#include "myLibraryBMR.h"

using namespace std;

enum gamePiece { X_PIECE='X', O_PIECE='O', EMPTY_PIECE = ' '};
enum gameState { X_WINS=1, O_WINS=2, TIE=3, NOT_OVER=4 };


void displayRules();
void displayGame(gamePiece[], const int);
enum gamePiece whoFirst();
int getHumanMove();
int getComputerMove(gamePiece[], const int);
enum gameState whoWins(gamePiece[], const int);


int main()
{
    gamePiece gameBoard[9];
    gamePiece computer, human;
    int choice;
    const int gameBoardSize = 9;
    int keepGoing;

    while(1)//allows game to be played until exit
    {
        displayRules();

        keepGoing = 4;

        for (int i = 0; i < gameBoardSize; i++)
        {
            gameBoard[i] = EMPTY_PIECE;
        } //intializes gameBoard array to black space

        human = whoFirst();

        if (human == X_PIECE)
        {
            computer = O_PIECE; //if human is X_PIECE then computer assigned O
        }
        else
        {
            computer = X_PIECE; //if human not X_PIECE assigns computer X.
        }                       //human already assigned O at this point

        do
        {
            if (human == X_PIECE && keepGoing >TIE )//if human is first it uses this sequence
            {
                displayGame(gameBoard, gameBoardSize);
                choice = getHumanMove();
                gameBoard[choice] = human;
                keepGoing=whoWins(gameBoard, gameBoardSize);
                //human cycle over
                if (keepGoing > TIE)
                {
                    displayGame(gameBoard, gameBoardSize);
                    choice = getComputerMove(gameBoard, gameBoardSize);
                    gameBoard[choice] = computer;
                    keepGoing = whoWins(gameBoard, gameBoardSize);
                    //computer cycle over
                }
            }
            else if (computer == X_PIECE && keepGoing > TIE)//if computer is first it uses this sequence
            {
                displayGame(gameBoard, gameBoardSize);
                choice = getComputerMove(gameBoard, gameBoardSize);
                gameBoard[choice] = computer;
                keepGoing = whoWins(gameBoard, gameBoardSize);
                //computer cycle over
                if (keepGoing > TIE) {
                    displayGame(gameBoard, gameBoardSize);
                    choice = getHumanMove();
                    gameBoard[choice] = human;
                    keepGoing = whoWins(gameBoard, gameBoardSize);
                    //human cycle over
                }
            }

        } while (keepGoing > TIE); //if greater than tie should always keep going

        switch (keepGoing)
        {
        case 1:
            cout << "\n\nX WINS!\n \n\nX WINS!\n \n\nX WINS!\n\n";
            displayGame(gameBoard, gameBoardSize);
            break;

        case 2:
            cout << "\n\nO WINS!\n \n\nO WINS!\n \n\nO WINS!\n\n";
            displayGame(gameBoard, gameBoardSize);
            break;
        case 3:
            cout << "\n\nIt's a Tie, better luck next time.\n";
            displayGame(gameBoard, gameBoardSize);
            break;
        }

        cout << "\nPress any key to play again.\n";
        system("pause");

    }
    system("pause");
    return 0;
}

void displayRules()
{
    cout << "\nWelcome to the game of Tic-Tac-Toe!";
    cout << "\n\nMake your move known by entering a number, 0-8.";
    cout << "The number \ncorresponds to the desired board position as shown below: \n\n";

    for (int i = 0; i < 9; i++)
    {
        cout << i;
        if (i == 0 || i == 1 || i == 3 || i == 4 || i == 6 || i == 7)
        {
            cout << " | ";
        }
        if (i == 2 || i == 5)
        {
            cout << "\n----------\n";
        }
    }
    cout << "\n\n";
}

void displayGame(gamePiece game[], const int size)  //passes this function gameBoard array and size of the array
{
    for (int i = 0; i < 9; i++)
    {
        cout << (char)game[i]; //cast enums to X, O, Blank space
        if (i == 0 || i == 1 || i == 3 || i == 4 || i == 6 || i == 7)
        {
            cout << " | ";
        }
        if (i == 2 || i == 5)
        {
            cout << "\n----------\n";
        }
    }
    cout << "\n\n";
}

gamePiece whoFirst()
{
    cout << "\n\Would you like to go first? Enter Y for yes or N for no. ";
    char move = readChar();  //checks for valid char, function from fund.1

    if (move == 'Y')
    {
        return X_PIECE;  //based on y or n they will be assigned to X or O
    }
    else
    {
        return O_PIECE;
    }
}

int getHumanMove()
{
    cout << "\nWhere will you move? (0-8): ";
    return readInt("your choice", 0, 8);
}

int getComputerMove(gamePiece game[], const int size)
{
    int choice;
    const int BEST_MOVES[] = { 4, 0, 2, 6, 8, 1, 3, 5, 7 };
    for (int i = 0; i < 9; i++)
    {
        choice = BEST_MOVES[i];
        if(game[choice]==EMPTY_PIECE) //checks if square chosen is empty returns choice if true
        {
            cout << "You cannot out smart me. I choose square " << choice << endl << endl;
            return choice;
        }
    }
}

gameState whoWins(gamePiece game[], const int size)
{   //checks all winning combos
    if (game[0] == X_PIECE && game[1] == X_PIECE && game[2] == X_PIECE ||
        game[3] == X_PIECE && game[4] == X_PIECE && game[5] == X_PIECE ||
        game[6] == X_PIECE && game[7] == X_PIECE && game[8] == X_PIECE ||
        game[0] == X_PIECE && game[3] == X_PIECE && game[6] == X_PIECE ||
        game[1] == X_PIECE && game[4] == X_PIECE && game[7] == X_PIECE ||
        game[2] == X_PIECE && game[5] == X_PIECE && game[8] == X_PIECE ||
        game[0] == X_PIECE && game[4] == X_PIECE && game[8] == X_PIECE ||
        game[2] == X_PIECE && game[4] == X_PIECE && game[6] == X_PIECE)
    {
        return X_WINS;
    }

    else if (game[0] == O_PIECE && game[1] == O_PIECE && game[2] == O_PIECE ||
        game[3] == O_PIECE && game[4] == O_PIECE && game[5] == O_PIECE ||
        game[6] == O_PIECE && game[7] == O_PIECE && game[8] == O_PIECE ||
        game[0] == O_PIECE && game[3] == O_PIECE && game[6] == O_PIECE ||
        game[1] == O_PIECE && game[4] == O_PIECE && game[7] == O_PIECE ||
        game[2] == O_PIECE && game[5] == O_PIECE && game[8] == O_PIECE ||
        game[0] == O_PIECE && game[4] == O_PIECE && game[8] == O_PIECE ||
        game[2] == O_PIECE && game[4] == O_PIECE && game[6] == O_PIECE)
    {
        return O_WINS;
    }


    for (int i = 0; i < 9; i++)
    {

        if (game[i]==EMPTY_PIECE)
        {
            return NOT_OVER;
        }
    }
    //if all prior fail it must be a tie
    return TIE;
}