#include <queue.h>
#include <errcode.h>
#include <utils.h>
#include <kmalloc.h>

queue_t *make_queue()
{
  queue_t *ret = kmalloc(sizeof(queue_t));
  ret->size = 0;
  ret->begin = kmalloc(sizeof(queue_node_t));
  ret->end = kmalloc(sizeof(queue_node_t));
  *ret->begin = *ret->end = (queue_node_t){
    .prev = (queue_node_t *)ret->begin,
    .next = (queue_node_t *)ret->end,
    .value = 0,
  };

  return ret;
}

uint64_t queue_back(const queue_t *queue)
{
  if (!queue->size)
    exit(ERR_OUT_OF_BOUND);
  return queue->end->prev->value;
}

uint64_t queue_front(const queue_t *queue)
{
  if (!queue->size)
    exit(ERR_OUT_OF_BOUND);
  return queue->begin->next->value;
}

void queue_push_back(queue_t *queue, uint64_t val)
{
  queue->end->value = val;
  queue->end->next = kmalloc(sizeof(queue_node_t));
  *queue->end->next = (queue_node_t){
    .prev = queue->end,
    .next = queue->end->next,
    .value = 0,
  };
  queue->end = queue->end->next;
}

void queue_push_front(queue_t *queue, uint64_t val)
{
  queue->begin->value = val;
  queue->begin->prev = kmalloc(sizeof(queue_node_t));
  *queue->begin->prev = (queue_node_t){
    .prev = queue->begin->prev,
    .next = queue->begin,
    .value = 0,
  };
  queue->begin = queue->begin->prev;
}