package cn.home1.oss.lib.common.crypto;
   
   import static com.google.common.base.Charsets.UTF_8;
   import static com.google.common.base.Preconditions.checkArgument;
   
   import lombok.Getter;
   import lombok.SneakyThrows;
   
   import java.security.Provider;
  import java.security.PublicKey;
  
  import javax.crypto.Cipher;
  
  import cn.home1.oss.lib.common.CodecUtils;
  
  /**
   * Created by zhanghaolun on 16/10/25.
   */
  public class RsaEncryptor implements EncodeEncryptor {
  
    private final Provider provider;
    @Getter
    private final RsaKey key;
  
    public RsaEncryptor(final Provider provider, final KeyExpression keyExpression) {
      this.provider = provider;
      this.key = new RsaKey(keyExpression);
    }
  
    @Override
    public String encrypt(final String plaintext) {
      return encryptAndEncode(this.provider, this.key.getRsaPublicKey(), plaintext);
    }
  
    @Override
    public String encrypt(final String plainText, final Integer maxAge) {
      throw new UnsupportedOperationException();
    }
  
    @SneakyThrows
    public static byte[] encryptBytes(final Provider provider, final PublicKey publicKey, final byte[] binary) {
      final Cipher cipher = Cipher.getInstance(CryptoConstants.RSA_ECB_PKCS1_PADDING, provider);
      cipher.init(Cipher.ENCRYPT_MODE, publicKey);
      return cipher.doFinal(binary);
    }
  
    public static String encryptAndEncode(final Provider provider, final PublicKey publicKey, final String plaintext) {
      checkArgument(publicKey != null, "publicKey must not null");
      final String result;
      if (plaintext == null) {
        result = null;
      } else if (plaintext.length() == 0) {
        result = "";
      } else {
        final byte[] encrypted = encryptBytes(provider, publicKey, plaintext.getBytes(UTF_8));
        result = CodecUtils.encodeBase64(encrypted);
      }
      return result;
    }
  }