/********************************************************************************
 * Copyright (c) 2015-2018 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 ********************************************************************************/
package org.eclipse.mdm.apicopy.boundary;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import javax.ejb.EJB;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.StreamingOutput;

import org.eclipse.mdm.shoppingbasket.entity.ShoppingBasket;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@javax.ws.rs.Path("/export")
public class ExportResource {
	private static final Logger LOG = LoggerFactory.getLogger(ExportResource.class);

	@EJB
	private ExportService exportService;

	/**
	 * Default public constructor for JAX-RS
	 */
	public ExportResource() {
	}

	/**
	 * Used to provide service for unit tests
	 * @param exportService
	 */
	protected ExportResource(ExportService exportService) {
		this.exportService = exportService;
	}

	@POST
	@Consumes(MediaType.APPLICATION_XML)
	@Produces(MediaType.APPLICATION_XML)
	public Response exportAtfx(ShoppingBasket basket) throws IOException {

		final Path exportAtfx = exportService.exportAtfx(basket);

		List<File> files = Files.list(exportAtfx).map(p -> p.toFile()).collect(Collectors.toList());
		if (files.size() == 1) {
			StreamingOutput output = new StreamingOutput() {
				@Override
				public void write(OutputStream out) throws IOException {
					try (final InputStream responseStream = new FileInputStream(files.get(0))) {
						int length;
						byte[] buffer = new byte[1024];
						while((length = responseStream.read(buffer)) != -1) {
							out.write(buffer, 0, length);
						}
						out.flush();
					}
					finally {
						if (exportAtfx != null) {
							try {
								deleteDirectory(exportAtfx);
							} catch (IOException e) {
								LOG.warn("Could not delete temporary directory " + exportAtfx.getParent().toFile().getAbsolutePath(), e);
							}
						}
					}
				}
			};

			return Response.ok(output, MediaType.APPLICATION_XML).build();
		} else {
			StreamingOutput out = new StreamingOutput() {
				@Override
				public void write(OutputStream output) throws IOException, WebApplicationException {
					try (ZipOutputStream out = new ZipOutputStream(output)) {
						List<File> files = Files.list(exportAtfx).map(p -> p.toFile()).collect(Collectors.toList());
						for (File f : files) {
							out.putNextEntry(new ZipEntry(f.getName()));
							try (InputStream in = new FileInputStream(f)) {
								int read = 0;
								byte[] bytes = new byte[1024];

								while ((read = in.read(bytes)) != -1) {
									out.write(bytes, 0, read);
								}
							}
						}
					}
					catch (Exception e) {
						e.printStackTrace();
					}
					finally {
						if (exportAtfx != null) {
							try {
								deleteDirectory(exportAtfx);
							} catch (IOException e) {
								LOG.warn("Could not delete temporary directory " + exportAtfx.toFile().getAbsolutePath(), e);
							}
						}
					}
				}
			};
			return Response.ok(out, "application/zip").build();
		}
	}

	/**
	 * Deletes a directory.
	 * @param pathToBeDeleted directory to delete
	 * @throws IOException
	 */
	private void deleteDirectory(java.nio.file.Path pathToBeDeleted) throws IOException {
		Files.walk(pathToBeDeleted)
		.sorted(Comparator.reverseOrder())
		.map(Path::toFile)
		.forEach(File::delete);
	}
}