#!/usr/bin/env node
/**
 * Design Diff Analyzer
 * Analyzes changes to ui-design.pen and generates implementation tasks for Claude Code
 */

import { execSync } from 'child_process';
import fs from 'fs';

function getDiff() {
  try {
    return execSync('git diff HEAD~1 ui-design.pen', { encoding: 'utf8' });
  } catch (e) {
    return '';
  }
}

function analyzeDiff(diff) {
  const changes = {
    colors: [],
    typography: [],
    spacing: [],
    layout: [],
    content: []
  };

  const lines = diff.split('\n');
  
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    
    // Color changes
    if (line.includes('"fill":') || line.includes('"backgroundColor":')) {
      const oldMatch = lines[i-1]?.match(/"(fill|backgroundColor)":\s*"([^"]+)"/);
      const newMatch = line.match(/"(fill|backgroundColor)":\s*"([^"]+)"/);
      
      if (oldMatch && newMatch && oldMatch[2] !== newMatch[2]) {
        changes.colors.push({
          type: oldMatch[1],
          from: oldMatch[2],
          to: newMatch[2]
        });
      }
    }
    
    // Font size changes
    if (line.includes('"fontSize":')) {
      const oldMatch = lines[i-1]?.match(/"fontSize":\s*(\d+)/);
      const newMatch = line.match(/"fontSize":\s*(\d+)/);
      
      if (oldMatch && newMatch && oldMatch[1] !== newMatch[1]) {
        changes.typography.push({
          type: 'fontSize',
          from: parseInt(oldMatch[1]),
          to: parseInt(newMatch[1])
        });
      }
    }
    
    // Spacing/padding changes
    if (line.includes('"padding":') || line.includes('"margin":') || line.includes('"gap":')) {
      const oldMatch = lines[i-1]?.match(/"(padding|margin|gap)":\s*(\d+)/);
      const newMatch = line.match(/"(padding|margin|gap)":\s*(\d+)/);
      
      if (oldMatch && newMatch && oldMatch[2] !== newMatch[2]) {
        changes.spacing.push({
          type: oldMatch[1],
          from: parseInt(oldMatch[2]),
          to: parseInt(newMatch[2])
        });
      }
    }
    
    // Content changes (text only - no implementation needed)
    if (line.includes('"content":')) {
      const oldMatch = lines[i-1]?.match(/"content":\s*"([^"]+)"/);
      const newMatch = line.match(/"content":\s*"([^"]+)"/);
      
      if (oldMatch && newMatch && oldMatch[1] !== newMatch[1]) {
        changes.content.push({
          from: oldMatch[1],
          to: newMatch[1]
        });
      }
    }
  }
  
  return changes;
}

function generateTasks(changes) {
  const tasks = [];
  
  // Color changes → update theme.json or CSS variables
  if (changes.colors.length > 0) {
    const colorList = changes.colors.map(c => 
      `  - ${c.type}: ${c.from} → ${c.to}`
    ).join('\n');
    
    tasks.push({
      priority: 'high',
      description: 'Update color palette',
      details: `Color changes detected:\n${colorList}\n\nUpdate src/theme.json or CSS variables to match the design.`
    });
  }
  
  // Typography changes → update theme.json
  if (changes.typography.length > 0) {
    const typoList = changes.typography.map(t =>
      `  - ${t.type}: ${t.from}px → ${t.to}px`
    ).join('\n');
    
    tasks.push({
      priority: 'medium',
      description: 'Update typography',
      details: `Typography changes detected:\n${typoList}\n\nUpdate src/theme.json typography settings.`
    });
  }
  
  // Spacing changes → update theme.json
  if (changes.spacing.length > 0) {
    const spacingList = changes.spacing.map(s =>
      `  - ${s.type}: ${s.from}px → ${s.to}px`
    ).join('\n');
    
    tasks.push({
      priority: 'medium',
      description: 'Update spacing',
      details: `Spacing changes detected:\n${spacingList}\n\nUpdate src/theme.json spacing values.`
    });
  }
  
  return tasks;
}

function formatOutput(tasks, changes) {
  if (tasks.length === 0 && changes.content.length === 0) {
    return null;
  }
  
  let output = '🎨 Design changes detected:\n\n';
  
  if (tasks.length > 0) {
    output += '📋 Implementation tasks:\n\n';
    tasks.forEach((task, i) => {
      output += `${i + 1}. [${task.priority.toUpperCase()}] ${task.description}\n`;
      output += `${task.details}\n\n`;
    });
  }
  
  if (changes.content.length > 0) {
    output += '📝 Content changes (mockup text only, no code changes needed):\n';
    changes.content.forEach(c => {
      output += `  - "${c.from}" → "${c.to}"\n`;
    });
    output += '\n';
  }
  
  return { output, tasks };
}

function main() {
  const diff = getDiff();
  
  if (!diff) {
    console.log('No design changes detected');
    process.exit(0);
  }
  
  const changes = analyzeDiff(diff);
  const tasks = generateTasks(changes);
  const result = formatOutput(tasks, changes);
  
  if (!result) {
    console.log('No significant design changes detected');
    process.exit(0);
  }
  
  console.log(result.output);
  
  // Output JSON for automation
  if (process.argv.includes('--json')) {
    console.log('\n---JSON---');
    console.log(JSON.stringify({ tasks, changes }, null, 2));
  }
  
  process.exit(tasks.length > 0 ? 1 : 0); // Exit 1 if there are tasks to implement
}

main();