backend/src/services/screenshotService.js

import puppeteer from 'puppeteer';
import playwright from 'playwright';
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';

// 获取当前文件的目录路径
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

class ScreenshotService {
  constructor() {
    this.puppeteerBrowser = null;
    this.playwrightBrowser = null;
    this.isInitializing = false;
    this.puppeteerReady = false;
    this.playwrightReady = false;
    
    // 页面池 - 重用页面以提高性能
    this.puppeteerPagePool = [];
    this.playwrightPagePool = [];
    this.maxPoolSize = 3; // 最大页面池大小
    
    // 字体配置
    this.googleFonts = [
      'Noto+Sans+SC:400,700',
      'Noto+Serif+SC:400,700'
    ];
    
    console.log('📸 Screenshot service initialized (optimized version)');
    
    // 启动时预热浏览器
    this.warmupBrowsers();
  }
  
  // 预热浏览器实例
  async warmupBrowsers() {
    setTimeout(async () => {
      try {
        console.log('🔥 Warming up browser instances...');
        await this.initPuppeteer();
        console.log('✅ Browser warmup complete');
      } catch (error) {
        console.error('❌ Browser warmup failed:', error.message);
      }
    }, 1000); // 延迟1秒启动，避免与服务器启动冲突
  }

  // Initialize Puppeteer browser with optimizations
  async initPuppeteer() {
    if (this.puppeteerBrowser || this.isInitializing) return;
    
    this.isInitializing = true;
    
    try {
      console.log('🚀 Starting Puppeteer browser (optimized)...');
      
      // 优化的启动选项
      const launchOptions = {
        headless: 'new', // 使用新的无头模式
        args: [
          // 安全性设置
          '--no-sandbox',
          '--disable-setuid-sandbox',
          
          // 内存和性能优化
          '--disable-dev-shm-usage',
          '--disable-gpu',
          '--disable-extensions',
          '--disable-background-timer-throttling',
          '--disable-backgrounding-occluded-windows',
          '--disable-renderer-backgrounding',
          '--no-first-run',
          '--no-default-browser-check',
          '--disable-default-apps',
          '--disable-features=TranslateUI',
          '--disable-ipc-flooding-protection',
          
          // 内存限制优化
          '--js-flags=--max-old-space-size=512', // 降低JS内存使用
          '--memory-pressure-off',
          
          // 进程优化
          '--single-process', // 使用单进程模式减少资源消耗
          '--disable-background-networking',
          '--disable-background-mode',
          
          // 字体渲染优化
          '--font-render-hinting=none',
          
          // 禁用不必要的功能
          '--disable-breakpad',
          '--disable-component-update',
          '--disable-domain-reliability',
          '--disable-sync',
          '--disable-hang-monitor',
          '--disable-prompt-on-repost',
          '--disable-client-side-phishing-detection',
          '--disable-component-extensions-with-background-pages',
          '--blink-settings=imagesEnabled=true'
        ],
        timeout: 20000, // 减少超时时间
        ignoreHTTPSErrors: true,
        defaultViewport: null, // 动态设置视口
        handleSIGINT: false, // 由我们自己处理
        handleSIGTERM: false,
        handleSIGHUP: false,
        dumpio: false, // 禁用浏览器日志输出到控制台
        protocolTimeout: 15000
      };

      // 检测环境并应用特定优化
      const isLowMemoryEnv = process.env.LOW_MEMORY === 'true';
      if (isLowMemoryEnv) {
        console.log('🔧 Applying low memory optimizations');
        launchOptions.args.push(
          '--disable-javascript',
          '--disable-images',
          '--disable-css-animations'
        );
      }

      this.puppeteerBrowser = await puppeteer.launch(launchOptions);
      this.puppeteerReady = true;
      console.log('✅ Puppeteer browser started successfully');
      
      // 预创建页面池
      await this.initPagePool();
      
      // 监控浏览器健康状态
      this.startBrowserMonitoring();
      
