package com.carrotsearch.hppc;

import static com.carrotsearch.hppc.Containers.DEFAULT_EXPECTED_ELEMENTS;

import java.util.Arrays;
import java.util.Iterator;

import com.carrotsearch.hppc.cursors.ObjectCursor;
import com.carrotsearch.hppc.predicates.ObjectPredicate;
import com.carrotsearch.hppc.procedures.ObjectProcedure;

/** An array-backed {@link ObjectDeque}. */
@SuppressWarnings("unchecked")
@com.carrotsearch.hppc.Generated(date = "2024-06-04T15:20:17+0200", value = "KTypeArrayDeque.java")
public class ObjectArrayDeque<KType> extends AbstractObjectCollection<KType>
		implements ObjectDeque<KType>, Preallocable, Cloneable, Accountable {

	/**
	 * An iterator implementation for {@link ObjectArrayDeque#descendingIterator()}.
	 */
	private final class DescendingValueIterator extends AbstractIterator<ObjectCursor<KType>> {
		private final ObjectCursor<KType> cursor;
		private int remaining;

		public DescendingValueIterator() {
			cursor = new ObjectCursor<KType>();
			cursor.index = tail;
			this.remaining = size();
		}

		@Override
		protected ObjectCursor<KType> fetch() {
			if (remaining == 0)
				return done();

			remaining--;
			cursor.value = (KType) buffer[cursor.index = oneLeft(cursor.index, buffer.length)];
			return cursor;
		}
	}

	/** An iterator implementation for {@link ObjectArrayDeque#iterator}. */
	private final class ValueIterator extends AbstractIterator<ObjectCursor<KType>> {
		private final ObjectCursor<KType> cursor;
		private int remaining;

		public ValueIterator() {
			cursor = new ObjectCursor<KType>();
			cursor.index = oneLeft(head, buffer.length);
			this.remaining = size();
		}

		@Override
		protected ObjectCursor<KType> fetch() {
			if (remaining == 0) {
				return done();
			}

			remaining--;
			cursor.value = (KType) buffer[cursor.index = oneRight(cursor.index, buffer.length)];
			return cursor;
		}
	}

	/** Reuse the same strategy instance. */
	private static final BoundedProportionalArraySizingStrategy DEFAULT_SIZING_STRATEGY = BoundedProportionalArraySizingStrategy.DEFAULT_INSTANCE;

	/**
	 * Create a new deque by pushing a variable number of arguments to the end of
	 * it.
	 */
	@SafeVarargs
	public static <KType> ObjectArrayDeque<KType> from(KType... elements) {
		final ObjectArrayDeque<KType> coll = new ObjectArrayDeque<KType>(elements.length);
		coll.addLast(elements);
		return coll;
	}

	/** Move one index to the left, wrapping around buffer. */
	protected static int oneLeft(int index, int modulus) {
		if (index >= 1) {
			return index - 1;
		}
		return modulus - 1;
	}

	/** Move one index to the right, wrapping around buffer. */
	protected static int oneRight(int index, int modulus) {
		if (index + 1 == modulus) {
			return 0;
		}
		return index + 1;
	}

	/** Internal array for storing elements of the deque. */
	public Object[] buffer = ObjectArrayList.EMPTY_ARRAY;

	/**
	 * The index of the element at the head of the deque or an arbitrary number
	 * equal to tail if the deque is empty.
	 */
	public int head;

	/**
	 * The index at which the next element would be added to the tail of the deque.
	 */
	public int tail;

	/** Buffer resizing strategy. */
	protected final ArraySizingStrategy resizer;

	/** New instance with sane defaults. */
	public ObjectArrayDeque() {
		this(DEFAULT_EXPECTED_ELEMENTS);
	}

	/**
	 * New instance with sane defaults.
	 *
	 * @param expectedElements The expected number of elements guaranteed not to
	 *                         cause buffer expansion (inclusive).
	 */
	public ObjectArrayDeque(int expectedElements) {
		this(expectedElements, DEFAULT_SIZING_STRATEGY);
	}

