package composite;
import java.util.ArrayList;
import java.util.List;
/**
 * Composite — a directory that holds both Files (leaves) and other Directories.
 *
 * getSize() is recursive: asks each child for its size and sums them.
 * print() recurses with deeper indentation.
 *
 * The caller doesn't care whether a child is a File or Directory —
 * both answer getSize() and print() the same way.
 */
public class Directory implements FileSystemItem {
    private final String name;
    private final List<FileSystemItem> children = new ArrayList<>();
    public Directory(String name) { this.name = name; }
    // Fluent add() — allows chaining: dir.add(file1).add(file2).add(subDir)
    public Directory add(FileSystemItem item) {
        children.add(item);
        return this;
    }
    public void remove(FileSystemItem item) { children.remove(item); }
    @Override public String getName() { return name; }
    @Override
    public long getSize() {
        // Each child knows its own size: files return bytes, directories recurse.
        // This is the Composite's core: uniform delegation down the tree.
        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 + "    ");  // each level indents 4 more spaces
        }
    }
}