with Ada.Text_IO, Ada.Characters.Handling;
procedure bead is

    type Color_Type is (Red, RedYellow, Green, Yellow);

    task type Signal;

    protected Lamp is
        procedure Switch;
        function Color return Color_Type;
    private
        Agent : access Signal;
        Actual_Color : Color_Type := Red;
    end Lamp;

    protected body Lamp is
        function Color return Color_Type is
        begin
            return Actual_Color;
        end Color;

        procedure Switch is
        begin
            Agent := new Signal;
            if Actual_Color = Yellow then
                Actual_Color := Red;
            else
                Actual_Color := Color_Type'Val(Color_Type'Pos(Actual_Color) + 1);
            end if;
        end Switch;
    end Lamp;

    task Controller is
        entry Stop;
    end Controller;

    task body Controller is
    begin
        loop
            select
                accept Stop;
                exit;
            else
                delay 3.0;
                Lamp.Switch;
                delay 1.0;
                Lamp.Switch;
                delay 3.0;
                Lamp.Switch;
                delay 2.0;
                Lamp.Switch;
            end select;
        end loop;
    end Controller;

    protected Crossroad is
        entry Cross(Time_To_Cross : Duration);
        procedure Wake_Up;
    end Crossroad;

    task body Signal is
    begin
        Crossroad.Wake_Up;
    end Signal;

    type String_Access is access String;

    task type Vehicle(Plate: String_Access);

    task body Vehicle is
    Crossed : Boolean := False;
    Time_To_Cross : Duration := 1.0;
    begin
        Ada.Text_IO.Put_Line(Plate.all & " a lampahoz erkezett.");
        while not Crossed loop
            select
                Crossroad.Cross(Time_To_Cross);
                Crossed := True;
            else
                if Time_To_Cross = 1.0 then
                    Time_To_Cross := 3.0;
                end if;
            end select;
        end loop;
        Ada.Text_IO.Put_Line(Plate.all & " athaladt.");
    end Vehicle;

    protected body Crossroad is

        entry Cross(Time_To_Cross : Duration) when Lamp.Color = Green is
        begin
                delay Time_To_Cross;
        end Cross;

        procedure Wake_Up is
        begin
            null;
        end Wake_Up;

    end Crossroad;

    Car : access Vehicle;

begin
    for i in 1..10 loop
        Car := new Vehicle(new String'("Auto" & Integer'Image(i)));
        delay 1.0;
    end loop;
    Ada.Text_IO.Skip_Line;
    Controller.Stop;
    Ada.Text_IO.Put_Line("A vezerlo leallt.");
end bead;