const crypto = require('crypto');

console.log('=== DIFFIEHELLMAN ERRORS ===\n');

// 1. Invalid prime length
console.log('1. Creating with invalid prime length:');
try {
  // Prime length must be a multiple of 8 and >= 8
  const dh = crypto.createDiffieHellman(7);
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 2. Invalid prime
console.log('\n2. Creating with invalid prime:');
try {
  // Prime must be a prime number
  const prime = Buffer.from('0f', 'hex');
  const dh = crypto.createDiffieHellman(prime);
  dh.generateKeys();
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 3. Invalid generator
console.log('\n3. Using invalid generator:');
try {
  const prime = crypto.createDiffieHellman(512).getPrime();
  const dh = crypto.createDiffieHellman(prime, Buffer.from('01', 'hex')); // Generator too small
  dh.generateKeys();
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 4. Invalid public key in computeSecret
console.log('\n4. Computing secret with invalid public key:');
try {
  const alice = crypto.createDiffieHellman(512);
  const bob = crypto.createDiffieHellman(512);
  alice.generateKeys();
  bob.generateKeys();
  
  // Using a key that's too short
  const invalidKey = Buffer.alloc(10);
  alice.computeSecret(invalidKey);
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 5. Using wrong group parameters
console.log('\n5. Using mismatched group parameters:');
try {
  const alice = crypto.createDiffieHellman(512);
  const bob = crypto.createDiffieHellman(512); // Different prime/generator
  
  alice.generateKeys();
  bob.generateKeys();
  
  // Exchange public keys
  const alicePublicKey = alice.getPublicKey();
  const bobPublicKey = bob.getPublicKey();
  
  // This will work (but the shared secret will be different)
  alice.computeSecret(bobPublicKey);
  bob.computeSecret(alicePublicKey);
  
  console.log('  - Warning: This works but is insecure! Different groups should not be used together');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 6. Invalid encoding in getPublicKey
console.log('\n6. Using invalid encoding:');
try {
  const dh = crypto.createDiffieHellman(512);
  dh.generateKeys();
  
  // Invalid encoding
  dh.getPublicKey('invalid-encoding');
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 7. Verify error codes
console.log('\n7. Verifying parameters:');
try {
  // Create a valid DH instance
  const dh = crypto.createDiffieHellman(512);
  dh.generateKeys();
  
  // Force an error by setting an invalid public key
  const invalidKey = Buffer.alloc(64);
  dh.setPublicKey(invalidKey);
  
  // Check verifyError
  console.log(`  - Verify error code: ${dh.verifyError}`);
  console.log(`  - Verify error message: ${dh.verifyError ? 'Invalid public key' : 'No error'}`);
  
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}

// 8. Using unsupported group
console.log('\n8. Using unsupported group:');
try {
  const dh = crypto.getDiffieHellman('nonexistent-group');
  console.log('  - Should not reach here');
} catch (err) {
  console.log(`  - Error: ${err.code} - ${err.message}`);
}