package org.warp.commonutils.functional;

import java.util.Iterator;
import java.util.function.Consumer;
import java.util.function.Function;
import org.jetbrains.annotations.Nullable;

public class MappedIterator<A, B> implements Iterator<B> {

	private final Iterator<A> iterator;
	private final Function<A,B> mappingFunction;

	private MappedIterator(Iterator<A> iterator, Function<A, B> mappingFunction) {
		this.iterator = iterator;
		this.mappingFunction = mappingFunction;
	}

	public static <T, U> Iterator<U> of(Iterator<T> originalIterator, Function<@Nullable T, @Nullable U> mappingFunction) {
		return new MappedIterator<>(originalIterator, mappingFunction);
	}

	@Override
	public boolean hasNext() {
		return iterator.hasNext();
	}

	@Override
	public B next() {
		return mappingFunction.apply(iterator.next());
	}

	@Override
	public void remove() {
		iterator.remove();
	}

	@Override
	public void forEachRemaining(Consumer<? super B> action) {
		iterator.forEachRemaining((item) -> {
			action.accept(mappingFunction.apply(item));
		});
	}
}