/*
    * 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
    *
    *     http://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.shardingsphere.globalclock.type.tso.provider.redis;
  
  import com.google.common.base.Strings;
  import org.apache.shardingsphere.globalclock.type.tso.provider.TSOProvider;
  import redis.clients.jedis.Jedis;
  import redis.clients.jedis.JedisPool;
  import redis.clients.jedis.JedisPoolConfig;
  
  import java.util.Properties;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * Redis TSO provider.
   */
  public final class RedisTSOProvider implements TSOProvider {
      
      private static final String CSN_KEY = "csn";
      
      private static final long ERROR_CSN = 0L;
      
      private static final long INIT_CSN = Integer.MAX_VALUE;
      
      private final AtomicBoolean initialized = new AtomicBoolean(false);
      
      private JedisPool jedisPool;
      
      @Override
      public void init(final Properties props) {
          if (initialized.compareAndSet(false, true)) {
              createJedisPool(props);
              checkJedisPool();
              initCSN();
          }
      }
      
      private void createJedisPool(final Properties props) {
          JedisPoolConfig config = new JedisPoolConfig();
          config.setMaxIdle(Integer.parseInt(getValue(props, RedisTSOPropertyKey.MAX_IDLE)));
          config.setMaxTotal(Integer.parseInt(getValue(props, RedisTSOPropertyKey.MAX_TOTAL)));
          jedisPool = new JedisPool(config, getValue(props, RedisTSOPropertyKey.HOST), Integer.parseInt(getValue(props, RedisTSOPropertyKey.PORT)),
                  Integer.parseInt(getValue(props, RedisTSOPropertyKey.TIMEOUT_INTERVAL)), getValue(props, RedisTSOPropertyKey.PASSWORD));
      }
      
      private String getValue(final Properties props, final RedisTSOPropertyKey propertyKey) {
          return props.containsKey(propertyKey.getKey()) ? props.getProperty(propertyKey.getKey()) : propertyKey.getDefaultValue();
      }
      
      private void checkJedisPool() {
          try (Jedis jedis = jedisPool.getResource()) {
              jedis.ping();
          }
      }
      
      private void initCSN() {
          try (Jedis jedis = jedisPool.getResource()) {
              String originalCSN = jedis.get(CSN_KEY);
              if (Strings.isNullOrEmpty(originalCSN) || String.valueOf(ERROR_CSN).equals(originalCSN)) {
                  jedis.set(CSN_KEY, String.valueOf(INIT_CSN));
              }
          }
      }
      
      @Override
      public long getCurrentTimestamp() {
          try (Jedis jedis = jedisPool.getResource()) {
              // TODO use redis lock to instead of reg center's lock. lock here #35041
              return Long.parseLong(jedis.get(CSN_KEY));
          }
      }
      
      @Override
      public long getNextTimestamp() {
          try (Jedis jedis = jedisPool.getResource()) {
              return jedis.incr(CSN_KEY);
              // TODO use redis lock to instead of reg center's lock. unlock here #35041
          }
      }
      
      @Override
      public String getType() {
          return "TSO.redis";
      }
 }