#!/usr/bin/env node

/**
 * Design System Migration Script
 * 
 * Migrates existing theme classes to new design system classes
 * Replaces hardcoded colors with semantic design system alternatives
 */

const fs = require('fs');
const path = require('path');

// Comprehensive class mappings from old theme/hardcoded classes to design system
const DESIGN_SYSTEM_REPLACEMENTS = {
  // Background replacements
  'theme-bg': 'ds-bg',
  'theme-bg-secondary': 'ds-bg-secondary', 
  'theme-bg-page': 'ds-bg-page',
  'bg-white dark:bg-gray-900': 'ds-bg',
  'bg-gray-50 dark:bg-gray-900': 'ds-bg-page',
  'bg-gray-100 dark:bg-gray-800': 'ds-bg-secondary',
  
  // Text replacements
  'theme-text': 'ds-text',
  'theme-text-secondary': 'ds-text-secondary',
  'theme-text-muted': 'ds-text-muted',
  'text-gray-900 dark:text-gray-100': 'ds-text',
  'text-gray-600 dark:text-gray-400': 'ds-text-secondary',
  'text-gray-500 dark:text-gray-400': 'ds-text-muted',
  'text-gray-500': 'ds-text-muted',
  
  // Button replacements
  'theme-toggle': 'ds-theme-toggle',
  'btn-primary': 'ds-btn-primary',
  'btn-secondary': 'ds-btn-secondary',
  'btn-ghost': 'ds-btn-ghost',
  
  // Navigation replacements
  'nav-link': 'ds-nav-link',
  'nav-link-active': 'ds-nav-link-active',
  
  // Card replacements
  'theme-card': 'ds-card',
  'card-base': 'ds-card',
  'card-hover': 'ds-card-hover',
  
  // Border replacements
  'theme-border': 'ds-border',
  'border-gray-200 dark:border-gray-700': 'ds-border',
  'border-gray-300 dark:border-gray-600': 'ds-border',
  
  // Typography scale replacements
  'text-4xl font-semibold tracking-tight': 'ds-heading-1',
  'text-3xl font-semibold': 'ds-heading-2',
  'text-2xl font-semibold': 'ds-heading-3',
  'text-xl font-semibold': 'ds-heading-4',
  'text-lg': 'ds-body',
  'text-sm': 'ds-caption',
  
  // Hardcoded color replacements
  'bg-blue-200': 'bg-ds-brand-primary/20',
  'bg-blue-600': 'bg-ds-brand-primary',
  'bg-green-200': 'bg-ds-success/20',
  'bg-green-600': 'bg-ds-success',
  'bg-purple-500': 'bg-ds-brand-secondary',
  'bg-pink-500': 'bg-ds-brand-accent',
  'text-blue-600 dark:text-blue-400': 'text-ds-brand-primary',
  'text-green-600 dark:text-green-400': 'text-ds-success',
  'text-gray-800 dark:text-gray-200': 'ds-text',
  
  // Shadow replacements
  'shadow-sm': 'ds-shadow-sm',
  'shadow-md': 'ds-shadow-md',
  'shadow-lg': 'ds-shadow-lg',
  
  // Spacing replacements with container
  'mx-auto max-w-4xl py-16 sm:py-24': 'ds-container-md py-ds-16 sm:py-ds-24',
  'mx-auto max-w-2xl': 'ds-container-sm',
  'mx-auto max-w-6xl': 'ds-container-lg',
  'px-6 lg:px-8': 'ds-container',
  
  // Grid and layout
  'grid grid-cols-1 md:grid-cols-2 gap-8': 'grid grid-cols-1 md:grid-cols-2 gap-ds-8',
  'space-y-2': 'space-y-ds-2',
  'space-x-2': 'space-x-ds-2',
  'flex space-x-2': 'flex space-x-ds-2',
  'mb-4': 'mb-ds-4',
  'mb-12': 'mb-ds-12',
  'mt-6': 'mt-ds-6',
  'mt-12': 'mt-ds-12',
  'p-6': 'p-ds-6',
  'p-2': 'p-ds-2',
  'px-6 py-3': 'px-ds-6 py-ds-3',
  'px-4 py-2': 'px-ds-4 py-ds-2',
  
