package de.lmu.ifi.dbs.elki.visualization.gui.overview;
/*
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2013
 Ludwig-Maximilians-Universität München
 Lehr- und Forschungseinheit für Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
import java.util.*;

import org.w3c.dom.Element;

import de.lmu.ifi.dbs.elki.utilities.pairs.Pair;
import de.lmu.ifi.dbs.elki.visualization.VisualizationTask;
import de.lmu.ifi.dbs.elki.visualization.visualizers.Visualization;

/**
 * Class to help keeping track of the materialized layers of the different visualizations.
 * 
 * @author Erich Schubert
 * 
 * @apiviz.has PlotItem
 * @apiviz.has VisualizationTask
 */
public class LayerMap {
  /**
   * The actual map
   */
  private HashMap<Pair<PlotItem, VisualizationTask>, Pair<Element, Visualization>> map = new HashMap<>();
  
  /**
   * Helper function for building a key object
   * 
   * @param item Plot item
   * @param task Visualization Task
   * @return Key
   */
  private Pair<PlotItem, VisualizationTask> key(PlotItem item, VisualizationTask task) {
    return new Pair<>(item, task);
  }

  /**
   * Helper function to build a value pair
   * 
   * @param elem Container element
   * @param vis Visualization
   * @return Value object
   */
  private Pair<Element, Visualization> value(Element elem, Visualization vis) {
    return new Pair<>(elem, vis);
  }

  /**
   * Get the visualization referenced by a item/key combination.
   * 
   * @param item Plot ttem
   * @param task Visualization task
   * @return Visualization
   */
  public Visualization getVisualization(PlotItem item, VisualizationTask task) {
    Pair<Element, Visualization> pair = map.get(key(item, task));
    if (pair == null) {
      return null;
    } else {
      return pair.second;
    }
  }

  /**
   * Get the container element referenced by a item/key combination.
   * 
   * @param item Plot item
   * @param task Visualization task
   * @return Container element
   */
  public Element getContainer(PlotItem item, VisualizationTask task) {
    Pair<Element, Visualization> pair = map.get(key(item, task));
    if (pair == null) {
      return null;
    } else {
      return pair.first;
    }
  }

  /**
   * Iterate over values
   * 
   * @return Value iterable
   */
  public Iterable<Pair<Element, Visualization>> values() {
    return map.values();
  }

  /**
   * Clear a map
   */
  public void clear() {
    map.clear();
  }

  /**
   * Put a new combination into the map.
   * 
   * @param it Plot item
   * @param task Visualization Task
   * @param elem Container element
   * @param vis Visualization
   */
  public void put(PlotItem it, VisualizationTask task, Element elem, Visualization vis) {
    map.put(key(it, task), value(elem, vis));
  }

  /**
   * Remove a combination.
   * 
   * @param it Plot item
   * @param task Visualization task
   * @return Previous value
   */
  public Pair<Element, Visualization> remove(PlotItem it, VisualizationTask task) {
    return map.remove(key(it, task));
  }

  /**
   * Put a new item into the visualizations
   * 
   * @param it Plot item
   * @param task Visualization task
   * @param pair Pair object
   */
  public void put(PlotItem it, VisualizationTask task, Pair<Element, Visualization> pair) {
    map.put(key(it, task), pair);
  }

  /**
   * Get a pair from the map
   * 
   * @param it Plot item
   * @param task Visualization task
   * @return Pair object
   */
  public Pair<Element, Visualization> get(PlotItem it, VisualizationTask task) {
    return map.get(key(it, task));
  }
}