/******************************************************************************
* Description	: Tic Tac Toe game
* Author	: dsl
*
* Write a program that lets two humans play a game of Tic Tac Toe in a
* terminal. The program should let the players take turns to input their
* moves. The program should report the outcome of the game.
*
* During your interview, you will pair on adding support for a computer player
* to your game. You can start with random moves and make the AI smarter if you
* have time.
****************************************************************************/

#include <stdio.h>

int isWinner();
int status;
int move;
int selected;
int player = 1;

char position[] = {'1', '2', '3', '4', '5', '6', '7', '8', '9'};
char playerSymbol;

void gameBoard()
{
	int boardSize 	= sizeof(position)/sizeof(position[0]);

	for (int i = 0; i < boardSize; i++) {
		printf(" %c |", position[i]);
		if ( i == 2 || i == 5) {
			printf("\n------------\n");
		}
	}
}

int play()
{
	const int MIN = 0;
	const int MAX = 9;

	status = isWinner(); // -1 when in play

	while (status == -1) {
		if (player == 1) {
			playerSymbol = 'X';
		} else {
			playerSymbol = 'O';
		}

		printf("\n\nOk %c, it's your move. Which square? ", playerSymbol);

		do {
			scanf("%d", &move);

			if (move < MIN || move > MAX) {
				printf("\nWrong input\n");
				fflush(stdin);
			}
		} while (move < MIN || move > MAX);

		printf("\n\n");
		selected = move - 1 ;

		if (player == 1) {
			position[selected] = 'X';
			player--;
		} else {
			position[selected] = 'O';
			player++;
		}

		gameBoard();
		status = isWinner();
	}

	if (status == 1) {
		printf("\nWe have a WIENER.\n");
		if (player == 0) {
			printf("X wins!\n");
		} else if (player == 1) {
			printf("O wins!\n");
		}
	}

	return 0;
}

int isWinner()
{
	if (position[0] == position[1] && position[1] == position[2]) {
		return 1;
	} else if (position[3] == position[4] && position[4] == position[5]) {
		return 1;
	} else if (position[6] == position[7] && position[7] == position[8]) {
		return 1;
	} else if (position[0] == position[3] && position[3] == position[6]) {
		return 1;
	} else if (position[1] == position[4] && position[4] == position[7]) {
		return 1;
	} else if (position[2] == position[5] && position[5] == position[8]) {
		return 1;
	} else if (position[0] == position[4] && position[4] == position[8]) {
		return 1;
	} else if (position[2] == position[4] && position[4] == position[6]) {
		return 1;
	} else if (position[0] != '1' && position[1] != '2' && position[2] != '3' && position[3] != '4' && position[4] != '5' && position[5] != '6' && position[6] != '7' && position[7] != '8' && position[8] != '9'){
		printf("\nYou both failed to best each other. For shame! Game is null.\n");
		return 0;
	} else {
		return -1;
	}
}

int main()
{
	printf("Hello, players!\nX starts.\n\nHere be the board: \n\n");
	gameBoard();
	play();
}