library ieee;
use ieee.std_logic_1164.all;

entity key is
	port (clk, rst   : in std_logic;
	      keypad     : in std_logic_vector(7 downto 0);
	      door, beep : out std_logic);
end key;

architecture JMJS_Logic of key is
	type states is (state0, state1, state2, state3, state4, Err1, Err2, Err3, Err4);
	signal state : states;
	signal key_en1, key_en : std_logic;
begin
	process(clk, rst, keypad)
	begin
		key_en <= keypad(0) or keypad(1) or keypad(2) or keypad(3) or keypad(4) or keypad(5) or keypad(6) or keypad(7);
		if (clk'event and clk='1') then
			key_en1 <= key_en;
		end if;

		if (rst = '1') then
			state <= state0;
		elsif (clk'event and clk='1') then
			case state is
				when state0 =>
					if (key_en1='0' and key_en='1') then
						if (keypad(3)='1') then
							state <= state1;
						else
							state <= Err1;
						end if;
					end if;
				when state1 =>
					if (key_en1='0' and key_en='1') then
						if (keypad(7)='1') then
							state <= state2;
						else
							state <= Err2;
						end if;
					end if;
				when state2 =>
					if (key_en1='0' and key_en='1') then
						if (keypad(2)='1') then
							state <= state3;
						else
							state <= Err3;
						end if;
					end if;
				when state3 =>
					if (key_en1='0' and key_en='1') then
						if (keypad(5)='1') then
							state <= state4;
						else
							state <= Err4;
						end if;
					end if;
				when state4 => state <= state0;
				when Err1 => 
					if (key_en1='0' and key_en = '1') then 
						state <= Err2;
					else
						state <= Err1;
					end if;
				when Err2 =>
					if (key_en1='0' and key_en = '1') then
						state <= Err3;
					else
						state <= Err2;
					end if;
				when Err3 =>
					if (key_en1='0' and key_en = '1') then
						state <= Err4;
					else
						state <= Err3;
					end if;
				when Err4 => state <= state0;
			end case;
		end if;
	end process;

	process (clk)
	begin
		if (rst = '1') then
			door <= '0';
			beep <= '0';
		elsif (clk'event and clk='1') then
			case state is
				when state4 =>
					door <= '1';
					beep <= '0';
				when Err4 =>
					door <= '0';
					beep <= '1';
				when others =>
					door <= '0';
					beep <= '0';
			end case;
		end if;
	end process;

end JMJS_Logic;