typedef enum {OPEN, CLOSED} door;
typedef enum {UNHEATED, HEATING, HEATED} coil;
typedef enum {NOTSTARTED, STARTED} start;
typedef enum {NOERROR, ERROR} error;


//**********************************************
module main(clk);
input clk;
door reg oven_door;
coil reg oven_coil;
start reg oven_start;
error reg oven_error;
wire random;
wire random1;
wire delay;
wire delay2;

initial begin
	oven_door = OPEN;
	oven_coil = UNHEATED;
	oven_start = NOTSTARTED;
	oven_error = NOERROR;
end

assign random = $ND(0, 1);
assign delay = $ND(0, 1);

assign random1 = $ND(0, 1);
assign delay2 = $ND(0, 1);

always@(posedge clk) begin
	if(random) oven_door = OPEN;
	else oven_door = CLOSED;

	if(oven_error == ERROR && oven_door == CLOSED && delay) begin
		oven_error = NOERROR;
		oven_start = NOTSTARTED;
		oven_coil = UNHEATED;
	end

	else begin
		oven_start = STARTED;
	
		if(oven_door == OPEN) 
			oven_error = ERROR;
		else
			oven_coil = HEATING;
	end
end


always@(posedge clk) begin
	if(random1) oven_door = OPEN;
	else oven_door = CLOSED;

	if(oven_door == OPEN && oven_coil == HEATING) begin
		oven_start = NOTSTARTED;
		oven_coil = UNHEATED;
	end
	else begin
		if(delay2)
			oven_coil = HEATED;
	end
end
endmodule