	/**
	 * New instance with sane defaults.
	 *
	 * @param expectedElements The expected number of elements guaranteed not to
	 *                         cause buffer expansion (inclusive).
	 * @param resizer          Underlying buffer sizing strategy.
	 */
	public ObjectArrayDeque(int expectedElements, ArraySizingStrategy resizer) {
		assert resizer != null;
		this.resizer = resizer;
		ensureCapacity(expectedElements);
	}

	/**
	 * Creates a new deque from elements of another container, appending elements at
	 * the end of the deque in the iteration order.
	 */
	public ObjectArrayDeque(ObjectContainer<? extends KType> container) {
		this(container.size());
		addLast(container);
	}

	/**
	 * Inserts all elements from the given iterable to the front of this deque.
	 *
	 * @param iterable The iterable to iterate over.
	 * @return Returns the number of elements actually added as a result of this
	 *         call.
	 */
	public int addFirst(Iterable<? extends ObjectCursor<? extends KType>> iterable) {
		int size = 0;
		for (ObjectCursor<? extends KType> cursor : iterable) {
			addFirst(cursor.value);
			size++;
		}
		return size;
	}

	/** {@inheritDoc} */
	@Override
	public void addFirst(KType e1) {
		int h = oneLeft(head, buffer.length);
		if (h == tail) {
			ensureBufferSpace(1);
			h = oneLeft(head, buffer.length);
		}
		buffer[head = h] = e1;
	}

	/**
	 * Vararg-signature method for adding elements at the front of this deque.
	 *
	 * <p>
	 * <b>This method is handy, but costly if used in tight loops (anonymous array
	 * passing)</b>
	 *
	 * @param elements The elements to add.
	 */
	@SafeVarargs
	public final void addFirst(KType... elements) {
		ensureBufferSpace(elements.length);
		for (KType k : elements) {
			addFirst(k);
		}
	}

	/**
	 * Inserts all elements from the given container to the front of this deque.
	 *
	 * @param container The container to iterate over.
	 * @return Returns the number of elements actually added as a result of this
	 *         call.
	 */
	public int addFirst(ObjectContainer<? extends KType> container) {
		int size = container.size();
		ensureBufferSpace(size);

		for (ObjectCursor<? extends KType> cursor : container) {
			addFirst(cursor.value);
		}

		return size;
	}

	/**
	 * Inserts all elements from the given iterable to the end of this deque.
	 *
	 * @param iterable The iterable to iterate over.
	 * @return Returns the number of elements actually added as a result of this
	 *         call.
	 */
	public int addLast(Iterable<? extends ObjectCursor<? extends KType>> iterable) {
		int size = 0;
		for (ObjectCursor<? extends KType> cursor : iterable) {
			addLast(cursor.value);
			size++;
		}
		return size;
	}

	/** {@inheritDoc} */
	@Override
	public void addLast(KType e1) {
		int t = oneRight(tail, buffer.length);
		if (head == t) {
			ensureBufferSpace(1);
			t = oneRight(tail, buffer.length);
		}
		buffer[tail] = e1;
		tail = t;
	}

	/**
	 * Vararg-signature method for adding elements at the end of this deque.
	 *
	 * <p>
	 * <b>This method is handy, but costly if used in tight loops (anonymous array
	 * passing)</b>
	 *
	 * @param elements The elements to iterate over.
	 */
	@SafeVarargs
	public final void addLast(KType... elements) {
		ensureBufferSpace(1);
		for (KType k : elements) {
			addLast(k);
		}
	}

	/**
	 * Inserts all elements from the given container to the end of this deque.
	 *
	 * @param container The container to iterate over.
	 * @return Returns the number of elements actually added as a result of this
	 *         call.
	 */
	public int addLast(ObjectContainer<? extends KType> container) {
		int size = container.size();
		ensureBufferSpace(size);

		for (ObjectCursor<? extends KType> cursor : container) {
			addLast(cursor.value);
		}

