PART B

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity my_pass_setter is
    generic (
        g_max_attempt       :   integer                 := 16;
        g_password_width    :   positive range 4 to 16  := 16;
        g_sys_freq          :   integer                 := 100000000
    );
    port (
        clk : in std_logic;
        reset : in std_logic;

        btn_down    :   in  std_logic;
        sw          :   in  std_logic_vector(15 downto 0);

        pass        :   out std_logic_vector(15 downto 0);
        new_pass    :   out std_logic;
        leds        :   out std_logic_vector(15 downto 0)
    );
end my_pass_setter;

architecture behavioral of my_pass_setter is

    constant    c_one_second_count      :   integer                         := g_sys_freq;
    constant    c_three_second_count    :   integer                         := 3* c_one_second_count;
    constant    c_default_psw           :   std_logic_vector(pass'range)    := std_logic_vector(to_unsigned(1,pass'length));

    constant    c_debug_ns_count        :   integer                         := 300 ;
    constant    c_debug_count_ccycles   :   integer                         := (c_debug_ns_count/10**2)*(g_sys_freq/(10**7));

    type state_type is (IDLE,
                        CHECK_BTN,
                        READ_SW_SET_PASS,
                        LED_ON_1_SEC
                        );


    signal state : state_type   := IDLE;
    --signal    r_switch    :   std_logic_vector(sw'RANGE)  := (others => '0') ;
    signal  r_counter       :   integer                     := 0;
    signal  r_new_pass      :   std_logic_vector(pass'range):= c_default_psw;
    signal  r_leds          :   std_logic_vector(leds'range):= c_default_psw;
    signal  r_new_psw_flag  :   std_logic                   := '0';

    begin

    pass        <= r_new_pass;
    leds        <= r_leds;
    new_pass    <= r_new_psw_flag;

    FSM_PROC : process(clk)
    begin
        if rising_edge(clk) then
            if reset = '1' then
                state       <= IDLE;
                r_new_pass  <= c_default_psw;
                r_leds      <= c_default_psw;
            else
                case state is

                    when IDLE =>
                                    state   <= CHECK_BTN;
                    when CHECK_BTN  =>

                                    if btn_down = '1' then
                                        r_counter <= r_counter + 1;
                                        if r_counter = c_debug_count_ccycles-1 then
                                            state       <= READ_SW_SET_PASS;
                                            r_new_pass  <= (others => '0'); -- devo settarle entrambe a 0 altrimenti ho
                                            r_leds      <= (others => '0');  -- la parte della vecchia password in mezzo alle palle
                                            r_counter   <= 0;
                                        end if;
                                    else
                                        r_counter <= 0;
                                    end if;

                    when READ_SW_SET_PASS   =>

                                    r_new_pass      <=  r_new_pass(r_new_pass'high downto r_new_pass'low + g_password_width  )  & sw(g_password_width-1 downto 0);
                                    r_leds          <=  r_leds(r_new_pass'high downto r_new_pass'low + g_password_width )           & sw(g_password_width-1 downto 0);
                                    r_new_psw_flag  <= '1';
                                    state           <= LED_ON_1_SEC;

                    when LED_ON_1_SEC   =>

                                    r_new_psw_flag  <= '0';

                                    if r_counter = c_one_second_count-1 then
                                        r_counter   <=  0;
                                        r_leds      <=  (others => '0');
                                        state       <=  CHECK_BTN;
                                    else
                                        r_counter   <= r_counter + 1;
                                    end if;

                end case;

            end if;
        end if;
    end process;



end architecture;