with

    FLTK.Screen;


package body Displays is


    package WD renames FLTK.Widgets.Groups.Windows.Double;
    package B renames FLTK.Widgets.Boxes;




    function Max (A, B : in Integer) return Integer is
    begin
        if B > A then return B; else return A; end if;
    end Max;

    function Min (A, B : in Integer) return Integer is
    begin
        if B < A then return B; else return A; end if;
    end Min;




    function Create
           (X, Y, W, H : in Integer;
            Text       : in String)
        return Display
    is
        Message_Text : String :=
            "Move with the arrow keys. Press u for undo." & ASCII.LF &
            "To move to a square where there is a clear path, click with the mouse." & ASCII.LF &
            "Press n to skip this level, q to quit, and r to restart this level.";

        My_Width  : Integer := Max (Message_Box_Width, W);
        My_Height : Integer := Max (Message_Box_Height, H);
    begin
        return This : Display :=
                   (WD.Double_Window'(WD.Create (X, Y, My_Width, My_Height, Text)) with

                    Message_Box => B.Box'(B.Create
                        (0, 0, Message_Box_Width, Message_Box_Height, Message_Text)),
                    Current_Grid => null) do

            This.Add (This.Message_Box);
            This.Message_Box.Set_Label_Size (Text_Size);
        end return;
    end Create;




    function Create
           (W, H : in Integer)
        return Display is
    begin
        return Create (0, 0, W, H, "Sokoban");
    end Create;




    function Create
        return Display is
    begin
        return Create (0, 0, Message_Box_Width, Message_Box_Height, "Sokoban");
    end Create;




    procedure Set_Grid
           (This : in out Display;
            To   : in out Grids.Grid) is
    begin
        if This.Current_Grid /= null then
            This.Remove (This.Current_Grid.all);
        end if;
        This.Current_Grid := To'Unchecked_Access;
        This.Add (To);
        This.Ensure_Correct_Size;
    end Set_Grid;




    procedure Adjust_Grid
           (This       : in out Display;
            Cols, Rows : in     Natural) is
    begin
        This.Current_Grid.Set_Cols (Cols);
        This.Current_Grid.Set_Rows (Rows);
        This.Ensure_Correct_Size;
    end Adjust_Grid;




    procedure Ensure_Correct_Size
           (This : in out Display)
    is
        New_Width : Integer :=
            Max (Message_Box_Width, This.Current_Grid.Get_W);
        New_Height : Integer :=
            Message_Box_Height + This.Current_Grid.Get_H;
        Grid_X : Integer :=
            Max (0, (Message_Box_Width - This.Current_Grid.Get_W) / 2);
    begin
        This.Current_Grid.Reposition (Grid_X, 0);
        This.Message_Box.Resize (New_Width, This.Message_Box.Get_H);
        This.Message_Box.Reposition (This.Message_Box.Get_X, This.Current_Grid.Get_H);
        This.Resize (New_Width, New_Height);
    end Ensure_Correct_Size;




    procedure Centre_On_Screen
           (This : in out Display)
    is
        use FLTK.Screen;
    begin
        This.Reposition
           (Get_X + (Get_W - This.Get_W) / 2,
            Get_Y + (Get_H - This.Get_H) / 2);
    end Centre_On_Screen;


end Displays;