#include <cstdlib>
#include <cstdio>
#include <iostream>
using namespace std;
#include "IntLinkedList.h"

IntLinkedList::IntLinkedList()
{
	head = NULL;
	tail = NULL;
	// add the initialization for the tail pointer
}

/* addHead
 * add an item to the front of the linked list
 *
 * TODO: Add code that modifies the tail properly
 */

void IntLinkedList::addHead(int v)
{
	// create a new IntNode and put v into that IntNode
	IntNode *l = new IntNode(v);
	// if the list is empty, this link is the only thing in it
	// all we need to do is point head to the link
	if (head == NULL)
	{
		head = l;
		tail = l;
	}
	// if there is already something there, we point this new link
	// to the old head of the list.  Then, when we point head to this
	// IntNode, it becomes the beginning of the list, and the old beginning
	// is now 2nd.
	else
	{
		l->setNext(head);
		head = l;
	}
}

/* addTail
 *
 * Add an item to the end (tail) of the list
 * TODO: Make sure tail is updated properly AND make the code more
 * efficient by taking advantage of the tail pointer
 */

void IntLinkedList::addTail(int v)
{
	// make a new link for the new item
	IntNode *l = new IntNode(v);
	// if the list is empty, this is the only one
	if (head == NULL)
	{
		head = l;
	}
	// otherwise, we need to go to the back and add the node
	else
	{
		// TODO: Modify this so it takes advantage of tail pointer
		// advance l2 so it points to the last link
		IntNode *l2;
		for(l2 = head;l2->getNext() != NULL; l2 = l2->getNext())
			;
		// now add this l to the end by hooking l2 to it
		l2->setNext(l);
		tail = l2;
	}
}

/* removeHead
 *
 * Removes the item at the head of the list
 * TODO: Update the tail pointer
 */

bool IntLinkedList::removeHead()
{
	// if the list is empty, return 0
	if (head == NULL)
		return false;
	// set a temporary pointer to head
	IntNode *tmp = head;
	// advance head so it points to the next one
	head = head->getNext();
	// delete the IntNode
	if(tmp->getNext() == NULL)
		tail = NULL;
	delete tmp;
	// return the value
	return true;
}

/* removeTail
 * removes the last (tail) item from a linked list
 * Returns true if it removed something, false if the list was empty
 * TODO:  Write the code for this method.
 * hint: Be very careful about where you stop your loop
 */
bool IntLinkedList::removeTail()
{
	IntNode *tmp = head;
	if(head == NULL)
		return false;
	if(tail ==NULL)
		return false;
	if(tmp->getNext() ==NULL)
	{
		tail = NULL;
		head = NULL;
		delete tmp;
		return true;
	}
	else
	{
		while(tmp->getNext()!=tail)
		{
			tmp = tmp->getNext();
		}
		delete tail;
		tail = tmp;
		return true;
	}
}

/* peekHead
 * return the item at the head of the list
 * If the list is empty, return 0
 */
int IntLinkedList::peekHead()
{
	// TODO: fill in this code
	if(head == NULL)
		return 0;
	else
	{
		IntNode *tmp = head;
		return tmp->getValue();
	}
}

/* peekTail
 * return the item at the end (tail) of the list
 * If the list is empty, return 0
 * TODO: Implement this function.  Make sure you take advantage of the tail ptr
 */
int IntLinkedList::peekTail()
{
	// TODO: fill in this code
	if(head == NULL)
		return 0;
	else
	{
		IntNode *tmp = tail;
		return tmp->getValue();
	}
}

/* printList
 *
 * print all of the items in the linked list
 */
void IntLinkedList::printList(FILE *f)
{
	IntNode *l;
	fprintf(f,"List: ");
	for(l = head; l != NULL; l = l->getNext())
	{
		l->printIntNode(f);
		fprintf(f, ", ");
	}
	fprintf(f,"\n");
}

IntLinkedList::~IntLinkedList()
{
	IntNode *temp = this->head;
	while(temp!=NULL)
	{
		IntNode *temp1 = temp;
		temp = temp->getNext();
		delete temp1;
	}
}