library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity Domaci4 is
    Port ( inOK : in  STD_LOGIC;
           inHAZ : in  STD_LOGIC;
           iCLK : in  STD_LOGIC;
           inRST : in  STD_LOGIC;
           oRED : out  STD_LOGIC_VECTOR (1 downto 0);
           oYELLOW : out  STD_LOGIC_VECTOR (1 downto 0);
           oGREEN : out  STD_LOGIC_VECTOR (1 downto 0));
end Domaci4;

architecture Behavioral of Domaci4 is

    type tSTANJE is (IDLE,GREEN,RED,YELLOW,RY,HAZARD,GR,YG,RYG);
			signal sSTANJE : tSTANJE;
			signal sNEXT : tSTANJE;
    signal sCNT : STD_LOGIC_VECTOR(24 downto 0);
    signal sTC,sPOM : STD_LOGIC;
    signal sRED,sGREEN,sYELLOW : STD_LOGIC_VECTOR(1 downto 0);


begin
--Next state logic
    process(sTC,sSTANJE,inOK,inHAZ) begin
        case(sSTANJE) is
					when IDLE =>if(inOK = '0') then
                                    sNEXT <= RED;
                                else
                                    sNEXT <= sSTANJE;
                                end if;

                when RED => if(inHAZ = '0') then
                                    sNEXT <= HAZARD;
                                elsif(sTC='1') then
                                    sNEXT <= RY;
										  else
												sNEXT <= RED;
                                end if;

                when RY =>  if(inHAZ = '0') then
                                    sNEXT <= HAZARD;
                                elsif(sTC='1') then
                                    sNEXT <= YG;
										  else
												sNEXT <= RY;
                                end if;

                when GREEN =>   if(inHAZ = '0') then
                                    sNEXT <= HAZARD;
                                elsif(sTC='1') then
                                    sNEXT <= GR;
										  else
												sNEXT <= GREEN;
                                end if;

                when YELLOW =>  if(inHAZ = '0') then
                                    sNEXT <= HAZARD;
                                elsif(sTC='1') then
                                    sNEXT <= RYG;
										  else
												sNEXT <= YELLOW;
                                end if;

                when HAZARD =>  if(inOK = '0') then
                                    sNEXT <= RED;
                                else
                                    sNEXT <= sSTANJE;
                                end if;
					 when YG => if(sTC='1') then
										sNEXT <= GREEN;
									else
										sNEXT <= YG;
									 end if;
					 when GR => if(sTC='1') then
										sNEXT <= YELLOW;
									else
										sNEXT <= GR;
									 end if;

					 when RYG => if(sTC='1') then
										sNEXT <= RED;
									else
										sNEXT <= RYG;
									 end if;

            end case;
    end process;

 --Brojac pola sekunde
    process(inRST,iCLK) begin
        if(inRST = '0') then
            sPOM <= '0';
            sCNT <= (others => '0');
        elsif(iCLK'event and iCLK = '1') then
            if(sCNT = 11999999) then
                sPOM <= not(sPOM);
                sCNT <= (others => '0');
            else
                sCNT <= sCNT + 1;
            end if;
        end if;
    end process;

--Terminal count
    sTC <=  '1' when sCNT = 0 else
                '0';
--Stanje posle pola sekunde
    process(inRST,iCLK) begin
        if(inRST = '0') then
            sSTANJE <= IDLE;
        elsif(iCLK'event and iCLK = '1') then
                sSTANJE <= sNEXT;
        end if;
    end process;

--Lampice
    process(sSTANJE,sPOM) begin
        case(sSTANJE) is
            when IDLE =>        sRED <= "00";
                                sGREEN <= "00";
                                sYELLOW <= "00";

            when RED =>         sRED <= "11";
                                sGREEN <= "00";
                                sYELLOW <= "00";

            when RY =>          sRED <= "11";
                                sGREEN <= "00";
                                sYELLOW <= "11";

            when GREEN =>       sRED <= "00";
                                sGREEN <= "11";
                                sYELLOW <= "00";

            when YELLOW =>      sRED <= "00";
                                sGREEN <= "00";
                                sYELLOW <= "11";

            when HAZARD =>      if(sPOM = '1') then
												sRED <= "00";
                                    sGREEN <= "00";
                                    sYELLOW <= "11";
                                 else
                                    sRED <= "00";
                                    sGREEN <= "00";
                                    sYELLOW <= "00";
                                 end if;
				when YG => sRED <= "11";
							  sGREEN <= "00";
							  sYELLOW <= "11";
				when GR => sRED <= "11";
							  sGREEN <= "11";
							  sYELLOW <= "00";
				when RYG => sRED <= "11";
							  sGREEN <= "11";
							  sYELLOW <= "11";

				when others =>       sYELLOW <= "00";
										   sRED <= "00";
									      sGREEN <= "00";
        end case;
    end process;

--Izlazi
    oRED <= sRED;
    oYELLOW <= sYELLOW;
    oGREEN <= sGREEN;

end Behavioral;