from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from jose import JWTError, jwt
from typing import Optional

from ..database import get_db
from ..models.user import User
from ..schemas.token import TokenData
from ..config import settings

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl=f"{settings.API_V1_PREFIX}/auth/login",
    auto_error=False
)

async def get_current_user(
    token: Optional[str] = Depends(oauth2_scheme),
    db: Session = Depends(get_db)
) -> Optional[User]:
    """获取当前用户"""
    if not token:
        print("dfsfdsfdfdsfd")
        return None
    
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        username: str = payload.get("sub")
        token_type: str = payload.get("type")
        
        if username is None or token_type != "access":
            raise credentials_exception
        
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    
    user = db.query(User).filter(
        User.username == token_data.username,
        User.is_active == True
    ).first()
    
    if user is None:
        raise credentials_exception
    
    return user

async def get_current_active_user(
    current_user: User = Depends(get_current_user)
) -> User:
    """获取当前活跃用户"""
    if not current_user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Not authenticated"
        )
    
    if not current_user.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user"
        )
    
    return current_user

async def get_current_superuser(
    current_user: User = Depends(get_current_user)
) -> User:
    """获取超级用户"""
    if not current_user or not current_user.is_superuser:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Not enough permissions"
        )
    
    return current_user

def require_auth(current_user: Optional[User] = Depends(get_current_user)) -> User:
    """要求认证的依赖"""
    if not current_user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Not authenticated"
        )
    return current_user

# 权限检查装饰器
def require_permission(permission: str):
    """权限检查装饰器"""
    def permission_dependency(
        current_user: User = Depends(get_current_active_user)
    ) -> User:
        # 这里实现具体的权限检查逻辑
        # 可以从数据库或缓存中获取用户权限
        if not current_user.is_superuser:
            # 检查用户是否有特定权限
            user_permissions = []  # 从数据库获取
            if permission not in user_permissions:
                raise HTTPException(
                    status_code=status.HTTP_403_FORBIDDEN,
                    detail="Insufficient permissions"
                )
        return current_user
    return permission_dependency