/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.io.IOException;
import java.io.InputStream;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.URI;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.concurrent.ThreadLocalRandom;

public final class MavenWrapperDownloader {

  private static final String WRAPPER_VERSION = "3.3.4";

  private static final boolean VERBOSE = Boolean.parseBoolean(System.getenv("MVNW_VERBOSE"));

  public static void main(String[] args) {
    log("Apache Maven Wrapper Downloader " + WRAPPER_VERSION);

    if (args.length != 2) {
      System.err.println(" - ERROR wrapperUrl or wrapperJarPath parameter missing");
      System.exit(1);
    }

    try {
      log(" - Downloader started");
      final URL wrapperUrl = URI.create(args[0]).toURL();
      final Path baseDir = Paths.get(".").toAbsolutePath().normalize();
      final Path wrapperJarPath = baseDir.resolve(args[1]).normalize();
      if (!wrapperJarPath.startsWith(baseDir)) {
        throw new IOException("Invalid path: outside of allowed directory");
      }
      downloadFileFromURL(wrapperUrl, wrapperJarPath);
      log("Done");
    } catch (IOException e) {
      System.err.println("- Error downloading: " + e.getMessage());
      if (VERBOSE) {
        e.printStackTrace();
      }
      System.exit(1);
    }
  }

  private static void downloadFileFromURL(URL wrapperUrl, Path wrapperJarPath) throws IOException {
    log(" - Downloading to: " + wrapperJarPath);
    if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
      final String username = System.getenv("MVNW_USERNAME");
      final char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
      Authenticator.setDefault(new Authenticator() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
          return new PasswordAuthentication(username, password);
        }
      });
    }

    Path temp = wrapperJarPath.getParent()
      .resolve(wrapperJarPath.getFileName() + "." + Long.toUnsignedString(ThreadLocalRandom.current().nextLong()) + ".tmp");

    try (InputStream inStream = wrapperUrl.openStream()) {
      Files.copy(inStream, temp, StandardCopyOption.REPLACE_EXISTING);
      Files.move(temp, wrapperJarPath, StandardCopyOption.REPLACE_EXISTING);
    } finally {
      Files.deleteIfExists(temp);
    }
    log(" - Downloader complete");
  }

  private static void log(String msg) {
    if (VERBOSE) {
      System.out.println(msg);
    }
  }
}
