import { test, expect } from '@playwright/test';
import { TEST_CONFIG } from './utils/test-helpers';

/**
 * Performance Tests
 * 
 * These tests measure page load times, render performance, and Core Web Vitals.
 * Performance metrics are captured using Playwright's performance API and
 * browser Performance Timing API.
 * 
 * To run only performance tests:
 * - Run: npx playwright test performance
 * 
 * Performance thresholds:
 * - Page load time: < 3 seconds
 * - First Contentful Paint (FCP): < 1.8 seconds
 * - Largest Contentful Paint (LCP): < 2.5 seconds
 * - Time to Interactive (TTI): < 3.8 seconds
 * - Total Blocking Time (TBT): < 300ms
 */

interface PerformanceMetrics {
  loadTime: number;
  domContentLoaded: number;
  firstPaint: number;
  firstContentfulPaint: number;
  largestContentfulPaint: number;
  timeToInteractive: number;
  totalBlockingTime: number;
  cumulativeLayoutShift: number;
  firstInputDelay: number;
  networkRequests: number;
  jsHeapSizeUsed: number;
}

/**
 * Capture performance metrics from the browser
 */
async function capturePerformanceMetrics(page: any): Promise<PerformanceMetrics> {
  return await page.evaluate(() => {
    const navigation = performance.getEntriesByType('navigation')[0] as PerformanceNavigationTiming;
    const paint = performance.getEntriesByType('paint');
    const measure = performance.getEntriesByType('measure');
    
    // Calculate load time
    const loadTime = navigation.loadEventEnd - navigation.fetchStart;
    const domContentLoaded = navigation.domContentLoadedEventEnd - navigation.fetchStart;
    
    // Get paint metrics
    const firstPaint = paint.find((entry) => entry.name === 'first-paint')?.startTime || 0;
    const firstContentfulPaint = paint.find((entry) => entry.name === 'first-contentful-paint')?.startTime || 0;
    
    // Get LCP (Largest Contentful Paint) - approximate using load event
    const largestContentfulPaint = navigation.loadEventEnd - navigation.fetchStart;
    
    // Calculate TTI (Time to Interactive) - approximate
    const timeToInteractive = navigation.domInteractive - navigation.fetchStart;
    
    // Calculate TBT (Total Blocking Time) - approximate
    // This is a simplified calculation
    const totalBlockingTime = Math.max(0, navigation.domInteractive - navigation.domContentLoadedEventEnd);
    
    // Get CLS (Cumulative Layout Shift) - requires PerformanceObserver
    let cumulativeLayoutShift = 0;
    if ('PerformanceObserver' in window) {
      try {
        const clsEntries: any[] = [];
        const observer = new PerformanceObserver((list) => {
          for (const entry of list.getEntries()) {
            if (!(entry as any).hadRecentInput) {
              clsEntries.push(entry);
            }
          }
        });
        observer.observe({ type: 'layout-shift', buffered: true });
        cumulativeLayoutShift = clsEntries.reduce((sum, entry: any) => sum + entry.value, 0);
      } catch (e) {
        // CLS not supported
      }
    }
    
    // Get FID (First Input Delay) - approximate
    const firstInputDelay = 0; // Would need PerformanceObserver for real measurement
    
    // Count network requests
    const networkRequests = performance.getEntriesByType('resource').length;
    
    // Get memory usage (if available)
    const memory = (performance as any).memory;
    const jsHeapSizeUsed = memory ? memory.usedJSHeapSize : 0;
    
    return {
      loadTime,
      domContentLoaded,
      firstPaint,
      firstContentfulPaint,
      largestContentfulPaint,
      timeToInteractive,
      totalBlockingTime,
      cumulativeLayoutShift,
      firstInputDelay,
      networkRequests,
      jsHeapSizeUsed,
    };
  });
}

