package socialnetwork.domain;

import java.util.concurrent.locks.ReentrantLock;

public class IDList<E> {
    ReentrantLock lock = new ReentrantLock();
    private objectTuple<E> head;
    private int length;

    public IDList() {
        this.head = null;
        this.length = 0;
    }

    public objectTuple<E> getHead() {
        return head;
    }

    public void append(final E object) {
        if (head == null) {
            head = new objectTuple<>(object);
            head.setNext(null);
        } else {
            objectTuple<E> cursor = head;
            while (cursor.getNext() != null) {
                cursor = cursor.next;
            }
            objectTuple<E> appendice = new objectTuple<>(object);
            cursor.setNext(appendice);
            appendice.setNext(null);
        }

    }

    public void add(final E object) {

        if (head == null) {
            head = new objectTuple<>(object);
            head.setNext(null);
        } else {
            objectTuple<E> previous = head;
            head = new objectTuple<>(object);
            head.setNext(previous);
        }

    }

    public void remove(E object) {
        assert contains(object) : "can't remove inexistant object";
        if (head.getObject() == object) {
            head = head.getNext();
        } else {
            objectTuple<E> cursor = head;
            while (object.hashCode() != cursor.getNext().getObject().hashCode()) {
                cursor = cursor.getNext();
            }
            cursor.setNext(cursor.getNext().getNext());
        }
    }

    public boolean contains(E obj) {
        if (head == null) {
            return false;
        } else {
            objectTuple<E> cursor = head;
            for (int i = 0; i < this.ListSize(); i++) {
                if (cursor.getObject() == obj) {
                    return true;
                }
                cursor = cursor.getNext();
            }
            return false;
        }

    }


    public E get(int position) {
        if (position == 0) {
            return head.getObject();
        } else {
            objectTuple<E> cursor = head;
            int k = 0;
            while (position > k) {
                cursor = cursor.getNext();
                k++;
            }
            return cursor.getObject();
        }

    }


    public E getLast() {
        objectTuple<E> cursor = head;
        int k = 0;
        while (this.ListSize()-1 > k) {
            cursor = cursor.getNext();
            k++;
        }
        return cursor.getObject();
    }

    public int ListSize() {

        int size = 0;
        objectTuple<E> cursor = head;
        while (cursor != null) {
            cursor = cursor.next;
            size++;
        }
        this.length = size;

        return size;
    }

    private class objectTuple<E> {
        private E object;
        private objectTuple<E> next;

        objectTuple(E newobject) {
            this.object = newobject;
        }

        objectTuple() {
            this.object = null;
        }

        E getObject() {
            return this.object;
        }

        objectTuple<E> getNext() {
            return this.next;
        }

        void setNext(objectTuple<E> newmsg) {

            this.next = newmsg;

        }
    }

}