#include <iostream>
#include <fstream>
// Predem se omlovam ze pisu v anglictine, doufam ze to neni problem

using namespace std;
struct node {
    int key;
    struct node *next;// Creating a node sctructure
};

class linked_list {// declaration of class
private:
    struct node *head;
    struct node *tail;// made those private for safety reasons
public:
    linked_list() {
        head = nullptr;
        tail = nullptr;

    }

    void create(int key) {//creating an empty list
        struct node *temp;
        temp = new struct node;
        temp->key = key;
        temp->next = nullptr;
        head = temp;
        tail = head;
    }

    //ВОТ ЭТА ПРОКЛЯТАЯ ЗАЛУПА НЕ РАБОТАЕТ
    //************************************
    //************************************
    void readFrom(){
        string line;
        ifstream myfile("data.txt");
        if(myfile)
        {   create(0);
            while( getline(myfile, line)){
                int a = atoi(line.c_str());
                insert(a);
            }
         myfile.close();
        }
    }
    //************************************
    //************************************
    void insert(int key) {
        struct node* prev = nullptr;
        struct node* curr = head;
        //
        while ((curr != nullptr) && (key > curr->key))
        {
            prev = curr;
            curr = curr->next;
        }

        // Creating a node with a user's value
        struct node* newNode = new struct node;
        newNode->key = key;
        newNode->next = nullptr;

        // Insertion
        if (curr == nullptr)
        {
            tail = newNode;
        }
        else
        {
            newNode->next = curr;
        }

        if (prev == nullptr)
        {
            head = newNode;
        }
        else
        {
            prev->next = newNode;
        }
    }

    void delete_node(int key) {
        if (head == nullptr) {// In case the list is empty
            cout << "List is empty\n";
            return;
        }

        if (head->key == key) {// In case the list has only 1 element
            if (head->next == nullptr) {
                delete(head);
                head = tail = nullptr;
            }
            struct node *temp = head;
            head = head->next;
            delete(temp);
        }
        // Looking for a position and checking if there's a node with a value we want to be deleted
        else {
            struct node *current = head;
            struct node *prev = current;

            while ((current->key != key) && (current->next != nullptr)) {
                prev = current;
                current = current->next;
            }

            if ((current->key != key) && (current->next == nullptr)) {
                cout << "Key not found\n";
            }
            else if ((current->key == key) && (current->next == nullptr)) {
                tail = prev;
                prev->next = nullptr;
                delete(current);
            }
            else {
                prev->next = current->next;
                delete(current);
            }

        }
    }

    void search_node(int key) {
        if (head->key == key || tail->key == key) {// If the node we're looking for is in the head of in the tail
            cout << "Node found\n";
            return;
        }
        struct node *current = head;
        while ((current->key != key) && (current->next != nullptr)) {// Looking for a position
            current = current->next;
        }
        // Checking if there the value equivalent to the one we're looking for
        if (current->key == key) {
            cout << "Node found\n";
        }
        else {
            cout << "Node not found\n";
        }
    }

    void print_nodes(void) {// Printing the list
        struct node *current = head;
        while (current != nullptr) {
            cout << current->key << '\n';
            current = current->next;
        }
    }

};


int main(void) {
    linked_list list;

    //list.create(0);

   /* for (int i = 1; i < 15; ++i) {
        list.insert(i);
    }*/
    cout << "Hello! " << endl;
    menu :cout << "What would u like to do with the your linked list?\n"<<
        "1.Print the list\n"<<
        "2.Add new node\n"<<
        "3.Delete node\n"<<
        "4.Search for node\n"<<
        "5.Read from file\n"<<
        "6.Exit"<< endl;
    int x;
    cin >> x;
    switch (x)
    {
    default:
    case 1:
        list.print_nodes();
        break;
    case 2:
        cout << "Input the value please: " << endl;
        int a;
        cin >> a;
        list.insert(a);
        break;
    case 3:
        cout << "Input the value please: " << endl;
        int b;
        cin >> b;
        list.delete_node(b);
        break;
    case 4:
        int c;
        cin >> c;
        list.search_node(c);
        break;
    case 5:
        list.readFrom();
        break;

    case 6:
        exit(0);
        break;// Don't really know if break is needed in this case
    }
    cout << "Done. Would you like to continue?\n" <<
        "1. Yes\n"<<
        "2. No"<< endl;
    int x2;
    cin >> x2;
    switch (x2)
    {
    case 1:
        goto menu;
        break;
    case 2:
        exit(0);
        break;
    }
    system("PAUSE");
    return 0;
}