import java.util.Arrays;


public class IntegerLinkedList implements IntegerList {

	private int elements;
	private Node head;
	
	/* Create list with no elements
	 */
	public IntegerLinkedList(){
		elements = 0;
		this.head = null;
	}
	
	/*	Create list with all elements of initList in the order 0...n-1
	 */
	public IntegerLinkedList( int[] initList ){
		this();
		for( int i : initList ){
			this.add( i );
		}
	}
	
	/*	Create list with all the elements of otherList in the order 0...n-1
	 */
	public IntegerLinkedList( IntegerList otherList ){
		this();
		for( int i = 0; i < otherList.size(); ++i ){
			this.add( otherList.get( i ));
		}
	}
	
	/********* Private Methods *********/
	/*	Returns node object at an index.
	 * 	Throws IndexOutOfBoundsException if index is not w/i bounds [0...size)
	 */
	private Node getNode( int index ){
		if( index < 0 ) throw new IndexOutOfBoundsException("index < 0 access: [" +index +"]");
		else if( index >= this.size() ) throw new IndexOutOfBoundsException("index >= size() access [" +index +"]");
		
		Node iter = this.head;
		for( int i = 0; i < index; ++i ){
			iter = iter.getRight();
		}
		return iter; 
	}
	
	/********* Public Methods *********/
	
	/** Accessors/Getters **/
	/*	Returns integer at the index
	 *	Throws IndexOutOfBoundsException if index is not w/i bounds [0...size)
	 */
	public int get(int index) {
		return getNode( index ).getNumber();
	}
	
	/*	Returns the number of elements in the list
	 */
	public int size() {
		return this.elements;
	}

	/*	Returns a copy of all the elements in the array; size = size()
	 */
	public int capacity() {
		return Integer.MAX_VALUE;
	}

	/*	Returns true if there are 0 elements in the list
	 */
	public boolean isEmpty(){
		return this.size() == 0;
	}
	
	/*	Returns a copy of all the elements in the array; size = size()
	 */
	public int[] toArray() {
		int[] copyArray = new int[ this.size() ];
		for( int i = 0; i < this.size(); ++i ){
			copyArray[i] = this.get( i );
		}
		
		return copyArray;
	}

	/*	Returns a String representation of the elements in the array;
	 * (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	public String toString(){
		return Arrays.toString( this.toArray() );
	}
	
	/** Modifiers/Setters **/
	
	/*	Insert integer into array at index
	 * 	If index is within existing array, [0-size), performs left shift then insert
	 * 	If index is == size, inserts only
	 * 	if index is > size throws
	 */
	public void insert(int index, int integer) {
		if( index < 0 ) throw new IndexOutOfBoundsException("index < 0 access: [" +index +"]");
		else if( index > this.size() ) throw new IndexOutOfBoundsException("index > size() access [" +index +"]");
		
		
		if( this.size() == 0 ){ // empty list operation
			if( index != 0) throw new IndexOutOfBoundsException("Attempting to assign to index [" + index +"] in empty list");
			
			this.head = new Node( integer, null, null );

		} else { // nonempty list operation
			if( index == 0 ){
				this.head = this.head.insertLeft( integer );
			} else {
				Node modNode = this.getNode(index-1);
				modNode.insertRight( integer );
			
			}
			
		}
		
		this.elements += 1;
	}

	/*	Appends integer onto the list
	 *	Returns the index integer was inserted to
	 */
	public int add(int integer) {
		this.insert( this.size(), integer );
		return this.size()-1;
	}

	/*	Appends list of integers onto the list
	 *	Returns the last index inserted into
	 */
	public int add(int[] listOfInteger) {
		for( int i : listOfInteger ){
			this.add( i );
		}
		return this.size()-1;
	}

	/*	Removes element at index from the array
	 *	Returns the element removed
	 *	Throws IndexOutOfBoundsException if index is not w/i bounds [0...size)
	 */
	public int remove(int index) {
		Node removeNode = this.getNode( index );
		this.elements -= 1;
		if( removeNode == this.head ) this.head = removeNode.getRight();
		return removeNode.remove();
	}

	/*	Sets value of element at index
	 * 	Returns the previous value of the element at index
	 * 	Throws IndexOutOfBoundsException if index is not w/i bounds [0...size)
	 */
	public int set(int index, int integer ) {
		Node modifyNode = this.getNode( index );
		int previous = modifyNode.getNumber();
		modifyNode.setNumber( integer );
		return previous;
	}
	
	
	
	


}