/*
 * Copyright (c) 2002-2010 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.opengl;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.lwjgl.LWJGLUtil;

/**
 * Utility for working with the xrandr commmand-line utility. Assumes
 * xrandr v1.2 or higher.
 * 
 * @author ryanm
 */
public class XRandR
{
	private static Screen[] current;

	private static Map /* <String, Screen[]> */screens;

	private static void populate()
	{
		if( screens == null )
		{
			screens = new HashMap/* <String, Screen[]> */();

			// ProcessBuilder pb = new ProcessBuilder( "xrandr", "-q" );
			// pb.redirectErrorStream();
			try
			{
				// Process p= pb.start();
				Process p = Runtime.getRuntime().exec( new String[] { "xrandr", "-q" } );

				List/* <Screen> */currentList = new ArrayList/* <Screen> */();
				List/* <Screen> */possibles = new ArrayList/* <Screen> */();
				String name = null;

				BufferedReader br = new BufferedReader( new InputStreamReader( p.getInputStream() ) );
				String line;
				while( ( line = br.readLine() ) != null )
				{
					line = line.trim();
					String[] sa = line.split( "\\s+" );

					if( sa[ 1 ].equals( "connected" ) )
					{
						// found a new screen block
						if( name != null )
						{
							screens.put( name, possibles.toArray( new Screen[ possibles.size() ] ) );
							possibles.clear();
						}
						name = sa[ 0 ];

						// record the current config
						parseScreen( currentList, name, sa[ 2 ] );
					}
					else if( Pattern.matches( "\\d*x\\d*", sa[ 0 ] ) )
					{
						// found a new mode line
						parseScreen( possibles, name, sa[ 0 ] );
					}
				}

				screens.put( name, possibles.toArray( new Screen[ possibles.size() ] ) );

				current = (Screen[]) currentList.toArray(new Screen[currentList.size()]);
			}
			catch( Throwable e )
			{
				LWJGLUtil.log( "Exception in XRandR.populate(): " + e.getMessage() );
				screens.clear();
				current = new Screen[ 0 ];
			}
		}
	}

	/**
	 * @return The current screen configuration, or an empty array if
	 *         xrandr is not supported
	 */
	public static Screen[] getConfiguration()
	{
		populate();

		return (Screen[]) current.clone();
	}

	/**
	 * @param screens
	 *           The desired screen set, may not be <code>null</code>
	 * @throws IllegalArgumentException
	 *            if no screens are specified
	 */
	public static void setConfiguration( Screen[]/* ... */screens )
	{
		if( screens.length == 0 )
		{
			throw new IllegalArgumentException( "Must specify at least one screen" );
		}

		List/* <String> */cmd = new ArrayList/* <String> */();
		cmd.add( "xrandr" );

		// switch off those in the current set not in the new set
		for( int i = 0; i < current.length; i++ )
		{
			boolean found = false;
			for( int j = 0; j < screens.length; j++ )
			{
				if( screens[ j ].name.equals( current[ i ].name ) )
				{
					found = true;
					break;
				}
			}

			if( !found )
			{
				cmd.add( "--output" );
				cmd.add( current[ i ].name );
				cmd.add( "--off" );
			}
		}

		// set up new set
		for( int i = 0; i < screens.length; i++ )
		{
			screens[ i ].getArgs( cmd );
		}

		try
		{
			// ProcessBuilder pb = new ProcessBuilder( cmd );
			// pb.redirectErrorStream();
			// Process p = pb.start();
			Process p =
					Runtime.getRuntime().exec( ( String[] ) cmd.toArray( new String[ cmd.size() ] ) );
			// no output is expected, but check anyway
			BufferedReader br = new BufferedReader( new InputStreamReader( p.getInputStream() ) );
			String line;
			while( ( line = br.readLine() ) != null )
			{
				LWJGLUtil.log( "Unexpected output from xrandr process: " + line );
			}
			current = screens;
		}
		catch( IOException e )
		{
			LWJGLUtil.log( "XRandR exception in setConfiguration(): " + e.getMessage() );
		}
	}

	/**
	 * @return the name of connected screens, or an empty array if
	 *         xrandr is not supported
	 */
	public static String[] getScreenNames()
	{
		populate();
		return ( String[] ) screens.keySet().toArray( new String[ screens.size() ] );
	}

	/**
	 * @param name
	 * @return the possible resolutions of the named screen, or
	 *         <code>null</code> if there is no such screen
	 */
	public static Screen[] getResolutions( String name )
	{
		populate();
		// clone the array to prevent held copies being altered
		return (Screen[]) ((Screen[]) screens.get(name)).clone();
	}

	private static final Pattern SCREEN_PATTERN1 =
			Pattern.compile( "^(\\d+)x(\\d+)\\+(\\d+)\\+(\\d+)$" );

	private static final Pattern SCREEN_PATTERN2 = Pattern.compile( "^(\\d+)x(\\d+)$" );

	/**
	 * Parses a screen configuration and adds it to the list if it's
	 * valid.
	 * 
	 * @param list
	 *           the list to add the Screen to if it's valid
	 * @param name
	 *           the name of this screen
	 * @param what
	 *           config string, format either widthxheight or
	 *           widthxheight+xPos+yPos
	 */
	private static void parseScreen( List /* <Screen> */list, String name, String what )
	{
		Matcher m = SCREEN_PATTERN1.matcher( what );
		if( !m.matches() )
		{
			m = SCREEN_PATTERN2.matcher( what );
			if( !m.matches() )
			{
				LWJGLUtil.log( "Did not match: " + what );
				return;
			}
		}
		int width = Integer.parseInt( m.group( 1 ) );
		int height = Integer.parseInt( m.group( 2 ) );
		int xpos, ypos;
		if( m.groupCount() > 3 )
		{
			xpos = Integer.parseInt( m.group( 3 ) );
			ypos = Integer.parseInt( m.group( 4 ) );
		}
		else
		{
			xpos = 0;
			ypos = 0;
		}
		list.add( new Screen( name, width, height, xpos, ypos ) );
	}

	/**
	 * Encapsulates the configuration of a monitor. Resolution is
	 * fixed, position is mutable
	 * 
	 * @author ryanm
	 */
	public static class Screen implements Cloneable
	{
		/**
		 * Name for this output
		 */
		public final String name;

		/**
		 * Width in pixels
		 */
		public final int width;

		/**
		 * Height in pixels
		 */
		public final int height;

		/**
		 * Position on the x-axis, in pixels
		 */
		public int xPos = 0;

		/**
		 * Position on the y-axis, in pixels
		 */
		public int yPos = 0;

		private Screen( String name, int width, int height, int xPos, int yPos )
		{
			this.name = name;
			this.width = width;
			this.height = height;
			this.xPos = xPos;
			this.yPos = yPos;
		}

		private void getArgs( List/* <String> */argList )
		{
			argList.add( "--output" );
			argList.add( name );
			argList.add( "--mode" );
			argList.add( width + "x" + height );
			argList.add( "--pos" );
			argList.add( xPos + "x" + yPos );
		}

		//@Override
		public String toString()
		{
			return name + " " + width + "x" + height + " @ " + xPos + "x" + yPos;
		}
	}
}