import { Page, Locator, expect } from '@playwright/test';

/**
 * Page Object Model for Problem Set page
 * URL: /proset
 */
export class ProblemSetPage {
  readonly page: Page;
  readonly problemLinks: Locator;
  readonly searchInput: Locator;
  readonly proClassSelect: Locator;

  constructor(page: Page) {
    this.page = page;
    
    // Problem list elements
    this.problemLinks = page.locator('a[href^="/pro/"]');
    this.searchInput = page.locator('input[placeholder*="搜尋"], input[placeholder*="Search"]');
    this.proClassSelect = page.locator('select');
  }

  /**
   * Navigate to the problem set page
   */
  async goto() {
    await this.page.goto('/proset');
    await this.page.waitForLoadState('networkidle');
  }

  /**
   * Get all visible problems
   */
  async getVisibleProblems() {
    return await this.problemLinks.all();
  }

  /**
   * Click on a problem by its ID
   */
  async clickProblem(problemId: number) {
    await this.page.click(`a[href="/pro/${problemId}"]`);
    await this.page.waitForLoadState('networkidle');
  }

  /**
   * Search for problems by name
   */
  async searchProblem(searchText: string) {
    if (await this.searchInput.isVisible()) {
      await this.searchInput.fill(searchText);
      await this.page.keyboard.press('Enter');
      await this.page.waitForLoadState('networkidle');
    }
  }

  /**
   * Select a ProClass filter
   */
  async selectProClass(proClassName: string) {
    if (await this.proClassSelect.isVisible()) {
      await this.proClassSelect.selectOption({ label: proClassName });
      await this.page.waitForLoadState('networkidle');
    }
  }

  /**
   * Verify we are on the problem set page
   */
  async verifyOnPage() {
    await expect(this.page).toHaveURL(/\/proset/);
  }

  /**
   * Get the first problem ID from the list
   */
  async getFirstProblemId(): Promise<number | null> {
    const firstProblem = this.problemLinks.first();
    if (await firstProblem.count() === 0) {
      return null;
    }
    
    const href = await firstProblem.getAttribute('href');
    if (!href) return null;
    
    const match = href.match(/\/pro\/(\d+)/);
    return match ? parseInt(match[1]) : null;
  }
}