      // Cleanup when process exits
      process.on('exit', () => this.cleanup());
      process.on('SIGINT', () => this.cleanup());
      process.on('SIGTERM', () => this.cleanup());
      
    } catch (error) {
      console.error('❌ Puppeteer initialization failed:', error.message);
      this.puppeteerReady = false;
    } finally {
      this.isInitializing = false;
    }
  }
  
  // 初始化页面池
  async initPagePool() {
    if (!this.puppeteerReady || !this.puppeteerBrowser) return;
    
    try {
      console.log(`🔄 Initializing page pool (size: ${this.maxPoolSize})...`);
      
      // 清空现有池
      for (const page of this.puppeteerPagePool) {
        await page.close().catch(console.error);
      }
      this.puppeteerPagePool = [];
      
      // 创建新页面
      for (let i = 0; i < this.maxPoolSize; i++) {
        const page = await this.puppeteerBrowser.newPage();
        
        // 优化页面设置
        await page.setRequestInterception(true);
        page.on('request', (request) => {
          // 阻止不必要的资源加载
          const resourceType = request.resourceType();
          if (resourceType === 'media' || resourceType === 'font') {
            // 允许字体资源加载
            request.continue();
          } else if (resourceType === 'stylesheet' || resourceType === 'script' || resourceType === 'image') {
            // 允许基本资源
            request.continue();
          } else {
            // 阻止其他资源
            request.abort();
          }
        });
        
        // 注入Google字体
        await this.injectGoogleFonts(page);
        
        // 设置默认视口
        await page.setViewport({ width: 1000, height: 562 });
        
        // 添加到池中
        this.puppeteerPagePool.push(page);
      }
      
      console.log(`✅ Page pool initialized with ${this.puppeteerPagePool.length} pages`);
    } catch (error) {
      console.error('❌ Failed to initialize page pool:', error.message);
    }
  }
  
  // 注入Google字体
  async injectGoogleFonts(page) {
    try {
      // 构建Google字体URL
      const googleFontsUrl = `https://fonts.googleapis.com/css2?family=${this.googleFonts.join('&family=')}&display=swap`;
      
      // 注入字体CSS
      await page.evaluateOnNewDocument((fontsUrl) => {
        // 创建link元素加载Google字体
        const link = document.createElement('link');
        link.rel = 'stylesheet';
        link.href = fontsUrl;
        
        // 当文档创建时添加到head
        document.addEventListener('DOMContentLoaded', () => {
          document.head.appendChild(link);
        });
      }, googleFontsUrl);
    } catch (error) {
      console.warn('⚠️ Failed to inject Google Fonts:', error.message);
    }
  }
  
  // 监控浏览器健康状态
  startBrowserMonitoring() {
    const checkInterval = 5 * 60 * 1000; // 5分钟检查一次
    
    setInterval(async () => {
      if (!this.puppeteerBrowser) return;
      
      try {
        // 检查浏览器是否响应
        await this.puppeteerBrowser.version();
        
        // 检查内存使用情况
        const pages = await this.puppeteerBrowser.pages();
        console.log(`🔍 Browser health check: ${pages.length} pages open`);
        
        // 如果页面过多，关闭多余页面
        if (pages.length > this.maxPoolSize * 2) {
          console.log(`⚠️ Too many pages open (${pages.length}), cleaning up...`);
          
          // 保留页面池中的页面，关闭其他页面
          const poolPageIds = this.puppeteerPagePool.map(p => p.target()._targetId);
          
          for (const page of pages) {
            const pageId = page.target()._targetId;
            if (!poolPageIds.includes(pageId)) {
              await page.close().catch(console.error);
            }
          }
        }
      } catch (error) {
        console.error('❌ Browser health check failed:', error.message);
        
        // 尝试重启浏览器
        await this.restartBrowser();
      }
    }, checkInterval);
  }
  
  // 重启浏览器
  async restartBrowser() {
    console.log('🔄 Attempting to restart browser...');
    
    try {
      // 清理现有资源
      await this.cleanup();
      
