import connectDB from './db';
import AnalyticsEvent from '@/models/AnalyticsEvent';

export class AnalyticsService {
  private static instance: AnalyticsService;

  private constructor() {}

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

  /**
   * Track a system or module event
   */
  public async track(data: {
    moduleId: string;
    event: string;
    metadata?: Record<string, unknown>;
    severity?: 'info' | 'warn' | 'error';
  }) {
    try {
      await connectDB();
      const newEvent = new AnalyticsEvent({
        ...data,
        timestamp: new Date(),
      });
      await newEvent.save();
    } catch (err) {
      console.error('[AnalyticsService] Failed to track event:', err);
    }
  }

  /**
   * Get recent events with filtering
   */
  public async getRecentEvents(limit: number = 50, filter: Record<string, unknown> = {}) {
    try {
      await connectDB();
      return await AnalyticsEvent.find(filter).sort({ timestamp: -1 }).limit(limit).lean();
    } catch (err) {
      console.error('[AnalyticsService] Failed to fetch events:', err);
      return [];
    }
  }
}

export const analyticsService = AnalyticsService.getInstance();