#include <iostream>
#include <memory>

// 抽象处理者
class Approver {
protected:
    std::unique_ptr<Approver> next;
    std::string name;

public:
    Approver(const std::string& n) : name(n) {}

    // 设置后继者
    void setNext(std::unique_ptr<Approver> nextApprover) {
        next = std::move(nextApprover);
    }

    // 处理请求
    virtual void processRequest(double amount) = 0;

    // 转发请求到下一级
    void passToNext(double amount) {
        if (next) {
            next->processRequest(amount);
        } else {
            std::cout << "No one can approve the request for $" << amount << "\n";
        }
    }
};

// 具体处理者：主管
class Supervisor : public Approver {
public:
    Supervisor() : Approver("Supervisor") {}

    void processRequest(double amount) override {
        if (amount <= 1000) {
            std::cout << name << " approves request for $" << amount << "\n";
        } else {
            std::cout << name << " cannot handle $" << amount << ", passing to next...\n";
            passToNext(amount);
        }
    }
};

// 具体处理者：经理
class Manager : public Approver {
public:
    Manager() : Approver("Manager") {}

    void processRequest(double amount) override {
        if (amount <= 5000) {
            std::cout << name << " approves request for $" << amount << "\n";
        } else {
            std::cout << name << " cannot handle $" << amount << ", passing to next...\n";
            passToNext(amount);
        }
    }
};

// 具体处理者：总监
class Director : public Approver {
public:
    Director() : Approver("Director") {}

    void processRequest(double amount) override {
        if (amount <= 20000) {
            std::cout << name << " approves request for $" << amount << "\n&quot;;
        } else {
            std::cout << name << " cannot handle $" << amount << ", escalating...\n";
            passToNext(amount);
        }
    }
};

int main() {
    // 构建责任链
    auto supervisor = std::make_unique<Supervisor>();
    auto manager = std::make_unique<Manager>();
    auto director = std::make_unique<Director>();

    supervisor->setNext(std::move(manager));
    supervisor->next->setNext(std::move(director));

    // 发送请求
    supervisor->processRequest(500);     // 主管处理
    supervisor->processRequest(3000);    // 经理处理
    supervisor->processRequest(15000);   // 总监处理
    supervisor->processRequest(25000);   // 无人处理

    return 0;
}