MODULE OkmPaint;
    EXTERN PROCEDURE new_window, destroy_window, draw_str_to_overlay, get_window_overlay_number,
        draw_widgets_to_window, draw_filled_rectangle_to_overlay, GetNextWindowEvent, DrawPixel,
        save_state_and_yield_task, start_dragging_window, handle_widget_click, fill_window,
        menu_update_event, menu_bar_click_event, close_menu: INT;
    EXTERN eventArgs: ARRAY 8 OF INT;
    EXTERN menuItemsRoot: POINTER TO CHAR;
    EXTERN EVENT_TYPE_MOUSE_CLICK,
        EVENT_TYPE_MOUSE_RELEASE,
        EVENT_TYPE_BUTTON_CLICK,
        EVENT_TYPE_MENU_BAR_CLICK,
        EVENT_TYPE_MENU_UPDATE,
        EVENT_TYPE_MENU_CLICK,
        EVENT_TYPE_MENU_ACK,
        WIDGET_TYPE_BUTTON: INT;

    TYPE Fox32OSButtonWidget = RECORD
        next, id, type, text, fgColor, bgColor, width: INT;
        x, y: SHORT;
    END;

    VAR running: CHAR;
        drawing: CHAR;
        size: CHAR;
        color: INT;
        canvasWindow: ARRAY 36 OF CHAR;

    PROCEDURE Main();
    BEGIN
        running := 1;
        drawing := 0;
        size := 2;
        color := 0FFFFFFFFH;

        new_window(PTROF(canvasWindow), "OkmPaint canvas", 256, 256, 128, 128, PTROF(menuItemsRoot), 0);

        WHILE running DO
            GetNextWindowEvent(PTROF(canvasWindow));

            (* mouse click event *)
            IF eventArgs[0] = PTROF(EVENT_TYPE_MOUSE_CLICK) THEN
                IF (eventArgs[1] <| 8) & (eventArgs[2] <| 16) THEN
                    (* clicked the window's close box *)
                    destroy_window(PTROF(canvasWindow));
                    running := 0;
                ELSIF eventArgs[2] <| 16 THEN
                    (* clicked the window's title bar *)
                    start_dragging_window(PTROF(canvasWindow));
                ELSE
                    drawing := 1;
                END;

            (* mouse release event *)
            ELSIF eventArgs[0] = PTROF(EVENT_TYPE_MOUSE_RELEASE) THEN
                drawing := 0;

            (* menu bar click event *)
            ELSIF eventArgs[0] = PTROF(EVENT_TYPE_MENU_BAR_CLICK) THEN
                menu_bar_click_event(PTROF(menuItemsRoot));

            (* menu update event *)
            ELSIF eventArgs[0] = PTROF(EVENT_TYPE_MENU_UPDATE) THEN
                menu_update_event();

            (* menu click event *)
            ELSIF eventArgs[0] = PTROF(EVENT_TYPE_MENU_CLICK) THEN
                MenuClickEvent(eventArgs[2], eventArgs[3]);

            (* menu ack event *)
            ELSIF eventArgs[0] = PTROF(EVENT_TYPE_MENU_ACK) THEN
                close_menu(PTROF(menuItemsRoot));
            END;

            IF drawing THEN
                DrawPixel();
            END;

            save_state_and_yield_task();
        END;
    END;

    PROCEDURE MenuClickEvent(rootIndex, itemIndex: INT;);
    BEGIN
        IF rootIndex = 0 THEN
            (* Canvas menu *)
            IF itemIndex = 0 THEN
                (* Clear to Black *)
                fill_window(0FF000000H, PTROF(canvasWindow));
            ELSIF itemIndex = 1 THEN
                (* Clear to White *)
                fill_window(0FFFFFFFFH, PTROF(canvasWindow));
            END;
        ELSIF rootIndex = 1 THEN
            (* Brush menu *)
            IF itemIndex = 0 THEN
                (* 2x2 *)
                size := 2;
            ELSIF itemIndex = 1 THEN
                (* 4x4 *)
                size := 4;
            ELSIF itemIndex = 2 THEN
                (* 8x8 *)
                size := 8;
            ELSIF itemIndex = 3 THEN
                (* 16x16 *)
                size := 16;
            END;
        ELSIF rootIndex = 2 THEN
            (* Color menu *)
            IF itemIndex = 0 THEN
                (* Black *)
                color := 0FF000000H;
            ELSIF itemIndex = 1 THEN
                (* White *)
                color := 0FFFFFFFFH;
            ELSIF itemIndex = 2 THEN
                (* Red *)
                color := 0FF0000FFH;
            ELSIF itemIndex = 3 THEN
                (* Green *)
                color := 0FF00FF00H;
            ELSIF itemIndex = 3 THEN
                (* Blue *)
                color := 0FFFF0000H;
            END;
        END;
    END;
END.