/*
    * Copyright 2013 The Netty Project
    *
    * The Netty Project 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 io.netty5.util.concurrent;
  
  import io.netty5.util.internal.StringUtil;
  
  import java.util.Locale;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A {@link ThreadFactory} implementation with a simple naming rule.
   */
  public class DefaultThreadFactory implements ThreadFactory {
  
      private static final AtomicInteger poolId = new AtomicInteger();
  
      private final AtomicInteger nextId = new AtomicInteger();
      private final String prefix;
      private final boolean daemon;
      private final int priority;
      protected final ThreadGroup threadGroup;
  
      public DefaultThreadFactory(Class<?> poolType) {
          this(poolType, false, Thread.NORM_PRIORITY);
      }
  
      public DefaultThreadFactory(String poolName) {
          this(poolName, false, Thread.NORM_PRIORITY);
      }
  
      public DefaultThreadFactory(Class<?> poolType, boolean daemon) {
          this(poolType, daemon, Thread.NORM_PRIORITY);
      }
  
      public DefaultThreadFactory(String poolName, boolean daemon) {
          this(poolName, daemon, Thread.NORM_PRIORITY);
      }
  
      public DefaultThreadFactory(Class<?> poolType, int priority) {
          this(poolType, false, priority);
      }
  
      public DefaultThreadFactory(String poolName, int priority) {
          this(poolName, false, priority);
      }
  
      public DefaultThreadFactory(Class<?> poolType, boolean daemon, int priority) {
          this(toPoolName(poolType), daemon, priority);
      }
  
      public static String toPoolName(Class<?> poolType) {
          requireNonNull(poolType, "poolType");
  
          String poolName = StringUtil.simpleClassName(poolType);
          switch (poolName.length()) {
              case 0:
                  return "unknown";
              case 1:
                  return poolName.toLowerCase(Locale.US);
              default:
                  if (Character.isUpperCase(poolName.charAt(0)) && Character.isLowerCase(poolName.charAt(1))) {
                      return Character.toLowerCase(poolName.charAt(0)) + poolName.substring(1);
                  } else {
                      return poolName;
                  }
          }
      }
  
      public DefaultThreadFactory(String poolName, boolean daemon, int priority, ThreadGroup threadGroup) {
          requireNonNull(poolName, "poolName");
          if (priority < Thread.MIN_PRIORITY || priority > Thread.MAX_PRIORITY) {
              throw new IllegalArgumentException(
                      "priority: " + priority + " (expected: Thread.MIN_PRIORITY <= priority <= Thread.MAX_PRIORITY)");
          }
  
          prefix = poolName + '-' + poolId.incrementAndGet() + '-';
          this.daemon = daemon;
          this.priority = priority;
          this.threadGroup = threadGroup;
      }
  
      public DefaultThreadFactory(String poolName, boolean daemon, int priority) {
         this(poolName, daemon, priority, null);
     }
 
     @Override
     public Thread newThread(Runnable r) {
         Thread t = newThread(FastThreadLocalRunnable.wrap(r), prefix + nextId.incrementAndGet());
         try {
             if (t.isDaemon() != daemon) {
                 t.setDaemon(daemon);
             }
 
             if (t.getPriority() != priority) {
                 t.setPriority(priority);
             }
         } catch (Exception ignored) {
             // Doesn't matter even if failed to set.
         }
         return t;
     }
 
     protected Thread newThread(Runnable r, String name) {
         return new FastThreadLocalThread(threadGroup, r, name);
     }
 }