = data.get("authed_user", {}).get("access_token")
    granted_scopes = data.get("authed_user", {}).get("scope", "")

    if not user_id or not access_token:
        return {"error": "Could not get user info from OAuth response"}

    required_scopes = [
        "channels:write",
        "channels:history",
        "channels:read",
        "chat:write",
        "im:history",
        "users:read"
    ]

    if not validate_user_scopes(granted_scopes, required_scopes):
        return {"error": "Missing required OAuth scopes. Please re-install the app without modifying the URL."}

    await add_user(user_id, access_token)

    return {"message": "Successfully joined Botnet!", "user_id": user_id}