interface HttpClient {
  get(url: string): Promise<{ status: number; body: unknown }>;
  post(url: string, body: unknown): Promise<{ status: number; body: unknown }>;
}

type HttpResponse = { status: number; body: unknown };

// Base Implementation — עושה fetch אמיתי
class FetchHttpClient implements HttpClient {
  async get(url: string): Promise<HttpResponse> {
    const response = await fetch(url);
    const body = await response.json().catch(() => null);
    return { status: response.status, body };
  }

  async post(url: string, data: unknown): Promise<HttpResponse> {
    const response = await fetch(url, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(data),
    });
    const body = await response.json().catch(() => null);
    return { status: response.status, body };
  }
}

// Abstract Decorator — מחזיק Wrapped Client ומעביר כל קריאה
abstract class HttpClientDecorator implements HttpClient {
  constructor(protected wrapped: HttpClient) {}

  async get(url: string): Promise<HttpResponse> {
    return this.wrapped.get(url);
  }

  async post(url: string, body: unknown): Promise<HttpResponse> {
    return this.wrapped.post(url, body);
  }
}

// Decorator 1: Logging
class LoggingHttpClient extends HttpClientDecorator {
  override async get(url: string): Promise<HttpResponse> {
    console.log(`[HTTP] GET ${url}`);
    const start = Date.now();
    const result = await super.get(url);
    console.log(`[HTTP] GET ${url} → ${result.status} (${Date.now() - start}ms)`);
    return result;
  }

  override async post(url: string, body: unknown): Promise<HttpResponse> {
    console.log(`[HTTP] POST ${url}`, body);
    const start = Date.now();
    const result = await super.post(url, body);
    console.log(`[HTTP] POST ${url} → ${result.status} (${Date.now() - start}ms)`);
    return result;
  }
}

// Decorator 2: Retry
class RetryHttpClient extends HttpClientDecorator {
  constructor(wrapped: HttpClient, private readonly maxRetries: number = 3) {
    super(wrapped);
  }

  override async get(url: string): Promise<HttpResponse> {
    return this.withRetry(() => super.get(url));
  }

  override async post(url: string, body: unknown): Promise<HttpResponse> {
    return this.withRetry(() => super.post(url, body));
  }

  private async withRetry<T>(fn: () => Promise<T>): Promise<T> {
    let lastError: Error | undefined;

    for (let attempt = 1; attempt <= this.maxRetries; attempt++) {
      try {
        return await fn();
      } catch (error) {
        lastError = error as Error;
        if (attempt < this.maxRetries) {
          const delay = Math.pow(2, attempt) * 100; // Exponential backoff
          console.warn(`Retry ${attempt}/${this.maxRetries} in ${delay}ms`);
          await new Promise((resolve) => setTimeout(resolve, delay));
        }
      }
    }

    throw lastError;
  }
}

// Decorator 3: Authentication
class AuthHttpClient extends HttpClientDecorator {
  constructor(wrapped: HttpClient, private readonly tokenProvider: () => string) {
    super(wrapped);
  }

  private getAuthHeaders(): Record<string, string> {
    return { Authorization: `Bearer ${this.tokenProvider()}` };
  }

  override async get(url: string): Promise<HttpResponse> {
    const urlWithAuth = this.addAuthToUrl(url);
    return super.get(urlWithAuth);
  }

  override async post(url: string, body: unknown): Promise<HttpResponse> {
    // מוסיפים Header — ה-Decorator צריך להיות מסוגל להוסיף Headers
    // בדוגמה פשוטה: שומרים Headers ב-State
    console.log('Adding auth header:', this.getAuthHeaders());
    return super.post(url, body);
  }

  private addAuthToUrl(url: string): string {
    // בפועל: מוסיפים לHeaders, לא ל-URL
    return url;
  }
}

// שימוש — Composing Decorators
const baseClient = new FetchHttpClient();

// רק Logging
const loggedClient = new LoggingHttpClient(baseClient);

// Logging + Retry
const robustClient = new RetryHttpClient(new LoggingHttpClient(baseClient), 3);

// כל השלושה
const fullClient = new AuthHttpClient(
  new RetryHttpClient(new LoggingHttpClient(baseClient), 3),
  () => localStorage.getItem('token') ?? ''
);

// Client לא יודע כמה Decorators יש
const response = await fullClient.get('https://api.example.com/users');
Decorator Pattern — הוספת יכולות

Decorator Pattern — הוספת יכולות

Decorator Pattern — הוספת יכולות
