import { Page } from '@playwright/test';
import { PerformanceMetrics, NetworkTiming, ResourceTiming } from '../../types';

export class PerformanceMonitor {
  constructor(private page: Page) {}

  async measurePageLoad(): Promise<PerformanceMetrics> {
    const metrics = await this.page.evaluate(() => {
      const performance = window.performance;
      const timing = performance.timing;
      const navigation = performance.getEntriesByType('navigation')[0] as PerformanceNavigationTiming;

      return {
        loadTime: timing.loadEventEnd - timing.navigationStart,
        domContentLoaded: timing.domContentLoadedEventEnd - timing.navigationStart,
        firstPaint: navigation ? navigation.loadEventEnd - navigation.fetchStart : 0,
        firstContentfulPaint: navigation ? navigation.domContentLoadedEventEnd - navigation.fetchStart : 0,
      };
    });

    return metrics;
  }

  async measureNetworkTiming(): Promise<NetworkTiming> {
    return await this.page.evaluate(() => {
      const timing = performance.timing;
      return {
        dns: timing.domainLookupEnd - timing.domainLookupStart,
        tcp: timing.connectEnd - timing.connectStart,
        ssl: timing.connectEnd - timing.secureConnectionStart,
        request: timing.responseStart - timing.requestStart,
        response: timing.responseEnd - timing.responseStart,
        total: timing.loadEventEnd - timing.navigationStart,
      };
    });
  }

  async measureResourceTiming(): Promise<ResourceTiming[]> {
    return await this.page.evaluate(() => {
      const resources = performance.getEntriesByType('resource') as PerformanceResourceTiming[];
      return resources.map(r => ({
        name: r.name,
        duration: r.duration,
        size: r.transferSize,
        type: r.initiatorType
      }));
    });
  }

  async measureMemoryUsage(): Promise<{ usedJSHeapSize: number; totalJSHeapSize: number }> {
    return await this.page.evaluate(() => {
      const memory = (performance as any).memory;
      return {
        usedJSHeapSize: memory.usedJSHeapSize,
        totalJSHeapSize: memory.totalJSHeapSize
      };
    });
  }
}