/*=========================================================================

  Program:   FusionViewer
  Module:    $RCSfile: WindowLevelPresets.java,v $
  Language:  Java
  Date:      $Date: 2007/02/02 19:26:29 $
  Version:   $Revision: 1.3 $
  
  Copyright (c) Insightful Corporation.  All rights reserved.
  See Copyright.txt for details.
  
  This software is distributed WITHOUT ANY WARRANTY; without even
  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

package org.fusionviewer.io;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;


/**\class WindowLevelPresets
 *\brief A list of presets for window and level image constrast settings that
 * can be loaded from an XML file.
 */
public class WindowLevelPresets {	
	private final static String SETTING_TAG = "setting";
	private final static String NAME_ATTRIBUTE = "name";
	private final static String WINDOW_TAG = "window";
	private final static String LEVEL_TAG = "level";
	
	private ArrayList m_settings = new ArrayList();
	
	
	/**
	 * Read a list of window and level settings from an XML file.
	 *  
	 * @param presetsFile file to read settings from
	 * @throws IOException if there is an error reading presetsFile
	 */
	public WindowLevelPresets(File presetsFile) throws IOException {
		if (presetsFile.exists())
			load(presetsFile);
	}
	
	/*
	 * Read the XML file.
	 */
	private void load(File presetsFile) throws IOException {
		try {
			SAXBuilder builder = new SAXBuilder();
			Document doc = builder.build(presetsFile);
			Element root = doc.getRootElement();
			
			Iterator it = root.getChildren(SETTING_TAG).iterator();
			while (it.hasNext()) {
				Element setting = (Element) it.next();
				m_settings.add(new WindowLevel(
						setting.getAttribute(NAME_ATTRIBUTE).getValue(),
						Float.parseFloat(setting.getChildText(WINDOW_TAG)),
						Float.parseFloat(setting.getChildText(LEVEL_TAG))));
			}
		} catch (NumberFormatException e) {
			throw new IOException(e.getMessage());
		} catch (JDOMException e) {
			throw new IOException(e.getMessage());
		}
	}
	
	/**
	 * Get the number of window and level settings
	 * 
	 * @return number of window and level settings
	 */
	public int getNumSettings() {
		return m_settings.size();
	}
	
	/**
	 * Get a window and level setting
	 * 
	 * @param i index of the window and level to get
	 * @return the window and level
	 */
	public WindowLevel getWindowLevel(int i) {
		return (WindowLevel) m_settings.get(i);
	}
	
	/**
	 * A named window and level pair.
	 */
	public static final class WindowLevel {
		private final String name;
		private final float window;
		private final float level;
		private final int hash;
		
		/**
		 * Create a named window and level pair.
		 * 
		 * @param name name of the pair
		 * @param window see ImageDisplaySettings
		 * @param level see ImageDisplaySettings
		 */
		public WindowLevel(String name, float window, float level) {
			this.name = name;
			this.window = window;
			this.level = level;
			
			// Hash code computation from Effective Java by Joshua Block
			int result = 17;
			result = 37 * result + name.hashCode();
			result = 37 * result + Float.floatToIntBits(window);
			result = 37 * result + Float.floatToIntBits(level);
			hash = result;
		}
		
		/**
		 * Determine if this object is equivalent to another FilePair.
		 */
		public boolean equals(Object o) {
			if (o == this)
				return true;
			
			if (!(o instanceof WindowLevel))
				return false;
			
			WindowLevel p = (WindowLevel) o;
			return name.equals(p.name) && (window == p.window) && (level == p.level);
		}
		
		/**
		 * Compute the hash code for this object.
		 */
		public int hashCode() {
			return hash;
		}
		
		/**
		 * @return Returns the name.
		 */
		public String getName() {
			return name;
		}
		
		/**
		 * @return Returns the level.
		 */
		public float getLevel() {
			return level;
		}
		
		/**
		 * @return Returns the window.
		 */
		public float getWindow() {
			return window;
		}
	}
}