game_board.sv

module game_board
(
	input [0:5] x_1,
	input [0:5] y_1, 
	input [0:5] x_2,
	input [0:5] y_2,
	input 		compute_move,
	
	output [0:5]	x_out,
	output [0:5] 	y_out 
);

// 19x19 array of 4 bit registers. 
// reg =     XX | XXXX
//           54   3210 
//      (Player) (Board Weight)
// ---------------------------------
// Players = 	0 - Not Played
//					1 - Us
//					2 - Them
reg [4:0] game_board [0:18] [0:18];

// This will be called only on the first initilization of the gameboard. 
// It will initilize all of the player indicators to 0 and all of the 
// gameboard weights to a default value of 6. 
initial begin
	integer x; 
	integer y; 
	
	for( x = 0; x < 19; x = x + 1 ) begin
		for( y = 0; y < 19; y = y + 1 ) begin
			reg [0:5] temp = game_board[x][y]; 
			temp[0:3] = 6; 
			temp[4:5] = 0; 
			game_board[x][y] = temp; 
		end
	end
end

task modify_board; 
	input [0:5] x; 
	input [0:5] y; 
	input 		player; 
	
	begin
		// 0 should be the weight you figure out :) 
		reg [0:3] temp = 0; 
		temp[0][4] = player; 
		game_board[x][y] = temp; 
	end
endtask

// This is responsible for determining where we will play. 
// Default weighting of the board is 6. If it is greater
// than 9 we will play defensively. Less than 3 we play 
// offensively. starts with a win condition check. 
task play_move;
	reg [3:0] 	current_weight; 
	int 			moves_left;
	int			count_up; 
	int			count_up_right; 
	int 			count_right;
	int			count_down_right; 
	int			count_down; 
	int 			count_down_left; 
	int 			count_left; 
	int			count_up_left; 
	
	begin
		while( moves_left > 0 && moves_left <= 2 ) begin
			
			///// START WIN CONDITION CHECKING
			for( int x = 0; x < 19; x++) begin
				for( int y = 0; y < 19; y++ ) begin
					integer steps = 0; 
					// look up
					while( steps < 6 && y+steps > 0 && y+steps < 19 ) begin
						reg [0:5] temp = game_board[x][y+steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_up++; 									
						end
						steps++; 
					end
					if( count_up > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x][y+z]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x, y+z, 1 );									
							end
						end
					end
					// look up && Right
					while( steps < 6 && y+steps > 0 && y+steps < 19 && x+steps > 0 && x+steps < 19) begin
						reg [0:5] temp = game_board[x+steps][y+steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_up_right++; 									
						end
						steps++; 
					end
					if( count_up_right > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x+z][y+z]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x+z, y+z, 1 );									
							end
						end
					end
					// look RIGHT
					while( steps < 6 && x+steps > 0 && x+steps < 19 ) begin
						reg [0:5] temp = game_board[x+steps][y]; 
						if( temp[0][4:5] == 1 ) begin 
							count_right++; 									
						end
						steps++; 
					end
					if( count_right > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x+z][y]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x+z, y, 1 );									
							end
						end
					end
					// look Down && Right
					while( steps < 6 && y-steps > 0 && y-steps < 19 && x+steps > 0 && x+steps < 19) begin
						reg [0:5] temp = game_board[x+steps][y-steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_down_right++; 									
						end
						steps++; 
					end
					if( count_down_right > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x-z][y+z]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x-z, y+z, 1 );									
							end
						end
					end
					// Look DOWN
					while( steps < 6 && y-steps > 0 && y-steps < 19 ) begin
						reg [0:5] temp = game_board[x][y-steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_down++; 									
						end
						steps++; 
					end
					if( count_down > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x-z][y]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x-z, y, 1 );									
							end
						end
					end
					// look Down && LEFT
					while( steps < 6 && y-steps > 0 && y-steps < 19 && x-steps > 0 && x-steps < 19) begin
						reg [0:5] temp = game_board[x-steps][y-steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_down_left++; 									
						end
						steps++; 
					end
					if( count_down_left > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x-z][y-z]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x-z, y-z, 1 );									
							end
						end
					end
					// look LEFT
					while( steps < 6 && x-steps > 0 && x-steps < 19 ) begin
						reg [0:5] temp = game_board[x-steps][y]; 
						if( temp[0][4:5] == 1 ) begin 
							count_left++; 									
						end
						steps++; 
					end
					if( count_left > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x-z][y]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x-z, y, 1 );									
							end
						end
					end
					// look up && left
					while( steps < 6 && y+steps > 0 && y+steps < 19 && x-steps > 0 && x-steps < 19) begin
						reg [0:5] temp = game_board[x-steps][y+steps]; 
						if( temp[0][4:5] == 1 ) begin 
							count_up_right++; 									
						end
						steps++; 
					end
					if( count_up_left > 3 ) begin
						for( int z = 0; z < 6; z++ ) begin
							reg [0:5] temp = game_board[x-z][y+z]; 
							if( temp[0][4:5] == 0 ) begin 
								modify_board( x-z, y+z, 1 );									
							end
						end
					end
				end
			end
			///// END WIN CONDITION CHECKING
			
			if( moves_left > 0 ) begin
				// look for defensive plays
				integer break_out1 = 0; 
				for( int x = 0; x < 19; x = x + 1 ) begin
					for( int y = 0; y < 19; y = y + 1 ) begin
						current_weight = game_board[x][y]; 
						if( current_weight == 11 ) begin
							modify_board( x, y, 1 ); 
							moves_left = moves_left -1; 
							break_out1 = 1; 
							break; 
						end
						else if( current_weight == 10 ) begin
							modify_board( x, y, 1 ); 
							moves_left = moves_left -1; 
							break_out1 = 1; 
							break; 
						end
						else begin
							// keep calm and carry on. 
						end
					end
					if( break_out1 == 1 ) begin
							break; 
					end
				end
				
				if( moves_left > 0 ) begin
					// look for offsensive moves :) 
					integer break_out2 = 0; 
					for( int x = 0; x < 19; x++ ) begin
						for( int y = 0; y < 19; y++ ) begin
							current_weight = game_board[x][y]; 
							if( current_weight == 3 ) begin
								modify_board( x, y, 1 ); 
								moves_left = moves_left -1; 
								break_out2 = 1; 
								break; 
							end
							else if( current_weight == 2 ) begin
								modify_board( x, y, 1 ); 
								moves_left = moves_left -1; 
								break_out2 = 1; 
								break; 
							end
							else begin
								// keep calm and carry on.
							end
						end
						if( break_out2 == 1 ) begin
							break; 
						end
					end
				end
			end
		end
	end
endtask

always @( compute_move ) begin

	
	if( !compute_move )begin			// PLACE OPPONENT MOVE
		modify_board( x_1, y_1, 0 ); 
		modify_board( x_2, y_2, 0 ); 
	end
	else if( compute_move ) begin		// COMPUTE OUR MOVE ... PLACE OUR MOVE
		play_move(); 
	end
	else begin									// SHIT GOT WEIRD 
	end
end

endmodule