/*
  Copyright (c) 2024 Alex Diener
  
  This software is provided 'as-is', without any express or implied
  warranty. In no event will the authors be held liable for any damages
  arising from the use of this software.
  
  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:
  
  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
  
  Alex Diener alex@ludobloom.com
*/

#include "utilities/Queue.h"
#include <stdlib.h>
#include <string.h>

Queue * Queue_create(void) {
	Queue * queue = malloc(sizeof(*queue));
	Queue_init(queue);
	return queue;
}

Queue * Queue_copy(Queue * queue) {
	Queue * copy = Queue_create();
	Queue_initCopy(copy, queue);
	return copy;
}

void Queue_dispose(Queue * queue) {
	Queue_disposeContents(queue);
	free(queue);
}

void Queue_init(Queue * queue) {
	queue->itemCount = 0;
	queue->itemAllocatedCount = 0;
	queue->items = NULL;
}

void Queue_initCopy(Queue * queue, Queue * from) {
	queue->itemCount = from->itemCount;
	if (from->itemCount > 0) {
		queue->itemAllocatedCount = from->itemCount;
		queue->items = malloc(queue->itemAllocatedCount * sizeof(*queue->items));
		memcpy(queue->items, from->items, from->itemCount * sizeof(*from->items));
	}
}

void Queue_disposeContents(Queue * queue) {
	free(queue->items);
}

static void sizeQueueForInsert(Queue * queue) {
	if (queue->itemAllocatedCount <= queue->itemCount) {
		queue->itemAllocatedCount = queue->itemAllocatedCount * 2 + (queue->itemAllocatedCount == 0) * 16;
		queue->items = realloc(queue->items, queue->itemAllocatedCount * sizeof(*queue->items));
	}
}

void Queue_push(Queue * queue, void * item) {
	sizeQueueForInsert(queue);
	queue->items[queue->itemCount++] = item;
}

void * Queue_pop(Queue * queue) {
	if (queue->itemCount == 0) {
		return NULL;
	}
	queue->itemCount--;
	return queue->items[queue->itemCount];
}

void Queue_unshift(Queue * queue, void * item) {
	sizeQueueForInsert(queue);
	queue->itemCount++;
	for (unsigned int itemIndex = queue->itemCount; itemIndex > 0; itemIndex--) {
		queue->items[itemIndex] = queue->items[itemIndex - 1];
	}
	queue->items[0] = item;
}

void * Queue_shift(Queue * queue) {
	if (queue->itemCount == 0) {
		return NULL;
	}
	queue->itemCount--;
	void * result = queue->items[0];
	for (unsigned int index = 0; index < queue->itemCount; index++) {
		queue->items[index] = queue->items[index + 1];
	}
	return result;
}

void Queue_insert(Queue * queue, void * item, unsigned int index) {
	sizeQueueForInsert(queue);
	queue->itemCount++;
	for (unsigned int itemIndex = queue->itemCount; itemIndex > index; itemIndex--) {
		queue->items[itemIndex] = queue->items[itemIndex - 1];
	}
	if (index > queue->itemCount) {
		index = queue->itemCount - 1;
	}
	queue->items[index] = item;
}

void * Queue_remove(Queue * queue, unsigned int index) {
	if (index >= queue->itemCount) {
		return NULL;
	}
	queue->itemCount--;
	void * result = queue->items[index];
	while (index < queue->itemCount) {
		queue->items[index] = queue->items[index + 1];
		++index;
	}
	return result;
}

void Queue_removeAll(Queue * queue) {
	queue->itemCount = 0;
}

void Queue_merge(Queue * to, Queue * from) {
	if (to->itemAllocatedCount < to->itemCount + from->itemCount) {
		to->itemAllocatedCount = to->itemCount + from->itemCount;
		to->items = realloc(to->items, to->itemAllocatedCount * sizeof(*to->items));
	}
	memcpy(to->items + to->itemCount, from->items, from->itemCount * sizeof(*from->items));
	to->itemCount += from->itemCount;
}

void Queue_foreach(Queue * queue, Queue_foreachCallback callback, void * callbackContext) {
	for (unsigned int itemIndex = 0; itemIndex < queue->itemCount; itemIndex++) {
		if (!callback(queue, queue->items[itemIndex], callbackContext)) {
			break;
		}
	}
}

void Queue_foreachReverse(Queue * queue, Queue_foreachCallback callback, void * callbackContext) {
	for (unsigned int itemIndex = queue->itemCount - 1; itemIndex < queue->itemCount; itemIndex--) {
		if (!callback(queue, queue->items[itemIndex], callbackContext)) {
			break;
		}
	}
}