import os
import uuid
from typing import Optional

from fastapi import Depends, Request
from fastapi_users import BaseUserManager, FastAPIUsers, UUIDIDMixin
from fastapi_users.authentication import (
    AuthenticationBackend,
    BearerTransport,
)
from fastapi_users.authentication.strategy.jwt import JWTStrategy
from fastapi_users.db import SQLAlchemyUserDatabase

from app.models.user import User
from app.services.db import get_user_db
from app.core.queue import enqueue_email

SECRET = os.getenv("SECRET", "CHANGE_ME_SECRET")
FRONTEND_URL = os.getenv("FRONTEND_URL", "http://localhost:5173")
BACKEND_URL = os.getenv("BACKEND_URL", "http://localhost:8000")

class UserManager(UUIDIDMixin, BaseUserManager[User, uuid.UUID]):
    reset_password_token_secret = SECRET
    verification_token_secret = SECRET

    async def on_after_register(self, user: User, request: Optional[Request] = None):
        await self.request_verify(user, request)

    async def on_after_forgot_password(
            self, user: User, token: str, request: Optional[Request] = None
    ):
        print(f"User {user.id} has forgot their password. Reset token: {token}")

    async def on_after_request_verify(
            self, user: User, token: str, request: Optional[Request] = None
    ):
        verify_frontend_link = f"{FRONTEND_URL}/verify?token={token}"
        verify_backend_link = f"{BACKEND_URL}/auth/verify?token={token}"
        subject = "Ověření účtu"
        body = (
            "Ahoj,\n\n"
            "děkujeme za registraci. Prosíme, ověř svůj účet kliknutím na tento odkaz:\n"
            f"{verify_frontend_link}\n\n"
            "Pokud by odkaz nefungoval, můžeš použít i přímý odkaz na backend:\n"
            f"{verify_backend_link}\n\n"
            "Pokud jsi registraci neprováděl(a), tento email ignoruj.\n"
        )
        try:
            enqueue_email(to=user.email, subject=subject, body=body)
        except Exception as e:
            print("[Email Fallback] To:", user.email)
            print("[Email Fallback] Subject:", subject)
            print("[Email Fallback] Body:\n", body)

async def get_user_manager(user_db: SQLAlchemyUserDatabase = Depends(get_user_db)):
    yield UserManager(user_db)

bearer_transport = BearerTransport(tokenUrl="auth/jwt/login")

def get_jwt_strategy() -> JWTStrategy:
    return JWTStrategy(secret=SECRET, lifetime_seconds=3600)

auth_backend = AuthenticationBackend(
    name="jwt",
    transport=bearer_transport,
    get_strategy=get_jwt_strategy,
)

fastapi_users = FastAPIUsers[User, uuid.UUID](get_user_manager, [auth_backend])

current_active_user = fastapi_users.current_user(active=True)
current_active_verified_user = fastapi_users.current_user(active=True, verified=True)