/*
    * Copyright 2024 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.pkitesting;
  
  import org.bouncycastle.jce.provider.BouncyCastleProvider;
  
  import java.security.GeneralSecurityException;
  import java.security.KeyPairGenerator;
  import java.security.NoSuchAlgorithmException;
  import java.security.Provider;
  import java.security.SecureRandom;
  import java.security.Signature;
  import java.security.spec.AlgorithmParameterSpec;
  import java.util.Locale;
  
  final class Algorithms {
      private static Provider bouncyCastle;
  
      private Algorithms() {
      }
  
      static String oidForAlgorithmName(String algorithmIdentifier) {
          // See the Java Security Standard Algorithm Names documentation for names and links to RFCs.
          // https://docs.oracle.com/en/java/javase/22/docs/specs/security/standard-names.html#signature-algorithms
          switch (algorithmIdentifier.toLowerCase(Locale.ROOT)) {
              case "sha256withecdsa":
                  return "1.2.840.10045.4.3.2";
              case "sha384withecdsa":
                  return "1.2.840.10045.4.3.3";
              case "sha256withrsa":
                  return "1.2.840.113549.1.1.11";
              case "sha384withrsa":
                  return "1.2.840.113549.1.1.12";
              case "ed25519":
                  return "1.3.101.112";
              case "ed448":
                  return "1.3.101.113";
              default:
                  throw new UnsupportedOperationException("Algorithm not supported: " + algorithmIdentifier);
          }
      }
  
      static KeyPairGenerator keyPairGenerator(String keyType, AlgorithmParameterSpec spec, SecureRandom rng)
              throws GeneralSecurityException {
          try {
              KeyPairGenerator keyGen = KeyPairGenerator.getInstance(keyType);
              keyGen.initialize(spec, rng);
              return keyGen;
          } catch (GeneralSecurityException e) {
              try {
                  KeyPairGenerator keyGen = KeyPairGenerator.getInstance(keyType, bouncyCastle());
                  keyGen.initialize(spec, rng);
                  return keyGen;
              } catch (GeneralSecurityException ex) {
                  e.addSuppressed(ex);
              }
              throw e;
          }
      }
  
      static Signature signature(String algorithmIdentifier) throws NoSuchAlgorithmException {
          try {
              return Signature.getInstance(algorithmIdentifier);
          } catch (NoSuchAlgorithmException e) {
              try {
                  return Signature.getInstance(algorithmIdentifier, bouncyCastle());
              } catch (NoSuchAlgorithmException ex) {
                  e.addSuppressed(ex);
              }
              throw e;
          }
      }
  
      private static synchronized Provider bouncyCastle() {
          if (bouncyCastle == null) {
              bouncyCastle = new BouncyCastleProvider();
          }
          return bouncyCastle;
      }
  }