import express from 'express';
import cors from 'cors';
import { exec } from 'child_process';
import { promisify } from 'util';
import fs from 'fs-extra';
import path from 'path';
import { fileURLToPath } from 'url';

const execAsync = promisify(exec);
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
const PORT = process.env.API_PORT || 3001;

// Enable CORS for all origins
app.use(cors({
  origin: '*',
  methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
  allowedHeaders: ['Content-Type', 'Authorization']
}));

app.use(express.json());

// Logging middleware
app.use((req, res, next) => {
  console.log(`[${new Date().toISOString()}] ${req.method} ${req.url}`);
  next();
});

// Health check endpoint
app.get('/health', (req, res) => {
  res.json({ 
    status: 'ok', 
    timestamp: new Date().toISOString(),
    services: {
      api: 'running',
      vitepress: 'running'
    }
  });
});

// Export PDF endpoint
app.get('/export-pdf', async (req, res) => {
  const docsPath = process.env.DOCS_PATH || '/app/docs';
  const pdfFileName = req.query.fileName || `export-${Date.now()}.pdf`;
  const vitepressPort = process.env.VITEPRESS_PORT || 3000;

  console.log(`[${new Date().toISOString()}] Starting PDF export...`);
  console.log(`Docs path: ${docsPath}`);
  console.log(`PDF output: ${path.join(docsPath, pdfFileName)}`);
  console.log(`VitePress port: ${vitepressPort}`);

  try {
    // Ensure PDF directory exists
    await fs.ensureDir(docsPath);

    // Clean old dist directory
    const distDir = path.join(docsPath, '.vitepress', 'dist');
    console.log('Cleaning old dist directory...');
    await fs.remove(distDir).catch(() => {});

    // Build the VitePress site
    /*
    console.log('Building VitePress site...');
    try {
      await execAsync('npm run docs:build', { 
        cwd: '/app',
        stdio: 'inherit',
        timeout: 120000 // 2 minutes timeout
      });
    } catch (buildError) {
      console.error('Build warning/error:', buildError.message);
      // Continue anyway, sometimes there are non-fatal warnings
    }
    */

    // Run PDF export (VitePress preview is already running)
    console.log('Starting PDF export using running VitePress server...');
    
    const exportEnv = {
      ...process.env,
      NODE_ENV: 'development'
    };
    
    try {
      /*
      console.log('Installing vitepress-export-pdf...');
      await execAsync('npm install vitepress-export-pdf -D', {
        cwd: '/app',
        stdio: 'inherit',
        env: exportEnv,
        timeout: 120000
      });
      */
      
      console.log('Running export-pdf...');
      await execAsync('npm run export-pdf', {
        cwd: '/app',
        stdio: 'inherit',
        env: exportEnv,
        timeout: 180000,
        maxBuffer: 1024 * 1024 * 100
      });
    } catch (exportError) {
      console.error('Export command failed:', exportError.message);
      throw new Error(`PDF export failed: ${exportError.message}`);
    }

    // Verify PDF was created
    const pdfPath = path.join(docsPath, pdfFileName);
    const pdfExists = await fs.pathExists(pdfPath);
    
    if (!pdfExists) {
      // Try to find any PDF file in the directory
      const files = await fs.readdir(docsPath);
      const pdfFiles = files.filter(f => f.endsWith('.pdf'));
      
      if (pdfFiles.length > 0) {
        console.log(`PDF found with different name: ${pdfFiles[0]}`);
        const stats = await fs.stat(path.join(docsPath, pdfFiles[0]));
        
        console.log(`[${new Date().toISOString()}] PDF export completed successfully!`);
        console.log(`PDF size: ${(stats.size / 1024 / 1024).toFixed(2)} MB`);

        return res.json({
          success: true,
          message: 'PDF exported successfully',
          pdfPath: path.join(docsPath, pdfFiles[0]),
          pdfUrl: `${pdfFiles[0]}`,
          fileName: pdfFiles[0],
          fileSize: stats.size,
          fileSizeMB: (stats.size / 1024 / 1024).toFixed(2)
        });
      } else {
        throw new Error('PDF file was not created');
      }
    }

    const stats = await fs.stat(pdfPath);
    
    console.log(`[${new Date().toISOString()}] PDF export completed successfully!`);
    console.log(`PDF path: ${pdfPath}`);
    console.log(`PDF size: ${(stats.size / 1024 / 1024).toFixed(2)} MB`);

    res.json({
      success: true,
      message: 'PDF exported successfully',
      pdfPath: pdfPath,
      pdfUrl: `${pdfFileName}`,
      fileName: pdfFileName,
      fileSize: stats.size,
      fileSizeMB: (stats.size / 1024 / 1024).toFixed(2)
    });

  } catch (error) {
    console.error(`[${new Date().toISOString()}] PDF export failed:`, error);
    
    res.status(500).json({
      success: false,
      error: error.message,
      stack: process.env.NODE_ENV === 'development' ? error.stack : undefined
    });
  }
});

// List all PDF files
app.get('/pdf-files', async (req, res) => {
  const docsPath = process.env.DOCS_PATH || '/app/docs';

  try {
    await fs.ensureDir(docsPath);
    const files = await fs.readdir(docsPath);
    const pdfFiles = files.filter(f => f.endsWith('.pdf'));
    
    const fileDetails = await Promise.all(
      pdfFiles.map(async (file) => {
        const stats = await fs.stat(path.join(docsPath, file));
        return {
          name: file,
          size: stats.size,
          sizeMB: (stats.size / 1024 / 1024).toFixed(2),
          created: stats.birthtime,
          modified: stats.mtime
        };
      })
    );

    res.json({
      count: pdfFiles.length,
      files: fileDetails
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Error handling middleware
app.use((err, req, res, next) => {
  console.error(`[${new Date().toISOString()}] Error:`, err);
  res.status(500).json({ 
    error: err.message || 'Internal server error',
    stack: process.env.NODE_ENV === 'development' ? err.stack : undefined
  });
});

app.listen(PORT, '0.0.0.0', () => {
  console.log(`========================================`);
  console.log(`VitePress API Server`);
  console.log(`========================================`);
  console.log(`API Server running on port: ${PORT}`);
  console.log(`VitePress Server: http://localhost:${process.env.VITEPRESS_PORT || 3000}`);
  console.log(`PDF output directory: ${process.env.DOCS_PATH || '/app/docs'}`);
  console.log(`========================================`);
  console.log(`Available API endpoints:`);
  console.log(`  GET  /health        - Health check`);
  console.log(`  GET  /export-pdf     - Export PDF`);
  console.log(`  GET  /pdf-files      - List all PDF files`);
  console.log(`========================================`);
});