/*
    * 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.listeners;
  
  import java.util.HashMap;
  
  import psiprobe.Utils;
  import psiprobe.tools.SizeExpression;
  
  /**
   * The listener interface for receiving threshold events. The class that is interested in processing
   * a threshold event implements this interface, and the object created with that class is registered
   * with a component using the component's {@code addThresholdListener} method. When the threshold
   * event occurs, that object's appropriate method is invoked.
   */
  public abstract class AbstractThresholdListener extends AbstractStatsCollectionListener {
  
    /** The Constant DEFAULT_THRESHOLD. */
    public static final long DEFAULT_THRESHOLD = Long.MAX_VALUE;
  
    /** The Constant DEFAULT_VALUE. */
    public static final long DEFAULT_VALUE = Long.MIN_VALUE;
  
    /** The previous values. */
    private final HashMap<String, Long> previousValues = new HashMap<>();
  
    /** The series disabled. */
    private final HashMap<String, Boolean> seriesDisabled = new HashMap<>();
  
    /**
     * Crossed above threshold.
     *
     * @param sce the sce
     */
    protected abstract void crossedAboveThreshold(StatsCollectionEvent sce);
  
    /**
     * Crossed below threshold.
     *
     * @param sce the sce
     */
    protected abstract void crossedBelowThreshold(StatsCollectionEvent sce);
  
    /**
     * Remained above threshold.
     *
     * @param sce the sce
     */
    protected abstract void remainedAboveThreshold(StatsCollectionEvent sce);
  
    /**
     * Remained below threshold.
     *
     * @param sce the sce
     */
    protected abstract void remainedBelowThreshold(StatsCollectionEvent sce);
  
    @Override
    public void statsCollected(StatsCollectionEvent sce) {
      String name = sce.getName();
      if (isSeriesDisabled(name)) {
        return;
      }
      long value = sce.getValue();
      if (isValueAboveThreshold(sce)) {
        if (isPreviousValueAboveThreshold(sce)) {
          remainedAboveThreshold(sce);
        } else {
          crossedAboveThreshold(sce);
        }
      } else if (isPreviousValueAboveThreshold(sce)) {
        crossedBelowThreshold(sce);
      } else {
        remainedBelowThreshold(sce);
      }
      setPreviousValue(name, value);
    }
  
    @Override
    public void reset() {
      previousValues.clear();
      super.reset();
    }
  
    /**
     * Checks if is previous value above threshold.
     *
     * @param sce the sce
     *
     * @return true, if is previous value above threshold
     */
   protected boolean isPreviousValueAboveThreshold(StatsCollectionEvent sce) {
     String name = sce.getName();
     long threshold = getThreshold(name);
     long previousValue = getPreviousValue(name);
     return previousValue != DEFAULT_VALUE && previousValue > threshold;
   }
 
   /**
    * Checks if is value above threshold.
    *
    * @param sce the sce
    *
    * @return true, if is value above threshold
    */
   protected boolean isValueAboveThreshold(StatsCollectionEvent sce) {
     String name = sce.getName();
     long value = sce.getValue();
     long threshold = getThreshold(name);
     return value > threshold;
   }
 
   /**
    * Gets the threshold.
    *
    * @param name the name
    *
    * @return the threshold
    */
   protected long getThreshold(String name) {
     if (isSeriesDisabled(name)) {
       return DEFAULT_THRESHOLD;
     }
     String threshold = getPropertyValue(name, "threshold");
     if (threshold == null && !isSeriesDisabled(name)) {
       logger.info(
           "Required property '{}' is not defined or inherited.  Disabling listener for '{}' series",
           getPropertyKey(name, "threshold"), name);
       setSeriesDisabled(name, true);
       return DEFAULT_THRESHOLD;
     }
     try {
       return SizeExpression.parse(threshold);
     } catch (NumberFormatException ex) {
       logger.trace("", ex);
       return DEFAULT_THRESHOLD;
     }
   }
 
   /**
    * Gets the previous value.
    *
    * @param name the name
    *
    * @return the previous value
    */
   protected long getPreviousValue(String name) {
     Long value = previousValues.get(name);
     return Utils.toLong(value, DEFAULT_VALUE);
   }
 
   /**
    * Sets the previous value.
    *
    * @param name the name
    * @param previousValue the previous value
    */
   protected void setPreviousValue(String name, long previousValue) {
     Long value = previousValue;
     previousValues.put(name, value);
   }
 
   /**
    * Checks if is series disabled.
    *
    * @param name the name
    *
    * @return true, if is series disabled
    */
   protected boolean isSeriesDisabled(String name) {
     Boolean disabled = seriesDisabled.get(name);
     if (disabled == null) {
       disabled = Boolean.FALSE;
     }
     return disabled;
   }
 
   /**
    * Sets the series disabled.
    *
    * @param name the name
    * @param disabled the disabled
    */
   protected void setSeriesDisabled(String name, boolean disabled) {
     seriesDisabled.put(name, disabled);
   }
 
 }