Library ieee;
Use ieee.std_logic_1164.all;
Use ieee.numeric_std.all;

entity elevador IS
	PORT    (ck,
				clk_button,
				rst_button, -- SW[0]
				rst_db, -- SW[1]
				botoes_andar_switch0, --SW[9]
				botoes_andar_switch1, --SW[8]
				botoes_andar_switch2, --SW[7]
				botoes_andar_switch3 --SW[6]
					: IN STD_LOGIC;

				ANDAR_REQUISITADO_LED, -- LED[9-6]
				ANDAR_ATUAL_LED -- LED[5-2]
					: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);

				STATE_RESPONSE -- LED[1-0] -- diz se o elevador esta parado "00", subindo "01" ou descendo "11"
					: OUT STD_LOGIC_VECTOR(1 DOWNTO 0)
			);
end elevador;

ARCHITECTURE arch OF elevador IS
	COMPONENT debouncer
	PORT(
		clk, rst_n, inb : in STD_LOGIC;
		outb : OUT STD_LOGIC
	);
	END COMPONENT;

	TYPE st IS (parado, subindo, descendo);
	SIGNAL estado : st;
	SIGNAL   out_clk_db,
				out_rst_db,
				botoes_andar0,
				botoes_andar1,
				botoes_andar2,
				botoes_andar3
					: STD_LOGIC;
	SIGNAL andar_atual, andar_requisitado : STD_LOGIC_VECTOR (3 downto 0);

	BEGIN
		D1 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => clk_button, outb => out_clk_db);
		D2 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => rst_button, outb => out_rst_db);
		D3 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => botoes_andar_switch0, outb => botoes_andar0);
		D4 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => botoes_andar_switch1, outb => botoes_andar1);
		D5 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => botoes_andar_switch2, outb => botoes_andar2);
		D6 : debouncer PORT MAP(clk => ck, rst_n => rst_db, inb => botoes_andar_switch3, outb => botoes_andar3);

		PROCESS(out_clk_db, out_rst_db)
		BEGIN

		IF out_rst_db = '1' THEN
			estado <= parado;
			andar_atual <= "0000";
			ANDAR_ATUAL_LED <= "0000";
			ANDAR_REQUISITADO_LED <= "0000";
			STATE_RESPONSE <= "00";
		ELSIF rising_edge(out_clk_db) THEN
				CASE estado IS

------------------------------------------------------------------------------------
						WHEN parado =>
							STATE_RESPONSE <= "00";
							andar_requisitado <= "0000";
							IF (botoes_andar0 = '1') THEN
								andar_requisitado <= std_logic_vector(unsigned(andar_requisitado) + "0001");
							END IF;
							IF (botoes_andar1 = '1') THEN
								andar_requisitado <= std_logic_vector(unsigned(andar_requisitado) + "0010");
							END IF;
							IF (botoes_andar2 = '1') THEN
								andar_requisitado <= std_logic_vector(unsigned(andar_requisitado) + "0100");
							END IF;
							IF (botoes_andar3 = '1') THEN
								andar_requisitado <= std_logic_vector(unsigned(andar_requisitado) + "1000");
							END IF;

							ANDAR_REQUISITADO_LED <= andar_requisitado;

							IF (to_integer(unsigned(andar_requisitado)) > to_integer(unsigned(andar_atual))) THEN
								estado <= subindo;
							ELSIF (to_integer(unsigned(andar_requisitado)) < to_integer(unsigned(andar_atual))) THEN
								estado <= descendo;
							ELSE
								estado <= parado;
							END IF;
------------------------------------------------------------------------------------
						WHEN subindo =>
							STATE_RESPONSE <= "01";
							IF (to_integer(unsigned(andar_requisitado)) > to_integer(unsigned(andar_atual))) THEN
								andar_atual <= std_logic_vector(unsigned(andar_atual) + "0001");
								ANDAR_ATUAL_LED <= andar_atual;
							ELSE
								estado <= parado;
							END IF;
------------------------------------------------------------------------------------
						WHEN descendo =>
							STATE_RESPONSE <= "11";
							IF (to_integer(unsigned(andar_requisitado)) < to_integer(unsigned(andar_atual))) THEN
								andar_atual <= std_logic_vector(unsigned(andar_atual) - "0001");
								ANDAR_ATUAL_LED <= andar_atual;
							ELSE
								estado <= parado;
							END IF;
------------------------------------------------------------------------------------


				END CASE;
			END IF;
		END process;

	END arch;