/*
    * 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.server.auth;
  
  import static java.util.Objects.requireNonNull;
  
  import java.io.Serializable;
  import java.time.Duration;
  import java.time.Instant;
  
  import javax.annotation.Nullable;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
  import com.fasterxml.jackson.databind.annotation.JsonSerialize;
  import com.google.common.base.MoreObjects;
  
  import com.linecorp.centraldogma.internal.Util;
  
  /**
   * An authenticated session which can be replicated to the other Central Dogma replicas as a serialized form.
   */
  public final class Session {
  
      private static final long serialVersionUID = 4253152956820423809L;
  
      private final String id;
      private final String username;
      private final Instant creationTime;
      private final Instant expirationTime;
      @Nullable
      private final Serializable rawSession;
  
      /**
       * Creates a new {@link Session} instance.
       *
       * @param id the session ID
       * @param username the name of the user which belongs to this session
       * @param sessionValidDuration the {@link Duration} that this session is valid
       */
      public Session(String id, String username, Duration sessionValidDuration) {
          this.id = requireNonNull(id, "id");
          this.username = requireNonNull(username, "username");
          creationTime = Instant.now();
          expirationTime = creationTime.plus(requireNonNull(sessionValidDuration, "sessionValidDuration"));
          rawSession = null;
      }
  
      /**
       * Creates a new {@link Session} instance.
       *
       * @param id the session ID
       * @param username the name of the user which belongs to this session
       * @param creationTime the created time {@link Instant}
       * @param expirationTime the time {@link Instant} that this session is to be expired at
       * @param rawSession the serializable session object which is specific to authentication provider
       */
      @JsonCreator
      public Session(@JsonProperty("id") String id,
                     @JsonProperty("username") String username,
                     @JsonProperty("creationTime") Instant creationTime,
                     @JsonProperty("expirationTime") Instant expirationTime,
                     @JsonProperty("rawSession")
                     @JsonDeserialize(using = RawSessionJsonDeserializer.class)
                     @Nullable Serializable rawSession) {
          this.id = requireNonNull(id, "id");
          this.username = requireNonNull(username, "username");
          this.creationTime = requireNonNull(creationTime, "creationTime");
          this.expirationTime = requireNonNull(expirationTime, "expirationTime");
          this.rawSession = rawSession;
      }
  
      /**
       * Returns the session ID.
       */
      @JsonProperty
      public String id() {
          return id;
      }
  
      /**
       * Returns the name of the user which belongs to this session.
       */
      @JsonProperty
      public String username() {
         return username;
     }
 
     /**
      * Returns the created time {@link Instant}.
      */
     @JsonProperty
     public Instant creationTime() {
         return creationTime;
     }
 
     /**
      * Returns the time {@link Instant} that this session is to be expired at.
      */
     @JsonProperty
     public Instant expirationTime() {
         return expirationTime;
     }
 
     /**
      * Returns a raw session instance.
      */
     @Nullable
     @JsonProperty
     @JsonSerialize(using = RawSessionJsonSerializer.class)
     public Serializable rawSession() {
         return rawSession;
     }
 
     /**
      * Returns a raw session instance which is casted to {@code T} type.
      *
      * @throws NullPointerException if the {@code rawSession} is {@code null}
      * @throws ClassCastException if the {@code rawSession} cannot be casted to {@code T}
      */
     <T> T castRawSession() {
         return Util.unsafeCast(requireNonNull(rawSession, "rawSession"));
     }
 
     @Override
     public String toString() {
         return MoreObjects.toStringHelper(this)
                           .add("id", id)
                           .add("username", username)
                           .add("creationTime", creationTime)
                           .add("expirationTime", expirationTime)
                           .add("rawSession",
                                rawSession != null ? rawSession.getClass().getSimpleName() : null)
                           .toString();
     }
 }