/*******************************************************************************
    * Copyhacked (H) 2012-2020.
    * This program and the accompanying materials
    * are made available under no term at all, use it like
    * you want, but share and discuss about it
    * every time possible with every body.
    * 
    * Contributors:
    *      ron190 at ymail dot com - initial implementation
   ******************************************************************************/
  package com.jsql.util;
  
  import com.jsql.model.InjectionModel;
  import com.jsql.model.bean.database.AbstractElementDatabase;
  import com.jsql.model.suspendable.AbstractSuspendable;
  import com.jsql.model.suspendable.callable.ThreadFactoryCallable;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Utility class managing running threads on which the user can act.
   * It must be noted that as SwingWorker class are used then only 10 jobs can be run
   * at the same time, the 11th will be waiting in the thread pool until one of the 10
   * actives one is freed.
   */
  public final class ThreadUtil {
      
      /**
       * Log4j logger sent to view.
       */
      private static final Logger LOGGER = LogManager.getRootLogger();
      
      /**
       * List of running jobs associated to a database injection task.
       * We can interact with those tasks in order to pause/resume and stop the process.
       */
      // Fix #8258: ConcurrentModificationException on java.util.HashMap$ValueIterator.next()
      private final Map<AbstractElementDatabase, AbstractSuspendable> suspendables = new ConcurrentHashMap<>(new HashMap<>());
  
      private final InjectionModel injectionModel;
      
      public ThreadUtil(InjectionModel injectionModel) {
          this.injectionModel = injectionModel;
      }
  
      /**
       * Add a job to the list of ongoing tasks. It is used to allow the user to act
       * on the job and stop/pause a running process.
       * @param elementDatabase component associated to the active job
       * @param suspendable active job to act on
       */
      public void put(AbstractElementDatabase elementDatabase, AbstractSuspendable suspendable) {
          this.suspendables.put(elementDatabase, suspendable);
      }
      
      /**
       * Get the task associated to the database component.
       * It's usually done to act on the task like stop/pause the corresponding process, or
       * to check the status of the job.
       * @param elementDatabase component associated to the active job
       * @return job currently running
       */
      public AbstractSuspendable get(AbstractElementDatabase elementDatabase) {
          return this.suspendables.get(elementDatabase);
      }
      
      /**
       * Remove the thread corresponding to the component in order to be
       * garbage collected. The thread should be stopped prior the deletion.
       * @param elementDatabase component associated to thread
       */
      public void remove(AbstractElementDatabase elementDatabase) {
          this.suspendables.remove(elementDatabase);
      }
      
      /**
       * Force to stop every threads still running and empty the list where
       * they were instantiated in order to be garbage collected.
       */
      public void reset() {
          
          this.suspendables.values().forEach(AbstractSuspendable::stop);
          this.suspendables.clear();
      }
      
      public ExecutorService getExecutor(String nameThread) {
  
          ExecutorService taskExecutor;
          
          if (this.injectionModel.getMediatorUtils().getPreferencesUtil().isLimitingThreads()) {
              
              int countThreads = this.injectionModel.getMediatorUtils().getPreferencesUtil().countLimitingThreads();
             taskExecutor = Executors.newFixedThreadPool(countThreads, new ThreadFactoryCallable(nameThread));
             
         } else {
             taskExecutor = Executors.newCachedThreadPool(new ThreadFactoryCallable(nameThread));
         }
         
         return taskExecutor;
     }
 
     public void shutdown(ExecutorService taskExecutor) {
 
         int timeout = 15;
         if (this.injectionModel.getMediatorUtils().getPreferencesUtil().isConnectionTimeout()) {
             timeout = this.injectionModel.getMediatorUtils().getPreferencesUtil().countConnectionTimeout();
         }
 
         try {
             taskExecutor.shutdown();
             if (!taskExecutor.awaitTermination(timeout, TimeUnit.SECONDS)) {
                 taskExecutor.shutdownNow();
             }
         } catch (InterruptedException e) {
 
             LOGGER.log(LogLevelUtil.IGNORE, e, e);
             Thread.currentThread().interrupt();
         }
     }
 }