/*
 * Moonlight|3D Copyright (C) 2005 The Moonlight|3D team
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library 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 Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 * 
 * Created on Dec 9, 2005
 */
package ml.image;

import java.util.ArrayList;
import java.util.List;

import ml.core.exceptions.Exception;
import ml.core.helper.NamePool;

/**
 * This class keeps track of all supported image file formats and
 * wraps loading and saving images through the registered ImageFormat
 * handlers.
 * 
 * @author gregor
 */
public class FormatManager {
	private ArrayList<ImageFormat> imageFormats;
	private NamePool formatPool;

	/**
	 * Simple constructor.
	 */
	public FormatManager() {
		imageFormats=new ArrayList<ImageFormat>();
		formatPool=new NamePool();
	}

	/**
	 * Register a new image file format.
	 * 
	 * @param format the image file format to register
	 * @throws Exception
	 */
	public void registerImageFormat(ImageFormat format) throws Exception {
		if(!formatPool.isNameUnique(format.getName())) {
			throw new Exception("image format name is not unique");
		}
		imageFormats.add(format);
		formatPool.add(format);
	}

	/**
	 * Unregister the image file format handle for the given file
	 * format name.
	 * 
	 * @param formatName the unique name of the image file format 
	 * @throws Exception
	 */
	public void unregisterImageFormat(String formatName) throws Exception {
		for(int i=0;i<imageFormats.size();i++) {
			if(imageFormats.get(i).getName().equals(formatName)) {
				formatPool.remove(imageFormats.get(i));
				imageFormats.remove(i);
				return;
			}
		}
		
		throw new Exception("image format with given name not found");
	}
	
	/**
	 * Return all registered image file format handlers.
	 * 
	 * @return a list of all image file format handlers
	 */
	public List<ImageFormat> getFormats() {
		return (ArrayList<ImageFormat>) imageFormats.clone();
	}
	
	/**
	 * Load an image from the file with the given filename through the
	 * image file format handler for the given image file format name.
	 * 
	 * @param filename the file name to load the image from
	 * @param formatName the image file format to expect
	 * @return the framebuffer with the loaded image
	 * @throws Exception
	 */
	public Framebuffer loadImage(String filename, String formatName) throws Exception {
		Framebuffer image = null;

		ImageFormat neededFormat=null;
		for (ImageFormat format : imageFormats) {
			if (format.getName().equals(formatName)) {
				neededFormat = format;
			}
		}

		if (neededFormat == null) {
			throw new Exception("speficfied image format not found");
		}

		image = neededFormat.loadFile(filename);
		return image;
	}
	
	/**
	 * Load an image from the given file. Try to guess the file format
	 * from the file extension.
	 * 
	 * @param filename the name of the file to load
	 * @return the framebuffer with the loaded image
	 * @throws Exception
	 */
	public Framebuffer loadImage(String filename) throws Exception {
		Framebuffer image = null;

		for (ImageFormat format : imageFormats) {
			if(format.getFileType().matches(filename)) {
				try {
					image=format.loadFile(filename);
					return image;
				} catch(Exception e) {
					// do nothing here, the catch statement is here to skip the return above
				}				
			}
		}

		throw new Exception("unable to detect image format");
	}
	
	/**
	 * Save the given framebuffer as an image to the file with the given name
	 * using the given image file format.
	 *  
	 * @param image the framebuffer containing the image to be saved
	 * @param filename the name of the file the image is to be saved to
	 * @param formatName the name of the file format to use
	 * @throws Exception
	 */
	public void saveImage(Framebuffer image, String filename, String formatName) throws Exception {
		ImageFormat neededFormat=null;
		for(ImageFormat format : imageFormats) {
			if(format.getName().equals(formatName)) {
				neededFormat=format;
			}
		}
		
		if(neededFormat==null) {
			throw new Exception("speficfied image format not found");
		}
		
		neededFormat.saveFile(filename,image);
	}
}