content: /*
   ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
   ~                                                                               ~
   ~ The MIT License (MIT)                                                         ~
   ~                                                                               ~
   ~ Copyright (c) 2015-2025 miaixz.org and other contributors.                    ~
   ~                                                                               ~
   ~ Permission is hereby granted, free of charge, to any person obtaining a copy  ~
   ~ of this software and associated documentation files (the "Software"), to deal ~
   ~ in the Software without restriction, including without limitation the rights  ~
   ~ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell     ~
   ~ copies of the Software, and to permit persons to whom the Software is         ~
   ~ furnished to do so, subject to the following conditions:                      ~
   ~                                                                               ~
   ~ The above copyright notice and this permission notice shall be included in    ~
   ~ all copies or substantial portions of the Software.                           ~
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   ~ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR    ~
   ~ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,      ~
   ~ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE   ~
   ~ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER        ~
   ~ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, ~
   ~ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN     ~
   ~ THE SOFTWARE.                                                                 ~
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   ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
  */
  package org.miaixz.bus.cron.timings;
  
  import java.util.function.Consumer;
  
  import org.miaixz.bus.cron.crontab.TimerCrontab;
  import org.miaixz.bus.logger.Logger;
  
  /**
   * 多层时间轮，常用于延时任务 时间轮是一种环形数据结构，由多个槽组成，每个槽中存放任务集合 一个单独的线程推进时间一槽一槽的移动，并执行槽中的任务
   *
   * @author Kimi Liu
   * @since Java 17+
   */
  public class TimingWheel {
  
      /**
       * 一个时间槽的范围
       */
      private final long tickMs;
  
      /**
       * 时间轮大小，时间轮中时间槽的个数
       */
      private final int wheelSize;
  
      /**
       * 时间跨度，当前时间轮总间隔，即单个槽的跨度*槽个数
       */
      private final long interval;
  
      /**
       * 时间槽
       */
      private final TimerTaskList[] timerTaskLists;
      /**
       * 任务处理器
       */
      private final Consumer<TimerTaskList> consumer;
      /**
       * 当前时间，指向当前操作的时间格，代表当前时间
       */
      private long currentTime;
      /**
       * 上层时间轮
       */
      private volatile TimingWheel overflowWheel;
  
      /**
       * 构造
       *
       * @param tickMs    一个时间槽的范围，单位毫秒
       * @param wheelSize 时间轮大小
       * @param consumer  任务处理器
       */
      public TimingWheel(final long tickMs, final int wheelSize, final Consumer<TimerTaskList> consumer) {
          this(tickMs, wheelSize, System.currentTimeMillis(), consumer);
      }
  
      /**
       * 构造
       *
       * @param tickMs      一个时间槽的范围，单位毫秒
       * @param wheelSize   时间轮大小
       * @param currentTime 当前时间
       * @param consumer    任务处理器
       */
      public TimingWheel(final long tickMs, final int wheelSize, final long currentTime,
              final Consumer<TimerTaskList> consumer) {
          this.tickMs = tickMs;
          this.wheelSize = wheelSize;
          this.interval = tickMs * wheelSize;
          this.timerTaskLists = new TimerTaskList[wheelSize];
          for (int i = 0; i < wheelSize; i++) {
              this.timerTaskLists[i] = new TimerTaskList();
          }
  
          // currentTime为tickMs的整数倍 这里做取整操作
          this.currentTime = currentTime - (currentTime % tickMs);
          this.consumer = consumer;
      }
  
      /**
       * 添加任务到时间轮
       *
       * @param timerCrontab 任务
       * @return 是否成功
       */
      public boolean addTask(final TimerCrontab timerCrontab) {
          final long expiration = timerCrontab.getDelayMs();
          // 过期任务直接执行
          if (expiration < currentTime + tickMs) {
              return false;
          } else if (expiration < currentTime + interval) {
              // 当前时间轮可以容纳该任务 加入时间槽
              final long virtualId = expiration / tickMs;
              final int index = (int) (virtualId % wheelSize);
              Logger.debug("tickMs: {} ------index: {} ------expiration: {}", tickMs, index, expiration);
  
              final TimerTaskList timerTaskList = timerTaskLists[index];
              timerTaskList.addTask(timerCrontab);
              if (timerTaskList.setExpiration(virtualId * tickMs)) {
                  // 添加到delayQueue中
                  consumer.accept(timerTaskList);
              }
          } else {
              // 放到上一层的时间轮
              final TimingWheel timeWheel = getOverflowWheel();
              timeWheel.addTask(timerCrontab);
          }
          return true;
      }
  
      /**
       * 推进时间
       *
       * @param timestamp 推进的时间
       */
      public void advanceClock(final long timestamp) {
          if (timestamp >= currentTime + tickMs) {
              currentTime = timestamp - (timestamp % tickMs);
              if (overflowWheel != null) {
                  // 推进上层时间轮时间
                  this.getOverflowWheel().advanceClock(timestamp);
              }
          }
      }
  
      /**
       * 创建或者获取上层时间轮
       */
      private TimingWheel getOverflowWheel() {
          if (overflowWheel == null) {
              synchronized (this) {
                  if (overflowWheel == null) {
                      overflowWheel = new TimingWheel(interval, wheelSize, currentTime, consumer);
                  }
              }
          }
          return overflowWheel;
      }
  
  }
  