#include <stdlib.h>
#include <stdio.h>
#include "disk.h"

void destroyDiskQueue(DiskQueue *queue) {
	free(queue->requests);
	free(queue);
}

DiskQueue *sortQueueByPosition(DiskQueue *queue) {
	qsort(queue->requests, queue->size, sizeof(DiskRequest), compareDiskRequestsByPosition);
	return queue;
}

int compareDiskRequestsByPosition(const void *a, const void *b) {
	DiskRequest *requestA = (DiskRequest *) a;
	DiskRequest *requestB = (DiskRequest *) b;
	return requestA->position - requestB->position;
}

DiskQueue *queueOfLesserTime(DiskQueue *queue, double time) {
	DiskQueue *sameTimeQueue = createDiskQueue();
	for (int i = 0; i < queue->size; i++) {
		if (queue->requests[i].time <= time) {
			enqueue(sameTimeQueue, queue->requests[i]);
		}
	}
	return sameTimeQueue;
}

DiskRequest dequeue(DiskQueue *queue) {
	return delete(queue, peek(queue));
}

DiskRequest peek(DiskQueue *queue) {
	return queue->requests[0];
}

DiskQueue *clone(DiskQueue *queue) {
	DiskQueue *clone = createDiskQueue();
	for (int i = 0; i < queue->size; i++) {
		enqueue(clone, queue->requests[i]);
	}
	return clone;
}

DiskRequest delete(DiskQueue *queue, DiskRequest request) {
	// Find the index of the request
	int index = -1;
	for (int i = 0; i < queue->size; i++) {
		if (queue->requests[i].position == request.position && queue->requests[i].time == request.time) {
			index = i;
			break;
		}
	}
	if (index == -1) {
		printf("Error: Request not found in queue\n");
		exit(EXIT_FAILURE);
	}
	// Shift all the elements after the index down one
	for (int i = index; i < queue->size - 1; i++) {
		queue->requests[i] = queue->requests[i + 1];
	}
	// Resize the queue
	queue->requests = realloc(queue->requests, sizeof(DiskRequest) * (queue->size - 1));
	if (queue->requests == NULL) {
		printf("Error reallocating memory for queue requests\n");
		exit(EXIT_FAILURE);
	}
	queue->size--;
	return request;
}

void enqueue(DiskQueue *queue, DiskRequest request) {
	queue->requests = realloc(queue->requests, sizeof(DiskRequest) * (queue->size + 1));
	if (queue->requests == NULL) {
		printf("Error reallocating memory for queue requests\n");
		exit(EXIT_FAILURE);
	}
	queue->requests[queue->size] = request;
	queue->size++;
}

DiskRequest diskRequest(int position, int time) {
	DiskRequest request;
	request.position = position;
	request.time = time;
	return request;
}

DiskQueue *createDiskQueue() {
	DiskQueue *queue = malloc(sizeof(DiskQueue));
	if (queue == NULL) {
		printf("Error allocating memory for queue\n");
		exit(EXIT_FAILURE);
	}
	queue->requests = malloc(sizeof(DiskRequest));
	if (queue->requests == NULL) {
		printf("Error allocating memory for queue requests\n");
		exit(EXIT_FAILURE);
	}
	queue->size = 0;
	return queue;
}