const crypto = require('crypto');

// Helper function to demonstrate error handling
function demonstrateError(scenario) {
  console.log(`\n=== ${scenario} ===`);
  
  try {
    switch (scenario) {
      case 'INVALID_KEY_LENGTH':
        // Key is too short for AES-256 (needs 32 bytes)
        const shortKey = Buffer.from('tooshort', 'utf8');
        const iv = crypto.randomBytes(16);
        crypto.createDecipheriv('aes-256-cbc', shortKey, iv);
        break;
        
      case 'INVALID_IV_LENGTH':
        // IV is too short for AES-CBC (needs 16 bytes)
        const key = crypto.randomBytes(32);
        const shortIv = Buffer.from('tooshort', 'utf8');
        crypto.createDecipheriv('aes-256-cbc', key, shortIv);
        break;
        
      case 'INVALID_AUTH_TAG':
        // Using GCM without setting auth tag
        const gcmKey = crypto.randomBytes(32);
        const gcmIv = crypto.randomBytes(12);
        const gcmDecipher = crypto.createDecipheriv('aes-256-gcm', gcmKey, gcmIv);
        gcmDecipher.setAAD(Buffer.from('some data'));
        // Forgot to call setAuthTag()
        gcmDecipher.update('somedata', 'hex', 'utf8');
        gcmDecipher.final('utf8');
        break;
        
      case 'INVALID_CIPHERTEXT':
        // Corrupted ciphertext
        const cipher = crypto.createCipheriv('aes-256-cbc', crypto.randomBytes(32), crypto.randomBytes(16));
        const encrypted = cipher.update('test', 'utf8', 'hex') + cipher.final('hex');
        
        // Corrupt the ciphertext
        const corrupted = encrypted.substring(0, 10) + '00' + encrypted.substring(12);
        
        const decipher = crypto.createDecipheriv('aes-256-cbc', crypto.randomBytes(32), crypto.randomBytes(16));
        decipher.update(corrupted, 'hex', 'utf8');
        decipher.final('utf8');
        break;
    }
  } catch (error) {
    console.log(`Error: ${error.code} - ${error.message}`);
  }
}

// Demonstrate different error scenarios
demonstrateError('INVALID_KEY_LENGTH');
demonstrateError('INVALID_IV_LENGTH');
demonstrateError('INVALID_AUTH_TAG');
demonstrateError('INVALID_CIPHERTEXT');