#include <stdlib.h>
#include "some_queue.h"

queue *new_queue(void) {
    queue *q = malloc(sizeof(queue));
    if (!q)
        return NULL;

    q->elem_c = 0;
    q->curr_i = 0;
    q->q_head = NULL;

    return q;
}

void end_queue(queue *q) {
    if (q) {
        free(q->q_head);
        q->q_head = NULL;
        free(q);
        q = NULL;
    }
}

void enqueue(queue *q, int type, void *val) {
    if (!q)
        return;
    q->q_head = realloc(q->q_head, (sizeof(item_t) * (q->elem_c + 1)));
    (q->q_head + q->elem_c)->type  = type;
    (q->q_head + q->elem_c)->value = val;
    ++q->elem_c;
}

item_t *dequeue(queue *q) {
    if (!q || q->elem_c == 0)
        return NULL;
    return ((q->q_head) + (q->curr_i++));
}

item_t *queue_peek(queue *q) {
    if (!q || (q->elem_c == 0))
        return NULL;
    return (q->q_head + q->curr_i);
}

uint32 queue_size(queue *q) {
    return (q) ? q->elem_c : (uint32)-1;
}

int queue_next(queue *q) {
    if (!q || ((q->elem_c > 0) && (q->curr_i == q->elem_c - 1)))
        return 0;
    ++q->curr_i;
    return 1;
}

int queue_back(queue *q) {
    if (!q || (q->curr_i == 0))
        return 0;
    --q->curr_i;
    return 1;
}

int queue_first(queue *q) {
    if (!q)
        return 0;
    q->curr_i = 0;
    return 1;
}

int queue_last(queue *q) {
    if (!q)
        return 0;
    q->curr_i = q->elem_c - 1;
    return 1;
}