BUILDING

import java.nio.file.*
import java.util.function.*
import java.util.spi.*

class Arguments {
	List<String> list = new ArrayList<>();
	Arguments add(Object o) {
		list.add(String.valueOf(o));
		return this;
	}
	Arguments addPath(Predicate<Path> predicate, String... roots) throws Exception {
		List<String> paths = new ArrayList<>();
		for (String root : roots) {
			Files.walk(Paths.get(root)).filter(predicate).map(Object::toString).forEach(paths::add);
		}
		add(String.join(File.pathSeparator, paths));
		return this;
	}
	Arguments addPath(String... paths) {
		add(String.join(File.pathSeparator, paths));
		return this;
	}
	Arguments addAllFiles(String root, String extension) throws Exception {
	   return addAllFiles(root, path -> path.getFileName().toString().endsWith(extension));
	}
	Arguments addAllFiles(String root, Predicate<Path> predicate) throws Exception {
		Files.walk(Paths.get(root)).filter(predicate).forEach(this::add);
		return this;
	}
	String[] toArray() {
		return list.toArray(new String[0]);
	}
}

int run(String tool, String... args) {
	printCommandDetails("run", tool, args);
	return ToolProvider.findFirst(tool).get().run(System.out, System.err, args);
}

int exe(String executable, String... args) throws Exception {
	printCommandDetails("exe", executable, args);
	ProcessBuilder processBuilder = new ProcessBuilder(executable);
	Arrays.stream(args).forEach(processBuilder.command()::add);
	processBuilder.redirectErrorStream(true);
	Process process = processBuilder.start();
	process.getInputStream().transferTo(System.out);
	return process.waitFor();
}

void printCommandDetails(String context, String command, String... args) {
	if (args.length < 2) {
		System.out.printf("[%s] %s%s%n", context, command, (args.length == 1 ? " " + args[0] : ""));
		System.out.println();
		return;
	}
	System.out.printf("[%s] %s with %d arguments%n", context, command, args.length);
	boolean simple = true;
	int indent = 8;
	for (String arg : args) {
		indent = simple ? 8 : arg.startsWith("-") ? 8 : 10;
		simple = !arg.startsWith("-");
		if (arg.length() > 100) {
			if (arg.contains(File.pathSeparator)) {
				for (String path : arg.split(File.pathSeparator)) {
					System.out.printf("%-10s%s%n", "", path);
				}
				continue;
			}
			arg = arg.substring(0, 96) + "[...]";
		}
		System.out.printf("%-" + indent + "s%s%n", "", arg);
	}
	System.out.println();
}

void del(String directory) throws Exception {
	System.out.printf("[del] %s%n", directory);
	Path root = Paths.get(directory);
	if (Files.notExists(root)) {
		return;
	}
	try (Stream<Path> stream = Files.walk(root)) {
		Stream<Path> selected = stream.sorted((p, q) -> -p.compareTo(q));
		for (Path path : selected.collect(Collectors.toList())) {
			Files.deleteIfExists(path);
		}
	}
}

Path get(String directory, URI uri) throws Exception {
    String uriPath = uri.getPath();
    int begin = uriPath.lastIndexOf('/') + 1;
    String file = uriPath.substring(begin).split("\\?")[0].split("#")[0];
    Path folder = Paths.get(directory);
    Path target = folder.resolve(file);
    if (Files.exists(target)) {
        return target;
    }
    System.out.printf("[get] %s%n", target);
    Files.createDirectories(folder);
    try (InputStream sourceStream = uri.toURL().openStream(); OutputStream targetStream = Files.newOutputStream(target)) {
        sourceStream.transferTo(targetStream);
    }
    return target;
}

Path get(String directory, String group, String artifact, String version) throws Exception {
	String repo = "http://central.maven.org/maven2";
	String file = artifact + "-" + version + ".jar";
	URI uri = URI.create(String.join("/", repo, group.replace('.', '/'), artifact, version, file));
	return get(directory, uri);
}