library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use ieee.numeric_std.all;

entity SevenSegment is
    Port (  clk: in std_logic;
        --seg_value : in  STD_LOGIC_VECTOR (0 to 6);
        seg_value : in  STD_LOGIC_VECTOR (3 downto 0);
        dp_value: in  std_logic_vector(0 to 3);
        seg : out  STD_LOGIC_VECTOR (0 to 6) := "1111111";
        dp: out std_logic;
        an: out std_logic_vector (0 to 3));
end SevenSegment;

architecture Behavioral of SevenSegment is
signal clock_7segment:std_logic := '0';
signal current : STD_LOGIC_VECTOR (0 to 6) := "1111111";
begin
    process (clk)
    variable counter: integer := 0;
    begin
        if(clk 'event and clk = '1') then
        if(counter >= 0 and counter < 100) then
            counter := counter +1;
            clock_7segment <= '0';
        elsif (counter < 200) then
            counter := counter +1;
            clock_7segment <= '1';
        else
            counter := 0;
        end if;
        end if;
    end process;
    process (clock_7segment)
    variable state : integer := 0;

    begin
    if(clock_7segment'event and clock_7segment = '1') then
        if(state =0) then
            if (seg_value(3) = '0' and
                seg_value(2) = '0' and
                 seg_value(1) = '0' and
                 seg_value(0) = '0') then
                seg <= "0000001";
            else
                --A 1(0' + 3') + 2(1 + 3'0) + 1'(0'(3+2') + 32')
                if ( (seg_value(1) = '1' and
                      (seg_value(0) = '0' or
                         seg_value(3) = '0'))
                      or
                      (seg_value(2) = '1' and
                       (seg_value(1) = '1' or
                         (seg_value(3) = '0' and
                         seg_value(0) = '1')))
                      or
                       (seg_value(1) = '0' and
                         ((seg_value(0) = '0' and
                          (seg_value(3) = '1' or
                           seg_value(2) = '0')) or
                          (seg_value(3) = '1' and
                          seg_value(2) = '0')))
                ) then
                    seg(0) <= '0';
                else
                    seg(0) <= '1';
                end if;
                --B 2'(30'+3') + 3'(1 xnor 0) + 31'0
                if ((seg_value(3) = '0' and (seg_value(1) = '1' xnor seg_value(0) = '1')) or
                    (seg_value(3) = '1' and seg_value(1) = '0' and seg_value(0) = '1') or
                    (seg_value(2) = '0' and ((seg_value(3) = '1' and seg_value(0) = '0') or seg_value(3) = '0'))) then
                    seg(1) <= '0';
                else
                    seg(1) <= '1';
                end if;
                --C
                if ((seg_value(3) = '0' and seg_value(1) = '0') or (seg_value(0) = '1' and
                    (seg_value(3) = '0' or seg_value(1) = '0')) or (seg_value(3) = '1' xor
                    seg_value(2) = '1')) then
                    seg(2) <= '0';
                else
                    seg(2) <= '1';
                end if;
                --D 2'(3'0' + 10) + 2(1 xor 0) + 31' , 3'2'0' + 2'10 + 210' + 21'0 + 31'
                if ((seg_value(3) = '0' and seg_value(2) = '0' and seg_value(0) = '0') or
                    (seg_value(2) = '0' and seg_value(1) = '1' and seg_value(0) = '1') or
                    (seg_value(2) = '1' and seg_value(1) = '1' and seg_value(0) = '0') or
                    (seg_value(2) = '1' and seg_value(1) = '0' and seg_value(0) = '1') or
                    (seg_value(3) = '1' and seg_value(1) = '0')) then
                    seg(3) <= '0';
                else
                    seg(3) <= '1';
                end if;
                --E 0'(2'1' + 1) + 3(2 + 1)
                if ((seg_value(0) ='0' and (((seg_value(2)='0' and seg_value(1)='0') or
                    seg_value(1)='1'))) or (seg_value(3)='1' and (seg_value(2)='1'  or
                    seg_value(1)='1'))) then
                    seg(4) <= '0';
                else
                    seg(4) <= '1';
                end if;
                --F 3(2'+1) + 1'0' + 2(3'1' + 10')
                if ((seg_value(3)='1' and (seg_value(2) = '0' or seg_value(1) = '1')) or
                    (seg_value(1)='0' and seg_value(0)='0') or
                    (seg_value(2)='1' and ((seg_value(3) = '0' and seg_value(1)='0') or (seg_value(1) = '1' and seg_value(0)='0')))) then
                    seg(5) <= '0';
                else
                    seg(5) <= '1';
                end if;
                --G 3(2'+0) + 10' + 3'(2 xor 1)
                if ((seg_value(3) = '1' and (seg_value(2) = '0' or seg_value(0) = '1')) or
                    (seg_value(1) = '1' and seg_value(0)='0') or
                    (seg_value(3)='0' and (seg_value(2)='1' xor seg_value(1)='1'))
                     ) then
                    seg(6) <= '0';
                else
                    seg(6) <= '1';
                end if;
            end if;
        --end if;
            --seg <= seg_value (0 to 6);
            dp<=dp_value(0);
            an <= "1110";
            state := state+1;
        elsif (state =1) then
            --seg <=  seg_value (0 to 6) XOR "1111111";
            --seg <= seg_value (7 to 13);
            dp<=dp_value(1);
            an <= "1110";
            state := state+1;
        elsif (state =2) then
            --seg <=  seg_value (0 to 6) XOR "1010101";
            --seg <=  seg_value (14 to 20);
            dp<=dp_value(2);
            an <= "1110";
            state := state+1;
        elsif (state =3) then
            --seg <=  seg_value (0 to 6) XOR "0101010";
            --seg <=  seg_value (21 to 27);
            dp<=dp_value(3);
            an <= "1110";
            state := state+1;
        else
            state := 0;
        end if;
        end if;
    end process;
end Behavioral;