#ifndef LIST_MALLOC
#define LIST_MALLOC malloc
#endif

#ifndef LIST_FREE
#define LIST_FREE free
#endif

//
// list.c
//
// Copyright (c) 2010 TJ Holowaychuk <tj@vision-media.ca>
//

#include <stdint.h>
#include "clist.h"

/*
 * Allocates a new clist_node_t. NULL on failure.
 */

clist_node_t *
clist_node_new(void *val)
{
  clist_node_t *self;
  if (!(self = LIST_MALLOC(sizeof(clist_node_t))))
    return NULL;
  self->prev = NULL;
  self->next = NULL;
  self->val = val;
  return self;
}

/*
 * Allocate a new clist_t. NULL on failure.
 */

clist_t *
clist_new(void)
{
  clist_t *self;
  if (!(self = LIST_MALLOC(sizeof(clist_t))))
    return NULL;
  self->head = NULL;
  self->tail = NULL;
  self->free = NULL;
  self->compare = NULL;
  self->len = 0;
  return self;
}

/*
 * Remove all the node in list.
 * @self: Pointer to the list
 */

void clist_clear(clist_t *self)
{
  clist_node_t *next;
  clist_node_t *curr = self->head;

  while (curr != NULL)
  {
    next = curr->next;
    if (self->free)
      self->free(curr->val);
    LIST_FREE(curr);
    curr = next;
  }
  self->len = 0;
  self->head = NULL;
}

/*
 * Free the list.
 * @self: Pointer to the list
 */

void clist_destroy(clist_t *self)
{
  clist_clear(self);
  LIST_FREE(self);
}

/*
 * Append the given node to the list
 * and return the node, NULL on failure.
 * @self: Pointer to the list for popping node
 * @node: the node to push
 */

clist_node_t *
clist_rpush(clist_t *self, clist_node_t *node)
{
  if (!node)
    return NULL;

  if (self->len)
  {
    node->prev = self->tail;
    node->next = NULL;
    self->tail->next = node;
    self->tail = node;
  }
  else
  {
    self->head = self->tail = node;
    node->prev = node->next = NULL;
  }

  ++self->len;
  return node;
}

/*
 * Return / detach the last node in the list, or NULL.
 * @self: Pointer to the list for popping node
 */

clist_node_t *
clist_rpop(clist_t *self)
{
  if (!self->len)
    return NULL;

  clist_node_t *node = self->tail;

  if (--self->len)
  {
    (self->tail = node->prev)->next = NULL;
  }
  else
  {
    self->tail = self->head = NULL;
  }

  node->next = node->prev = NULL;
  return node;
}

/*
 * Return / detach the first node in the list, or NULL.
 * @self: Pointer to the list for popping node
 */

clist_node_t *
clist_lpop(clist_t *self)
{
  if (!self->len)
    return NULL;

  clist_node_t *node = self->head;

  if (--self->len)
  {
    (self->head = node->next)->prev = NULL;
  }
  else
  {
    self->head = self->tail = NULL;
  }

  node->next = node->prev = NULL;
  return node;
}

/*
 * Prepend the given node to the list
 * and return the node, NULL on failure.
 * @self: Pointer to the list for pushing node
 * @node: the node to push
 */

clist_node_t *
clist_lpush(clist_t *self, clist_node_t *node)
{
  if (!node)
    return NULL;

  if (self->len)
  {
    node->next = self->head;
    node->prev = NULL;
    self->head->prev = node;
    self->head = node;
  }
  else
  {
    self->head = self->tail = node;
    node->prev = node->next = NULL;
  }

  ++self->len;
  return node;
}

/*
 * Return the node associated to val or NULL.
 * @self: Pointer to the list for finding given value
 * @val: Value to find
 */

clist_node_t *
clist_find(clist_t *self, void *val)
{
  clist_iterator_t *it = clist_iterator_new(self, LIST_HEAD);
  clist_node_t *node;

  while ((node = clist_iterator_next(it)))
  {
    if (self->compare)
    {
      if (self->compare(val, node->val) == 0)
      {
        clist_iterator_destroy(it);
        return node;
      }
    }
    else
    {
      if (val == node->val)
      {
        clist_iterator_destroy(it);
        return node;
      }
    }
  }

  clist_iterator_destroy(it);
  return NULL;
}

/*
 * Return the node at the given index or NULL.
 * @self: Pointer to the list for finding given index
 * @index: the index of node in the list
 */

clist_node_t *
clist_at(clist_t *self, int index)
{
  clist_direction_t direction = LIST_HEAD;

  if (index < 0)
  {
    direction = LIST_TAIL;
    index = ~index;
  }

  if ((unsigned)index < self->len)
  {
    clist_iterator_t *it = clist_iterator_new(self, direction);
    clist_node_t *node = clist_iterator_next(it);
    while (index--)
      node = clist_iterator_next(it);
    clist_iterator_destroy(it);
    return node;
  }

  return NULL;
}

/*
 * Remove the given node from the list, freeing it and it's value.
 * @self: Pointer to the list to delete a node
 * @node: Pointer the node to be deleted
 */

void clist_remove(clist_t *self, clist_node_t *node)
{
  node->prev
      ? (node->prev->next = node->next)
      : (self->head = node->next);

  node->next
      ? (node->next->prev = node->prev)
      : (self->tail = node->prev);

  if (self->free)
    self->free(node->val);

  LIST_FREE(node);
  --self->len;
}

/*
 * Allocate a new clist_iterator_t. NULL on failure.
 * Accepts a direction, which may be LIST_HEAD or LIST_TAIL.
 */

clist_iterator_t *
clist_iterator_new(clist_t *list, clist_direction_t direction)
{
  clist_node_t *node = direction == LIST_HEAD
                          ? list->head
                          : list->tail;
  return clist_iterator_new_from_node(node, direction);
}

/*
 * Allocate a new clist_iterator_t with the given start
 * node. NULL on failure.
 */

clist_iterator_t *
clist_iterator_new_from_node(clist_node_t *node, clist_direction_t direction)
{
  clist_iterator_t *self;
  if (!(self = LIST_MALLOC(sizeof(clist_iterator_t))))
    return NULL;
  self->next = node;
  self->direction = direction;
  return self;
}

/*
 * Return the next clist_node_t or NULL when no more
 * nodes remain in the list.
 */

clist_node_t *
clist_iterator_next(clist_iterator_t *self)
{
  clist_node_t *curr = self->next;
  if (curr)
  {
    self->next = self->direction == LIST_HEAD
                     ? curr->next
                     : curr->prev;
  }
  return curr;
}

/*
 * Free the list iterator.
 */

void clist_iterator_destroy(clist_iterator_t *self)
{
  LIST_FREE(self);
  self = NULL;
}