// CSE 143, Winter 2012
// An ArrayIntList object stores an ordered list of integers using
// an unfilled array.
//
// Today's version adds:
//* toString method so that clients can easily print lists,
//* indexOf and contains methods for searching lists,
//* second constructor that accepts a capacity parameter,
//* checks preconditions on several methods (add, get, set, remove) and
//throws exceptions if the indexes passed are out of range.

import java.util.Arrays;

public class ArrayIntList {
	public static final int DEFAULT_CAPACITY = 3;
	
	private int[] elementData;
	private int size;
	
	// initializes a new empty list with initial capacity of 10 integers.
	public ArrayIntList() {
		this(DEFAULT_CAPACITY);
	}
	
	// initializes a new empty list with the given initial capacity.
	// pre: capacity > 0
	public ArrayIntList(int capacity) {
		if (capacity <= 0) {
			throw new IllegalArgumentException("capacity must be positive: " + capacity);
		}
		elementData = new int[capacity];
		size = 0;
	}
	
	// adds the given value to the end of the list.
	// resize if necessary
	public void add(int value) {
		add(size, value);
	}
	
	// inserts the given value into the list at the given index.
	// resize if necessary
	// pre: 0 <= index <= size (can add at very end)
	public void add(int index, int value) {
		checkIndex(index, 0, size);
		if (size == elementData.length) {
			elementData = Arrays.copyOf(elementData, size * 2);
		}
		// shifting over elementData to make room for the new value
		for (int i = size; i > index; i--) {
			elementData[i] = elementData[i - 1];
		}
		elementData[index] = value;
		size++;
	}
	
	// removes the value from the given index, shifting following elements left
	// by 1 slot to cover the hole.
	// pre: 0 <= index < size
	public void remove(int index) {
		checkIndex(index, 0, size - 1);
		for (int i = index; i <= size - 2; i++) {
			elementData[i] = elementData[i + 1];
		}
		elementData[size - 1] = 0;
		size--;
	}
	
	// returns the value in the list at the given index.
	// pre: 0 <= index < size
	public int get(int index) {
		checkIndex(index, 0, size - 1);
		return elementData[index];
	}
	
	// sets the given index to store the given value.
	// pre: 0 <= index < size
	public void set(int index, int value) {
		checkIndex(index, 0, size - 1);
		elementData[index] = value;
	}
	
	// returns the number of elements in the list.
	public int size() {
		return size;
	}
	
	// returns true if the list does not contain any elements.
	public boolean isEmpty() {
		return size == 0;
	}
	
	// returns the first index an element is found, or -1 if not
	public int indexOf(int value) {
		for (int i = 0; i < size ; i++) {
			if (get(i) == value) {
				return i;
			}
		}
		return -1;
	}
	
	// returns true if the list contains the given int value
	public boolean contains(int value) {
		return (indexOf(value) != -1);
	}
	
	// returns a comma-separated, bracketed representation of the list
	public String toString() {
		String result = "[";
		if (!isEmpty()) {
			result += elementData[0];
			for (int i = 1; i < size; i++) {
				result += ", " + elementData[i];
			}
		}
		result += "]";
		return result;
	}
	
	// if index is not within bounds, throw exception
	private void checkIndex(int index, int min, int max) {
		if (index < min || index > max) {
			throw new ArrayIndexOutOfBoundsException("Invalid index " + index);
		}
	}
}