/**
 * Wait for page to be fully loaded and stable
 */
async function waitForPageStable(page: any, timeout = 10000) {
  await page.waitForLoadState('networkidle', { timeout });
  await page.waitForLoadState('domcontentloaded');
  // Wait a bit more for any async operations
  await page.waitForTimeout(1000);
}

test.describe('Performance Tests', () => {
  // Use authenticated state for most tests
  test.use({ storageState: 'e2e/.auth/user.json' });

  test.describe('Page Load Performance', () => {
    test('dashboard page load time should be acceptable', async ({ page }) => {
      const startTime = Date.now();
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      const endTime = Date.now();
      const loadTime = endTime - startTime;
      
      const metrics = await capturePerformanceMetrics(page);
      
      // Log metrics for debugging
      console.log('Dashboard Performance Metrics:', {
        loadTime: `${loadTime}ms`,
        domContentLoaded: `${metrics.domContentLoaded.toFixed(2)}ms`,
        firstContentfulPaint: `${metrics.firstContentfulPaint.toFixed(2)}ms`,
        largestContentfulPaint: `${metrics.largestContentfulPaint.toFixed(2)}ms`,
        timeToInteractive: `${metrics.timeToInteractive.toFixed(2)}ms`,
        networkRequests: metrics.networkRequests,
      });
      
      // Assertions - thresholds based on Core Web Vitals
      expect(loadTime).toBeLessThan(5000); // 5 seconds max
      expect(metrics.domContentLoaded).toBeLessThan(3000); // 3 seconds
      expect(metrics.firstContentfulPaint).toBeLessThan(1800); // 1.8 seconds (Good FCP)
      expect(metrics.largestContentfulPaint).toBeLessThan(2500); // 2.5 seconds (Good LCP)
    });

    test('login page load time should be fast', async ({ page }) => {
      // Use unauthenticated state for login page
      await page.context().clearCookies();
      
      const startTime = Date.now();
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/login`);
      await waitForPageStable(page);
      
      const endTime = Date.now();
      const loadTime = endTime - startTime;
      
      const metrics = await capturePerformanceMetrics(page);
      
      console.log('Login Page Performance Metrics:', {
        loadTime: `${loadTime}ms`,
        firstContentfulPaint: `${metrics.firstContentfulPaint.toFixed(2)}ms`,
        networkRequests: metrics.networkRequests,
      });
      
      // Login page should be very fast (no data loading)
      expect(loadTime).toBeLessThan(2000); // 2 seconds max
      expect(metrics.firstContentfulPaint).toBeLessThan(1000); // 1 second
    });

    test('profile page load time should be acceptable', async ({ page }) => {
      const startTime = Date.now();
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/profile`);
      await waitForPageStable(page);
      
      const endTime = Date.now();
      const loadTime = endTime - startTime;
      
      const metrics = await capturePerformanceMetrics(page);
      
      expect(loadTime).toBeLessThan(5000);
      expect(metrics.firstContentfulPaint).toBeLessThan(1800);
    });

    test('tracks page load time should be acceptable', async ({ page }) => {
      const startTime = Date.now();
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/tracks`);
      await waitForPageStable(page);
      
      const endTime = Date.now();
      const loadTime = endTime - startTime;
      
      const metrics = await capturePerformanceMetrics(page);
      
      expect(loadTime).toBeLessThan(5000);
      expect(metrics.firstContentfulPaint).toBeLessThan(1800);
    });

    test('playlists page load time should be acceptable', async ({ page }) => {
      const startTime = Date.now();
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/playlists`);
      await waitForPageStable(page);
      
      const endTime = Date.now();
      const loadTime = endTime - startTime;
      
      const metrics = await capturePerformanceMetrics(page);
      
      expect(loadTime).toBeLessThan(5000);
      expect(metrics.firstContentfulPaint).toBeLessThan(1800);
    });
  });

  test.describe('Render Performance', () => {
    test('dashboard should render main content quickly', async ({ page }) => {
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      
      // Measure time to render main content
      const renderStart = Date.now();
      await page.waitForSelector('main, [role="main"]', { timeout: 10000 });
      const renderEnd = Date.now();
      const renderTime = renderEnd - renderStart;
      
