/**
 * @moduleName: Theme Selector Component - UI Theme Switching Interface
 * @version: 2.1.0
 * @since: 2025-07-21
 * @lastUpdated: 2025-07-27
 * @projectSummary: Enhanced MCP Quiz Server - Theme selection dropdown with light/dark/system modes
 * @techStack: TypeScript, Component Architecture, DOM Events, CSS Classes
 * @dependency: Component base class, ThemeService, ThemeConfig interfaces
 * @interModuleDependency: ThemeService for state management, header dropdown UI
 * @requirementsTraceability:
 *   {@link Requirements.REQ_CONFIG_003} (Theme System Management)
 *   {@link Requirements.REQ_UI_003} (Advanced Settings Interface)
 * @briefDescription: Component managing theme selection dropdown with light, dark, and system preference options
 * @methods: render, bindEvents, updateThemeButtons, toggleDropdown, selectTheme
 * @contributors: GitHub Copilot, Frontend Theme Team
 * @examples:
 *   - const themeSelector = new ThemeSelector()
 *   - themeSelector.render() // Initializes dropdown functionality
 * @vulnerabilitiesAssessment: DOM element validation, theme XSS prevention through allowlist, event cleanup
 */

import { ThemeService } from '../services/ThemeService';
import { ThemeConfig, ThemeMode } from '../types/index';
import { Component } from './Component';

export class ThemeSelector extends Component {
  private themeService: ThemeService;
  private themeMenuBtn: HTMLElement;
  private themeDropdown: HTMLElement;
  private unsubscribe: (() => void) | null = null;

  constructor() {
    super('body'); // We'll manage multiple elements
    this.themeService = ThemeService.getInstance();

    this.themeMenuBtn = document.querySelector('#theme-menu-btn') as HTMLElement;
    this.themeDropdown = document.querySelector('#theme-dropdown') as HTMLElement;
  }

  protected onMount(): void {
    this.unsubscribe = this.themeService.subscribe(theme => this.onThemeChange(theme));
    this.themeService.initialize();
  }

  protected onUnmount(): void {
    this.unsubscribe?.();
  }

  protected render(): void {
    // Initial render is handled by onThemeChange
  }

  protected bindEvents(): void {
    // Theme menu toggle
    this.themeMenuBtn?.addEventListener('click', e => {
      e.stopPropagation();
      this.themeDropdown?.classList.toggle('hidden');
    });

    // Close theme menu
    document.querySelector('#close-theme-menu')?.addEventListener('click', () => {
      this.themeDropdown?.classList.add('hidden');
    });

    // Close theme menu when clicking outside
    document.addEventListener('click', e => {
      if (
        !this.themeDropdown?.contains(e.target as Node) &&
        !this.themeMenuBtn?.contains(e.target as Node)
      ) {
        this.themeDropdown?.classList.add('hidden');
      }
    });

    // Theme option buttons (Light/Dark/System)
    document.querySelectorAll('.theme-option').forEach(btn => {
      btn.addEventListener('click', () => {
        const mode = (btn as HTMLElement).dataset.theme as ThemeMode;
        if (mode) {
          this.themeService.setMode(mode);
          this.updateActiveTheme(mode);
          this.themeDropdown?.classList.add('hidden');
        }
      });
    });
  }

  private onThemeChange(theme: ThemeConfig): void {
    this.updateActiveTheme(theme.mode);
    this.updateThemeButtonIcon(theme.mode);
  }

  private updateActiveTheme(currentMode: ThemeMode): void {
    document.querySelectorAll('.theme-option').forEach(btn => {
      const mode = (btn as HTMLElement).dataset.theme;
      if (mode === currentMode) {
        btn.classList.add('active');
      } else {
        btn.classList.remove('active');
      }
    });
  }

  private updateThemeButtonIcon(mode: ThemeMode): void {
    const icon = this.themeMenuBtn?.querySelector('i[data-lucide]');
    if (icon) {
      // Update icon based on current theme
      switch (mode) {
        case 'light':
          icon.setAttribute('data-lucide', 'sun');
          break;
        case 'dark':
          icon.setAttribute('data-lucide', 'moon');
          break;
        case 'system':
          icon.setAttribute('data-lucide', 'monitor');
          break;
        default:
          icon.setAttribute('data-lucide', 'palette');
      }

      // Refresh Lucide icons
      if ((window as any).lucide) {
        (window as any).lucide.createIcons();
      }
    }
  }
}