package composite;

/**
 * Composite Design Pattern — Runnable Demo
 *
 * Builds a file system tree with nested directories and files.
 * Demonstrates that getSize() and print() work uniformly on
 * leaves (File) and composites (Directory) without any instanceof checks.
 *
 * Run: javac composite/*.java && java composite.Main
 * Article: https://ankurm.com/composite-design-pattern-java/
 */
public class Main {

    public static void main(String[] args) {
        System.out.println("=== Composite Design Pattern Demo ===\n");

        // Build a file system tree
        Directory root = new Directory("project");

        Directory src = new Directory("src");
        Directory main = new Directory("main");
        main.add(new File("App.java",        4_200))
            .add(new File("Config.java",     1_800))
            .add(new File("Application.yml", 3_100));

        Directory test = new Directory("test");
        test.add(new File("AppTest.java", 2_600))
            .add(new File("ConfigTest.java", 1_200));

        src.add(main).add(test);

        Directory resources = new Directory("resources");
        resources.add(new File("application.yml",  1_500))
                 .add(new File("logback.xml",       900))
                 .add(new File("banner.txt",        200));

        root.add(src)
            .add(resources)
            .add(new File("pom.xml",     8_400))
            .add(new File("README.md",   2_100));

        // Print entire tree — recursion happens automatically
        System.out.println("File system tree:");
        root.print("");

        System.out.printf("%nTotal project size: %,d bytes%n", root.getSize());

        // Client treats File and Directory identically
        System.out.println("\n-- Treating File and Directory uniformly --");
        FileSystemItem[] items = { new File("standalone.txt", 500), src };
        for (FileSystemItem item : items) {
            System.out.printf("%s -> size: %,d bytes%n", item.getName(), item.getSize());
        }

        System.out.println("\n=== Demo complete ===");
    }
}