/*
    * Copyright 2018 LINE Corporation
    *
    * LINE Corporation 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 com.linecorp.centraldogma.internal.api.v1;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static java.util.Objects.requireNonNull;
  
  import java.time.Instant;
  import java.time.temporal.ChronoUnit;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.google.common.base.Ascii;
  import com.google.common.base.MoreObjects;
  
  /**
   * An OAuth 2.0 access token.
   *
   * @see <a href="https://tools.ietf.org/html/rfc6749#section-4.2.2">Access Token Response</a>
   */
  public class AccessToken {
  
      private static final String BEARER = "Bearer";
  
      private final String accessToken;
  
      /**
       * The lifetime in seconds of the access token. For example, the value "3600" denotes that the access
       * token will expire in one hour from the time the response was generated. If omitted, the authorization
       * server SHOULD provide the expiration time via other means or document the default value.
       */
      private final long expiresIn;
  
      private final String refreshToken;
  
      private final Instant deadline;
  
      //TODO(minwoox) Add scope if needed.
  
      public AccessToken(String accessToken, long expiresIn) {
          this(BEARER, accessToken, expiresIn, "");
      }
  
      @JsonCreator
      public AccessToken(@JsonProperty("token_type") String tokenType,
                         @JsonProperty("access_token") String accessToken,
                         @JsonProperty("expires_in") long expiresIn,
                         @JsonProperty("refresh_token") String refreshToken) {
          requireNonNull(tokenType, "tokenType");
          checkArgument(Ascii.equalsIgnoreCase(tokenType, BEARER),
                        "tokenType: %s (expected: %s)", tokenType, BEARER);
          this.accessToken = requireNonNull(accessToken, "accessToken");
          this.expiresIn = expiresIn;
          this.refreshToken = requireNonNull(refreshToken, "refreshToken");
  
          deadline = Instant.now().plus(expiresIn, ChronoUnit.SECONDS);
      }
  
      @JsonProperty("access_token")
      public String accessToken() {
          return accessToken;
      }
  
      @JsonProperty("expires_in")
      public long expiresIn() {
          return expiresIn;
      }
  
      @JsonProperty("token_type")
      public String tokenType() {
          return BEARER;
      }
  
      @JsonProperty("refresh_token")
      public String refreshToken() {
          return refreshToken;
      }
  
      public Instant deadline() {
          return deadline;
      }
  
      @Override
      public String toString() {
          return MoreObjects.toStringHelper(this)
                           .add("accessToken", accessToken)
                           .add("expiresIn", expiresIn)
                           .add("tokenType", BEARER)
                           .add("deadline", deadline)
                           .toString();
     }
 }