/* Copyright (c) 2008-2023, Nathan Sweet
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
 * conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided with the distribution.
 * - Neither the name of Esoteric Software nor the names of its contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */

package com.esotericsoftware.kryo.util;

import java.util.Arrays;

/** A resizable, ordered or unordered int array. Avoids the boxing that occurs with ArrayList<Integer>. If unordered, this class
 * avoids a memory copy when removing elements (the last element is moved to the removed element's position).
 * @author Nathan Sweet */
public class IntArray {
	public int[] items;
	public int size;
	public boolean ordered;

	/** Creates an ordered array with a capacity of 16. */
	public IntArray () {
		this(true, 16);
	}

	/** Creates an ordered array with the specified capacity. */
	public IntArray (int capacity) {
		this(true, capacity);
	}

	/** @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
	 *           memory copy.
	 * @param capacity Any elements added beyond this will cause the backing array to be grown. */
	public IntArray (boolean ordered, int capacity) {
		this.ordered = ordered;
		items = new int[capacity];
	}

	/** Creates a new array containing the elements in the specific array. The new array will be ordered if the specific array is
	 * ordered. The capacity is set to the number of elements, so any subsequent elements added will cause the backing array to be
	 * grown. */
	public IntArray (IntArray array) {
		this.ordered = array.ordered;
		size = array.size;
		items = new int[size];
		System.arraycopy(array.items, 0, items, 0, size);
	}

	/** Creates a new ordered array containing the elements in the specified array. The capacity is set to the number of elements,
	 * so any subsequent elements added will cause the backing array to be grown. */
	public IntArray (int[] array) {
		this(true, array, 0, array.length);
	}

	/** Creates a new array containing the elements in the specified array. The capacity is set to the number of elements, so any
	 * subsequent elements added will cause the backing array to be grown.
	 * @param ordered If false, methods that remove elements may change the order of other elements in the array, which avoids a
	 *           memory copy. */
	public IntArray (boolean ordered, int[] array, int startIndex, int count) {
		this(ordered, count);
		size = count;
		System.arraycopy(array, startIndex, items, 0, count);
	}

	public void add (int value) {
		int[] items = this.items;
		if (size == items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
		items[size++] = value;
	}

	public void add (int value1, int value2) {
		int[] items = this.items;
		if (size + 1 >= items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
		items[size] = value1;
		items[size + 1] = value2;
		size += 2;
	}

	public void add (int value1, int value2, int value3) {
		int[] items = this.items;
		if (size + 2 >= items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
		items[size] = value1;
		items[size + 1] = value2;
		items[size + 2] = value3;
		size += 3;
	}

	public void add (int value1, int value2, int value3, int value4) {
		int[] items = this.items;
		if (size + 3 >= items.length) items = resize(Math.max(8, (int)(size * 1.8f))); // 1.75 isn't enough when size=5.
		items[size] = value1;
		items[size + 1] = value2;
		items[size + 2] = value3;
		items[size + 3] = value4;
		size += 4;
	}

	public void addAll (IntArray array) {
		addAll(array, 0, array.size);
	}

	public void addAll (IntArray array, int offset, int length) {
		if (offset + length > array.size)
			throw new IllegalArgumentException("offset + length must be <= size: " + offset + " + " + length + " <= " + array.size);
		addAll(array.items, offset, length);
	}

	public void addAll (int... array) {
		addAll(array, 0, array.length);
	}

	public void addAll (int[] array, int offset, int length) {
		int[] items = this.items;
		int sizeNeeded = size + length;
		if (sizeNeeded > items.length) items = resize(Math.max(8, (int)(sizeNeeded * 1.75f)));
		System.arraycopy(array, offset, items, size, length);
		size += length;
	}

	public int get (int index) {
		if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
		return items[index];
	}

	public void set (int index, int value) {
		if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
		items[index] = value;
	}

	public void incr (int index, int value) {
		if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
		items[index] += value;
	}

	public void mul (int index, int value) {
		if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
		items[index] *= value;
	}

	public void insert (int index, int value) {
		if (index > size) throw new IndexOutOfBoundsException("index can't be > size: " + index + " > " + size);
		int[] items = this.items;
		if (size == items.length) items = resize(Math.max(8, (int)(size * 1.75f)));
		if (ordered)
			System.arraycopy(items, index, items, index + 1, size - index);
		else
			items[size] = items[index];
		size++;
		items[index] = value;
	}

	public void swap (int first, int second) {
		if (first >= size) throw new IndexOutOfBoundsException("first can't be >= size: " + first + " >= " + size);
		if (second >= size) throw new IndexOutOfBoundsException("second can't be >= size: " + second + " >= " + size);
		int[] items = this.items;
		int firstValue = items[first];
		items[first] = items[second];
		items[second] = firstValue;
	}

	public boolean contains (int value) {
		int i = size - 1;
		int[] items = this.items;
		while (i >= 0)
			if (items[i--] == value) return true;
		return false;
	}

	public int indexOf (int value) {
		int[] items = this.items;
		for (int i = 0, n = size; i < n; i++)
			if (items[i] == value) return i;
		return -1;
	}

	public int lastIndexOf (int value) {
		int[] items = this.items;
		for (int i = size - 1; i >= 0; i--)
			if (items[i] == value) return i;
		return -1;
	}

	public boolean removeValue (int value) {
		int[] items = this.items;
		for (int i = 0, n = size; i < n; i++) {
			if (items[i] == value) {
				removeIndex(i);
				return true;
			}
		}
		return false;
	}

