from enum import Enum

class UserRole(str, Enum):
    """用户角色枚举"""
    ADMIN = "ADMIN"        # 管理员 - 完全权限
    OPERATOR = "OPERATOR"  # 操作员 - 可修改数据
    USER = "USER"          # 普通用户 - 读写权限
    VIEWER = "VIEWER"      # 观察者 - 仅查询权限
    
    def __str__(self):
        return self.value
    
    @classmethod
    def get_hierarchy(cls) -> dict:
        """
        获取角色层级（数字越大权限越高）
        """
        return {
            cls.VIEWER: 1,
            cls.USER: 2,
            cls.OPERATOR: 3,
            cls.ADMIN: 4,
        }
    
    def has_permission(self, required_role: 'UserRole') -> bool:
        """
        检查当前角色是否有足够权限
        
        Args:
            required_role: 需要的最低角色
            
        Returns:
            True if has permission
        """
        hierarchy = self.get_hierarchy()
        return hierarchy[self] >= hierarchy[required_role]