/* 
 * 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.openal;

import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.Sys;

/**
 * $Id$
 * <br>
 * This is the OpenAL class. It extends the latest core.
 *
 * @author Brian Matzon <brian@matzon.dk>
 * @version $Revision$
 */
public final class AL {

	/** ALC instance. */
	protected static ALC alc;

	/** ALCdevice instance. */
	protected static ALCdevice device;

	/** Current ALCcontext. */
	protected static ALCcontext context;

	/** 
	 * String that requests a certain device or device configuration. 
	 * If null is specified, the implementation will provide an 
	 * implementation specific default. 
	 */
	protected static String deviceArguments;

	/** Frequency for mixing output buffer, in units of Hz. */
	protected static int contextFrequency = -1;

	/** Refresh intervalls, in units of Hz. */
	protected static int contextRefresh = -1;

	/** Flag, indicating a synchronous context. */
	protected static int contextSynchronized = ALC.ALC_FALSE;

	/** Have we been created? */
	protected static boolean created;

	static {
		Sys.initialize();
	}

	private AL() {
	}

	/**
	 * Native method to create AL instance
	 * 
	 * @param oalPaths Array of strings containing paths to search for OpenAL library
	 */
	protected static native void nCreate(String[] oalPaths) throws LWJGLException;

	/**
	 * Native method the destroy the AL
	 */
	protected static native void nDestroy();
	
	/**
	 * @return true if AL has been created
	 */
	public static boolean isCreated() {
		return created;
	}	
	
	/**
	 * Creates an OpenAL instance. Using this constructor will cause OpenAL to
	 * open the device using supplied device argument, and create a context using the context values
	 * supplied. 
	 * 
	 * @param deviceArguments Arguments supplied to native device
	 * @param contextFrequency Frequency for mixing output buffer, in units of Hz (Common values include 11025, 22050, and 44100).
	 * @param contextRefresh Refresh intervalls, in units of Hz.
	 * @param contextSynchronized Flag, indicating a synchronous context.* 
	 */
	public static void create(String deviceArguments, int contextFrequency, int contextRefresh, boolean contextSynchronized)
		throws LWJGLException {
			
		if (created) {
			return;
		}
			
			
		AL.deviceArguments = deviceArguments;
		AL.contextFrequency = contextFrequency;
		AL.contextRefresh = contextRefresh;
		AL.contextSynchronized = contextSynchronized ? ALC.ALC_TRUE : ALC.ALC_FALSE;

		create();
	}

	/**
	 * Creates an OpenAL instance. The empty create will cause OpenAL to
	 * open the default device, and create a context using default values. 
	 */
	public static void create() throws LWJGLException {
		if (created) {
			return;
		}
		String[] oalPaths = LWJGLUtil.getLibraryPaths(new String[]{
                                                  "lwjglaudio", "lwjglaudio.dll",
                                                  "openal", "libopenal.so",
                                                  "openal", "openal.dylib"}, AL.class.getClassLoader());
		LWJGLUtil.log("Found " + oalPaths.length + " OpenAL paths");
		nCreate(oalPaths);
		created = true;

		try {
			AL10.initNativeStubs();
			ALC.initNativeStubs();

			device = ALC.alcOpenDevice(deviceArguments);
			if (device == null)
				throw new LWJGLException("Could not open ALC device");
			//check if doing default values or not
			if (contextFrequency == -1) {
				context = ALC.alcCreateContext(device.device, null);
			} else {
				context = ALC.alcCreateContext(device.device,
						ALCcontext.createAttributeList(contextFrequency, contextRefresh, contextSynchronized));
			}
			ALC.alcMakeContextCurrent(context.context);
			created = true;
		} catch (LWJGLException e) {
			destroy();
			throw e;
		}
	}

	/**
	 * Exit cleanly by calling destroy.
	 */
	public static void destroy() {
		if (context != null) {
			ALC.alcDestroyContext(context.context);
			context = null;
		}
		if (device != null) {
			ALC.alcCloseDevice(device.device);
			device = null;
		}
		resetNativeStubs(AL10.class);
		resetNativeStubs(ALC.class);

		deviceArguments = null;

		contextFrequency = -1;
		contextRefresh = -1;
		contextSynchronized = ALC.ALC_FALSE;
		
		if (created)
			nDestroy();
		created = false;
	}

	private static native void resetNativeStubs(Class clazz);
	
	/**
	 * Gets a handle to the current openAL context. The handle is "opaque" right now
	 * because, realistically, there is nothing you can actually do with it. If it turns
	 * out that there are useful things you can do with it then it'll return an instance
	 * of ALCcontext (which will have to become a public class)
	 * @return an opaque handle to the AL context.
	 */
	public static Object getContext() {
		return context;
	}
}