backend/src/services/screenshotService.js

import puppeteer from 'puppeteer';
import playwright from 'playwright';

class ScreenshotService {
  constructor() {
    this.puppeteerBrowser = null;
    this.playwrightBrowser = null;
    this.isInitializing = false;
    this.puppeteerReady = false;
    this.playwrightReady = false;
    
    console.log('Screenshot service initialized');
  }

  // Initialize Puppeteer browser
  async initPuppeteer() {
    if (this.puppeteerBrowser || this.isInitializing) return;
    
    this.isInitializing = true;
    
    try {
      console.log('🚀 Starting Puppeteer browser...');
      
      const launchOptions = {
        headless: 'new',
        args: [
          '--no-sandbox',
          '--disable-setuid-sandbox',
          '--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',
          '--memory-pressure-off',
          '--max_old_space_size=4096'
        ],
        timeout: 30000
      };

      // Hugging Face Spaces optimizations
      if (process.env.SPACE_ID) {
        launchOptions.args.push(
          '--single-process',
          '--disable-background-networking',
          '--disable-background-mode'
        );
      }

      this.puppeteerBrowser = await puppeteer.launch(launchOptions);
      this.puppeteerReady = true;
      console.log('✅ Puppeteer browser started successfully');
      
      // 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;
    }
  }

  // Initialize Playwright browser (fallback)
  async initPlaywright() {
    if (this.playwrightBrowser) return;
    
    try {
      console.log('🎭 Starting Playwright browser...');
      
      this.playwrightBrowser = await playwright.chromium.launch({
        headless: true,
        args: [
          '--no-sandbox',
          '--disable-setuid-sandbox',
          '--disable-dev-shm-usage'
        ]
      });
      
      this.playwrightReady = true;
      console.log('✅ Playwright browser started successfully');
      
    } catch (error) {
      console.error('❌ Playwright initialization failed:', error.message);
      this.playwrightReady = false;
    }
  }

  // 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
  async generateWithPuppeteer(htmlContent, options) {
    const { format, quality, width, height, timeout } = options;
    let page = null;

    try {
      page = await this.puppeteerBrowser.newPage();
      
      // Set viewport
      await page.setViewport({ width, height });
      
      // Set content
      await page.setContent(htmlContent, { 
        waitUntil: 'networkidle0',
        timeout: timeout
      });

      // Wait for fonts
      await page.evaluate(() => {
        return document.fonts ? document.fonts.ready : Promise.resolve();
      });

      // Additional wait for rendering
      await page.waitForTimeout(300);

      // Take screenshot
      const screenshotOptions = {
        type: format,
        quality: format === 'jpeg' ? quality : undefined,
        fullPage: false,
        clip: { x: 0, y: 0, width, height }
      };

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

    } finally {
      if (page) {
        await page.close().catch(console.error);
      }
    }
  }

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

    try {
      page = await this.playwrightBrowser.newPage();
      
      // Set viewport
      await page.setViewportSize({ width, height });
      
      // Set content
      await page.setContent(htmlContent, { 
        waitUntil: 'networkidle',
        timeout: timeout
      });

      // Wait for fonts
      await page.evaluate(() => {
        return document.fonts ? document.fonts.ready : Promise.resolve();
      });

      // Take screenshot
      const screenshotOptions = {
        type: format,
        quality: format === 'jpeg' ? quality : undefined,
        fullPage: false,
        clip: { x: 0, y: 0, width, height }
      };

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

    } finally {
      if (page) {
        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();