lighttroupe/luz-next

#
# GuiMessageBar is the "flash message" area
#
class GuiMessageBar < GuiBox
    MESSAGE_DURATION = 2.0
    MESSAGE_DURATION_FAST = 0.2

    def initialize
        super
        self << (@background = GuiObject.new.set(:background_image => $engine.load_image('images/message-bar-background.png')))
        self << (@text = GuiLabel.new.set(:width => 20, :text_align => :center))
        @messages = []
    end

    def positive_message(message)
        @messages << message unless message.blank?
    end
    alias :negative_message :positive_message        # for now

    def gui_tick
        super
        next_message! if next_message?
    end

private

    def next_message?
        (@message_time.nil? && !@messages.empty?) ||        # introduce a message?
        (current_duration > desired_duration)        # move to next message?
    end

    def next_message!
        message = @messages.shift
        if message
            @text.set_string(message).set({:hidden => false})
            animate(:opacity, 1.0, duration=0.01)
            @message_time = $env[:frame_time]
        else
            animate(:opacity, 0.0, duration=0.2) { }
            @message_time = nil
        end
    end

    def desired_duration
        (@messages.size > 0) ? MESSAGE_DURATION_FAST : MESSAGE_DURATION
    end

    def current_duration
        (@message_time.nil?) ? 0.0 : $env[:frame_time] - @message_time
    end
end