const crypto = require('crypto');

// Message to sign
const message = 'Message for DSA and ECDSA signatures';

// Generate ECDSA key pair
function generateECKeyPair(curveName = 'prime256v1') {
  return crypto.generateKeyPairSync('ec', {
    namedCurve: curveName,
    publicKeyEncoding: {
      type: 'spki',
      format: 'pem'
    },
    privateKeyEncoding: {
      type: 'sec1', // or 'pkcs8'
      format: 'pem'
    }
  });
}

// Function to sign and verify with a specific algorithm and key pair
function testSignatureAlgorithm(algorithm, keyType, keyPair, message) {
  try {
    // Sign the message
    const sign = crypto.createSign(algorithm);
    sign.update(message);
    const signature = sign.sign(keyPair.privateKey, 'hex');
    
    // Verify the signature
    const verify = crypto.createVerify(algorithm);
    verify.update(message);
    const isValid = verify.verify(keyPair.publicKey, signature, 'hex');
    
    return {
      algorithm: `${keyType}-${algorithm}`,
      signatureLength: signature.length / 2, // Convert hex to bytes
      isValid
    };
  } catch (error) {
    return {
      algorithm: `${keyType}-${algorithm}`,
      error: error.message
    };
  }
}

// Test ECDSA with different curves
const curves = ['prime256v1', 'secp384r1', 'secp521r1'];

console.log(`Message: "${message}"`);
console.log('\nECDSA Signatures:');

curves.forEach(curve => {
  const ecKeyPair = generateECKeyPair(curve);
  
  // Test with different hash algorithms
  const hashAlgos = ['SHA256', 'SHA384', 'SHA512'];
  
  hashAlgos.forEach(hashAlgo => {
    const result = testSignatureAlgorithm(hashAlgo, `ECDSA-${curve}`, ecKeyPair, message);
    console.log(result);
  });
});

// Test EdDSA if available
try {
  console.log('\nEdDSA Signatures:');
  
  // Ed25519
  const ed25519KeyPair = crypto.generateKeyPairSync('ed25519', {
    publicKeyEncoding: {
      type: 'spki',
      format: 'pem'
    },
    privateKeyEncoding: {
      type: 'pkcs8',
      format: 'pem'
    }
  });
  
  // Sign with Ed25519
  const sign = crypto.createSign('SHA512'); // Hash algorithm is ignored for Ed25519
  sign.update(message);
  const signature = sign.sign(ed25519KeyPair.privateKey, 'hex');
  
  // Verify with Ed25519
  const verify = crypto.createVerify('SHA512');
  verify.update(message);
  const isValid = verify.verify(ed25519KeyPair.publicKey, signature, 'hex');
  
  console.log({
    algorithm: 'Ed25519',
    signatureLength: signature.length / 2,
    isValid
  });
} catch (error) {
  console.log({
    algorithm: 'Ed25519',
    error: error.message
  });
}