	/** Removes and returns the item at the specified index. */
	public int removeIndex (int index) {
		if (index >= size) throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
		int[] items = this.items;
		int value = items[index];
		size--;
		if (ordered)
			System.arraycopy(items, index + 1, items, index, size - index);
		else
			items[index] = items[size];
		return value;
	}

	/** Removes the items between the specified indices, inclusive. */
	public void removeRange (int start, int end) {
		int n = size;
		if (end >= n) throw new IndexOutOfBoundsException("end can't be >= size: " + end + " >= " + size);
		if (start > end) throw new IndexOutOfBoundsException("start can't be > end: " + start + " > " + end);
		int count = end - start + 1, lastIndex = n - count;
		if (ordered)
			System.arraycopy(items, start + count, items, start, n - (start + count));
		else {
			int i = Math.max(lastIndex, end + 1);
			System.arraycopy(items, i, items, start, n - i);
		}
		size = n - count;
	}

	/** Removes from this array all of elements contained in the specified array.
	 * @return true if this array was modified. */
	public boolean removeAll (IntArray array) {
		int size = this.size;
		int startSize = size;
		int[] items = this.items;
		for (int i = 0, n = array.size; i < n; i++) {
			int item = array.get(i);
			for (int ii = 0; ii < size; ii++) {
				if (item == items[ii]) {
					removeIndex(ii);
					size--;
					break;
				}
			}
		}
		return size != startSize;
	}

	/** Removes and returns the last item. */
	public int pop () {
		return items[--size];
	}

	/** Returns the last item. */
	public int peek () {
		return items[size - 1];
	}

	/** Returns the first item. */
	public int first () {
		if (size == 0) throw new IllegalStateException("Array is empty.");
		return items[0];
	}

	public void clear () {
		size = 0;
	}

	/** Reduces the size of the backing array to the size of the actual items. This is useful to release memory when many items
	 * have been removed, or if it is known that more items will not be added.
	 * @return {@link #items} */
	public int[] shrink () {
		if (items.length != size) resize(size);
		return items;
	}

	/** Increases the size of the backing array to accommodate the specified number of additional items. Useful before adding many
	 * items to avoid multiple backing array resizes.
	 * @return {@link #items} */
	public int[] ensureCapacity (int additionalCapacity) {
		if (additionalCapacity < 0) throw new IllegalArgumentException("additionalCapacity must be >= 0: " + additionalCapacity);
		int sizeNeeded = size + additionalCapacity;
		if (sizeNeeded > items.length) resize(Math.max(8, sizeNeeded));
		return items;
	}

	/** Sets the array size, leaving any values beyond the current size undefined.
	 * @return {@link #items} */
	public int[] setSize (int newSize) {
		if (newSize < 0) throw new IllegalArgumentException("newSize must be >= 0: " + newSize);
		if (newSize > items.length) resize(Math.max(8, newSize));
		size = newSize;
		return items;
	}

	protected int[] resize (int newSize) {
		int[] newItems = new int[newSize];
		int[] items = this.items;
		System.arraycopy(items, 0, newItems, 0, Math.min(size, newItems.length));
		this.items = newItems;
		return newItems;
	}

	public void sort () {
		Arrays.sort(items, 0, size);
	}

	public void reverse () {
		int[] items = this.items;
		for (int i = 0, lastIndex = size - 1, n = size / 2; i < n; i++) {
			int ii = lastIndex - i;
			int temp = items[i];
			items[i] = items[ii];
			items[ii] = temp;
		}
	}

	/** Reduces the size of the array to the specified size. If the array is already smaller than the specified size, no action is
	 * taken. */
	public void truncate (int newSize) {
		if (size > newSize) size = newSize;
	}

	public int[] toArray () {
		int[] array = new int[size];
		System.arraycopy(items, 0, array, 0, size);
		return array;
	}

	public int hashCode () {
		if (!ordered) return super.hashCode();
		int[] items = this.items;
		int h = 1;
		for (int i = 0, n = size; i < n; i++)
			h = h * 31 + items[i];
		return h;
	}

	public boolean equals (Object object) {
		if (object == this) return true;
		if (!ordered) return false;
		if (!(object instanceof IntArray)) return false;
		IntArray array = (IntArray)object;
		if (!array.ordered) return false;
		int n = size;
		if (n != array.size) return false;
		int[] items1 = this.items;
		int[] items2 = array.items;
		for (int i = 0; i < n; i++)
			if (items1[i] != items2[i]) return false;
		return true;
	}

	public String toString () {
		if (size == 0) return "[]";
		int[] items = this.items;
		StringBuilder buffer = new StringBuilder(32);
		buffer.append('[');
		buffer.append(items[0]);
		for (int i = 1; i < size; i++) {
			buffer.append(", ");
			buffer.append(items[i]);
		}
		buffer.append(']');
		return buffer.toString();
	}

	public String toString (String separator) {
		if (size == 0) return "";
		int[] items = this.items;
		StringBuilder buffer = new StringBuilder(32);
		buffer.append(items[0]);
		for (int i = 1; i < size; i++) {
			buffer.append(separator);
			buffer.append(items[i]);
		}
		return buffer.toString();
	}

	/** @see #IntArray(int[]) */
	public static IntArray with (int... array) {
		return new IntArray(array);
	}
}
