/*
 * 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.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
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.security.MessageDigest;
import java.util.Arrays;
import java.util.Properties;

public final class MavenWrapperHelper {

    private static final String WRAPPER_VERSION = "3.2.0";

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

    public static void main(String[] args) throws Exception {
        String action = args[0].toLowerCase();
        String[] actionArgs = Arrays.copyOfRange(args, 1, args.length);
        switch (action) {
            case "download":
                log("Apache Maven Wrapper Downloader " + WRAPPER_VERSION);
                if (actionArgs.length != 2) {
                    System.err.println(" - ERROR wrapperUrl or wrapperJarPath parameter missing");
                    System.exit(1);
                }
                try {
                    log(" - Downloader started");
                    final URL wrapperUrl = new URL(actionArgs[0]);
                    final String jarPath = actionArgs[1].replace("src/main", ""); // Sanitize path
                    final Path wrapperJarPath = Paths.get(jarPath).toAbsolutePath().normalize();
                    downloadFileFromURL(wrapperUrl, wrapperJarPath);
                    log("Done");
                } catch (IOException e) {
                    System.err.println("- Error downloading: " + e.getMessage());
                    if (VERBOSE) {
                        e.printStackTrace();
                    }
                    System.exit(1);
                }
                break;
            case "verify":
                String wrapperJar = actionArgs[0];
                String propertiesPath = actionArgs[1];
                log("maven-wrapper file checking: " + wrapperJar);
                Properties properties = new Properties();
                properties.load(Files.newInputStream(new File(propertiesPath).toPath()));
                String wrapperMd5 = properties.getProperty("wrapperMd5");
                if (wrapperMd5 == null) {
                    System.err.println("wrapperMd5 not in " + propertiesPath);
                    System.exit(1);
                }
                String fileMd5 = getFileMd5(wrapperJar);
                System.exit(wrapperMd5.equals(fileMd5) ? 0 : 1);
            default:
                throw new UnsupportedOperationException("Unknown action \"" + action + "\".");
        }
    }

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

    private static String getFileMd5(String path) throws Exception {
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        try (FileInputStream inputStream = new FileInputStream(path)) {
            byte[] buffer = new byte[1024];
            int len;
            while ((len = inputStream.read(buffer)) != -1) {
                md5.update(buffer, 0, len);
            }
            byte[] byteArray = md5.digest();
            StringBuilder sb = new StringBuilder();
            for (byte b : byteArray) {
                sb.append(String.format("%02x", b));
            }
            return sb.toString();
        }
    }

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