      // 重新初始化
      this.puppeteerReady = false;
      this.playwrightReady = false;
      await this.initPuppeteer();
      
      console.log('✅ Browser successfully restarted');
    } catch (error) {
      console.error('❌ Browser restart failed:', error.message);
    }
  }

  // Initialize Playwright browser (fallback) with optimizations
  async initPlaywright() {
    if (this.playwrightBrowser) return;
    
    try {
      console.log('🎭 Starting Playwright browser (optimized)...');
      
      // 优化的启动选项
      const launchOptions = {
        headless: true,
        args: [
          // 安全性设置
          '--no-sandbox',
          '--disable-setuid-sandbox',
          
          // 内存和性能优化
          '--disable-dev-shm-usage',
          '--disable-gpu',
          '--disable-extensions',
          '--js-flags=--max-old-space-size=512',
          '--single-process',
          '--disable-background-networking',
          
          // 字体渲染优化
          '--font-render-hinting=none'
        ],
        ignoreDefaultArgs: ['--enable-automation'],
        chromiumSandbox: false,
        handleSIGINT: false,
        handleSIGTERM: false,
        handleSIGHUP: false,
        timeout: 15000
      };
      
      this.playwrightBrowser = await playwright.chromium.launch(launchOptions);
      
      // 初始化页面池
      await this.initPlaywrightPagePool();
      
      this.playwrightReady = true;
      console.log('✅ Playwright browser started successfully');
      
    } catch (error) {
      console.error('❌ Playwright initialization failed:', error.message);
      this.playwrightReady = false;
    }
  }
  
  // 初始化Playwright页面池
  async initPlaywrightPagePool() {
    if (!this.playwrightBrowser) return;
    
    try {
      console.log(`🔄 Initializing Playwright page pool...`);
      
      // 清空现有池
      for (const page of this.playwrightPagePool) {
        await page.close().catch(console.error);
      }
      this.playwrightPagePool = [];
      
      // 创建新页面
      for (let i = 0; i < this.maxPoolSize; i++) {
        const context = await this.playwrightBrowser.newContext({
          viewport: { width: 1000, height: 562 },
          ignoreHTTPSErrors: true
        });
        
        const page = await context.newPage();
        
        // 注入Google字体
        await this.injectPlaywrightGoogleFonts(page);
        
        // 添加到池中
        this.playwrightPagePool.push(page);
      }
      
      console.log(`✅ Playwright page pool initialized with ${this.playwrightPagePool.length} pages`);
    } catch (error) {
      console.error('❌ Failed to initialize Playwright page pool:', error.message);
    }
  }
  
  // 注入Google字体到Playwright页面
  async injectPlaywrightGoogleFonts(page) {
    try {
      // 构建Google字体URL
      const googleFontsUrl = `https://fonts.googleapis.com/css2?family=${this.googleFonts.join('&family=')}&display=swap`;
      
      // 注入字体CSS
      await page.addInitScript(({ fontsUrl }) => {
        // 创建link元素加载Google字体
        const link = document.createElement('link');
        link.rel = 'stylesheet';
        link.href = fontsUrl;
        
        // 当文档创建时添加到head
        document.addEventListener('DOMContentLoaded', () => {
          document.head.appendChild(link);
        });
      }, { fontsUrl: googleFontsUrl });
    } catch (error) {
      console.warn('⚠️ Failed to inject Google Fonts to Playwright:', error.message);
    }
  }

  // Generate screenshot
  async generateScreenshot(htmlContent, options = {}) {
    const {
      format = 'jpeg',
      quality = 90,
      width = 1000,
      height = 562,
      timeout = 15000
    } = options;

    console.log(`📸 Generating screenshot: ${width}x${height}, ${format}@${quality}%`);

