#include "definitions.h"
#include "List.h"

Cell::Cell()
{
  item_ = NULL;
  next_ = NULL;
  prev_ = NULL;
}

Cell::Cell(Linkable *new_item)
{
  item_ = new_item;
  next_ = NULL;
  prev_ = NULL;
}

Cell::Cell(Linkable *new_item, Cell *prev)
{
  item_ = new_item;
  prev_ = prev;
  next_ = NULL;
}

Cell::Cell(Linkable *new_item, Cell *next, Cell *prev)
{
  item_ = new_item;
  next_ = next;
  prev_ = prev;
}


Cell::~Cell()
{
  next_ =  NULL;
  prev_ = NULL;
  item_ = NULL;   
}


Linkable* Cell::item(){return item_;}

Cell*  Cell::next(){return next_;}

Cell*  Cell::prev(){return prev_;}

void Cell::set_next(Cell *next) {next_ = next;}

void Cell::set_prev(Cell *prev) {next_ = prev;}

/*----------------------------------------------------*/

List::List()
{
  head_ = NULL;
  tail_ = NULL;
  old_search_val_ = NULL;
}

List::~List()
{
  Cell* ptr = head_;
  Cell* tmp;

  while(ptr != NULL)
  {
	tmp = ptr->next();
	delete ptr;
        ptr = tmp;
  }
  head_ = NULL;
  tail_ = NULL;
  old_search_val_ = NULL;
}


/* Simply add to the beginning of the list */
void List::insert(Linkable* new_item)
{
   add_first(new_item);
}


/* Add to the end of the list */  
void List::add_last(Linkable *new_item)
{
  Cell* tmp;

  if ((tail_ == NULL) && (head_ == NULL))
  {
	/* The list is empty */
	tmp  = new Cell(new_item);
	tail_ =tmp;
        head_ = tmp;
  	return;
  }
  else if ((tail_ != NULL) && (head_ != NULL))
  {
     	tmp = new Cell(new_item , tail_);
 	tail_->set_next(tmp);
	tail_ = tmp;
  	return;
  }
  else 
  {
	printf("Error in List obj\n");
  }

}

/* Add to the beginning of the list */
void List::add_first(Linkable *new_item)
{
  Cell *tmp;
  if ((tail_ == NULL) && (head_ == NULL))
  {
	/* The list is empty */
	tmp = new Cell(new_item);
        head_ = tmp;
	tail_ = tmp;
	return;
  }
  else if ((tail_ != NULL) && (head_ != NULL))
  {
	tmp = new Cell(new_item, head_);
	head_ = tmp;
	return;
  }
  else
  {
	printf("Error in List obj\n");
  }
}


/* Remove the item from the List */        
void List::remove(Linkable *new_item)
{
  Cell *ptr = head_, *prev, *next;
  while (ptr)
  {
	if (ptr->item()==new_item)
        {
		prev = ptr->prev();
		next = ptr->next();
	 	if ((prev != NULL) && (next != NULL))
		{
			prev->set_next(next);
			next->set_prev(prev);
			delete ptr;
		}
		else if (prev != NULL)
		{
			/* ptr must be the last  item */
			prev->set_next(NULL);
			tail_ = prev;
			delete ptr;
		}
		else if (next != NULL)
		{
			/* ptr must be the first item */
			next->set_prev(NULL);
			head_ = next;
			delete ptr;
		}
		else
		{
			head_ = tail_ = NULL;
			delete ptr;
		}
		return;
	}
	else ptr = ptr->next();
  }
}