const crypto = require('crypto');

// List of common ECDH curves to compare
const curves = [
  'secp256k1',    // Bitcoin's curve
  'prime256v1',   // Also known as secp256r1 or NIST P-256
  'secp384r1',    // NIST P-384
  'secp521r1',    // NIST P-521
  'brainpoolP256r1',
  'brainpoolP384r1',
  'brainpoolP512r1',
  'ed25519',      // Edwards curve (not all versions of Node.js support this for ECDH)
  'x25519'        // Curve25519 (not all versions of Node.js support this for ECDH)
].filter(curve => crypto.getCurves().includes(curve)); // Filter to only include supported curves

console.log('Comparing ECDH Curves');
console.log('='.repeat(50));

// Function to test a curve
function testCurve(curve) {
  try {
    // Time key generation
    const startGen = process.hrtime();
    const ecdh1 = crypto.createECDH(curve);
    ecdh1.generateKeys();
    
    const ecdh2 = crypto.createECDH(curve);
    ecdh2.generateKeys();
    const endGen = process.hrtime(startGen);
    
    // Time key exchange
    const startExch = process.hrtime();
    const secret1 = ecdh1.computeSecret(ecdh2.getPublicKey());
    const secret2 = ecdh2.computeSecret(ecdh1.getPublicKey());
    const endExch = process.hrtime(startExch);
    
    // Get key sizes
    const privateKeySize = ecdh1.getPrivateKey().length;
    const publicKeySize = ecdh1.getPublicKey().length;
    
    // Verify the secrets match
    const secretsMatch = secret1.equals(secret2);
    
    return {
      curve,
      keyGenTime: (endGen[0] * 1000 + endGen[1] / 1e6).toFixed(3) + 'ms',
      keyExchTime: (endExch[0] * 1000 + endExch[1] / 1e6).toFixed(3) + 'ms',
      privateKeySize: `${privateKeySize} bytes`,
      publicKeySize: `${publicKeySize} bytes`,
      secretSize: `${secret1.length} bytes`,
      secretsMatch
    };
  } catch (error) {
    return {
      curve,
      error: error.message
    };
  }
}

// Test all curves
const results = curves.map(testCurve);

// Sort by key exchange speed (fastest first)
results.sort((a, b) => {
  if (a.error) return 1;
  if (b.error) return -1;
  return parseFloat(a.keyExchTime) - parseFloat(b.keyExchTime);
});

// Print results
console.log('Curve Name'.padEnd(20), 'Key Gen Time'.padEnd(15), 'Key Exch Time'.padEnd(15), 
            'Priv Key'.padEnd(10), 'Pub Key'.padEnd(10), 'Secret'.padEnd(10), 'Status');
console.log('-'.repeat(100));

results.forEach(result => {
  if (result.error) {
    console.log(`${result.curve.padEnd(20)} ${'N/A'.padEnd(15)} ${'N/A'.padEnd(15)} ${'N/A'.padEnd(10)} ${'N/A'.padEnd(10)} ${'N/A'.padEnd(10)} Error: ${result.error}`);
  } else {
    console.log(
      result.curve.padEnd(20),
      result.keyGenTime.padEnd(15),
      result.keyExchTime.padEnd(15),
      result.privateKeySize.padEnd(10),
      result.publicKeySize.padEnd(10),
      result.secretSize.padEnd(10),
      result.secretsMatch ? '✓' : '✗'
    );
  }
});

// Additional information
console.log('\nNotes:');
console.log('- Key generation and exchange times are for a single operation and may vary by system load.');
console.log('- Key sizes include ASN.1 encoding overhead where applicable.');
console.log('- Not all curves provide the same security level despite similar key sizes.');
console.log('- Ed25519 and X25519 may not be supported for ECDH in all Node.js versions.');