    // Try Puppeteer first
    if (!this.puppeteerReady) {
      await this.initPuppeteer();
    }

    if (this.puppeteerReady) {
      try {
        return await this.generateWithPuppeteer(htmlContent, { format, quality, width, height, timeout });
      } catch (error) {
        console.warn('Puppeteer screenshot failed, trying Playwright:', error.message);
      }
    }

    // Fallback to Playwright
    if (!this.playwrightReady) {
      await this.initPlaywright();
    }

    if (this.playwrightReady) {
      try {
        return await this.generateWithPlaywright(htmlContent, { format, quality, width, height, timeout });
      } catch (error) {
        console.warn('Playwright screenshot failed:', error.message);
      }
    }

    // Final fallback: generate SVG
    console.warn('All screenshot methods failed, generating fallback SVG');
    return this.generateFallbackImage(width, height, 'Screenshot Service', 'Browser unavailable');
  }

  // Generate screenshot using Puppeteer with page pool optimization
  async generateWithPuppeteer(htmlContent, options) {
    const { format, quality, width, height, timeout } = options;
    let page = null;
    let pageFromPool = false;

    try {
      // 尝试从页面池获取页面
      if (this.puppeteerPagePool && this.puppeteerPagePool.length > 0) {
        page = this.puppeteerPagePool.shift();
        pageFromPool = true;
        console.log(`📄 Using page from Puppeteer pool (${this.puppeteerPagePool.length} remaining)`);
      } else {
        // 如果池为空，创建新页面
        page = await this.puppeteerBrowser.newPage();
        console.log(`📄 Created new Puppeteer page (pool empty)`);
        
        // 优化新页面设置
        await page.setRequestInterception(true);
        page.on('request', (request) => {
          // 阻止不必要的资源加载
          const resourceType = request.resourceType();
          if (resourceType === 'media' || resourceType === 'font') {
            // 允许字体资源加载
            request.continue();
          } else if (resourceType === 'stylesheet' || resourceType === 'script' || resourceType === 'image') {
            // 允许基本资源
            request.continue();
          } else {
            // 阻止其他资源
            request.abort();
          }
        });
        
        // 为新创建的页面注入Google字体
        await this.injectGoogleFonts(page);
      }
      
      // 设置视口大小（即使从池中获取的页面也需要重新设置，因为尺寸可能不同）
      await page.setViewport({ width, height });
      
      // 设置内容，使用更短的超时时间
      await page.setContent(htmlContent, { 
        waitUntil: 'networkidle0',
        timeout: Math.min(timeout, 10000) // 使用较短的超时时间
      });

      // 等待字体加载
      await page.evaluate(() => {
        return document.fonts ? document.fonts.ready : Promise.resolve();
      });

      // 减少等待时间
      await page.waitForTimeout(200);
      
      // 优化内存使用
      if (global.gc && Math.random() < 0.1) { // 随机触发GC，避免每次都执行
        global.gc();
      }

      // 截图选项
      const screenshotOptions = {
        type: format,
        quality: format === 'jpeg' ? quality : undefined,
        fullPage: false,
        omitBackground: format === 'png', // PNG格式可以透明背景
        clip: { x: 0, y: 0, width, height }
      };

      const screenshot = await page.screenshot(screenshotOptions);
      
      console.log(`✅ Puppeteer screenshot generated: ${screenshot.length} bytes`);
      return screenshot;

    } catch (error) {
      console.error(`❌ Puppeteer screenshot failed: ${error.message}`);
      throw error;
    } finally {
      if (page) {
        if (pageFromPool && this.puppeteerPagePool.length < this.maxPoolSize) {
          // 重置页面状态
          try {
            await page.goto('about:blank').catch(() => {});
            // 将页面放回池中
            this.puppeteerPagePool.push(page);
            console.log(`♻️ Returned Puppeteer page to pool (${this.puppeteerPagePool.length} total)`);
          } catch (e) {
            console.warn('⚠️ Failed to reset page, closing it:', e.message);
            await page.close().catch(console.error);
          }
        } else if (!pageFromPool) {
          // 关闭非池中的页面
          await page.close().catch(console.error);
        }
      }
    }
  }