		return size;
	}

	/**
	 * Return the index of the first (counting from head) element equal to
	 * <code>e1</code>. The index points to the {@link #buffer} array.
	 *
	 * @param e1 The element to look for.
	 * @return Returns the index of the first element equal to <code>e1</code> or
	 *         <code>-1</code> if not found.
	 */
	public int bufferIndexOf(KType e1) {
		final int last = tail;
		final int bufLen = buffer.length;
		for (int i = head; i != last; i = oneRight(i, bufLen)) {
			if (this.equals(e1, buffer[i])) {
				return i;
			}
		}

		return -1;
	}

	/**
	 * {@inheritDoc}
	 *
	 * <p>
	 * The internal array buffers are not released as a result of this call.
	 *
	 * @see #release()
	 */
	@Override
	public void clear() {
		if (head < tail) {
			Arrays.fill(buffer, head, tail, null);
		} else {
			Arrays.fill(buffer, 0, tail, null);
			Arrays.fill(buffer, head, buffer.length, null);
		}
		this.head = tail = 0;
	}

	/**
	 * Clone this object. The returned clone will reuse the same hash function and
	 * array resizing strategy.
	 */
	@Override
	public ObjectArrayDeque<KType> clone() {
		try {

			ObjectArrayDeque<KType> cloned = (ObjectArrayDeque<KType>) super.clone();
			cloned.buffer = buffer.clone();
			return cloned;
		} catch (CloneNotSupportedException e) {
			throw new RuntimeException(e);
		}
	}

	/** {@inheritDoc} */
	@Override
	public boolean contains(KType e) {
		int fromIndex = head;
		int toIndex = tail;

		final KType[] buffer = (KType[]) this.buffer;
		for (int i = fromIndex; i != toIndex; i = oneRight(i, buffer.length)) {
			if (this.equals(e, buffer[i])) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Applies <code>predicate</code> to a slice of the deque, <code>toIndex</code>,
	 * exclusive, down to <code>fromIndex</code>, inclusive or until the predicate
	 * returns <code>false</code>.
	 */
	private void descendingForEach(ObjectPredicate<? super KType> predicate, int fromIndex, final int toIndex) {
		if (fromIndex == toIndex)
			return;

		final KType[] buffer = (KType[]) this.buffer;
		int i = toIndex;
		do {
			i = oneLeft(i, buffer.length);
			if (!predicate.apply(buffer[i])) {
				break;
			}
		} while (i != fromIndex);
	}

	/**
	 * Applies <code>procedure</code> to a slice of the deque, <code>toIndex</code>,
	 * exclusive, down to <code>fromIndex</code>, inclusive.
	 */
	private void descendingForEach(ObjectProcedure<? super KType> procedure, int fromIndex, final int toIndex) {
		if (fromIndex == toIndex)
			return;

		final KType[] buffer = (KType[]) this.buffer;
		int i = toIndex;
		do {
			i = oneLeft(i, buffer.length);
			procedure.apply(buffer[i]);
		} while (i != fromIndex);
	}

	/**
	 * Applies <code>procedure</code> to all elements of this deque, tail to head.
	 */
	@Override
	public <T extends ObjectProcedure<? super KType>> T descendingForEach(T procedure) {
		descendingForEach(procedure, head, tail);
		return procedure;
	}

	/** {@inheritDoc} */
	@Override
	public <T extends ObjectPredicate<? super KType>> T descendingForEach(T predicate) {
		descendingForEach(predicate, head, tail);
		return predicate;
	}

	/**
	 * Returns a cursor over the values of this deque (in tail to head order). The
	 * iterator is implemented as a cursor and it returns <b>the same cursor
	 * instance</b> on every call to {@link Iterator#next()} (to avoid boxing of
	 * primitive types). To read the current value (or index in the deque's buffer)
	 * use the cursor's public fields. An example is shown below.
	 *
	 * <pre>
	 * for (Iterator&lt;IntCursor&gt; i = intDeque.descendingIterator(); i.hasNext();) {
	 * 	final IntCursor c = i.next();
	 * 	System.out.println(&quot;buffer index=&quot; + c.index + &quot; value=&quot; + c.value);
	 * }
	 * </pre>
	 */
	@Override
	public Iterator<ObjectCursor<KType>> descendingIterator() {
		return new DescendingValueIterator();
	}

