/**

 * copy-image-resizer

 * Copyright © 2014 František Kučera (frantovo.cz)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

package cz.frantovo.copyImageResizer;

import cz.frantovo.copyImageResizer.SingleImageResizer.ImageFormat;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.nio.channels.Channels;

import java.nio.channels.FileChannel;

import java.nio.channels.ReadableByteChannel;

import java.nio.channels.WritableByteChannel;

import java.util.logging.Level;

import java.util.logging.Logger;

import javax.imageio.ImageIO;

/**

 *

 * @author Ing. František Kučera (frantovo.cz)

 */

public class RecursiveImageResizer {

	private static final Logger log = Logger.getLogger(RecursiveImageResizer.class.getName());

	private final SingleImageResizer resizer = new SingleImageResizer();

	public void resize(RecursiveOptions options) throws RecursiveException, ResizeException {

		resizeDirectory(options.getInput(), options);

	}

	private void resizeFile(File inputFile, RecursiveOptions options) throws ResizeException {

		File inputFileRelative = relativize(options.getInput(), inputFile);

		log.log(Level.FINE, "Resizing file: {0}", inputFileRelative);

		ImageFormat format = ImageFormat.getMatching(inputFile.getName());

		if (format == null) {

			log.log(Level.FINE, "Skipping file: {0} (no image format matched this extension)", inputFileRelative);

		} else {

			try {

				for (SizeSpecification size : options.getSizes()) {

					File sizeRoot = new File(options.getOutput(), size.getDirectory());

					File outputFile = new File(sizeRoot, inputFileRelative.getPath());

					try (FileInputStream input = new FileInputStream(inputFile)) {

						BufferedImage image = readImage(input);

						if (shouldResize(image, size)) {

							try (FileOutputStream output = new FileOutputStream(outputFile)) {

								resizer.resize(image, output, size, format);

							}

						} else {

							log.log(Level.INFO, "File: {0} has already required size → just copy", inputFileRelative);

							justCopy(inputFile, outputFile);

						}

					}

				}

			} catch (FileNotFoundException e) {

				throw new ResizeException("Error while opening stream", e);

			} catch (IOException e) {

				throw new ResizeException("Error while closing stream", e);

			}

		}

	}

	private static boolean shouldResize(BufferedImage input, SizeSpecification requested) {

		if (requested.isResizeSmaller()) {

			return input.getHeight() != requested.getHeight() || input.getWidth() != requested.getWidth();

		} else {

			return input.getHeight() > requested.getHeight() || input.getWidth() > requested.getWidth();

		}

	}

	private static BufferedImage readImage(InputStream input) throws ResizeException {

		try {

			return ImageIO.read(input);

		} catch (IOException e) {

			throw new ResizeException("Unable to read image from stream", e);

		}

	}

	private static void justCopy(File inputFile, File outputFile) throws ResizeException {

		try {

			if (!outputFile.exists()) {

				outputFile.createNewFile();

			}

			try (FileChannel input = new FileInputStream(inputFile).getChannel()) {

				try (FileChannel output = new FileOutputStream(outputFile).getChannel()) {

					output.transferFrom(input, 0, input.size());

				}

			}

		} catch (IOException e) {

			throw new ResizeException("Unable copy stream/channel", e);

		}

	}

	private void resizeDirectory(File directory, RecursiveOptions options) throws ResizeException {

		log.log(Level.FINE, "Resizing directory: {0}", directory);

		for (SizeSpecification size : options.getSizes()) {

			File relative = relativize(options.getInput(), directory);

			File sizeRoot = new File(options.getOutput(), size.getDirectory());

			File dir = new File(sizeRoot, relative.getPath());

			dir.mkdirs();

		}

		for (File entry : directory.listFiles()) {

			if (entry.isDirectory()) {

				resizeDirectory(entry, options);

			} else {

				resizeFile(entry, options);

			}

		}

	}

	private static File relativize(File root, File child) {

		return root.toPath().relativize(child.toPath()).toFile();

	}

}