  // Rounded corners
  'rounded-lg': 'ds-rounded-lg',
  'rounded-full': 'ds-rounded-full',
  'rounded': 'ds-rounded',
};

// Individual class replacements for when full context patterns don't match
const INDIVIDUAL_CLASS_REPLACEMENTS = {
  // Hardcoded grays to design system neutrals
  'text-gray-900': 'text-ds-neutral-900',
  'text-gray-800': 'text-ds-neutral-800',
  'text-gray-700': 'text-ds-neutral-700',
  'text-gray-600': 'text-ds-neutral-600',
  'text-gray-500': 'text-ds-neutral-500',
  'text-gray-400': 'text-ds-neutral-400',
  'text-gray-300': 'text-ds-neutral-300',
  'text-gray-200': 'text-ds-neutral-200',
  'text-gray-100': 'text-ds-neutral-100',
  
  'bg-gray-900': 'bg-ds-neutral-900',
  'bg-gray-800': 'bg-ds-neutral-800',
  'bg-gray-700': 'bg-ds-neutral-700',
  'bg-gray-600': 'bg-ds-neutral-600',
  'bg-gray-500': 'bg-ds-neutral-500',
  'bg-gray-400': 'bg-ds-neutral-400',
  'bg-gray-300': 'bg-ds-neutral-300',
  'bg-gray-200': 'bg-ds-neutral-200',
  'bg-gray-100': 'bg-ds-neutral-100',
  'bg-gray-50': 'bg-ds-neutral-50',
  
  'border-gray-900': 'border-ds-neutral-900',
  'border-gray-800': 'border-ds-neutral-800',
  'border-gray-700': 'border-ds-neutral-700',
  'border-gray-600': 'border-ds-neutral-600',
  'border-gray-500': 'border-ds-neutral-500',
  'border-gray-400': 'border-ds-neutral-400',
  'border-gray-300': 'border-ds-neutral-300',
  'border-gray-200': 'border-ds-neutral-200',
  'border-gray-100': 'border-ds-neutral-100',
  
  // Legacy theme classes to design system
  'theme-text': 'ds-text',
  'theme-text-secondary': 'ds-text-secondary',
  'theme-text-muted': 'ds-text-muted',
  'theme-bg': 'ds-bg',
  'theme-bg-secondary': 'ds-bg-secondary',
  'theme-bg-page': 'ds-bg-page',
  'theme-border': 'ds-border',
  'theme-card': 'ds-card',
  'theme-toggle': 'ds-theme-toggle',
  'nav-link': 'ds-nav-link',
  
  // Brand colors
  'bg-blue-500': 'bg-ds-brand-primary',
  'bg-blue-600': 'bg-ds-brand-primary',
  'text-blue-500': 'text-ds-brand-primary',
  'text-blue-600': 'text-ds-brand-primary',
  'border-blue-500': 'border-ds-brand-primary',
  
  // Success colors
  'bg-green-500': 'bg-ds-success',
  'bg-green-600': 'bg-ds-success',
  'text-green-500': 'text-ds-success',
  'text-green-600': 'text-ds-success',
  
  // Error colors
  'bg-red-500': 'bg-ds-error',
  'bg-red-600': 'bg-ds-error',
  'text-red-500': 'text-ds-error',
  'text-red-600': 'text-ds-error',
  
  // Warning colors  
  'bg-yellow-500': 'bg-ds-warning',
  'bg-amber-500': 'bg-ds-warning',
  'text-yellow-500': 'text-ds-warning',
  'text-amber-500': 'text-ds-warning',
};

function findRustFiles(dir) {
  const files = [];
  
  function walk(currentPath) {
    const items = fs.readdirSync(currentPath);
    
    for (const item of items) {
      const fullPath = path.join(currentPath, item);
      const stat = fs.statSync(fullPath);
      
      if (stat.isDirectory() && !item.startsWith('.') && item !== 'target') {
        walk(fullPath);
      } else if (item.endsWith('.rs')) {
        files.push(fullPath);
      }
    }
  }
  
  walk(dir);
  return files;
}

function migrateFileToDesignSystem(filePath, dryRun = false) {
  console.log(`🎨 ${dryRun ? 'Analyzing' : 'Migrating'}: ${filePath}`);
  
  let content = fs.readFileSync(filePath, 'utf8');
  let changes = 0;
  