	/**
	 * Ensures the internal buffer has enough free slots to store
	 * <code>expectedAdditions</code>. Increases internal buffer size if needed.
	 */
	protected void ensureBufferSpace(int expectedAdditions) {
		final int bufferLen = buffer.length;
		final int elementsCount = size();

		if (elementsCount + expectedAdditions >= bufferLen) {
			final int emptySlot = 1; // deque invariant: always an empty slot.
			final int newSize = resizer.grow(bufferLen, elementsCount + emptySlot, expectedAdditions);
			assert newSize >= (elementsCount + expectedAdditions + emptySlot) : "Resizer failed to"
					+ " return sensible new size: " + newSize + " <= " + (elementsCount + expectedAdditions);

			try {
				final KType[] newBuffer = ((KType[]) new Object[newSize]);
				if (bufferLen > 0) {
					toArray(newBuffer);
					tail = elementsCount;
					head = 0;
				}
				this.buffer = newBuffer;
			} catch (OutOfMemoryError e) {
				throw new BufferAllocationException("Not enough memory to allocate new buffers: %,d -> %,d", e,
						bufferLen, newSize);
			}
		}
	}

	/**
	 * Ensure this container can hold at least the given number of elements without
	 * resizing its buffers.
	 *
	 * @param expectedElements The total number of elements, inclusive.
	 */
	@Override
	public void ensureCapacity(int expectedElements) {
		ensureBufferSpace(expectedElements - size());
	}

	/**
	 * Compare order-aligned elements against another {@link ObjectDeque}. Equality
	 * comparison is performed with this object's {@link #equals(Object, Object)}
	 * method.
	 */
	protected boolean equalElements(ObjectArrayDeque<?> other) {
		int max = size();
		if (other.size() != max) {
			return false;
		}

		Iterator<ObjectCursor<KType>> i1 = this.iterator();
		Iterator<? extends ObjectCursor<?>> i2 = other.iterator();

		while (i1.hasNext() && i2.hasNext()) {
			if (!this.equals(i1.next().value, i2.next().value)) {
				return false;
			}
		}

		return !i1.hasNext() && !i2.hasNext();
	}

	/**
	 * Returns <code>true</code> only if the other object is an instance of the same
	 * class and with the same elements. Equality comparison is performed with this
	 * object's {@link #equals(Object, Object)} method.
	 */
	@Override
	public boolean equals(Object obj) {
		return (this == obj) || (obj != null && getClass() == obj.getClass() && equalElements(getClass().cast(obj)));
	}

	/**
	 * Applies <code>procedure</code> to a slice of the deque,
	 * <code>fromIndex</code>, inclusive, to <code>toIndex</code>, exclusive.
	 */
	private void forEach(ObjectProcedure<? super KType> procedure, int fromIndex, final int toIndex) {
		final KType[] buffer = (KType[]) this.buffer;
		for (int i = fromIndex; i != toIndex; i = oneRight(i, buffer.length)) {
			procedure.apply(buffer[i]);
		}
	}

	/** {@inheritDoc} */
	@Override
	public <T extends ObjectProcedure<? super KType>> T forEach(T procedure) {
		forEach(procedure, head, tail);
		return procedure;
	}

	/** {@inheritDoc} */
	@Override
	public <T extends ObjectPredicate<? super KType>> T forEach(T predicate) {
		int fromIndex = head;
		int toIndex = tail;

		final KType[] buffer = (KType[]) this.buffer;
		for (int i = fromIndex; i != toIndex; i = oneRight(i, buffer.length)) {
			if (!predicate.apply(buffer[i])) {
				break;
			}
		}

		return predicate;
	}

	/** {@inheritDoc} */
	@Override
	public KType getFirst() {
		assert size() > 0 : "The deque is empty.";

		return (KType) buffer[head];
	}

	/** {@inheritDoc} */
	@Override
	public KType getLast() {
		assert size() > 0 : "The deque is empty.";

		return (KType) buffer[oneLeft(tail, buffer.length)];
	}

	/** {@inheritDoc} */
	@Override
	public int hashCode() {
		int h = 1;
		int fromIndex = head;
		int toIndex = tail;

		final KType[] buffer = (KType[]) this.buffer;
		for (int i = fromIndex; i != toIndex; i = oneRight(i, buffer.length)) {
			h = 31 * h + BitMixer.mix(this.buffer[i]);
		}
		return h;
	}

