#ifndef SINGLY_LINKED_LIST_HPP
#define SINGLY_LINKED_LIST_HPP


struct ListNode {
	int _data = 0;
	ListNode* _next = nullptr;
};

struct SinglyLinkedList {
	size_t _size;
	ListNode* _head = nullptr;
};


//SinglyLinkedList singlylinkedlist{};
//ListNode listnode{};
//
//listnode._data = 1;
//singlylinkedlist._head = &listnode;

bool Append(SinglyLinkedList* list, ListNode* node) {

	//if empty
	if (list->_size == 0)
	{
		list->_head = node;
		list->_size++;
		return true;
	}

	//if not empty
	ListNode* travel = nullptr;
	for (travel = list->_head; travel->_next != nullptr;)
	{
		travel = travel->_next;
	}

	travel->_next = node;
	list->_size++;
	return true;
}

bool Prepend(SinglyLinkedList* list, ListNode* node) {

	//if empty
	if (list->_size == 0)
	{
		list->_head = node;
		list->_size++;
		return true;
	}

	//if not empty
	ListNode* travel = list->_head;
	list->_head = node;
	node->_next = travel;

	list->_size++;
	return true;
}

bool RemoveFirst(SinglyLinkedList* list) {
	if (list->_size == 0)
		return false;

	ListNode* first = list->_head;

	list->_head = list->_head->_next;

	list->_size--;

	delete first;

	return true;
}

bool RemoveLast(SinglyLinkedList* list) {
	if (list->_size == 0)
		return false;

	/*if (list->_size == 1)
	{
		delete list->_head;
		list->_head = nullptr;
		list->_size--;
		return true;
	}
	*/
	
	
	ListNode* SecondToLast = list->_head;
	while (SecondToLast->_next->_next != nullptr)
	{
		SecondToLast = SecondToLast->_next;
	}

	delete SecondToLast->_next;
	SecondToLast->_next = nullptr;
	list->_size--;

	return true;
}


bool InsertAfter(SinglyLinkedList* list, ListNode* nodeBefore, ListNode* nodeToInsert)
{
	if (list->_size == 0)
		return false;

	ListNode* travel = list->_head;

	while (travel != nodeBefore)
	{
		travel = travel->_next;
	}

	if (travel == nullptr)
		return false;


	nodeToInsert->_next = nodeBefore->_next;
	nodeBefore->_next = nodeToInsert;

	list->_size++;
	return true;
}

bool InsertBefore(SinglyLinkedList* list, ListNode* node, ListNode* nodeToInsert)
{
	if (list->_size == 0)
		return false;

	ListNode* travel = list->_head;
	ListNode* temp = list->_head;

	while (travel != node)
	{
		travel = travel->_next;
	}

	while (temp->_next != node)
	{
		temp = temp->_next;
	}

	if (travel == nullptr)
		return false;

	nodeToInsert->_next = node;
	temp->_next = nodeToInsert;

	list->_size++;
	return true;
}


bool Clear(SinglyLinkedList* list)
{
	if (list->_size == 0)
		return true;

	ListNode* travel = list->_head;
	ListNode* next = nullptr;

	while (travel != nullptr)
	{
		next = travel->_next;
		delete travel;
		travel = next;
	}

	list->_head = nullptr;
	list->_size = 0;

	return true;
}

bool ExtractFrom(SinglyLinkedList* list, ListNode* NodetoExtract)
{
	if (list->_size == 0 || NodetoExtract == nullptr)
		return false;

	if (NodetoExtract == list->_head)
	{
		list->_head = NodetoExtract->_next;
		delete NodetoExtract;
		list->_size--;
		return true;
	}

	ListNode* NodeBefore = list->_head;

	while (NodeBefore->_next != NodetoExtract)
	{
		NodeBefore = NodeBefore->_next;
	}

	NodeBefore->_next = NodetoExtract->_next;
	delete NodetoExtract;
	list->_size--;

	return true;
}

#endif