#include <iostream>
#include <string>
#include <cstdlib>
#include <algorithm>
#include <ctime>
using namespace std;
string board[9] = { " ", " ", " ", " ", " ", " ", " ", " ", " " };

void showBoard() {
    cout << "  " << " | " << "  " << " | " << endl;
    cout << " " << board[6] << " | " << board[7] << "  | " << board[8] << endl;
    cout << "  " << " | " << "  " << " | " << endl;
    cout << "-------------" << endl;
    cout << "  " << " | " << "  " << " | " << endl;
    cout << " " << board[3] << " | " << board[4] << "  | " << board[5] << endl;
    cout << "  " << " | " << "  " << " | " << endl;
    cout << "-------------" << endl;
    cout << "  " << " | " << "  " << " | " << endl;
    cout << " " << board[0] << " | " << board[1] << "  | " << board[2] << endl;
    cout << "  " << " | " << "  " << " | " << endl;
    cout << endl;
}
bool spaceFree() {
    for(int i = 0; i<9; i++) {
        if(board[i] == " ")
            return true;
    }
    return false;
}
bool winner(string s) {
    if(board[6] == s && board[7] == s && board[8] == s)
        return true;
    else if(board[3] == s && board[4] == s && board[5] == s)
        return true;
    else if(board[0] == s && board[1] == s && board[2] == s)
        return true;
    else if(board[6] == s && board[3] == s && board[0] == s)
        return true;
    else if(board[7] == s && board[4] == s && board[1] == s)
        return true;
    else if(board[8] == s && board[5] == s && board[2] == s)
        return true;
    else if(board[6] == s && board[4] == s && board[2] == s)
        return true;
    else if(board[8] == s && board[4] == s && board[0] == s)
        return true;
    else
        return false;
}
void computer(string c) {
    string p;
    int count = 0;
    if(c == "X")
        p = "O";
    else
        p = "X";

    //check for computer win
    if(((board[8] == c && board[4] == c) || (board[6] == c && board[3] == c) || (board[1] == c && board[2] == c)) && board[0] == " ")
            board[0] = c;
    else if(((board[0] == c && board[4] == c) || (board[6] == c && board[7] == c) || (board[5] == c && board[2] == c)) && board[8] == " ")
            board[8] = c;
    else if(((board[8] == c && board[7] == c) || (board[0] == c && board[3] == c) || (board[4] == c && board[2] == c)) && board[6] == " ")
            board[6] = c;
    else if(((board[8] == c && board[0] == c) || (board[6] == c && board[2] == c) ||
        (board[1] == c && board[7] == c) || (board[5] == c && board[3] == c))&&board[4] == " ")
            board[4] = c;
    else if(((board[6] == c && board[4] == c) || (board[0] == c && board[1] == c) || (board[8] == c && board[5] == c))&&board[2] == " ")
            board[2] = c;
    else if(((board[6] == c && board[8] == c) || (board[1] == c && board[4] == c))&&board[7] == " ")
            board[7] = c;
    else if(((board[8] == c && board[2] == c) || (board[3] == c && board[4] == c))&&board[5] == " ")
            board[5] = c;
    else if(((board[6] == c && board[0] == c) || (board[5] == c && board[4] == c))&&board[3] == " ")
            board[3] = c;
    else if(((board[0] == c && board[2] == c) || (board[7] == c && board[4] == c))&&board[1] == " ")
            board[1] = c;
    //block player wins
    else if(((board[8] == p && board[4] == p) || (board[6] == p && board[3] == p) || (board[1] == p && board[2] == p))&&board[0] == " ")
            board[0] = c;
    else if(((board[0] == p && board[4] == p) || (board[6] == p && board[7] == p) || (board[5] == p && board[2] == p))&&board[8] == " ")
            board[8] = c;
    else if(((board[8] == p && board[7] == p) || (board[0] == p && board[3] == p) || (board[4] == p && board[2] == p))&&board[6] == " ")
            board[6] = c;
    else if(((board[8] == p && board[0] == p) || (board[6] == p && board[2] == p) ||
        (board[1] == p && board[7] == p) || (board[5] == p && board[3] == p))&&board[4] == " ")
            board[4] = c;
    else if(((board[6] == p && board[4] == p) || (board[0] == p && board[1] == p) || (board[8] == p && board[5] == p))&&board[2] == " ")
            board[2] = c;
    else if(((board[6] == p && board[8] == p) || (board[1] == p && board[4] == p))&&board[7] == " ")
            board[7] = c;
    else if(((board[8] == p && board[2] == p) || (board[3] == p && board[4] == p))&&board[5] == " ")
            board[5] = c;
    else if(((board[6] == p && board[0] == p) || (board[5] == p && board[4] == p))&&board[3] == " ")
            board[3] = c;
    else if(((board[0] == p && board[2] == p) || (board[7] == p && board[4] == p))&&board[1] == " ")
            board[1] = c;
    else {
        do {
            srand(time(0));
            int random = rand()%9;
            if(board[random] == " ") {
                board[random] = c;
                count++;
                break;
            }
        }
        while(count<=0);
        count = 0;
    }
}
int main() {
    cout << "Would you like to be X or O?: ";
    string userInput;
    string computerInput;
    getline(cin,userInput);
    transform(userInput.begin(), userInput.end(), userInput.begin(), ::toupper);

    while(!(userInput == "X" || userInput == "O")) {
        cout << "Please enter a valid input: ";
        getline(cin,userInput);
        transform(userInput.begin(), userInput.end(), userInput.begin(), ::toupper);
    }
    if(userInput == "X")
        computerInput = "O";
    else
        computerInput = "X";

    showBoard();
    do {
        int input = 0;
        while(input > 9 || input < 1) {
            attempt:
                cout << "Where would you like to move? Numberpad for indication: ";
                cin >> input;
                if(board[input-1] == " ")
                    board[input-1] = userInput;
                else
                    goto attempt;
        }
        if(spaceFree())
            computer(computerInput);
        showBoard();
        if(winner(userInput)) {
            cout << "\nPlayer wins!\n";
            break;
        }
        else if(winner(computerInput)) {
            cout << "\nComputer wins!\n";
            break;
        }
        else if(spaceFree() == false) {
            cout << "\nIt's a tie!\n";
            break;
        }
    }
    while(spaceFree() == true);
    cin.get();
    cin.get();
}