package a2;

public class DLinkedListImpl<E> implements DLinkedList<E> {

	private static class Node<E> {
		E value;
		Node prev;
		Node next;
		
		Node(E eValue, Node nPrev, Node nNext) {
			value = eValue;
			prev = nPrev;
			next = nNext;
		}
		
		Node() {}
		
		@Override
		public boolean equals(Object o) {
			if (o instanceof Node) {
				return value.equals(((Node)o).value);
			}
			return false;
		}
		
		@Override
		public String toString() {
			if (value != null) return value.toString();
			return super.toString();
		}
	}
	
	Node<E> head;
	Node<E> tail;
	int size = 0;
	
	public DLinkedListImpl() {
		tail = new Node<E>();
		head = tail;
	}
	
	private boolean addNew(E e) {
		Node<E> temp = tail;
		tail = new Node<E>(e, temp, null);
		temp.next = tail;
		size++;
		return true;
	}

	public boolean add(E e) {
		if (!contains(e))
			return addNew(e);
		else {
			return addR(head, e);
		}
	}
	
	private boolean addR(Node<E> n, E e) {
		if (e.equals(n.value) && (n.prev != null)) {
			Node<E> temp = n.prev;
			n.prev = new Node<E>(n.value, n.prev, n.next);
			n = new Node<E>(temp.value, temp.prev, temp.next);
			//swapNodes(n.prev, n);
			return true;
		}
		if (n.next == null) return false;
		return (containsR(n.next, e));
	}
	
	private void swapNodes(Node<E> n1, Node<E> n2) {
		//NOCH 100% FALSCH
		Node<E> temp = n1;
		n1 = new Node<E>(n2.value, n2.prev, n2.next);
		n2 = new Node<E>(temp.value, temp.prev, temp.next);
	}
	
	public boolean contains(E e) {
		return containsR(head, e);
	}
	
	private boolean containsR(Node<E> n, E e) {
		if (e.equals(n.value)) return true;
		if (n.next == null) return false;
		return (containsR(n.next, e));
	}
	
	public boolean remove(E e) {
		size--;
		return removeR(head, e);
	}

	private boolean removeR(Node<E> n, E e) {
		if (e.equals(n.value)) {
			n.prev.next = n.next;
			n.next.prev = n.prev;
			return true;
		}
		if (n.next == null) return false;
		return (removeR(n.next, e));
	}
	
	public int size() {
		return size;
	}
	
	public static void main(String[] args) {
		DLinkedListImpl<String> a = new DLinkedListImpl<String>();
		System.out.println(a.tail.value);
		System.out.println("head == tail? " + (a.head == a.tail));
		a.add("A");
		System.out.println("head == tail? " + (a.head == a.tail));
		a.add("B");
		a.add("C");
		a.add("C");
		a.add("C");
		a.add("C");
		System.out.println(a.tail.value);
		System.out.println(a.tail.prev.value);
		System.out.println(a.tail.prev.prev.value);
		System.out.println(a.tail.prev.prev.prev.value);
		System.out.println("---");
		System.out.println(a.head.value);
		System.out.println(a.head.next.value);
		System.out.println(a.head.next.next.value);
		System.out.println(a.head.next.next.next.value);
		System.out.println("---");
		System.out.println(a.contains("B"));
		System.out.println("Removing B...");
		a.remove("B");
		System.out.println(a.contains("B"));
		System.out.println(a.size());
		System.out.println("---");
		System.out.println(a.head.value);
		System.out.println(a.head.next.value);
		System.out.println(a.head.next.next.value);
	}
}