/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.com
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero 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
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License along with this program.
 * If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.repository.resource;

import java.io.IOException;
import java.nio.file.Paths;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import com.rapidminer.repository.DataEntry;
import com.rapidminer.repository.Entry;
import com.rapidminer.repository.Folder;
import com.rapidminer.repository.RepositoryException;


/**
 * Class for a folder in the repository that is associated with a {@link ZipStreamResource} and
 * contains the process and input data for this template.
 *
 * @author Gisa Schaefer, Marcel Michel
 * @since 7.0.0
 */
public class ZipResourceFolder extends ResourceFolder {

	private List<Folder> folders;
	private List<DataEntry> data;

	private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
	private final Lock readLock = lock.readLock();
	private final Lock writeLock = lock.writeLock();

	private final ZipStreamResource zipStream;

	protected ZipResourceFolder(ResourceFolder parent, String name, ZipStreamResource zipStream, String parentPath,
			ResourceRepository repository) {
		super(parent, name, parentPath + "/" + name, repository);
		this.zipStream = zipStream;
	}

	@Override
	public boolean containsEntry(String name) throws RepositoryException {
		acquireReadLock();
		try {
			if (isLoaded()) {
				return containsEntryNotThreadSafe(name);
			}
		} finally {
			releaseReadLock();
		}
		acquireWriteLock();
		try {
			ensureLoaded();
			return containsEntryNotThreadSafe(name);
		} finally {
			releaseWriteLock();
		}
	}

	private boolean containsEntryNotThreadSafe(String name) {
		for (Entry entry : data) {
			if (entry.getName().equals(name)) {
				return true;
			}
		}
		for (Entry entry : folders) {
			if (entry.getName().equals(name)) {
				return true;
			}
		}
		return false;
	}

	@Override
	public List<DataEntry> getDataEntries() throws RepositoryException {
		acquireReadLock();
		try {
			if (isLoaded()) {
				return Collections.unmodifiableList(data);
			}
		} finally {
			releaseReadLock();
		}
		acquireWriteLock();
		try {
			ensureLoaded();
			return Collections.unmodifiableList(data);
		} finally {
			releaseWriteLock();
		}
	}

	@Override
	protected boolean isLoaded() {
		return folders != null && data != null;
	}

	@Override
	protected void ensureLoaded() throws RepositoryException {
		if (isLoaded()) {
			return;
		}
		this.folders = new LinkedList<Folder>();
		this.data = new LinkedList<DataEntry>();

		try (ZipInputStream zip = zipStream.getStream()) {
			ZipEntry entry;
			while ((entry = zip.getNextEntry()) != null) {
				if (entry.isDirectory() || entry.getName().replaceFirst("/", "").contains("/")) {
					continue;
				}
				if (zipStream.getStreamPath() != null && !entry.getName().startsWith(zipStream.getStreamPath())) {
					continue;
				}
				String entryName = entry.getName();
				if (entryName.endsWith(".ioo")) {
					String ioObjectName = Paths.get(entryName).getFileName().toString().split("\\.")[0];
					data.add(new ZipResourceIOObjectEntry(this, ioObjectName, getPath() + "/" + ioObjectName,
							getRepository(), zipStream));
				} else if (entryName.endsWith(".rmp")) {
					String processName = Paths.get(entryName).getFileName().toString().split("\\.")[0];
					data.add(new ZipResourceProcessEntry(this, processName, getPath() + "/" + processName, getRepository(),
							zipStream));
				} else if (entryName.endsWith(".blob")) {
					String blobName = Paths.get(entryName).getFileName().toString().split("\\.")[0];
					data.add(new ZipResourceBlobEntry(this, blobName, getPath() + "/" + blobName, getRepository(),
							zipStream));
				}
			}
		} catch (IOException e) {
			throw new RepositoryException("Cannot load data from '" + getResource() + ": " + e, e);
		}
	}

	@Override
	public List<Folder> getSubfolders() throws RepositoryException {
		acquireReadLock();
		try {
			if (isLoaded()) {
				return Collections.unmodifiableList(folders);
			}
		} finally {
			releaseReadLock();
		}
		acquireWriteLock();
		try {
			ensureLoaded();
			return Collections.unmodifiableList(folders);
		} finally {
			releaseWriteLock();
		}
	}

	@Override
	public void refresh() throws RepositoryException {
		acquireWriteLock();
		try {
			folders = null;
			data = null;
		} finally {
			releaseWriteLock();
		}
		getRepository().fireRefreshed(this);
	}

	private void acquireReadLock() throws RepositoryException {
		try {
			readLock.lock();
		} catch (RuntimeException e) {
			throw new RepositoryException("Could not get read lock", e);
		}
	}

	private void releaseReadLock() throws RepositoryException {
		try {
			readLock.unlock();
		} catch (RuntimeException e) {
			throw new RepositoryException("Could not release read lock", e);
		}
	}

	private void acquireWriteLock() throws RepositoryException {
		try {
			writeLock.lock();
		} catch (RuntimeException e) {
			throw new RepositoryException("Could not get write lock", e);
		}
	}

	private void releaseWriteLock() throws RepositoryException {
		try {
			writeLock.unlock();
		} catch (RuntimeException e) {
			throw new RepositoryException("Could not release write lock", e);
		}
	}
}