  // Generate screenshot using Playwright with page pool optimization
  async generateWithPlaywright(htmlContent, options) {
    const { format, quality, width, height, timeout } = options;
    let page = null;
    let pageFromPool = false;

    try {
      // 尝试从页面池获取页面
      if (this.playwrightPagePool && this.playwrightPagePool.length > 0) {
        page = this.playwrightPagePool.shift();
        pageFromPool = true;
        console.log(`📄 Using page from Playwright pool (${this.playwrightPagePool.length} remaining)`);
      } else {
        // 如果池为空，创建新页面
        const context = await this.playwrightBrowser.newContext({
          viewport: { width, height },
          ignoreHTTPSErrors: true
        });
        page = await context.newPage();
        console.log(`📄 Created new Playwright page (pool empty)`);
        
        // 为新创建的页面注入Google字体
        await this.injectPlaywrightGoogleFonts(page);
      }
      
      // 设置视口大小（即使从池中获取的页面也需要重新设置，因为尺寸可能不同）
      await page.setViewportSize({ width, height });
      
      // 设置内容，使用更短的超时时间
      await page.setContent(htmlContent, { 
        waitUntil: 'networkidle',
        timeout: Math.min(timeout, 10000) // 使用较短的超时时间
      });

      // 等待字体加载
      await page.evaluate(() => {
        return document.fonts ? document.fonts.ready : Promise.resolve();
      });

      // 减少等待时间
      await page.waitForTimeout(200);
      
      // 优化内存使用
      if (global.gc && Math.random() < 0.1) { // 随机触发GC，避免每次都执行
        global.gc();
      }

      // 截图选项
      const screenshotOptions = {
        type: format,
        quality: format === 'jpeg' ? quality : undefined,
        fullPage: false,
        omitBackground: format === 'png', // PNG格式可以透明背景
        clip: { x: 0, y: 0, width, height }
      };

      const screenshot = await page.screenshot(screenshotOptions);
      
      console.log(`✅ Playwright screenshot generated: ${screenshot.length} bytes`);
      return screenshot;

    } catch (error) {
      console.error(`❌ Playwright screenshot failed: ${error.message}`);
      throw error;
    } finally {
      if (page) {
        if (pageFromPool && this.playwrightPagePool.length < this.maxPoolSize) {
          // 重置页面状态
          try {
            await page.goto('about:blank').catch(() => {});
            // 将页面放回池中
            this.playwrightPagePool.push(page);
            console.log(`♻️ Returned Playwright page to pool (${this.playwrightPagePool.length} total)`);
          } catch (e) {
            console.warn('⚠️ Failed to reset page, closing it:', e.message);
            await page.close().catch(console.error);
          }
        } else if (!pageFromPool) {
          // 关闭非池中的页面
          await page.close().catch(console.error);
        }
      }
    }
  }

  // Generate fallback SVG image
  generateFallbackImage(width = 1000, height = 562, title = 'PPT Screenshot', subtitle = '', message = '') {
    const svg = `<?xml version="1.0" encoding="UTF-8"?>
<svg width="${width}" height="${height}" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <linearGradient id="bg" x1="0%" y1="0%" x2="100%" y2="100%">
      <stop offset="0%" style="stop-color:#f8f9fa;stop-opacity:1" />
      <stop offset="100%" style="stop-color:#e9ecef;stop-opacity:1" />
    </linearGradient>
    <pattern id="dots" patternUnits="userSpaceOnUse" width="20" height="20">
      <circle cx="2" cy="2" r="1" fill="#dee2e6" opacity="0.5"/>
    </pattern>
  </defs>
  
  <!-- Background -->
  <rect width="100%" height="100%" fill="url(#bg)"/>
  <rect width="100%" height="100%" fill="url(#dots)"/>
  
  <!-- Border -->
  <rect x="20" y="20" width="${width-40}" height="${height-40}" 
        fill="none" stroke="#dee2e6" stroke-width="3" 
        stroke-dasharray="15,10" rx="10"/>
  