      console.log(`Dashboard main content render time: ${renderTime}ms`);
      
      expect(renderTime).toBeLessThan(2000); // Should render in under 2 seconds
    });

    test('navigation should be responsive', async ({ page }) => {
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      // Measure navigation time
      const navStart = Date.now();
      await page.click('a[href="/profile"]', { timeout: 5000 });
      await page.waitForURL('**/profile', { timeout: 5000 });
      await waitForPageStable(page);
      const navEnd = Date.now();
      const navTime = navEnd - navStart;
      
      console.log(`Navigation time (dashboard -> profile): ${navTime}ms`);
      
      expect(navTime).toBeLessThan(3000); // Navigation should be fast
    });
  });

  test.describe('Network Performance', () => {
    test('should minimize network requests on initial load', async ({ page }) => {
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      const metrics = await capturePerformanceMetrics(page);
      
      console.log(`Total network requests: ${metrics.networkRequests}`);
      
      // Should not have excessive network requests
      // This threshold may need adjustment based on actual usage
      expect(metrics.networkRequests).toBeLessThan(50);
    });

    test('API requests should complete quickly', async ({ page }) => {
      const requestTimes: number[] = [];
      
      // Track API request times
      page.on('response', (response: any) => {
        const url = response.url();
        if (url.includes('/api/')) {
          const timing = response.timing();
          if (timing) {
            const requestTime = timing.responseEnd - timing.requestStart;
            requestTimes.push(requestTime);
          }
        }
      });
      
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      if (requestTimes.length > 0) {
        const avgRequestTime = requestTimes.reduce((a, b) => a + b, 0) / requestTimes.length;
        const maxRequestTime = Math.max(...requestTimes);
        
        console.log(`Average API request time: ${avgRequestTime.toFixed(2)}ms`);
        console.log(`Max API request time: ${maxRequestTime.toFixed(2)}ms`);
        
        // API requests should complete reasonably quickly
        expect(avgRequestTime).toBeLessThan(1000); // Average under 1 second
        expect(maxRequestTime).toBeLessThan(3000); // Max under 3 seconds
      }
    });
  });

  test.describe('Memory Performance', () => {
    test('should not have excessive memory usage', async ({ page }) => {
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      const metrics = await capturePerformanceMetrics(page);
      
      if (metrics.jsHeapSizeUsed > 0) {
        const heapSizeMB = metrics.jsHeapSizeUsed / (1024 * 1024);
        console.log(`JS Heap Size Used: ${heapSizeMB.toFixed(2)}MB`);
        
        // Should not use excessive memory (threshold: 100MB)
        expect(heapSizeMB).toBeLessThan(100);
      }
    });
  });

  test.describe('Large Dataset Performance', () => {
    test('should render large track lists (1000+ tracks) smoothly', async ({ page }) => {
      // Mock a large track list with 1000+ tracks
      const largeTrackList = Array.from({ length: 1200 }, (_, i) => ({
        id: `track-${i + 1}`,
        title: `Track ${i + 1}`,
        artist: `Artist ${Math.floor(i / 10) + 1}`,
        duration: 180 + (i % 60), // Varying durations
        file_path: `/tracks/track-${i + 1}.mp3`,
        file_size: 5000000 + (i * 1000),
        format: 'mp3',
        is_public: true,
        play_count: Math.floor(Math.random() * 1000),
        like_count: Math.floor(Math.random() * 100),
        created_at: new Date().toISOString(),
        updated_at: new Date().toISOString(),
        creator_id: 'test-user',
        status: 'ready' as const,
      }));

      // Intercept tracks API call and return mocked data
      await page.route('**/api/v1/tracks**', async (route) => {
        if (route.request().method() === 'GET') {
          await route.fulfill({
            status: 200,
            contentType: 'application/json',
            body: JSON.stringify({
              success: true,
              data: largeTrackList,
              total: largeTrackList.length,
              page: 1,
              limit: largeTrackList.length,
            }),
          });
        } else {
          await route.continue();
        }
      });

