/*

 * node_list.c

 *

 *  Created on: Mar 8, 2011

 *      Author: posixninja

 *

 * Copyright (c) 2011 Joshua Hill. All Rights Reserved.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "node.h"

#include "node_list.h"

void node_list_destroy(node_list_t list)

{

  free(list);

}

node_list_t node_list_create()

{

  node_list_t list = (node_list_t)calloc(1, sizeof(struct node_list));

  if (list == NULL) {

    return NULL;

  }

  // Initialize structure

  list->begin = NULL;

  list->end = NULL;

  list->count = 0;

  return list;

}

int node_list_add(node_list_t list, node_t node)

{

  if (!list || !node) return -1;

  // Find the last element in the list

  node_t last = list->end;

  // Setup our new node as the new last element

  node->next = NULL;

  node->prev = last;

  // Set the next element of our old "last" element

  if (last) {

    // but only if the node list is not empty

    last->next = node;

  } else {

    // otherwise this is the start of the list

    list->begin = node;

  }

  // Set the lists prev to the new last element

  list->end = node;

  // Increment our node count for this list

  list->count++;

  return 0;

}

int node_list_insert(node_list_t list, unsigned int node_index, node_t node)

{

  if (!list || !node) return -1;

  if (node_index >= list->count) {

    return node_list_add(list, node);

  }

  // Get the first element in the list

  node_t cur = list->begin;

  unsigned int pos = 0;

  node_t prev = NULL;

  if (node_index > 0) {

    while (pos < node_index) {

      prev = cur;

      cur = cur->next;

      pos++;

    }

  }

  if (prev) {

    // Set previous node

    node->prev = prev;

    // Set next node of our new node to next node of the previous node

    node->next = prev->next;

    // Set next node of previous node to our new node

    prev->next = node;

  } else {

    node->prev = NULL;

    // get old first element in list

    node->next = list->begin;

    // set new node as first element in list

    list->begin = node;

  }

  if (node->next == NULL) {

    // Set the lists prev to the new last element

    list->end = node;

  } else {

    // set prev of the new next element to our node

    node->next->prev = node;

  }

  // Increment our node count for this list

  list->count++;

  return 0;

}

int node_list_remove(node_list_t list, node_t node)

{

  if (!list || !node) return -1;

  if (list->count == 0) return -1;

  int node_index = 0;

  node_t n;

  for (n = list->begin; n; n = n->next) {

    if (node == n) {

      node_t newnode = node->next;

      if (node->prev) {

        node->prev->next = newnode;

        if (newnode) {

          newnode->prev = node->prev;

        } else {

          // last element in the list

          list->end = node->prev;

        }

      } else {

        // we just removed the first element

        if (newnode) {

          newnode->prev = NULL;

        } else {

          list->end = NULL;

        }

        list->begin = newnode;

      }

      list->count--;

      return node_index;

    }

    node_index++;

  }

  return -1;

}