class SafetyManager:
    def __init__(self):
        self.banned_phrases = ["delete all", "shutdown", "format", "upload private"]
        self.allowed_actions = set()
        self.audit_log = []

    def is_safe_command(self, command: str) -> bool:
        for phrase in self.banned_phrases:
            if phrase in command.lower():
                self.log_event(f"Blocked unsafe command: '{command}'")
                return False
        return True

    def authorize_action(self, action_name: str):
        self.allowed_actions.add(action_name)

    def revoke_action(self, action_name: str):
        self.allowed_actions.discard(action_name)

    def is_action_allowed(self, action_name: str) -> bool:
        allowed = action_name in self.allowed_actions
        if not allowed:
            self.log_event(f"Unauthorized action attempt: '{action_name}'")
        return allowed

    def log_event(self, entry: str):
        self.audit_log.append(entry)

    def get_audit_log(self):
        return self.audit_log