#include <iostream>
using namespace std;
#include <iomanip>
#include <ctime>

enum  YNAns {Yes, No};
enum  MoveResult {Win, Done, Continue};
enum  messages {YouWin, YouLose, TieGame, SeeYa};
char  *endMessage[] = 
{
   "\n***** Congratulations!! You are a winner! *****\n\n",
   "\n***** Too bad.  I win again. *****\n\n",
   "\n***** Nobody Wins -- It's a tie! *****\n\n",
   "\n***** Game Over.  Thanks for playing! *****\n\n"
};

char  startBoard[] = {'0','1','2','3','4','5','6','7','8'};
char  gameBoard[] = {' ',' ',' ',' ',' ',' ',' ',' ',' '};

YNAns DisplayIntro();
// ***** This routine has already been coded below *******
void  DisplayBoard(char board[]);
// ***** This routine has already been coded below *******
YNAns getYesNoAns(const char* question);


void  coinToss(char &comptr, char &humn);
bool  winner(char bd[], char moveVal);


MoveResult ComputerMove(char bd[], char cMoveVal, char hMoveVal);
MoveResult humanMove(char bd[], char humMoveVal);


// ***** This routine has already been coded below *******
bool  isLegal(int move, char bd[], bool supressOutput = true);


// ***** This routine has already been coded below *******
void  DisplayEndMsg(char **MsgArr, messages msgIdx);


int main()
{
	bool win = false;
	int counter = 1;
	int lastturn = 0;
	char comptr, humn;

   if (getYesNoAns("\nDo you wish to play? Enter 'y' or 'n': ") == Yes)
      cout << "The answer was Yes.\n";
   else
      cout << "The answer was No.\n";

   cout << "These are the keys that you need to press to play the game." << endl;

   DisplayBoard(startBoard);

	cout << "Now we are going to flip a coin to determine who goes first." << endl;
	coinToss(comptr, humn);

	cout << "Here is the current game board layout:" << endl;

	DisplayBoard(gameBoard);

		if (comptr == 'x')
		{
			cout << "The computer went first, here is the board." << endl;
			ComputerMove(gameBoard, comptr, humn);
			counter++;
			lastturn = 1;
		}
		else
		{

			humanMove(gameBoard, humn);
			counter++;
			lastturn = 2;
		}

		while(win != true && counter < 9)
		{
			//lastturn {computer = 1, player = 2
			if(lastturn == 1)
			{
				humanMove(gameBoard, humn);
				counter++;
				lastturn = 2;
			}
			else
			{
				ComputerMove(gameBoard, comptr, humn);
				counter++;
				lastturn = 1;
			}
		}
		if(counter == 9)
		{
			if(win == true)
			{
				if(lastturn == 1)
				{
					cout << endMessage[1] << endl;
					cout << "Here is the final game board:" << endl;
					DisplayBoard(gameBoard);
				}
				else
				{
					cout << endMessage[0] << endl;
					cout << "Here is the final game board:" << endl;
					DisplayBoard(gameBoard);
				}
			}
			else
			{
				cout << endMessage[3] << endl;
				cout << "Here is the final board." << endl;
				DisplayBoard(gameBoard);
			}
		}
		cout << endMessage[4] << endl;
		return 0;
}

void  coinToss(char &comptr, char &humn)
{
	srand(time(0));

	int random_integer = rand()%2; 

	if (random_integer == 1)
	{
		cout << "Coin was flipped, heads landed." << endl;
		comptr = 'x';
		humn = 'o';
	}
	else
	{
		cout << "Coin was flipped, tails landed." << endl;
		comptr = 'o';
		humn = 'x';
	}

	cout << "Human is " << humn << " and Computer is " << comptr << "." << endl;

}


YNAns getYesNoAns(const char *question)
{
   char  resp;

   do
   {
      cout << question;
      cin >> resp;
   }while(resp != 'y' && resp != 'Y' && resp != 'n' && resp != 'N'); 

   if (resp == 'y' || resp == 'Y')
      return Yes;

   return No;
}


void  DisplayEndMsg(char **msgArr, messages msgIdx)
{
   cout << msgArr[msgIdx];
}



void  DisplayBoard(char bd[])
{
   cout << endl;
   cout << fixed << setw(1);
   cout << "\t-------------\n";
   for(int i=0; i<=2; i++)
   {
      cout << "\t";
      cout << "| " << bd[i*3] << " | ";
      cout <<  bd[i*3+1] << " | ";
      cout << bd[i*3+2] << " |" << endl;
      cout << "\t";
      cout << "-------------" << endl;
   }
   cout << endl;
}


bool  isLegal(int move, char bd[], bool supressOutput)
{
   if ((move < 0) || (move > 8) || (bd[move] != ' '))
   {
      if (!supressOutput)
         cout << "Illegal Move\n";
      return false;
   }
   return true;
}


bool  winner(char bd[], char moveVal)
{
   const int WINVALS[8][3] = {
      {0,1,2},
      {3,4,5},
      {6,7,8},
      {0,3,6},
      {1,4,7},
      {2,5,8},
      {0,4,8},
      {2,4,6} 
   };

   return true;

}

MoveResult humanMove(char bd[], char humMoveVal)
{
	int input = 0;
	bool okay = false;

	while(okay == false)
	{
		cout << "It is your turn to pick a spot to go." << endl;
		cin >> input;

		if(gameBoard[input] != ' ')
		{
			cout << "That spot is taken, please pick another spot." << endl;
		}
		else
		{
			okay = true;
		}
	}
	gameBoard[input] = humMoveVal;
	return Continue;
	



}

MoveResult   ComputerMove(char bd[], char compMoveVal, char humMoveVal)
{
   const int BEST_MOVES[] = {4,0,2,6,8,1,3,5,7};
    /*Logic:
	1. Check spaces to see if can win.
	2. Check spaces to see if can block.
	3. Pick BEST_MOVES spot.
	compMoveVal = computer's letter.
	humMoveVal = human's letter.

	const int WINVALS[8][3] =
					_______________
	{0,1,2}			|  0 | 1  | 2  |
    {3,4,5}			|____|____|____|
    {6,7,8}			|  3 | 4  | 5  |
    {0,3,6}			|____|____|____|
    {1,4,7)			|  6 | 7  | 8  |
    {2,5,8}			|____|____|____|
    {0,4,8}
    {2,4,6}
   */

   for(int i = 0; i < 9; i++)
   {
		if(isLegal(i, gameBoard) == true)
		{
			gameBoard[i] = compMoveVal;
			if(winner(gameBoard, compMoveVal) == true)
			{
				cout << "I shall take square number: " << i << endl;
				DisplayEndMsg(endMessage, YouLose);
				DisplayBoard(bd);
				return Win;
			}
			gameBoard[i] = ' ';
		}
   }	
   for(int j = 0; j < 9; j++)
   {
	   if(isLegal(j, gameBoard) == true)
	   {
			gameBoard[j] = humMoveVal;

			if(winner(gameBoard, humMoveVal) == true)
			{
				cout << "I shall take square number: " << j << endl;
				gameBoard[j] = compMoveVal;
				DisplayBoard(bd);
				return Continue;
			}
			bd[j] = ' ';
	   }

   }
   for(int k = 0; k < 9; k++)
   {
	   if(isLegal(BEST_MOVES[k], gameBoard) == true)
	   {
		   cout << "I shall take square number: " << BEST_MOVES[k] << endl;
		   gameBoard[BEST_MOVES[k]] = compMoveVal;
		   DisplayBoard(gameBoard);
			return Continue;
	   }
   }
   cout << "I shouldn't be here!" << endl;
   return Continue;
}