/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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 org.apache.accumulo.tserver.session;

import java.util.OptionalLong;
import java.util.concurrent.TimeUnit;

import org.apache.accumulo.core.securityImpl.thrift.TCredentials;
import org.apache.accumulo.core.util.Timer;
import org.apache.accumulo.server.rpc.TServerUtils;

import com.google.common.base.Preconditions;

public class Session {

  enum State {
    NEW, UNRESERVED, RESERVED, REMOVED
  }

  public final String client;
  public long lastAccessTime;
  public long startTime;
  private State state = State.NEW;
  boolean allowReservation = true;
  private final Timer stateChangeTimer = Timer.startNew();
  private final TCredentials credentials;
  private OptionalLong sessionId = OptionalLong.empty();

  Session(TCredentials credentials) {
    this.credentials = credentials;
    this.client = TServerUtils.clientAddress.get();
  }

  public String getUser() {
    return credentials.getPrincipal();
  }

  public TCredentials getCredentials() {
    return credentials;
  }

  public boolean cleanup() {
    return true;
  }

  public void setState(State state) {
    if (this.state != state) {
      this.state = state;
      stateChangeTimer.restart();
    }
  }

  public State getState() {
    return state;
  }

  public void setSessionId(long sessionId) {
    Preconditions.checkState(this.sessionId.isEmpty());
    this.sessionId = OptionalLong.of(sessionId);
  }

  public long getSessionId() {
    Preconditions.checkState(this.sessionId.isPresent());
    return sessionId.orElseThrow();
  }

  public long elaspedSinceStateChange(TimeUnit unit) {
    return stateChangeTimer.elapsed(unit);
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + " " + state + " sessionId:" + sessionId + " startTime:"
        + startTime + " lastAccessTime:" + lastAccessTime + " client:" + client;
  }
}
