/**
 * Build Verification Script
 * 
 * Verifies that the production build was successful and contains
 * all necessary files for deployment.
 */

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

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

const DIST_DIR = path.join(__dirname, '..', 'dist');
const REQUIRED_FILES = [
  'index.html',
  'assets' // Directory
];

const errors = [];
const warnings = [];

console.log('🔍 Verifying build output...\n');

// Check if dist directory exists
if (!fs.existsSync(DIST_DIR)) {
  errors.push('dist/ directory not found - build may have failed');
  console.error('❌ dist/ directory not found');
  process.exit(1);
}

console.log(`📁 Build directory: ${DIST_DIR}`);

// Check required files
console.log('\n📋 Checking required files:');
for (const file of REQUIRED_FILES) {
  const filePath = path.join(DIST_DIR, file);
  const exists = fs.existsSync(filePath);
  
  if (exists) {
    const stats = fs.statSync(filePath);
    const isDir = stats.isDirectory();
    console.log(`  ✅ ${file} ${isDir ? '(directory)' : `(${(stats.size / 1024).toFixed(2)} KB)`}`);
  } else {
    errors.push(`Required file missing: ${file}`);
    console.log(`  ❌ ${file} - MISSING`);
  }
}

// Check for JavaScript bundles
console.log('\n📦 Checking JavaScript bundles:');
const assetsDir = path.join(DIST_DIR, 'assets');
if (fs.existsSync(assetsDir)) {
  const files = fs.readdirSync(assetsDir);
  const jsFiles = files.filter(f => f.endsWith('.js'));
  const cssFiles = files.filter(f => f.endsWith('.css'));
  
  if (jsFiles.length === 0) {
    errors.push('No JavaScript bundles found in assets/');
    console.log('  ❌ No JavaScript bundles found');
  } else {
    console.log(`  ✅ Found ${jsFiles.length} JavaScript bundles`);
    
    // Show bundle sizes
    const totalJsSize = jsFiles.reduce((total, file) => {
      const stats = fs.statSync(path.join(assetsDir, file));
      return total + stats.size;
    }, 0);
    console.log(`     Total JS size: ${(totalJsSize / 1024 / 1024).toFixed(2)} MB`);
    
    // Warn if bundles are too large
    jsFiles.forEach(file => {
      const stats = fs.statSync(path.join(assetsDir, file));
      const sizeMB = stats.size / 1024 / 1024;
      if (sizeMB > 1) {
        warnings.push(`Large bundle detected: ${file} (${sizeMB.toFixed(2)} MB)`);
      }
    });
  }
  
  if (cssFiles.length === 0) {
    warnings.push('No CSS files found in assets/');
    console.log('  ⚠️  No CSS files found');
  } else {
    console.log(`  ✅ Found ${cssFiles.length} CSS files`);
  }
} else {
  errors.push('assets/ directory not found');
  console.log('  ❌ assets/ directory not found');
}

// Check index.html
console.log('\n📄 Checking index.html:');
const indexPath = path.join(DIST_DIR, 'index.html');
if (fs.existsSync(indexPath)) {
  const content = fs.readFileSync(indexPath, 'utf8');
  
  // Check for script tags
  const scriptTags = content.match(/<script[^>]*src="[^"]*"[^>]*>/g);
  if (scriptTags && scriptTags.length > 0) {
    console.log(`  ✅ Found ${scriptTags.length} script tag(s)`);
  } else {
    errors.push('No script tags found in index.html');
    console.log('  ❌ No script tags found');
  }
  
  // Check for stylesheet links
  const linkTags = content.match(/<link[^>]*rel="stylesheet"[^>]*>/g);
  if (linkTags && linkTags.length > 0) {
    console.log(`  ✅ Found ${linkTags.length} stylesheet link(s)`);
  } else {
    warnings.push('No stylesheet links found in index.html');
    console.log('  ⚠️  No stylesheet links found');
  }
} else {
  errors.push('index.html not found');
  console.log('  ❌ index.html not found');
}

// Calculate total build size
console.log('\n📊 Build Statistics:');
function getDirSize(dirPath) {
  let size = 0;
  const files = fs.readdirSync(dirPath);
  
  for (const file of files) {
    const filePath = path.join(dirPath, file);
    const stats = fs.statSync(filePath);
    
    if (stats.isDirectory()) {
      size += getDirSize(filePath);
    } else {
      size += stats.size;
    }
  }
  
  return size;
}

const totalSize = getDirSize(DIST_DIR);
console.log(`  Total build size: ${(totalSize / 1024 / 1024).toFixed(2)} MB`);

// Summary
console.log('\n' + '='.repeat(50));
if (errors.length > 0) {
  console.log('\n❌ Build verification FAILED\n');
  errors.forEach(error => console.error(`  - ${error}`));
  process.exit(1);
}

if (warnings.length > 0) {
  console.log('\n⚠️  Build verification passed with warnings:\n');
  warnings.forEach(warning => console.warn(`  - ${warning}`));
}

console.log('\n✅ Build verification PASSED');
console.log('   All required files present and valid');
console.log('   Ready for deployment\n');