package composite;

import java.util.ArrayList;
import java.util.List;

/**
 * Composite — a directory that can hold both Files (leaves)
 * and other Directories (composites).
 *
 * getSize() is recursive: it asks each child for its size and sums them.
 * The caller doesn't care whether a child is a File or Directory —
 * both implement FileSystemItem and answer getSize().
 *
 * This is the power of Composite: uniform treatment of simple and complex.
 */
public class Directory implements FileSystemItem {

    private final String name;
    private final List<FileSystemItem> children = new ArrayList<>();

    public Directory(String name) {
        this.name = name;
    }

    public Directory add(FileSystemItem item) {
        children.add(item);
        return this;  // fluent API for easy nesting
    }

    public void remove(FileSystemItem item) {
        children.remove(item);
    }

    @Override
    public String getName() { return name; }

    @Override
    public long getSize() {
        // Recursion: each child knows its own size.
        // Files return their bytes; directories sum their children.
        return children.stream()
                       .mapToLong(FileSystemItem::getSize)
                       .sum();
    }

    @Override
    public void print(String indent) {
        System.out.printf("%s[DIR]  %s/ (%,d bytes total)%n", indent, name, getSize());
        for (FileSystemItem child : children) {
            child.print(indent + "    ");  // recurse with deeper indent
        }
    }
}