from fastapi import APIRouter, HTTPException, Request
from fastapi.responses import RedirectResponse
from datetime import datetime, timedelta
import httpx
import os
import jwt

from api.database.mongodb import users_collection

router = APIRouter(prefix="/auth/google", tags=["auth"])

GOOGLE_CLIENT_ID = os.getenv("GOOGLE_CLIENT_ID")
GOOGLE_CLIENT_SECRET = os.getenv("GOOGLE_CLIENT_SECRET")
REDIRECT_URI = os.getenv("GOOGLE_REDIRECT_URI")
SECRET_KEY = os.getenv("SECRET_KEY")
FRONTEND_URL = os.getenv("FRONTEND_URL", "http://localhost:5173")

@router.get("/login")
async def google_login():
    google_auth_url = (
        "https://accounts.google.com/o/oauth2/auth"
        "?response_type=code"
        f"&client_id={GOOGLE_CLIENT_ID}"
        f"&redirect_uri={REDIRECT_URI}"
        "&scope=openid%20email%20profile"
        "&access_type=offline"
        "&prompt=consent"
    )

    return RedirectResponse(google_auth_url)

@router.get("/callback")
async def google_callback(request: Request):

    code = request.query_params.get("code")
    if not code:
        raise HTTPException(status_code=400, detail="Missing code parameter")

    token_url = "https://oauth2.googleapis.com/token"

    data = {
        "code": code,
        "client_id": GOOGLE_CLIENT_ID,
        "client_secret": GOOGLE_CLIENT_SECRET,
        "redirect_uri": REDIRECT_URI,
        "grant_type": "authorization_code",
    }

    async with httpx.AsyncClient() as client:
        token_response = await client.post(token_url, data=data)
        token_json = token_response.json()

    if "access_token" not in token_json:
        raise HTTPException(status_code=400, detail=token_json)

    access_token = token_json["access_token"]

    async with httpx.AsyncClient() as client:
        userinfo = await client.get(
            "https://www.googleapis.com/oauth2/v2/userinfo",
            headers={"Authorization": f"Bearer {access_token}"}
        )

    user_data = userinfo.json()

    google_id = user_data["id"]
    email = user_data["email"]
    name = user_data.get("name", "Usuario")

    user = await users_collection.find_one({"email": email})

    if not user:
        new_user = {
            "username": name,
            "email": email,
            "password_hash": None,
            "google_id": google_id,
            "history": [],
        }
        result = await users_collection.insert_one(new_user)
        user_id = result.inserted_id
    else:
        user_id = user["_id"]

    token = jwt.encode(
        {
            "sub": str(user_id),
            "email": email,
            "name": name,
            "exp": datetime.utcnow() + timedelta(hours=24)
        },
        SECRET_KEY,
        algorithm="HS256"
    )

    await users_collection.update_one(
        {"_id": user_id},
        {"$set": {"token": token}}
    )

    return RedirectResponse(f"{FRONTEND_URL}/login?token={token}")