/*
 * Copyright (c) 2012-2017 Red Hat, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Red Hat, Inc. - initial API and implementation
 */
package org.eclipse.che.api.core.util;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.util.concurrent.TimeUnit;
import javax.ws.rs.core.HttpHeaders;
import org.eclipse.che.commons.lang.NameGenerator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * DownloadPlugin that downloads single file.
 *
 * @author andrew00x
 */
public final class HttpDownloadPlugin implements DownloadPlugin {
  private static final Logger LOG = LoggerFactory.getLogger(HttpDownloadPlugin.class);

  private static final int CONNECT_TIMEOUT = (int) TimeUnit.MINUTES.toMillis(3);
  private static final int READ_TIMEOUT = (int) TimeUnit.MINUTES.toMillis(3);

  @Override
  public void download(String downloadUrl, java.io.File downloadTo, Callback callback) {
    HttpURLConnection conn = null;
    try {
      conn = (HttpURLConnection) new URL(downloadUrl).openConnection();
      conn.setConnectTimeout(CONNECT_TIMEOUT);
      conn.setReadTimeout(READ_TIMEOUT);
      final int responseCode = conn.getResponseCode();
      if (responseCode != 200) {
        throw new IOException(
            String.format("Invalid response status %d from remote server. ", responseCode));
      }
      final String contentDisposition = conn.getHeaderField(HttpHeaders.CONTENT_DISPOSITION);
      String fileName = null;
      if (contentDisposition != null) {
        int fNameStart = contentDisposition.indexOf("filename=");
        if (fNameStart > 0) {
          int fNameEnd = contentDisposition.indexOf(';', fNameStart + 1);
          if (fNameEnd < 0) {
            fNameEnd = contentDisposition.length();
          }
          fileName = contentDisposition.substring(fNameStart, fNameEnd).split("=")[1];
          if (fileName.charAt(0) == '"' && fileName.charAt(fileName.length() - 1) == '"') {
            fileName = fileName.substring(1, fileName.length() - 1);
          }
        }
      }
      final java.io.File downloadFile =
          new java.io.File(
              downloadTo,
              fileName == null ? NameGenerator.generate("downloaded.file", 4) : fileName);
      try (InputStream in = conn.getInputStream()) {
        Files.copy(in, downloadFile.toPath());
      }
      callback.done(downloadFile);
    } catch (IOException e) {
      LOG.debug(String.format("Failed access: %s, error: %s", downloadUrl, e.getMessage()), e);
      callback.error(e);
    } finally {
      if (conn != null) {
        conn.disconnect();
      }
    }
  }

  @Override
  public void download(
      String downloadUrl, java.io.File downloadTo, String fileName, boolean replaceExisting)
      throws IOException {
    HttpURLConnection conn = null;
    try {
      conn = (HttpURLConnection) new URL(downloadUrl).openConnection();
      conn.setConnectTimeout(CONNECT_TIMEOUT);
      conn.setReadTimeout(READ_TIMEOUT);
      final int responseCode = conn.getResponseCode();
      if (responseCode != 200) {
        throw new IOException(
            String.format("Invalid response status %d from remote server. ", responseCode));
      }
      final java.io.File downloadFile = new java.io.File(downloadTo, fileName);
      try (InputStream in = conn.getInputStream()) {
        if (replaceExisting) {
          Files.copy(in, downloadFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
        } else {
          Files.copy(in, downloadFile.toPath());
        }
      }
    } finally {
      if (conn != null) {
        conn.disconnect();
      }
    }
  }
}
