from typing import Annotated
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.core.database import get_db
from app.core.security import decode_token
from app.models.user import User

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/v1/auth/login")


async def get_current_user(
    token: Annotated[str, Depends(oauth2_scheme)],
    db: Annotated[AsyncSession, Depends(get_db)],
) -> User:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="인증 정보가 유효하지 않습니다",
        headers={"WWW-Authenticate": "Bearer"},
    )
    payload = decode_token(token)
    if not payload or payload.get("type") != "access":
        raise credentials_exception

    user_id: str = payload.get("sub")
    if not user_id:
        raise credentials_exception

    result = await db.execute(select(User).where(User.id == user_id, User.is_active == True))
    user = result.scalar_one_or_none()
    if not user:
        raise credentials_exception
    return user


async def get_current_active_user(
    current_user: Annotated[User, Depends(get_current_user)],
) -> User:
    if not current_user.is_active:
        raise HTTPException(status_code=400, detail="비활성 계정입니다")
    return current_user


async def require_admin(
    current_user: Annotated[User, Depends(get_current_active_user)],
) -> User:
    from app.models.user import UserRole
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(status_code=403, detail="관리자 권한이 필요합니다")
    return current_user


# Convenience type aliases
CurrentUser = Annotated[User, Depends(get_current_active_user)]
DB = Annotated[AsyncSession, Depends(get_db)]