import { WorkflowRun } from '../types/github';

export class NotificationService {
  private static instance: NotificationService;
  private hasPermission = false;

  private constructor() {
    this.checkPermission();
  }

  static getInstance(): NotificationService {
    if (!NotificationService.instance) {
      NotificationService.instance = new NotificationService();
    }
    return NotificationService.instance;
  }

  private checkPermission(): void {
    if (!('Notification' in window)) {
      console.log('This browser does not support desktop notification');
      return;
    }

    this.hasPermission = Notification.permission === 'granted';
  }

  async requestPermission(): Promise<boolean> {
    if (!('Notification' in window)) {
      console.log('This browser does not support desktop notification');
      return false;
    }

    if (Notification.permission === 'granted') {
      this.hasPermission = true;
      return true;
    }

    if (Notification.permission !== 'denied') {
      const permission = await Notification.requestPermission();
      this.hasPermission = permission === 'granted';
      return this.hasPermission;
    }

    return false;
  }

  canShowNotifications(): boolean {
    return this.hasPermission && 'Notification' in window;
  }

  showFailureNotification(failedRuns: WorkflowRun[]): void {
    if (!this.canShowNotifications()) {
      return;
    }

    const count = failedRuns.length;
    const title = count === 1 
      ? 'Build Failed' 
      : `${count} Builds Failed`;
    
    const body = count === 1
      ? `${failedRuns[0].repository.full_name} - ${failedRuns[0].display_title}`
      : `Multiple builds have failed across ${new Set(failedRuns.map(r => r.repository.full_name)).size} repositories`;

    const notification = new Notification(title, {
      body,
      icon: '/favicon.ico',
      badge: '/favicon.ico',
      tag: 'build-failure',
      renotify: true,
      requireInteraction: false,
      silent: false
    });

    // Auto-close after 5 seconds
    setTimeout(() => {
      notification.close();
    }, 5000);

    // Optional: Click to focus window
    notification.onclick = () => {
      window.focus();
      notification.close();
    };
  }

  showSuccessNotification(successRuns: WorkflowRun[]): void {
    if (!this.canShowNotifications()) {
      return;
    }

    const count = successRuns.length;
    const title = count === 1 
      ? 'Build Recovered' 
      : `${count} Builds Recovered`;
    
    const body = count === 1
      ? `${successRuns[0].repository.full_name} - ${successRuns[0].display_title}`
      : `Multiple builds have recovered across ${new Set(successRuns.map(r => r.repository.full_name)).size} repositories`;

    const notification = new Notification(title, {
      body,
      icon: '/favicon.ico',
      badge: '/favicon.ico',
      tag: 'build-success',
      renotify: true,
      requireInteraction: false,
      silent: false
    });

    // Auto-close after 3 seconds
    setTimeout(() => {
      notification.close();
    }, 3000);

    notification.onclick = () => {
      window.focus();
      notification.close();
    };
  }

  showWaitingNotification(waitingRuns: WorkflowRun[]): void {
    if (!this.canShowNotifications()) {
      return;
    }

    const count = waitingRuns.length;
    const title = count === 1 
      ? 'Build Waiting' 
      : `${count} Builds Waiting`;
    
    const body = count === 1
      ? `${waitingRuns[0].repository.full_name} - ${waitingRuns[0].display_title}`
      : `Multiple builds are now waiting across ${new Set(waitingRuns.map(r => r.repository.full_name)).size} repositories`;

    const notification = new Notification(title, {
      body,
      icon: '/favicon.ico',
      badge: '/favicon.ico',
      tag: 'build-waiting',
      renotify: true,
      requireInteraction: false,
      silent: false
    });

    // Auto-close after 4 seconds
    setTimeout(() => {
      notification.close();
    }, 4000);

    notification.onclick = () => {
      window.focus();
      notification.close();
    };
  }
}