      // Navigate to library page
      const renderStart = Date.now();
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/library`);
      
      // Wait for library content to be visible
      await page.waitForSelector('[data-testid="library-page"], .library-page, main', { timeout: 10000 });
      
      // Wait for tracks to be rendered (check for virtualized list or track items)
      await page.waitForSelector(
        '[data-testid="track-list"], .track-list, [role="list"], table, [role="table"], [data-testid="virtualized-list"]',
        { timeout: 10000 }
      ).catch(() => {
        // If specific selector not found, wait for any content
        console.warn('⚠️ [PERF] Specific track list selector not found, waiting for general content');
      });

      const renderEnd = Date.now();
      const renderTime = renderEnd - renderStart;

      // Measure performance metrics
      const metrics = await capturePerformanceMetrics(page);

      // Count rendered track items (virtualization may only render visible items)
      const trackCount = await page.evaluate(() => {
        const selectors = [
          '[data-testid*="track"]',
          '[data-track-id]',
          '[role="listitem"]',
          'tr[data-track-id]',
          '.track-item',
          'li',
        ];
        let count = 0;
        for (const selector of selectors) {
          const elements = document.querySelectorAll(selector);
          if (elements.length > 0) {
            count = elements.length;
            break;
          }
        }
        return count;
      });

      // Check if virtualization is working (should render fewer items than total)
      const isVirtualized = trackCount < largeTrackList.length;

      console.log('Large Track List Performance Metrics:', {
        renderTime: `${renderTime}ms`,
        totalTracks: `${largeTrackList.length} tracks`,
        renderedTracks: `${trackCount} tracks rendered`,
        isVirtualized: isVirtualized ? 'Yes' : 'No',
        domContentLoaded: `${metrics.domContentLoaded.toFixed(2)}ms`,
        firstContentfulPaint: `${metrics.firstContentfulPaint.toFixed(2)}ms`,
        largestContentfulPaint: `${metrics.largestContentfulPaint.toFixed(2)}ms`,
        timeToInteractive: `${metrics.timeToInteractive.toFixed(2)}ms`,
        networkRequests: metrics.networkRequests,
      });

      // Verify performance thresholds
      // Large track lists should render in reasonable time (8 seconds max for 1000+ tracks)
      expect(renderTime).toBeLessThan(8000);
      
      // Verify that tracks are being rendered (at least some tracks should be visible)
      expect(trackCount).toBeGreaterThan(0);
      
      // Verify smooth rendering - LCP should be acceptable for large lists
      expect(metrics.largestContentfulPaint).toBeLessThan(4000); // 4 seconds for very large lists
      
      // Verify virtualization is working (should not render all 1000+ tracks at once)
      if (isVirtualized) {
        console.log('✅ [PERF] Virtualization detected - only visible tracks rendered');
      } else {
        console.warn('⚠️ [PERF] Virtualization may not be working - all tracks may be rendered');
      }
      
      console.log('✅ [PERF] Large track list rendered smoothly');
    });

    test('should render large playlists (100+ tracks) smoothly', async ({ page }) => {
      // Mock a playlist with 100+ tracks
      const largePlaylist = {
        id: 'test-large-playlist',
        name: 'Large Playlist Test',
        description: 'Performance test with 100+ tracks',
        tracks: Array.from({ length: 120 }, (_, i) => ({
          id: `track-${i + 1}`,
          title: `Track ${i + 1}`,
          artist: `Artist ${i + 1}`,
          duration: 180 + (i % 60), // Varying durations
          file_path: `/tracks/track-${i + 1}.mp3`,
          file_size: 5000000 + (i * 1000),
          format: 'mp3',
          is_public: true,
          play_count: Math.floor(Math.random() * 1000),
          like_count: Math.floor(Math.random() * 100),
          created_at: new Date().toISOString(),
          updated_at: new Date().toISOString(),
          creator_id: 'test-user',
        })),
        created_at: new Date().toISOString(),
        updated_at: new Date().toISOString(),
        creator_id: 'test-user',
      };

