/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.hc.core5.reactor;
  
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicReference;
  
  import org.apache.hc.core5.io.CloseMode;
  import org.apache.hc.core5.io.Closer;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.TimeValue;
  import org.apache.hc.core5.util.Timeout;
  
  class MultiCoreIOReactor implements IOReactor {
  
      private final IOReactor[] ioReactors;
      private final Thread[] threads;
      private final AtomicReference<IOReactorStatus> status;
      private final AtomicBoolean terminated;
  
      MultiCoreIOReactor(final IOReactor[] ioReactors, final Thread[] threads) {
          super();
          this.ioReactors = ioReactors.clone();
          this.threads = threads.clone();
          this.status = new AtomicReference<>(IOReactorStatus.INACTIVE);
          this.terminated = new AtomicBoolean();
      }
  
      @Override
      public IOReactorStatus getStatus() {
          return this.status.get();
      }
  
      /**
       * Activates all worker I/O reactors.
       * The I/O main reactor will start reacting to I/O events and triggering
       * notification methods. The worker I/O reactor in their turn will start
       * reacting to I/O events and dispatch I/O event notifications to the
       * {@link IOEventHandler} associated with the given I/O session.
       */
      public final void start() {
          if (this.status.compareAndSet(IOReactorStatus.INACTIVE, IOReactorStatus.ACTIVE)) {
              for (int i = 0; i < this.threads.length; i++) {
                  this.threads[i].start();
              }
          }
      }
  
      @Override
      public final void initiateShutdown() {
          if (this.status.compareAndSet(IOReactorStatus.INACTIVE, IOReactorStatus.SHUT_DOWN) ||
                  this.status.compareAndSet(IOReactorStatus.ACTIVE, IOReactorStatus.SHUTTING_DOWN)) {
              for (int i = 0; i < this.ioReactors.length; i++) {
                  final IOReactor ioReactor = this.ioReactors[i];
                  ioReactor.initiateShutdown();
              }
          }
      }
  
      @Override
      public final void awaitShutdown(final TimeValue waitTime) throws InterruptedException {
          Args.notNull(waitTime, "Wait time");
          final long deadline = System.currentTimeMillis() + waitTime.toMilliseconds();
          long remaining = waitTime.toMilliseconds();
          for (int i = 0; i < this.ioReactors.length; i++) {
              final IOReactor ioReactor = this.ioReactors[i];
              if (ioReactor.getStatus().compareTo(IOReactorStatus.SHUT_DOWN) < 0) {
                  ioReactor.awaitShutdown(TimeValue.of(remaining, TimeUnit.MILLISECONDS));
                  remaining = deadline - System.currentTimeMillis();
                  if (remaining <= 0) {
                      return;
                  }
              }
         }
         for (int i = 0; i < this.threads.length; i++) {
             final Thread thread = this.threads[i];
             thread.join(remaining);
             remaining = deadline - System.currentTimeMillis();
             if (remaining <= 0) {
                 return;
             }
         }
     }
 
     @Override
     public final void close(final CloseMode closeMode) {
         close(closeMode, Timeout.ofSeconds(5));
     }
 
     /**
      * Shuts down the I/O reactor either gracefully or immediately.
      * During graceful shutdown individual I/O sessions should be
      * informed about imminent termination and be given a grace period
      * to complete the ongoing I/O sessions. During immediate shutdown
      * all ongoing I/O sessions get aborted immediately.
      *
      * @param closeMode How to close the IO reactor.
      * @param timeout  How long to wait for the IO reactor to close gracefully.
      * @since 5.2
      */
     public void close(final CloseMode closeMode, final Timeout timeout) {
         if (closeMode == CloseMode.GRACEFUL) {
             initiateShutdown();
             try {
                 awaitShutdown(timeout);
             } catch (final InterruptedException e) {
                 Thread.currentThread().interrupt();
             }
         }
         this.status.set(IOReactorStatus.SHUT_DOWN);
         if (this.terminated.compareAndSet(false, true)) {
             for (int i = 0; i < this.ioReactors.length; i++) {
                 Closer.close(this.ioReactors[i], CloseMode.IMMEDIATE);
             }
             for (int i = 0; i < this.threads.length; i++) {
                 this.threads[i].interrupt();
             }
         }
     }
 
     @Override
     public final void close() {
         close(CloseMode.GRACEFUL);
     }
 
     @Override
     public String toString() {
         return getClass().getSimpleName() + " [status=" + status + "]";
     }
 
 }