#include <stdio.h>
#include <stdlib.h>

#define SIZE_OF_LIST 10

struct node
{
  int data;
  struct node* link;
};

int GetListLength(struct node** list);
void PrintHRLine();
void PrintListData(struct node** list);
void AddLastNode(struct node** list, struct node** new_node);
void SearchNode(struct node** list, int data);
void RemoveNodeByIndex(struct node** list, int index);
void InsertNode(struct node** list, struct node** new_node, int position);
struct node* GetLastNode(struct node** list);
struct node* GetNodeByIndex(struct node** list, int index);

int main()
{
  struct node* head = NULL;
  struct node* item = NULL;
  struct node* edit_node = NULL;

  int i;

  head = (struct node*)malloc(sizeof(struct node));
  item = (struct node*)malloc(sizeof(struct node) * 10);
  edit_node = (struct node*)malloc(sizeof(struct node));

  head->data = 999;
  head->link = item;

  // Create a list of 10 elements
  for (i = 0; i < SIZE_OF_LIST; i++)
    {
      (item+i)->data = i;
      printf("(item+%d)->data = %d\n",i,i);
      if (i<SIZE_OF_LIST-1)
    {
      (item+i)->link = (item+i+1);
      printf("(item+%d->link = (item+%d+1);\n", i, i);
      printf("(item+%d adress = 0x%lx\n",i, (unsigned long int) &item+i);
    }
      else
    {
      (item+i)->link = NULL;
      printf("(item+%d->link = NULL;\n", i);
    }
    }

  // RemoveNodeByIndex(head, 5);
  // PrintListData(&head);
  edit_node->data = 1001;
  AddLastNode(&head, &edit_node);
  SearchNode(&head, 101);
  RemoveNodeByIndex(&head, 8);
  PrintListData(&head);

  // Free memory
  free(item);
  free(edit_node);
  free(head);

  return 0;
}


void PrintListData(struct node** list)
{
  int index = 0;
  struct node* current = *list;
  if (current)
    {
      while (current != NULL)
    {
      printf("List[%d] = %d\n", index, current->data);
      index++;
      current = current->link;
    }
      printf("In total %d items in list\n", index);
    }
}

int GetListLength(struct node** list)
{
  // Return length of list
  /* While node<-link != null
         increase node
         increase count
     return count
  */
  struct node* current = *list;
  int len = 0;

  if (current != NULL)
    {
      len++;
      while (current->link != NULL)
    {
      len++;
      current = current->link;
    }
    }
  return len;
}



struct node* GetLastNode(struct node** list)
{
  // Return the last node of the list
  struct node* current = *list;

  if (current)
    {
      while (current->link != NULL)
    {
      current = current->link;
    }
    }
  else
    {
      return NULL;
    }

  return current;
}



struct node* GetNodeByIndex(struct node** list, int index)
{
  // Return node by an index given
  // if error it returns NULL
  // for i < index
  //       next_node <- node.link
  //     node <- next.node
  // return next_node

  struct node* current = *list;
  int counter = 0;

  if (current)
    {
      while (current->link != NULL)
    {
      if (counter == index)
        return current;

      current = current->link;
      counter++;
    }
    }
  else
    {
      return NULL;
    }

  return NULL;
}


void AddLastNode(struct node** list, struct node** new_node)
{
  // Add an extra node to the list at the last position
  struct node* curr_new = *new_node;
  struct node* curr_list = *list;
  struct node* current = GetLastNode(&curr_list);
  PrintHRLine();
  printf("Trying add node to last\n");
  printf("Data in new node = %d\n", curr_new->data);
  current->link = *new_node;
  printf("Data in current last node = %d\n", current->data);
  PrintHRLine();
}


void AddStartNode(struct node** head, struct node** new_node)
{
  // Add an extra node to the lit at the start position
  // This won't do it bc head is the entrance to the list
  struct node* new = *new_node;
  new->link = *head;
}


void SearchNode(struct node** list, int data)
{
  // Search the node for given data
  struct node* current = *list;
  int index = 0;
  PrintHRLine();
  printf("Searching list for item with value = %d\n", data);
  if (current)
    {
      while (current != NULL)
    {
      if (current->data == data)
        {
          printf("FOUND! at adress :0x%lx , index = %d\n", (unsigned long int) &current,index);
          break;
        }
      index++;
      current = current->link;
    }
    }

  PrintHRLine();
}


void RemoveNodeByIndex(struct node** head,int index) // NOT WORKING YET
{
  // Remove node list
  struct node* current = GetNodeByIndex(*(&head), index);
  struct node* prev    = GetNodeByIndex(*(&head), index);

  // For debugging
  PrintHRLine();
  printf("Deleting item %d from list. Located : 0x%lx\n", index, (unsigned long int) &current);
  printf("Item %d data = %d\n", index, current->data);
  PrintHRLine();
  // Change link from prev link node to the next
  prev->link = current->link;

  // Unlink node wished to delete
  current->link = NULL;
  current->data = 0;

  // Free data
  free((struct node*) current);
}



void InsertNode(struct node** list, struct node** new_node, int position)
{
  // Insert node list

  if (position == 0)
    {
      // Head node
    }
 else if (position == GetListLength(list))
   {
     // End nodoe
   }
 else
    {
      struct node* prev = GetNodeByIndex(&(*list), position-1);
      struct node* next = GetNodeByIndex(&(*list), position);
      struct node* new  = *new_node;
      new->link = (struct node*) prev->link;
      prev->link     = *new_node;
    }

}

void PrintHRLine()
{
  printf("===================================\n");
}