#!/usr/bin/env node

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

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

const distPath = path.join(__dirname, '..', 'dist');

console.log('📦 Bundle Analysis\n');

function getFileSize(filePath) {
  const stats = fs.statSync(filePath);
  const sizeInKB = (stats.size / 1024).toFixed(2);
  const sizeInBytes = stats.size;
  return { kb: `${sizeInKB} KB`, bytes: sizeInBytes };
}

function analyzeFiles() {
  if (!fs.existsSync(distPath)) {
    console.log('❌ No dist folder found. Run `npm run build` first.');
    return;
  }

  const files = fs.readdirSync(distPath).filter(f => !f.includes('utils'));
  
  console.log('📊 File Sizes:');
  files.forEach(file => {
    const filePath = path.join(distPath, file);
    if (fs.statSync(filePath).isFile()) {
      const size = getFileSize(filePath);
      const icon = file.endsWith('.esm.js') ? '📦 ESM' : 
                   file.endsWith('.js') ? '📦 CJS' : 
                   file.endsWith('.d.ts') ? '📄 Types' : '📄';
      console.log(`  ${icon}: ${file} - ${size.kb}`);
    }
  });

  // Calculate totals
  const jsFiles = files.filter(f => f.endsWith('.js') && !f.includes('.map'));
  const totalSize = jsFiles.reduce((acc, file) => {
    const filePath = path.join(distPath, file);
    const size = getFileSize(filePath);
    return acc + size.bytes;
  }, 0);

  console.log(`\n💾 Total JS Size: ${(totalSize / 1024).toFixed(2)} KB`);
  
  // Tree shaking effectiveness
  const esmFiles = files.filter(f => f.endsWith('.esm.js'));
  const cjsFiles = files.filter(f => f.endsWith('.js') && !f.endsWith('.esm.js') && !f.includes('.map'));
  
  console.log(`\n🌳 Tree-shaking ready: ${esmFiles.length} ESM builds`);
  console.log(`🔧 CommonJS compatible: ${cjsFiles.length} CJS builds`);
  
  // Size comparison
  if (esmFiles.length > 0) {
    const avgEsmSize = esmFiles.reduce((acc, file) => {
      const filePath = path.join(distPath, file);
      return acc + getFileSize(filePath).bytes;
    }, 0) / esmFiles.length;
    console.log(`📏 Average ESM build size: ${(avgEsmSize / 1024).toFixed(2)} KB`);
  }
}

analyzeFiles();