#include "pch.h"
#include <iostream>
using namespace std;

class Element
{
    int key;
    Element* next;
    friend class List;
public:

    int getKey();
    int ListElement(int key);
};
class List
{
    Element* head;
    int size;

public:
    void addToBeginning(int key);
    void addToEnd(int key);
    bool contains(int key);
    Element*getElement(int key);
    Element*getByIndex(int idx);
    void removeKey(int key);
    void clearAll();
    void printList();
    List();
};

void List::addToBeginning(int key)
{
    Element* newElem = new Element();
    newElem->key = key;
    newElem->next = head;
    head = newElem;
    size++;
}

void List::addToEnd(int key)
{
    Element* newElem = new Element();
    newElem->key = key;

    if (head != NULL)
    {
        Element* helper = head;

        while (helper->next != NULL)
        {
            helper = helper->next;
        }

        helper->next = newElem;
    }
    else
    {
        head = newElem;
    }
}

Element* List::getElement(int key)
{
    if (head == NULL)
    {
        return NULL;
    }

    Element* helper = head;
    while (helper->key != key)
    {
        if (helper->next == NULL) //key is not present
        {
            return NULL;
        }

        helper = helper->next;
    }

    return helper; //moze wskaznik?
}

bool List::contains(int key)
{
    if(List::getElement(key)==NULL){
        return false;
    }
    else
    {
        return true;
    }

    // if (head == NULL)
    // {
        // return false;
    // }

    // Element* helper = head;
    // while (helper->key != key)
    // {
        // if (helper->next == NULL) //key is not present
        // {
            // return false;
        // }

        // helper = helper->next;
    // }

    // return true; //moze wskaznik?
}

Element* List::getByIndex(int idx)
{
    if (head == NULL)
    {
        return NULL;
    }

    Element* helper = head;

    for(int i=0; i<idx; i++)
    {
        if (helper->next!= NULL)
        {
            helper = helper->next;
        }
        else
        {
            return NULL;
        }
    }

    return helper;
}

void List::remove(int key)
{
    if (head==NULL)
    {
        cout << "Element o podanym kluczu nieznaleziony." << endl;
        return;
    }

    Element* helper = head;
    Element* previous = NULL;

    while (helper->key != key){
        if (helper->next != NULL)
        {
            cout << "Element o podanym kluczu nieznaleziony." << endl;
            return;
        }

        previous = helper;
        helper = helper->next;
    }

    prevous->next = helper->next;
    delete helper;
}

void List::clearAll()
{
    Element *helper = head;
    Element *next = helper->next;
    head = NULL;

    while (next != NULL)
    {
        helper = next;
        next = helper->next;
        delete helper;
    }
    size = 0;
}

void List :: printList()
{
    if (head == NULL)
    {
        cout << "lista jest pusta";
    }

    cout << "List=[";

    Element *helper = head;
    while (helper != NULL)
    {
        cout << helper;
        cout << ", ";

        helper = helper->next;
    }

    cout << "] size=" << size;
}

int Element::getKey()
{
    return this->key;
}

List::List()
{
    this->head = NULL;
    this->size = 0;
}

int main()
{
    List* list = new List();

    //list->addToEnd(3);
    list->addToBeginning(2);
    list->printList();
    list->addToBeginning(1);
    //list->addToEnd(4);
    list->printList();

    if (list->contains(3))
    {
        cout << "contains 3" << endl;
    }
    else
    {
        cout << "not contains 3" << endl;
    }
    return 0;
}