/Scenes/UserInterfaces/Controls/Scrollbar.cs

using Delta.InputSystem;

using Delta.Scenes.Enums;

using Delta.Utilities.Datatypes;



namespace Delta.Scenes.UserInterfaces.Controls

{

	/// <summary>

	/// Scrollbar

	/// Note: Is only horizontal yet.

	/// </summary>

	internal class Scrollbar : BaseControl

	{

		#region ScrollingType Enum

		/// <summary>

		/// Scrolling type

		/// Note: That is currently NO CONTROL YET.

		/// </summary>

		protected enum ScrollingType

		{

			Horizontal,



			Vertical,

		}

		#endregion



		#region Constants

		/// <summary>

		/// ScrollbarHeight

		/// </summary>

		public const float ScrollbarHeight = 0.02f;

		#endregion



		#region CurrentScrollOffset (Public)

		/// <summary>

		/// The current amount that the scrollbar was scrolled in the panel.

		/// </summary>

		public float CurrentScrollOffset;

		#endregion



		#region VisibleScrollArea (Public)

		/// <summary>

		/// Represents the current visible area resulting from the current used/set

		/// scrolled offset.

		/// </summary>

		public Rectangle VisibleScrollArea

		{

			get

			{

				return new Rectangle(CurrentScrollOffset, 0.0f, ScrollWidth,

					owner.Size.Height);

			} // get

		}

		#endregion



		#region ScrollWidth (Public)

		/// <summary>

		/// Represents the amount that the inner panel elements would be

		/// moved/scrolled at the next time the "Forward" or "Backward" action

		/// of the scrollbar is executed.

		/// </summary>

		public float ScrollWidth

		{

			get

			{

				return owner.Size.Width;

			} // get

		}

		#endregion



		#region Protected



		#region ScrollingMode (Protected)

		/// <summary>

		/// Scrolling mode

		/// </summary>

		protected ScrollingType ScrollingMode

		{

			get;

			private set;

		}

		#endregion



		// ScrollWidth



		///// <summary>

		///// Is visible

		///// </summary>

		//public bool IsVisible

		//{

		//  get

		//  {

		//    return backwardButton.State > ControlState.Invisible;

		//  }

		//  set

		//  {

		//    // You do something if the state would change now

		//    if (value == IsVisible)

		//    {

		//      return;

		//    } // if



		//    // If the scrollbar should be hidden now

		//    if (value == false)

		//    {

		//      // then hide all inner controls

		//      backwardButton.State = ControlState.Invisible;

		//      forwardButton.State = ControlState.Invisible;

		//    } // if



		//    // if the it should be visible now again

		//    else

		//    {

		//      // then show all inner controls again too

		//      backwardButton.State = ControlState.Enabled;

		//      forwardButton.State = ControlState.Enabled;

		//    } // else

		//  } // set

		//} // IsVisible



		#region FallbackDesign (Protected)

		/// <summary>

		/// Fallback design

		/// </summary>

		protected override ControlDesign FallbackDesign

		{

			get

			{

				return Theme.Current.ImageDesign;

			} // get

		}

		#endregion



		#endregion



		#region Private



		#region owner (Private)

		private readonly Panel owner;

		#endregion



		#region backwardButton (Private)

		private readonly Button backwardButton;

		#endregion



		#region forwardButton (Private)

		private readonly Button forwardButton;

		#endregion



		#endregion



		#region Constructors

		/// <summary>

		/// Create scrollbar

		/// </summary>

		/// <param name="setOwner">Set owner</param>

		public Scrollbar(Panel setOwner)

		{

			// Init the data of the scrollbar

			owner = setOwner;

			ScrollingMode = ScrollingType.Horizontal;



			CurrentScrollOffset = 0.0f;



			Size buttonSize = new Size(ScrollbarHeight, ScrollbarHeight);

			backwardButton = new Button

			{

				Name = setOwner.Name + "." + ScrollingMode + GetType().Name +

				       "BackwardButton",

				Size = buttonSize,

				//LocalArea = new Rectangle(0, 0, ScrollbarHeight, ScrollbarHeight),

				//LocalArea = GetDockingArea(owner.Size, buttonSize,

				//  DockingMode.BottomLeft),

				Text = "<",

			};

			backwardButton.Clicked += delegate(BaseControl sender,

				CommandTrigger input)

			{

				ScrollBackwards();

				input.IsHandled = true;

			};

			Add(backwardButton);



			forwardButton = new Button

			{

				Name = setOwner.Name + "." + ScrollingMode + GetType().Name +

				       "ForewardButton",

				Size = buttonSize,

				//LocalArea = new Rectangle(0, 0, ScrollbarHeight, ScrollbarHeight),

				//LocalArea = GetDockingArea(owner.Size, buttonSize,

				//  DockingMode.BottomRight),

				Text = ">",

			};

			forwardButton.Clicked += delegate(BaseControl sender,

				CommandTrigger input)

			{

				ScrollForewards();

				input.IsHandled = true;

			};

			Add(forwardButton);



			// The initial Size and MinSize of the scrollbar is the size of the

			// back and forward button

			//MinSize = buttonSize;

			Size = buttonSize;

		}

		#endregion



		#region ScrollForewards (Public)

		/// <summary>

		/// Scroll foreward

		/// </summary>

		public void ScrollForewards()

		{

			float horizontalContentWidth = owner.GetContentWidth();



			if (horizontalContentWidth <= ScrollWidth)

			{

				// It only make sense to scroll if the content area is bigger than the

				// panel area

				return;

			} // if



			float newScrollOffset = CurrentScrollOffset + ScrollWidth;

			if ((newScrollOffset + ScrollWidth) < horizontalContentWidth)

			{

				CurrentScrollOffset = newScrollOffset;

			} // if

			else

			{

				CurrentScrollOffset = horizontalContentWidth - ScrollWidth;

			} // else

		}

		#endregion



		#region ScrollBackwards (Public)

		/// <summary>

		/// Scroll backwards

		/// </summary>

		public void ScrollBackwards()

		{

			float horizontalContentWidth = owner.GetContentWidth();



			if (horizontalContentWidth <= ScrollWidth)

			{

				// It only make sense to scroll if the content area is bigger than the

				// panel area

				return;

			} // if



			float newScrollOffset = CurrentScrollOffset - ScrollWidth;

			// If there is even after this scrolling content left that we can scroll

			// next time

			if (newScrollOffset > 0.0f)

			{

				// then make a "full" scrolling

				CurrentScrollOffset = newScrollOffset;

			} // if



				// else if we have reached the beginning again

			else

			{

				// then let's start there

				CurrentScrollOffset = 0.0f;

			} // else

		}

		#endregion



		#region Methods (Private)



		#region OnSizeChanging

		/// <summary>

		/// On size changing

		/// </summary>

		/// <param name="oldSize">Old size</param>

		/// <returns>

		/// 'True' if the new value can be used or 'false' if the change should be

		/// aborted.

		/// </returns>

		protected override bool OnSizeChanging(Size oldSize)

		{

			if (base.OnSizeChanging(oldSize))

			{

				backwardButton.LocalArea = Panel.GetAlignmentArea(Size,

					backwardButton.Size, Alignment.BottomLeft);

				forwardButton.LocalArea = Panel.GetAlignmentArea(Size,

					forwardButton.Size, Alignment.BottomRight);



				return true;

			} // if



			return false;

		}

		#endregion



		#endregion

	}

}