/**

 * Relational pipes

 * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * 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, version 3 of the License.

 *

 * 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/>.

 */

import java.io.File;

import java.io.IOException;

import java.util.LinkedList;

import java.util.List;

import java.util.jar.JarFile;

/**

 * <p>

 * This streamlet provides metadata from JAR (or ZIP) files.</p>

 *

 * <p>

 * With no options it returns the main class (if any) and number of entries (files and directories) in the archive.</p>

 *

 * <p>

 * Specific attributes can be selected using options – e.g. --option 'attribute' '…' Supported attributes are:</p>

 *

 * <ul>

 * <li>comment</li>

 * <li>entries</li>

 * <li>main_class</li>

 * </ul>

 */

public class JarInfo extends Streamlet {

	// TODO: total size 

	// TODO: OSGi metadata etc.

	// TODO: more OOP, move to separate repository, proper Maven project, clean-up, stabilize API

	public static final String ATTRIBUTE_COMMENT = "comment";

	public static final String ATTRIBUTE_ENTRIES = "entries";

	public static final String ATTRIBUTE_MAIN_CLASS = "main_class";

	private final List<String> jarAttributes = new LinkedList<>();

	public static void main(String[] args) throws IOException {

		JarInfo s = new JarInfo();

		int status = s.run();

		System.exit(status);

	}

	protected List<Streamlet.AttributeMetadata> getOutputAttributesMetadata() {

		List<Option> attributeOptions = getOptions("attribute");

		if (attributeOptions.isEmpty()) {

			attributeOptions.add(new Option("attribute", ATTRIBUTE_MAIN_CLASS));

			attributeOptions.add(new Option("attribute", ATTRIBUTE_ENTRIES));

		}

		List<Streamlet.AttributeMetadata> result = new LinkedList<>();

		for (int i = 0; i < attributeOptions.size(); i++) {

			Streamlet.Option o = attributeOptions.get(i);

			Streamlet.Type type;

			switch (o.value) {

				case ATTRIBUTE_COMMENT:

				case ATTRIBUTE_MAIN_CLASS:

					type = Streamlet.Type.STRING;

					break;

				case ATTRIBUTE_ENTRIES:

					type = Streamlet.Type.INTEGER;

					break;

				default:

					throw new IllegalArgumentException("Unsupported attribute: " + o.value);

			}

			result.add(new Streamlet.AttributeMetadata(getAlias(i, o.value), type));

			jarAttributes.add(o.value);

		}

		return result;

	}

	@Override

	protected List<Object> getOutputAttributes() {

		List<Object> result = new LinkedList<>();

		try {

			JarFile jar = new JarFile(new File(getCurrentFile()));

			for (String attributeName : jarAttributes) {

				switch (attributeName) {

					case ATTRIBUTE_COMMENT:

						result.add(jar.getComment());

						break;

					case ATTRIBUTE_MAIN_CLASS:

						String mainClass = jar.getManifest() == null ? null : jar.getManifest().getMainAttributes().getValue("Main-Class");

						result.add(mainClass);

						break;

					case ATTRIBUTE_ENTRIES:

						result.add(jar.size());

						break;

				}

			}

		} catch (Exception e) {

			for (String attributeName : jarAttributes) {

				result.add(null);

			}

		}

		return result;

	}

}