	/** {@inheritDoc} */
	@Override
	public boolean isEmpty() {
		return size() == 0;
	}

	/**
	 * Returns a cursor over the values of this deque (in head to tail order). The
	 * iterator is implemented as a cursor and it returns <b>the same cursor
	 * instance</b> on every call to {@link Iterator#next()} (to avoid boxing of
	 * primitive types). To read the current value (or index in the deque's buffer)
	 * use the cursor's public fields. An example is shown below.
	 *
	 * <pre>
	 * for (IntValueCursor c : intDeque) {
	 * 	System.out.println(&quot;buffer index=&quot; + c.index + &quot; value=&quot; + c.value);
	 * }
	 * </pre>
	 */
	@Override
	public Iterator<ObjectCursor<KType>> iterator() {
		return new ValueIterator();
	}

	/**
	 * Return the index of the last (counting from tail) element equal to
	 * <code>e1</code>. The index points to the {@link #buffer} array.
	 *
	 * @param e1 The element to look for.
	 * @return Returns the index of the first element equal to <code>e1</code> or
	 *         <code>-1</code> if not found.
	 */
	public int lastBufferIndexOf(KType e1) {
		final int bufLen = buffer.length;
		final int last = oneLeft(head, bufLen);
		for (int i = oneLeft(tail, bufLen); i != last; i = oneLeft(i, bufLen)) {
			if (this.equals(e1, buffer[i]))
				return i;
		}

		return -1;
	}

	@Override
	public long ramBytesAllocated() {
		// int: head, tail
		return RamUsageEstimator.NUM_BYTES_OBJECT_HEADER + Integer.BYTES * 2 + resizer.ramBytesAllocated()
				+ RamUsageEstimator.shallowSizeOfArray(buffer);
	}

	@Override
	public long ramBytesUsed() {
		// int: head, tail
		return RamUsageEstimator.NUM_BYTES_OBJECT_HEADER + Integer.BYTES * 2 + resizer.ramBytesUsed()
				+ RamUsageEstimator.shallowUsedSizeOfArray(buffer, size());
	}

	/**
	 * Release internal buffers of this deque and reallocate with the default
	 * buffer.
	 */
	@Override
	public void release() {
		this.head = tail = 0;
		buffer = ObjectArrayList.EMPTY_ARRAY;
		ensureBufferSpace(0);
	}

	/** {@inheritDoc} */
	@Override
	public int removeAll(KType e1) {
		int removed = 0;
		final int last = tail;
		final int bufLen = buffer.length;
		int from, to;
		for (from = to = head; from != last; from = oneRight(from, bufLen)) {
			if (this.equals(e1, buffer[from])) {
				buffer[from] = null;
				removed++;
				continue;
			}

			if (to != from) {
				buffer[to] = buffer[from];
				buffer[from] = null;
			}

			to = oneRight(to, bufLen);
		}

		tail = to;
		return removed;
	}

	/** {@inheritDoc} */
	@Override
	public int removeAll(ObjectPredicate<? super KType> predicate) {
		final KType[] buffer = (KType[]) this.buffer;
		final int last = tail;
		final int bufLen = buffer.length;
		int removed = 0;
		int from, to;
		from = to = head;
		try {
			for (from = to = head; from != last; from = oneRight(from, bufLen)) {
				if (predicate.apply(buffer[from])) {
					buffer[from] = null;
					removed++;
					continue;
				}

				if (to != from) {
					buffer[to] = buffer[from];
					buffer[from] = null;
				}

				to = oneRight(to, bufLen);
			}
		} finally {
			// Keep the deque in consistent state even if the predicate throws an exception.
			for (; from != last; from = oneRight(from, bufLen)) {
				if (to != from) {
					buffer[to] = buffer[from];
					buffer[from] = null;
				}

