/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.beans.stats.collectors;
  
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  import javax.inject.Inject;
  
  import org.jfree.data.xy.XYDataItem;
  
  import psiprobe.Utils;
  import psiprobe.beans.stats.listeners.StatsCollectionEvent;
  import psiprobe.beans.stats.listeners.StatsCollectionListener;
  import psiprobe.model.stats.StatsCollection;
  
  /**
   * The Class AbstractStatsCollectorBean.
   */
  public abstract class AbstractStatsCollectorBean {
  
    /** The stats collection. */
    @Inject
    private StatsCollection statsCollection;
  
    /** The max series. */
    private int maxSeries = 240;
  
    /** The listeners. */
    private List<StatsCollectionListener> listeners;
  
    /** The previous data. */
    private final Map<String, Long> previousData = new TreeMap<>();
  
    /** The previous data2 d. */
    private final Map<String, Entry> previousData2D = new TreeMap<>();
  
    /**
     * Gets the stats collection.
     *
     * @return the stats collection
     */
    public StatsCollection getStatsCollection() {
      return statsCollection;
    }
  
    /**
     * Sets the stats collection.
     *
     * @param statsCollection the new stats collection
     */
    public void setStatsCollection(StatsCollection statsCollection) {
      this.statsCollection = statsCollection;
    }
  
    /**
     * Gets the max series.
     *
     * @return the max series
     */
    public int getMaxSeries() {
      return maxSeries;
    }
  
    /**
     * Sets the max series.
     *
     * @param maxSeries the new max series
     */
    public void setMaxSeries(int maxSeries) {
      this.maxSeries = maxSeries;
    }
  
    /**
     * Gets the listeners.
     *
     * @return the listeners
     */
    public List<StatsCollectionListener> getListeners() {
      return listeners;
    }
  
    /**
     * Sets the listeners.
     *
     * @param listeners the new listeners
     */
    public void setListeners(List<StatsCollectionListener> listeners) {
      this.listeners = listeners;
    }
 
   /**
    * Collect.
    *
    * @throws Exception the exception
    */
   public abstract void collect() throws Exception;
 
   /**
    * Builds the delta stats.
    *
    * @param name the name
    * @param value the value
    *
    * @return the long
    *
    * @throws InterruptedException the interrupted exception
    */
   protected long buildDeltaStats(String name, long value) throws InterruptedException {
     return buildDeltaStats(name, value, System.currentTimeMillis());
   }
 
   /**
    * Builds the delta stats.
    *
    * @param name the name
    * @param value the value
    * @param time the time
    *
    * @return the long
    *
    * @throws InterruptedException the interrupted exception
    */
   protected long buildDeltaStats(String name, long value, long time) throws InterruptedException {
     long delta = 0;
     if (statsCollection != null) {
       long previousValue = Utils.toLong(previousData.get(name), 0);
       delta = value - previousValue;
       delta = delta > 0 ? delta : 0;
       buildAbsoluteStats(name, delta, time);
       previousData.put(name, value);
     }
     return delta;
   }
 
   /**
    * Builds the absolute stats.
    *
    * @param name the name
    * @param value the value
    *
    * @throws InterruptedException the interrupted exception
    */
   protected void buildAbsoluteStats(String name, long value) throws InterruptedException {
     buildAbsoluteStats(name, value, System.currentTimeMillis());
   }
 
   /**
    * Builds the absolute stats.
    *
    * @param name the name
    * @param value the value
    * @param time the time
    *
    * @throws InterruptedException the interrupted exception
    */
   protected void buildAbsoluteStats(String name, long value, long time)
       throws InterruptedException {
 
     List<XYDataItem> stats = statsCollection.getStats(name);
     if (stats == null) {
       statsCollection.newStats(name, maxSeries);
     } else {
       XYDataItem data = new XYDataItem(time, value);
       statsCollection.lockForUpdate();
       try {
         stats.add(data);
         houseKeepStats(stats);
       } finally {
         statsCollection.releaseLock();
       }
       if (listeners != null) {
         StatsCollectionEvent event = new StatsCollectionEvent(name, data);
         for (StatsCollectionListener listener : listeners) {
           if (listener.isEnabled()) {
             listener.statsCollected(event);
           }
         }
       }
     }
   }
 
   /**
    * The Class Entry.
    */
   private static class Entry {
 
     /** The time. */
     long time;
 
     /** The value. */
     long value;
 
     /**
      * Instantiates a new entry.
      */
     public Entry() {
       // Prevent Emulation by Synthetic Accessor
     }
 
   }
 
   /**
    * If there is a value indicating the accumulated amount of time spent on something it is possible
    * to build a series of values representing the percentage of time spent on doing something. For
    * example:
    *
    * <p>
    * at point T1 the system has spent A milliseconds performing tasks at point T2 the system has
    * spent B milliseconds performing tasks
    * </p>
    *
    * <p>
    * so between in a timeframe T2-T1 the system spent B-A milliseconds being busy. Thus (B - A)/(T2
    * - T1) * 100 is the percentage of all time the system spent being busy.
    * </p>
    *
    * @param name the name of the value, which allows the collector to be used for multiple values
    * @param value time spent on the task in milliseconds (A or B in the example above)
    * @param time system time in milliseconds (T1 or T2 in the example above)
    *
    * @throws InterruptedException if a lock could not be obtained
    */
   protected void buildTimePercentageStats(String name, long value, long time)
       throws InterruptedException {
 
     Entry entry = previousData2D.get(name);
     if (entry == null) {
       entry = new Entry();
       entry.value = value;
       entry.time = time;
       previousData2D.put(name, entry);
     } else {
       double valueDelta = (double) value - entry.value;
       double timeDelta = (double) time - entry.time;
       double statValue = valueDelta * 100 / timeDelta;
       statsCollection.lockForUpdate();
       try {
         List<XYDataItem> stats = statsCollection.getStats(name);
         if (stats == null) {
           stats = statsCollection.newStats(name, maxSeries);
         }
         stats.add(stats.size(), new XYDataItem(time, statValue));
         houseKeepStats(stats);
       } finally {
         statsCollection.releaseLock();
       }
     }
   }
 
   /**
    * Reset stats.
    *
    * @param name the name
    */
   protected void resetStats(String name) {
     statsCollection.resetStats(name);
   }
 
   /**
    * House keep stats.
    *
    * @param stats the stats
    */
   private void houseKeepStats(List<XYDataItem> stats) {
     while (stats.size() > maxSeries) {
       stats.remove(0);
     }
   }
 }