package org.andork.util;

import java.util.IdentityHashMap;
import java.util.function.Function;

/**
 * A general-purpose replacement to the cruftastic {@link Cloneable} design.
 *
 * @author James
 */
public interface PowerCloneable {
	/**
	 * Various hierarchical cloning functions.
	 *
	 * @author James
	 */
	public static class Cloners {
		/**
		 * Clones an array of Objects.
		 *
		 * @param toClone
		 *            the array to clone.
		 * @param subcloner
		 *            the subcloner used to clone each element of the array.
		 * @return a new array of the same length as {@code toClone} where each
		 *         element was the result of applying {@code subcloner} to the
		 *         corresponding element in {@code toClone}.
		 */
		public static Object[] cloneArray(Object[] toClone, Function<Object, Object> subcloner) {
			Object[] result = new Object[toClone.length];
			for (int i = 0; i < toClone.length; i++) {
				result[i] = subcloner.apply(toClone[i]);
			}
			return result;
		}

		/**
		 * The default subcloner implementation.
		 *
		 * @param toClone
		 *            the object to clone.
		 * @return if {@code toClone} is a {@link PowerCloneable}, returns
		 *         {@code toClone.clone( Cloners::defaultClone )}. Otherwise,
		 *         returns {@code toClone}.
		 */
		public static Object defaultClone(Object toClone) {
			if (toClone instanceof PowerCloneable) {
				return ((PowerCloneable) toClone).clone(Cloners::defaultClone);
			}
			return toClone;
		}
	}

	/**
	 * Clones this object. The returned object should not be {@code ==} to this
	 * object, but should {@code #equals(this)} .
	 *
	 * @param subcloner
	 *            a function that clones fields or other "elements" of this
	 *            object. Being able to choose the function allows you to
	 *            perform different styles of cloning, like deep or shallow
	 *            copying, or even a graph structure-preserving clone using an
	 *            {@link IdentityHashMap}.
	 * @return A clone of this object.
	 */
	public PowerCloneable clone(Function<Object, Object> subcloner);
}