with HWIF, HWIF_Types, Ada.Calendar;
use HWIF, HWIF_Types, Ada.Calendar;

procedure Controller is

   Tl_Flag     : Boolean  := true; -- true := North/South; false := East/West
   Dir1, Dir2  : Direction;
   State       : Integer  := 4;

   HC_TL, HC_TL2, HC_PL, PL_Check : Time;
   TL_Check    : Time := Clock + 1.0;

   inner_loop  : Boolean  := false;
   FRAME_LOOP  : constant Duration := 2.0;

   task P_Wait;

   procedure TL_Switch(Flag : Boolean) is
   begin
      if (Flag) then
         Tl_Flag := false;
         Dir1    := East;
         Dir2    := West;
      else
         Tl_Flag := true;
         Dir1    := North;
         Dir2    := South;
      end if;
   end TL_Switch;

   procedure TL_State(Dir1 : Direction; Dir2 : Direction; State1 : Integer) is
   begin
      case (State1) is
         when 1 => -- amber-red
            Traffic_Light(Dir1) := 6;
            Traffic_Light(Dir2) := 6;
            State := 2;
            TL_Check := Clock + 0.5;
         when 2 => -- green
            Traffic_Light(Dir1) := 1;
            Traffic_Light(Dir2) := 1;
            State := 3;
            TL_Check := Clock + 5.1;
         when 3 => -- amber
            Traffic_Light(Dir1) := 2;
            Traffic_Light(Dir2) := 2;
            State := 4;
            TL_Check := Clock + 3.1;
         when 4 => -- red
            Traffic_Light(Dir1) := 4;
            Traffic_Light(Dir2) := 4;
            State := 1;
            TL_Check := Clock + 0.1;
            if (Tl_Flag) then
               HC_TL := Clock + 50.0;
            else
               HC_TL2 := Clock + 50.0;
            end if;
            TL_Switch(TL_Flag);
         when others =>
            null;
      end case;
   end TL_State;

   procedure Ped_Cross is
   begin
      if (Pedestrian_Wait(North) = 1 or Pedestrian_Wait(South) = 1) or
        (Pedestrian_Wait(East) = 1 or Pedestrian_Wait(West) = 1) then
         for O in Direction_Octet'Range loop
            Pedestrian_Wait(O)  := 0;
            Pedestrian_Light(O) := 1;
            PL_Check := Clock + 6.1;
         end loop;
         while (Clock <= PL_Check) loop
            null; -- do nothing while the lights for pedestrians stay green
         end loop;
         for O in Direction_Octet'Range loop
            Pedestrian_Light(O) := 2;
         end loop;
      end if;
   end Ped_Cross;

   task body P_Wait is
   begin
      loop
         if (Pedestrian_Light(North) /= 1 and Pedestrian_Light(South) /= 1 and Pedestrian_Light(East) /= 1 and Pedestrian_Light(West) /= 1) then
            if (Pedestrian_Button(North) = 1 or Pedestrian_Button(South) = 1 or Pedestrian_Button(East) = 1 or Pedestrian_Button(West) = 1) then
               for O in Direction_Octet'Range loop
                  Pedestrian_Wait(O)  := 1;
               end loop;
               HC_PL := Clock + 50.0;
            end if;
         end if;
         delay 0.1;
      end loop;
   end P_Wait;

   procedure EV_Check is
   begin
      if (Emergency_Vehicle_Sensor(North) = 1 or Emergency_Vehicle_Sensor(South) = 1) then
         if (Traffic_Light(North) = 1 or Traffic_Light(South) = 1) then
            while (Emergency_Vehicle_Sensor(North) = 1 or Emergency_Vehicle_Sensor(South) = 1) loop
               null; -- do nothing while ev is on green
            end loop;
            TL_Check := Clock + 10.0;
         elsif (Traffic_Light(East) = 4 and TL_Flag = false) then
            TL_Switch(TL_Flag);
         end if;
      elsif (Emergency_Vehicle_Sensor(East) = 1 or Emergency_Vehicle_Sensor(West) = 1) then
         if (Traffic_Light(East) = 1 or Traffic_Light(West) = 1) then
            while (Emergency_Vehicle_Sensor(East) = 1 or Emergency_Vehicle_Sensor(West) = 1) loop
               null; -- do nothing while ev is on green
            end loop;
            TL_Check := Clock + 10.0;
         elsif (Traffic_Light(North) = 4 and TL_Flag) then
            TL_Switch(TL_Flag);
         end if;
      end if;
   end EV_Check;

begin
   loop
      for O in Direction_Octet'Range loop
         Traffic_Light(O)    := 4;
         Pedestrian_Light(O) := 2;
      end loop;
      inner_loop := true;
      while (inner_loop) loop
         begin
            if (Traffic_Light(North) = 4 and Traffic_Light(West) = 4) then
               if (Emergency_Vehicle_Sensor(North) = 1 or Emergency_Vehicle_Sensor(South) = 1 or
                     Emergency_Vehicle_Sensor(East) = 1 or Emergency_Vehicle_Sensor(West) = 1) then -- prioritise ev if true.
                  EV_Check;
               elsif (Clock > HC_PL) then -- prioritise ped crossing if true.
                  Ped_Cross;
               elsif (Clock > HC_TL) then -- prioritise n/s lights if true.
                  TL_Switch(false);
               elsif (Clock > HC_TL2) then -- prioritise e/w lights if true.
                  TL_Switch(true);
               else
                  Ped_Cross;
               end if;
            end if;
            EV_Check;
            if (Clock >= TL_Check and Pedestrian_Light(North) /= 1) then
               TL_State(Dir1, Dir2, State);
            end if;
         end;
         delay FRAME_LOOP;
      end loop;
   end loop;
end Controller;