      // Intercept playlist API call and return mocked data
      await page.route('**/api/v1/playlists/**', async (route) => {
        if (route.request().method() === 'GET') {
          await route.fulfill({
            status: 200,
            contentType: 'application/json',
            body: JSON.stringify({
              success: true,
              data: largePlaylist,
            }),
          });
        } else {
          await route.continue();
        }
      });

      // Navigate to playlist page
      const renderStart = Date.now();
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/playlists/${largePlaylist.id}`);
      
      // Wait for playlist content to be visible
      await page.waitForSelector('[data-testid="playlist-detail"], .playlist-detail, main', { timeout: 10000 });
      
      // Wait for tracks to be rendered (check for track list or items)
      await page.waitForSelector(
        '[data-testid="playlist-tracks"], .playlist-tracks, [role="list"], table, [role="table"]',
        { timeout: 10000 }
      ).catch(() => {
        // If specific selector not found, wait for any content
        console.warn('⚠️ [PERF] Specific track list selector not found, waiting for general content');
      });

      const renderEnd = Date.now();
      const renderTime = renderEnd - renderStart;

      // Measure performance metrics
      const metrics = await capturePerformanceMetrics(page);

      // Count rendered track items
      const trackCount = await page.evaluate(() => {
        const selectors = [
          '[data-testid*="track"]',
          '[role="listitem"]',
          'tr[data-track-id]',
          '.track-item',
          'li',
        ];
        let count = 0;
        for (const selector of selectors) {
          const elements = document.querySelectorAll(selector);
          if (elements.length > 0) {
            count = elements.length;
            break;
          }
        }
        return count;
      });

      console.log('Large Playlist Performance Metrics:', {
        renderTime: `${renderTime}ms`,
        trackCount: `${trackCount} tracks rendered`,
        domContentLoaded: `${metrics.domContentLoaded.toFixed(2)}ms`,
        firstContentfulPaint: `${metrics.firstContentfulPaint.toFixed(2)}ms`,
        largestContentfulPaint: `${metrics.largestContentfulPaint.toFixed(2)}ms`,
        timeToInteractive: `${metrics.timeToInteractive.toFixed(2)}ms`,
        networkRequests: metrics.networkRequests,
      });

      // Verify performance thresholds
      // Large playlists should render in reasonable time (5 seconds max for 100+ tracks)
      expect(renderTime).toBeLessThan(5000);
      
      // Verify that tracks are being rendered (at least some tracks should be visible)
      // Note: Virtualization might only render visible tracks, so we check for > 0
      expect(trackCount).toBeGreaterThan(0);
      
      // Verify smooth rendering - LCP should be acceptable
      expect(metrics.largestContentfulPaint).toBeLessThan(3000); // 3 seconds for large lists
      
      console.log('✅ [PERF] Large playlist rendered smoothly');
    });

    test('should render many conversations (100+) smoothly', async ({ page }) => {
      // Mock a large conversation list with 100+ conversations
      const largeConversationList = Array.from({ length: 120 }, (_, i) => ({
        id: `conversation-${i + 1}`,
        name: `Conversation ${i + 1}`,
        type: i % 3 === 0 ? 'direct' : 'channel',
        participants: i % 3 === 0 ? [`user-${i}`, `user-${i + 1}`] : [],
        unread_count: i % 5 === 0 ? Math.floor(Math.random() * 10) : 0,
        created_at: new Date().toISOString(),
        updated_at: new Date().toISOString(),
      }));

      // Intercept conversations API call and return mocked data
      await page.route('**/api/v1/conversations**', async (route) => {
        if (route.request().method() === 'GET') {
          await route.fulfill({
            status: 200,
            contentType: 'application/json',
            body: JSON.stringify({
              success: true,
              conversations: largeConversationList,
            }),
          });
        } else {
          await route.continue();
        }
      });

      // Navigate to chat page
      const renderStart = Date.now();
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/chat`);
      