  // Apply complex pattern replacements first (order matters)
  const sortedReplacements = Object.entries(DESIGN_SYSTEM_REPLACEMENTS)
    .sort(([a], [b]) => b.length - a.length); // Longer patterns first
  
  for (const [pattern, replacement] of sortedReplacements) {
    const regex = new RegExp(pattern.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\$&'), 'g');
    const matches = content.match(regex);
    
    if (matches) {
      console.log(`  📝 ${matches.length}x: ${pattern} → ${replacement}`);
      content = content.replace(regex, replacement);
      changes += matches.length;
    }
  }
  
  // Apply individual class replacements
  for (const [oldClass, newClass] of Object.entries(INDIVIDUAL_CLASS_REPLACEMENTS)) {
    // Use word boundaries to avoid partial matches
    const regex = new RegExp(`\\\\b${oldClass.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\$&')}\\\\b`, 'g');
    const matches = content.match(regex);
    
    if (matches) {
      console.log(`  🔄 ${matches.length}x: ${oldClass} → ${newClass}`);
      content = content.replace(regex, newClass);
      changes += matches.length;
    }
  }
  
  if (!dryRun && changes > 0) {
    fs.writeFileSync(filePath, content);
    console.log(`✅ Applied ${changes} changes to ${filePath}`);
  } else if (changes > 0) {
    console.log(`📋 Would apply ${changes} changes (use --apply to execute)`);
  } else {
    console.log(`✨ No design system changes needed`);
  }
  
  return changes;
}

function migrateAllFiles(clientDir, dryRun = false) {
  console.log('🎨 Migrating all files to design system...\\n');
  
  const files = findRustFiles(clientDir);
  let totalChanges = 0;
  let filesChanged = 0;
  
  for (const file of files) {
    const changes = migrateFileToDesignSystem(file, dryRun);
    if (changes > 0) {
      totalChanges += changes;
      filesChanged++;
    }
    console.log(''); // Add spacing between files
  }
  
  console.log(`📊 Migration Summary:`);
  console.log(`   Files processed: ${files.length}`);
  console.log(`   Files ${dryRun ? 'needing changes' : 'changed'}: ${filesChanged}`);
  console.log(`   Total class migrations: ${totalChanges}`);
  
  if (totalChanges > 0) {
    console.log('\\n💡 Next Steps:');
    console.log('1. Build CSS: node scripts/build/build-design-system.js');
    console.log('2. Test in browser: just dev');
    console.log('3. Verify themes work: check light/dark mode');
    console.log('4. Test responsive: check mobile/tablet/desktop');
  }
  
  return totalChanges;
}

// CLI handling
if (require.main === module) {
  const args = process.argv.slice(2);
  const command = args[0];
  
  if (command === 'file') {
    const filePath = args[1];
    const dryRun = !args.includes('--apply');
    
    if (!filePath) {
      console.error('Usage: migrate-to-design-system.js file <path> [--apply]');
      process.exit(1);
    }
    
    migrateFileToDesignSystem(filePath, dryRun);
  } else if (command === 'all' || !command) {
    const clientDir = path.join(__dirname, '..', 'crates', 'client');
    const dryRun = !args.includes('--apply');
    
    migrateAllFiles(clientDir, dryRun);
  } else {
    console.log('Usage:');
    console.log('  node migrate-to-design-system.js all [--apply]     # Migrate all files');
    console.log('  node migrate-to-design-system.js file <path> [--apply]  # Migrate single file');
    console.log('');
    console.log('Examples:');
    console.log('  node migrate-to-design-system.js all                    # Dry run all files');
    console.log('  node migrate-to-design-system.js all --apply            # Migrate all files');
    console.log('  node migrate-to-design-system.js file src/pages/Home.rs # Dry run single file');
  }
}

module.exports = { migrateFileToDesignSystem, migrateAllFiles, DESIGN_SYSTEM_REPLACEMENTS };