class ApiService {
  request() {
    console.log('Making API request...');
    return 'Response from API';
  }
}
class ApiServiceProxy {
  constructor() {
    this.apiservice = new ApiService();
    this.cache = null;
  }
  request() {
    if (!this.cache) {
      console.log('Fetching from API...');
      this.cache = this.apiservice.request();
    } else {
      console.log('Returning cached response...');
    }
    return this.cache;
  }
}
// 使用代理模式
const apiProxy = new ApiServiceProxy();
console.log(apiProxy.request()); // Fetching from API... Response from API
console.log(apiProxy.request()); // Returning cached response... Response from API

class OldApi {
  oldRequest() {
    return 'Old API response';
  }
}
class Adapter {
  constructor(oldApi) {
    this.oldApi = oldApi;
  }
  newRequest() {
    return this.oldApi.oldRequest();
  }
}
// 使用適配器模式
const oldApi = new OldApi();
const adapter = new Adapter(oldApi);
console.log(adapter.newRequest()); // Old API response

class Coffee {
  cost() {
    return 5;
  }
}
class MilkDecorator {
  constructor(coffee) {
    this.coffee = coffee;
  }
  cost() {
    return this.coffee.cost() + 1;
  }
}
class SugarDecorator {
  constructor(coffee) {
    this.coffee = coffee;
  }
  cost() {
    return this.coffee.cost() + 0.5;
  }
}
// 使用裝飾器模式
let coffee = new Coffee();
coffee = new MilkDecorator(coffee);
coffee = new SugarDecorator(coffee);
console.log(coffee.cost()); // 6.5

class Shape {
  constructor(color) {
    this.color = color;
  }
  draw() {
    throw new Error('draw() must be implemented');
  }
}
class Circle extends Shape {
  draw() {
    console.log(`Drawing a ${this.color.getColor()} circle`);
  }
}
class Color {
  getColor() {
    throw new Error('getColor() must be implemented');
  }
}
class RedColor extends Color {
  getColor() {
    return 'red';
  }
}
class BlueColor extends Color {
  getColor() {
    return 'blue';
  }
}
// 使用橋接模式
const red = new RedColor();
const blue = new BlueColor();
const redCircle = new Circle(red);
redCircle.draw(); // Drawing a red circle
const blueCircle = new Circle(blue);
blueCircle.draw(); // Drawing a blue circle

class MenuItem {
  constructor(name) {
    this.name = name;
  }
  show() {
    console.log(this.name);
  }
}
class Menu {
  constructor(name) {
    this.name = name;
    this.items = [];
  }
  add(item) {
    this.items.push(item);
  }
  show() {
    console.log(this.name);
    this.items.forEach(item => item.show());
  }
}
// 使用組合模式
const fileMenu = new Menu('File');
fileMenu.add(new MenuItem('New'));
fileMenu.add(new MenuItem('Open'));
const editMenu = new Menu('Edit');
editMenu.add(new MenuItem('Undo'));
editMenu.add(new MenuItem('Redo'));
const mainMenu = new Menu('Main Menu');
mainMenu.add(fileMenu);
mainMenu.add(editMenu);
mainMenu.show();

class Subsystem1 {
  operation() {
    return 'Subsystem1 operation';
  }
}
class Subsystem2 {
  operation() {
    return 'Subsystem2 operation';
  }
}
class Facade {
  constructor() {
    this.subsystem1 = new Subsystem1();
    this.subsystem2 = new Subsystem2();
  }
  operation() {
    return `${this.subsystem1.operation()} + ${this.subsystem2.operation()}`;
  }
}
// 使用外觀模式
const facade = new Facade();
console.log(facade.operation()); // Subsystem1 operation + Subsystem2 operation

class Flyweight {
  constructor(sharedState) {
    this.sharedState = sharedState;
  }
  operation(uniqueState) {
    console.log(`Shared: ${this.sharedState}, Unique: ${uniqueState}`);
  }
}
class FlyweightFactory {
  constructor() {
    this.flyweights = {};
  }
  getFlyweight(sharedState) {
    if (!this.flyweights[sharedState]) {
      this.flyweights[sharedState] = new Flyweight(sharedState);
    }
    return this.flyweights[sharedState];
  }
}
// 使用享元模式
const factory = new FlyweightFactory();
const flyweight1 = factory.getFlyweight('Shared1');
flyweight1.operation('Unique1');
const flyweight2 = factory.getFlyweight('Shared1');
flyweight2.operation('Unique2');
console.log(flyweight1 === flyweight2); // true