      // Wait for chat content to be visible
      await page.waitForSelector('[data-testid="chat-page"], .chat-page, main, [data-testid="chat-sidebar"]', { timeout: 10000 });
      
      // Wait for conversations to be rendered (check for conversation list or items)
      await page.waitForSelector(
        '[data-testid="conversation-list"], .conversation-list, [role="list"], [data-testid*="conversation"]',
        { timeout: 10000 }
      ).catch(() => {
        // If specific selector not found, wait for any content
        console.warn('⚠️ [PERF] Specific conversation list selector not found, waiting for general content');
      });

      const renderEnd = Date.now();
      const renderTime = renderEnd - renderStart;

      // Measure performance metrics
      const metrics = await capturePerformanceMetrics(page);

      // Count rendered conversation items
      const conversationCount = await page.evaluate(() => {
        const selectors = [
          '[data-testid*="conversation"]',
          '[data-conversation-id]',
          '[role="listitem"]',
          '.conversation-item',
          'li',
        ];
        let count = 0;
        for (const selector of selectors) {
          const elements = document.querySelectorAll(selector);
          if (elements.length > 0) {
            count = elements.length;
            break;
          }
        }
        return count;
      });

      console.log('Many Conversations Performance Metrics:', {
        renderTime: `${renderTime}ms`,
        totalConversations: `${largeConversationList.length} conversations`,
        renderedConversations: `${conversationCount} conversations rendered`,
        domContentLoaded: `${metrics.domContentLoaded.toFixed(2)}ms`,
        firstContentfulPaint: `${metrics.firstContentfulPaint.toFixed(2)}ms`,
        largestContentfulPaint: `${metrics.largestContentfulPaint.toFixed(2)}ms`,
        timeToInteractive: `${metrics.timeToInteractive.toFixed(2)}ms`,
        networkRequests: metrics.networkRequests,
      });

      // Verify performance thresholds
      // Many conversations should render in reasonable time (5 seconds max for 100+ conversations)
      expect(renderTime).toBeLessThan(5000);
      
      // Verify that conversations are being rendered (at least some conversations should be visible)
      expect(conversationCount).toBeGreaterThan(0);
      
      // Verify smooth rendering - LCP should be acceptable
      expect(metrics.largestContentfulPaint).toBeLessThan(3000); // 3 seconds for large lists
      
      console.log('✅ [PERF] Many conversations rendered smoothly');
    });
  });

  test.describe('Core Web Vitals', () => {
    test('should meet Core Web Vitals thresholds', async ({ page }) => {
      await page.goto(`${TEST_CONFIG.FRONTEND_URL}/dashboard`);
      await waitForPageStable(page);
      
      const metrics = await capturePerformanceMetrics(page);
      
      // Core Web Vitals thresholds (Good)
      const coreWebVitals = {
        LCP: metrics.largestContentfulPaint, // Should be < 2.5s
        FID: metrics.firstInputDelay, // Should be < 100ms (not measured here)
        CLS: metrics.cumulativeLayoutShift, // Should be < 0.1
        FCP: metrics.firstContentfulPaint, // Should be < 1.8s
        TBT: metrics.totalBlockingTime, // Should be < 300ms
      };
      
      console.log('Core Web Vitals:', {
        LCP: `${coreWebVitals.LCP.toFixed(2)}ms (target: < 2500ms)`,
        FCP: `${coreWebVitals.FCP.toFixed(2)}ms (target: < 1800ms)`,
        TBT: `${coreWebVitals.TBT.toFixed(2)}ms (target: < 300ms)`,
        CLS: `${coreWebVitals.CLS.toFixed(4)} (target: < 0.1)`,
      });
      
      // Assert Core Web Vitals thresholds
      expect(coreWebVitals.LCP).toBeLessThan(2500);
      expect(coreWebVitals.FCP).toBeLessThan(1800);
      expect(coreWebVitals.TBT).toBeLessThan(300);
      expect(coreWebVitals.CLS).toBeLessThan(0.1);
    });
  });
});