/* 
 * Copyright (c) 2002-2004 LWJGL Project
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are 
 * met:
 * 
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'LWJGL' nor the names of 
 *   its contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.lwjgl.util;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;

import org.lwjgl.LWJGLUtil;
import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.DisplayMode;

/**
 * $Id$
 * Display initialization utility, that can be used to find display modes and pick
 * one for you based on your criteria.
 * @author $Author$
 * @version $Revision$
 */
public final class Display {
	
	private static final boolean DEBUG = false;
	
	/**
	 * Determine the available display modes that match the specified minimum and maximum criteria.
	 * If any given criterium is specified as -1 then it is ignored.
	 * 
	 * @param minWidth the minimum display resolution in pixels
	 * @param minHeight the minimum display resolution in pixels
	 * @param maxWidth the maximum display resolution in pixels
	 * @param maxHeight the maximum display resolution in pixels
	 * @param minBPP the minimum bit depth per pixel
	 * @param maxBPP the maximum bit depth per pixel
	 * @param minFreq the minimum display frequency in Hz
	 * @param maxFreq the maximum display frequency in Hz
	 * @return an array of matching display modes
	 */
	public static DisplayMode[] getAvailableDisplayModes(int minWidth, int minHeight, int maxWidth, int maxHeight, int minBPP, int maxBPP,
		int minFreq, int maxFreq) throws LWJGLException
	{
		// First get the available display modes
		DisplayMode[] modes = org.lwjgl.opengl.Display.getAvailableDisplayModes();
		
		if (LWJGLUtil.DEBUG || DEBUG) {
			System.out.println("Available screen modes:");
			for (int i = 0; i < modes.length; i ++) {
				System.out.println(modes[i]);
			}
		}
		
		ArrayList matches = new ArrayList(modes.length);

		for (int i = 0; i < modes.length; i ++) {
			assert modes[i] != null : ""+i+" "+modes.length;
			if (minWidth != -1 && modes[i].getWidth() < minWidth)
				continue;
			if (maxWidth != -1 && modes[i].getWidth() > maxWidth)
				continue;
			if (minHeight != -1 && modes[i].getHeight() < minHeight)
				continue;
			if (maxHeight != -1 && modes[i].getHeight() > maxHeight)
				continue;
			if (minBPP != -1 && modes[i].getBitsPerPixel() < minBPP)
				continue;
			if (maxBPP != -1 && modes[i].getBitsPerPixel() > maxBPP)
				continue;
			//if (modes[i].bpp == 24)
			//	continue;
			if (modes[i].getFrequency() != 0) {
				if (minFreq != -1 && modes[i].getFrequency() < minFreq)
					continue;
				if (maxFreq != -1 && modes[i].getFrequency() > maxFreq)
					continue;
			}
			matches.add(modes[i]);
		}
		
		DisplayMode[] ret = new DisplayMode[matches.size()];
		matches.toArray(ret);
		if (LWJGLUtil.DEBUG && DEBUG) {
			System.out.println("Filtered screen modes:");
			for (int i = 0; i < ret.length; i ++) {
				System.out.println(ret[i]);
			}
		}
		
		return ret;
	}
	
	/**
	 * Create the display by choosing from a list of display modes based on an order of preference.
	 * You must supply a list of allowable display modes, probably by calling getAvailableDisplayModes(),
	 * and an array with the order in which you would like them sorted in descending order.
	 * This method attempts to create the topmost display mode; if that fails, it will try the next one,
	 * and so on, until there are no modes left. If no mode is set at the end, an exception is thrown.
	 * @param dm a list of display modes to choose from
	 * @param param the names of the DisplayMode fields in the order in which you would like them sorted.
	 * @return the chosen display mode
	 * @throws NoSuchFieldException if one of the params is not a field in DisplayMode
	 * @throws Exception if no display mode could be set
	 * @see org.lwjgl.DisplayMode
	 */
	public static DisplayMode setDisplayMode(DisplayMode[] dm, final String[] param) throws Exception {
		
		
		class Sorter implements Comparator {
			
			final Field[] field;
			final int[] order;
			final boolean[] usePreferred;
			final int[] preferred;
			
			Sorter() throws NoSuchFieldException {
				field = new Field[param.length];
				order = new int[param.length];
				preferred = new int[param.length];
				usePreferred = new boolean[param.length];
				for (int i = 0; i < field.length; i ++) {
					int idx = param[i].indexOf('=');
					if (idx > 0) {
						preferred[i] = Integer.parseInt(param[i].substring(idx + 1, param[i].length()));
						usePreferred[i] = true;
						param[i] = param[i].substring(0, idx);
						field[i] = DisplayMode.class.getDeclaredField(param[i]);
					} else if (param[i].charAt(0) == '-') {
						field[i] = DisplayMode.class.getDeclaredField(param[i].substring(1));
						order[i] = -1;
					} else {
						field[i] = DisplayMode.class.getDeclaredField(param[i]);
						order[i] = 1;
					}
					field[i].setAccessible(true);
				}
			}
			
			/**
			 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
			 */
			public int compare(Object o1, Object o2) {
				DisplayMode dm1 = (DisplayMode) o1;
				DisplayMode dm2 = (DisplayMode) o2;
				
				for (int i = 0; i < field.length; i ++) {
					try {
						int f1 = field[i].getInt(dm1);
						int f2 = field[i].getInt(dm2);
						
						if (usePreferred[i] && f1 != f2) {
							if (f1 == preferred[i])
								return -1;
							else if (f2 == preferred[i])
								return 1;
							else {
								// Score according to the difference between the values
								int absf1 = Math.abs(f1 - preferred[i]);
								int absf2 = Math.abs(f2 - preferred[i]);
								if (absf1 < absf2)
									return -1;
								else if (absf1 > absf2)
									return 1;
								else
									continue;
							}
						} else if (f1 < f2)
							return order[i];
						else if (f1 == f2)
							continue;
						else
							return -order[i];
					} catch (IllegalAccessException e) {
						throw new RuntimeException(e);
					}
				}
				
				return 0;
			}
		}
		
		// Sort the display modes
		Arrays.sort(dm, new Sorter());
		
		// Try them out in the appropriate order
		if (LWJGLUtil.DEBUG || DEBUG) {
			System.out.println("Sorted display modes:");
			for (int i = 0; i < dm.length; i ++) {
				System.out.println(dm[i]);
			}
		}
		for (int i = 0; i < dm.length; i ++) {
			try {
				if (LWJGLUtil.DEBUG || DEBUG)
					System.out.println("Attempting to set displaymode: "+dm[i]);
				org.lwjgl.opengl.Display.setDisplayMode(dm[i]);
				return dm[i];
			} catch (Exception e) {
				if (LWJGLUtil.DEBUG || DEBUG) {
					System.out.println("Failed to set display mode to "+dm[i]);
					e.printStackTrace();
				}
			}
		}
		
		throw new Exception("Failed to set display mode.");
	}
	
}