/*
 * Copyright 2016, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *
 *    * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.google.auth;

import java.util.Objects;

/**
 * Interface for a service account signer. A signer for a service account is capable of signing
 * bytes using the private key associated with its service account.
 */
public interface ServiceAccountSigner {

  class SigningException extends RuntimeException {

    private static final long serialVersionUID = -6503954300538947223L;

    public SigningException(String message, Exception cause) {
      super(message, cause);
    }

    @Override
    public boolean equals(Object obj) {
      if (obj == this) {
        return true;
      }
      if (!(obj instanceof SigningException)) {
        return false;
      }
      SigningException other = (SigningException) obj;
      return Objects.equals(getCause(), other.getCause())
          && Objects.equals(getMessage(), other.getMessage());
    }

    @Override
    public int hashCode() {
      return Objects.hash(getMessage(), getCause());
    }
  }

  /**
   * Returns the service account associated with the signer.
   *
   * @return The service account associated with the signer.
   */
  String getAccount();

  /**
   * Signs the provided bytes using the private key associated with the service account.
   *
   * @param toSign bytes to sign
   * @return signed bytes
   * @throws SigningException if the attempt to sign the provided bytes failed
   */
  byte[] sign(byte[] toSign);
}