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

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

uint64_t queue_front(const queue_t *queue)
{
  if (!queue->size)
    panic(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;
  ++queue->size;
}

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;
  ++queue->size;
}

uint64_t queue_pop_back(queue_t *queue)
{
  if (!queue->size)
    panic(ERR_OUT_OF_BOUND);

  uint64_t ret = queue->end->prev->value;
  queue->end->prev = queue->end->prev->prev;
  queue->end->prev->next = queue->end;

  --queue->size;
  return ret;
}

uint64_t queue_pop_front(queue_t *queue)
{
  if (!queue->size)
    panic(ERR_OUT_OF_BOUND);

  uint64_t ret = queue->begin->next->value;
  queue->begin->next = queue->begin->next->next;
  queue->begin->next->prev = queue->begin;

  --queue->size;
  return ret;
}