  <!-- Icon -->
  <g transform="translate(${width/2}, ${height*0.25})">
    <circle cx="0" cy="0" r="30" fill="#6c757d" opacity="0.3"/>
    <rect x="-15" y="-10" width="30" height="20" rx="3" fill="#6c757d"/>
    <rect x="-12" y="-7" width="24" height="3" fill="white"/>
    <rect x="-12" y="-2" width="24" height="3" fill="white"/>
    <rect x="-12" y="3" width="16" height="3" fill="white"/>
  </g>
  
  <!-- Title -->
  <text x="${width/2}" y="${height*0.45}" 
        text-anchor="middle" 
        font-family="Microsoft YaHei, PingFang SC, Hiragino Sans GB, Source Han Sans SC, Noto Sans SC, WenQuanYi Micro Hei, SimHei, SimSun, Arial, sans-serif"
        font-size="28" 
        font-weight="bold" 
        fill="#495057">${title}</text>
  
  ${subtitle ? `
  <!-- Subtitle -->
  <text x="${width/2}" y="${height*0.55}" 
        text-anchor="middle" 
        font-family="Microsoft YaHei, PingFang SC, Hiragino Sans GB, Source Han Sans SC, Noto Sans SC, WenQuanYi Micro Hei, SimHei, SimSun, Arial, sans-serif"
        font-size="18" 
        fill="#6c757d">${subtitle}</text>
  ` : ''}
  
  ${message ? `
  <!-- Message -->
  <text x="${width/2}" y="${height*0.65}" 
        text-anchor="middle" 
        font-family="Microsoft YaHei, PingFang SC, Hiragino Sans GB, Source Han Sans SC, Noto Sans SC, WenQuanYi Micro Hei, SimHei, SimSun, Arial, sans-serif"
        font-size="14" 
        fill="#adb5bd">${message}</text>
  ` : ''}
  
  <!-- Footer -->
  <text x="${width/2}" y="${height*0.85}" 
        text-anchor="middle" 
        font-family="Microsoft YaHei, PingFang SC, Hiragino Sans GB, Source Han Sans SC, Noto Sans SC, WenQuanYi Micro Hei, SimHei, SimSun, Arial, sans-serif"
        font-size="12" 
        fill="#ced4da">PPT Screenshot Service • ${new Date().toLocaleString('zh-CN')}</text>
        
  <!-- Dimensions info -->
  <text x="${width/2}" y="${height*0.92}" 
        text-anchor="middle" 
        font-family="Microsoft YaHei, PingFang SC, Hiragino Sans GB, Source Han Sans SC, Noto Sans SC, WenQuanYi Micro Hei, SimHei, SimSun, Arial, sans-serif"
        font-size="10" 
        fill="#ced4da">Size: ${width} × ${height}</text>
</svg>`;

    return Buffer.from(svg, 'utf-8');
  }

  // Get service status
  getStatus() {
    return {
      puppeteerReady: this.puppeteerReady,
      playwrightReady: this.playwrightReady,
      environment: process.env.NODE_ENV || 'development',
      isHuggingFace: !!process.env.SPACE_ID
    };
  }

  // Cleanup resources
  async cleanup() {
    console.log('🧹 Cleaning up screenshot service...');
    
    if (this.puppeteerBrowser) {
      try {
        await this.puppeteerBrowser.close();
        this.puppeteerBrowser = null;
        this.puppeteerReady = false;
        console.log('✅ Puppeteer browser closed');
      } catch (error) {
        console.error('Error closing Puppeteer browser:', error);
      }
    }
    
    if (this.playwrightBrowser) {
      try {
        await this.playwrightBrowser.close();
        this.playwrightBrowser = null;
        this.playwrightReady = false;
        console.log('✅ Playwright browser closed');
      } catch (error) {
        console.error('Error closing Playwright browser:', error);
      }
    }
  }
}

export default new ScreenshotService();