				to = oneRight(to, bufLen);
			}
			tail = to;
		}

		return removed;
	}

	/**
	 * Removes the element at <code>index</code> in the internal {#link
	 * {@link #buffer} array, returning its value.
	 *
	 * @param index Index of the element to remove. The index must be located
	 *              between {@link #head} and {@link #tail} in modulo
	 *              {@link #buffer} arithmetic.
	 */
	public void removeAtBufferIndex(int index) {
		assert (head <= tail ? index >= head && index < tail : index >= head || index < tail)
				: "Index out of range (head=" + head + ", tail=" + tail + ", index=" + index + ").";

		// Cache fields in locals (hopefully moved to registers).
		final KType[] buffer = (KType[]) this.buffer;
		final int bufLen = buffer.length;
		final int lastIndex = bufLen - 1;
		final int head = this.head;
		final int tail = this.tail;

		final int leftChunk = Math.abs(index - head) % bufLen;
		final int rightChunk = Math.abs(tail - index) % bufLen;

		if (leftChunk < rightChunk) {
			if (index >= head) {
				System.arraycopy(buffer, head, buffer, head + 1, leftChunk);
			} else {
				System.arraycopy(buffer, 0, buffer, 1, index);
				buffer[0] = buffer[lastIndex];
				System.arraycopy(buffer, head, buffer, head + 1, lastIndex - head);
			}
			buffer[head] = null;
			this.head = oneRight(head, bufLen);
		} else {
			if (index < tail) {
				System.arraycopy(buffer, index + 1, buffer, index, rightChunk);
			} else {
				System.arraycopy(buffer, index + 1, buffer, index, lastIndex - index);
				buffer[lastIndex] = buffer[0];
				System.arraycopy(buffer, 1, buffer, 0, tail);
			}
			buffer[tail] = null;
			this.tail = oneLeft(tail, bufLen);
		}
	}

	/** {@inheritDoc} */
	@Override
	public KType removeFirst() {
		assert size() > 0 : "The deque is empty.";

		final KType result = (KType) buffer[head];
		buffer[head] = null;
		head = oneRight(head, buffer.length);
		return result;
	}

	/** {@inheritDoc} */
	@Override
	public int removeFirst(KType e1) {
		final int index = bufferIndexOf(e1);
		if (index >= 0)
			removeAtBufferIndex(index);
		return index;
	}

	/** {@inheritDoc} */
	@Override
	public KType removeLast() {
		assert size() > 0 : "The deque is empty.";

		tail = oneLeft(tail, buffer.length);
		final KType result = (KType) buffer[tail];
		buffer[tail] = null;
		return result;
	}

	/** {@inheritDoc} */
	@Override
	public int removeLast(KType e1) {
		final int index = lastBufferIndexOf(e1);
		if (index >= 0) {
			removeAtBufferIndex(index);
		}
		return index;
	}

	/** {@inheritDoc} */
	@Override
	public int size() {
		if (head <= tail)
			return tail - head;
		else
			return (tail - head + buffer.length);
	}

	/** {@inheritDoc} */
	@Override
	public Object[] toArray() {

		final int size = size();
		return toArray(((KType[]) new Object[size]));
	}

	/**
	 * Copies elements of this deque to an array. The content of the
	 * <code>target</code> array is filled from index 0 (head of the queue) to index
	 * <code>size() - 1</code> (tail of the queue).
	 *
	 * @param target The target array must be large enough to hold all elements.
	 * @return Returns the target argument for chaining.
	 */
	public KType[] toArray(KType[] target) {
		assert target.length >= size() : "Target array must be >= " + size();

		if (head < tail) {
			// The contents is not wrapped around. Just copy.
			System.arraycopy(buffer, head, target, 0, size());
		} else if (head > tail) {
			// The contents is split. Merge elements from the following indexes:
			// [head...buffer.length - 1][0, tail - 1]
			final int rightCount = buffer.length - head;
			System.arraycopy(buffer, head, target, 0, rightCount);
			System.arraycopy(buffer, 0, target, rightCount, tail);
		}

		return target;
	}
}
