/**
 * Tic Tac Toe Game in Console
 * @author Bruce Zou
 */
import java.util.*;

public class TicTacToe {
	public static final int board_size = 3;
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		int[][] board = createBoard(board_size);
		boolean whoseTurn = true; //keeps track of whose turn it is true = p1 false = p2.
		int turnsTaken = 0;

		while(checkWinner(board)==0 && turnsTaken<board_size*board_size) {
			int row, col;

			do {
				if(whoseTurn) System.out.println("Player 1");
				else System.out.println("Player 2");
				System.out.println("Enter row you want to play (0-2): ");
				row = in.nextInt();
				System.out.println("Enter col you want to play (0-2): ");
				col = in.nextInt();
			}while(board[row][col]!=0);

			//Update the game board according to the player's chosen location
			if(whoseTurn) board[row][col]=1;
			else board[row][col]=2;
			drawBoard(board);
			whoseTurn=!whoseTurn;
			turnsTaken++;
		}
		displayWinner(checkWinner(board));
		}

	/**
	 * Creates an array filled with 0's as the initial game board of dimensions size x size
	 * @param size size of one side of the game board
	 * @return An array representation of the board (size x size)
	 */
	public static int[][] createBoard(int size){
		int[][] board = new int[size][size];
		for(int[] row : board)
			Arrays.fill(row, 0);
		return board;
	}

	/**
	 * Helper method to draw the horizontal lines by multiplying the given string a set number of times
	 * @param s String to multiply
	 * @param n number of times to duplicate/multiply the string
	 * @return a string that contains the String s n times
	 */
	public static String StringMultiply(String s, int n) {
		StringBuilder sb = new StringBuilder();
		for(int i=0;i<n;i++) {
			sb.append(s);
		}
		return sb.toString();
	}

	/**
	 * Draws the board in it's current state
	 * @param board Current game board
	 */
	public static void drawBoard(int[][] board) {
		for(int i=0;i<board.length;i++) {
			System.out.println(StringMultiply("----",board_size)); //Print horizontal lines
			for(int j=0;j<board.length;j++) {

				//Set string to fill that box of the grid
				String out = " ";
				if(board[i][j]==1) out = "X";
				else if(board[i][j]==2) out = "O";

				System.out.print("| " + out + " "); //Print numbers and vertical lines
				if(j==board.length-1) System.out.print("|\n"); //Print the last vertical line
			}
		}
		System.out.println(StringMultiply("----",board_size)); //Print the last horizontal line
	}


	/**
	 * Checks if there is a winner in the current board's state
	 * @param board Current game board
	 * @return 1 or 2 if that player has won. 0 if no player won
	 */
	public static int checkWinner(int[][] board) {
		//Check Row Winner
		for(int i=0;i<3;i++) {
			//Create a set of the current row
			Integer[] rowToCheck = {board[i][0],board[i][1],board[i][2]};
			Set<Integer> row = new HashSet<Integer>(Arrays.asList(rowToCheck));
			//Winner if the set only has 1 value and it isn't 0
			if(row.size()==1 && board[i][0]!=0)
				return board[i][0];
		}

		//Check Col Winner
		for(int i=0;i<3;i++) {
			//Create a set of the current col
			Integer[] colToCheck = {board[0][i],board[1][i],board[2][i]};
			Set<Integer> col = new HashSet<Integer>(Arrays.asList(colToCheck));
			//Winner if the set only has 1 value and it isn't 0
			if(col.size()==1 && board[0][i]!=0)
				return board[0][i];
		}

		//Check Diagonal
		//Create a set for each diagonal
		Integer[] diag1ToCheck = {board[0][0],board[1][1],board[2][2] };
		Integer[] diag2ToCheck = {board[0][2],board[1][1],board[2][0] };
		Set<Integer> diag1 = new HashSet<Integer>(Arrays.asList(diag1ToCheck));
		Set<Integer> diag2 = new HashSet<Integer>(Arrays.asList(diag2ToCheck));
		//Winner if either set has only 1 value and that value isn't 0
		if(diag1.size()==1 || diag2.size()==1 && board[1][1]!=0)
			return board[1][1];


		return 0;
	}

	/**
	 * Prints out the winner of the game.
	 * @param winner The int result of the checkWinner method
	 */
	public static void displayWinner(int winner) {
		if(winner!=0)
			System.out.println("Player " + winner + " wins!");
		else
			System.out.println("Tie.");
	}
}