using System.IO;

using Delta.Engine;

using Delta.InputSystem;

using Delta.Scenes.Enums;

using Delta.Utilities;

using Delta.Utilities.Datatypes;

using Delta.Utilities.Datatypes.Advanced;

using NUnit.Framework;



namespace Delta.Scenes.UserInterfaces.Controls

{

	/// <summary>

	/// This represents a simple checkBox control for check or uncheck things.

	/// </summary>

	public class Checkbox : Button

	{

		#region Constants

		/// <summary>

		/// The current version of the implementation of this control class.

		/// </summary>

		private const int VersionNumber = 1;

		#endregion



		#region Delegates

		/// <summary>

		/// The delegate declaration for the checked changed event.

		/// </summary>

		/// <param name="sender">Sender</param>

		public delegate void CheckedChangedEvent(Checkbox sender);

		#endregion



		#region IsChecked (Public)

		/// <summary>

		/// Is the checked property enabled ?

		/// </summary>

		public bool IsChecked

		{

			get;

			set;

		}

		#endregion



		#region Protected



		#region FallbackDesign (Protected)

		/// <summary>

		/// Defines the theme which will be used if no "Design" was set

		/// explicitely.

		/// </summary>

		protected override ControlDesign FallbackDesign

		{

			get

			{

				return Theme.Current.CheckboxDesign;

			} // get

		}

		#endregion



		#region CheckedSymbolArea (Protected)

		/// <summary>

		/// The element which describes the area where the checked or unchecked

		/// symbol will be shown.

		/// </summary>

		protected internal AlignableElement CheckedSymbolArea

		{

			get;

			private set;

		}

		#endregion



		#endregion



		#region Private



		#region lastIsChecked (Private)

		/// <summary>

		/// The last set 'IsChecked' value which is used to "detect" Checked

		/// changes of the control by the user.

		/// </summary>

		private bool lastIsChecked;

		#endregion



		#endregion



		#region Constructors

		/// <summary>

		/// Creates a checkbox.

		/// </summary>

		public Checkbox()

		{

			// Define the area of the "checked" indicator

			CheckedSymbolArea = new AlignableElement

			{

				HorizontalAlignment = HorizontalAlignment.Left,

				VerticalAlignment = VerticalAlignment.Centered,

			};

			Add(CheckedSymbolArea);



			// Align the text area at the right side of the control

			TextContentElement.HorizontalAlignment = HorizontalAlignment.Right;

			TextContentElement.VerticalAlignment = VerticalAlignment.Centered;



			IsChecked = false;

		}

		#endregion



		#region CheckedChanged (Event)

		/// <summary>

		/// Occurs every time the 'IsChecked' value of the Checkbox will be

		/// changed.

		/// </summary>

		public event CheckedChangedEvent CheckedChanged;

		#endregion



		#region Save (Public)

		/// <summary>

		/// Saves all data which are necessary to restore the object again.

		/// </summary>

		/// <param name="dataWriter">

		/// The writer which contains the stream where the data should be saved

		/// into now.

		/// </param>

		public override void Save(BinaryWriter dataWriter)

		{

			// At first we write the data of the base class

			base.Save(dataWriter);



			// and then save the version of the current data format

			dataWriter.Write(VersionNumber);



			// before we can finally save the properties

			dataWriter.Write(IsChecked);

		}

		#endregion



		#region Load (Public)

		/// <summary>

		/// Loads and restores all previously saved values that belongs to this

		/// class only from the given data reader.

		/// </summary>

		/// <param name="dataReader">

		/// The reader which contains the stream with the saved data which needs to

		/// be loaded now.

		/// </param>

		public override void Load(BinaryReader dataReader)

		{

			// At first we need to load all data of the base class

			base.Load(dataReader);



			// and then check which version of the data need to load now

			int version = dataReader.ReadInt32();

			switch (version)

			{

					// Version 1

				case VersionNumber:

					IsChecked = dataReader.ReadBoolean();

					break;



				default:

					Log.InvalidVersionWarning(GetType().Name, version, VersionNumber);

					break;

			} // switch

		}

		#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))

			{

				// Check if we need to auto-set the size of the "checked" symbol

				if (CheckedSymbolArea.Size == Size.Zero)

				{

					CheckedSymbolArea.Size = new Size(Size.Height);

				} // if



				if (IsTextElementAutoSizing)

				{

					// The text area is whole control area except the size of the

					// "Checked" symbol area

					TextContentElement.Size = new Size(

						Size.Width - CheckedSymbolArea.Size.Width, Size.Height);

				} // if



				return true;

			} // if



			return false;

		}

		#endregion



		#region OnClicked

		/// <summary>

		/// Contains the whole (Checkbox) logic which happens if the control was

		/// clicked.

		/// </summary>

		/// <param name="input">Input data like the click position.</param>

		/// <param name="isInsideControl">

		/// 'True' if the event is occurring inside the control, otherwise 'false'.

		/// </param>

		protected override void OnClicked(CommandTrigger input,

			bool isInsideControl)

		{

			base.OnClicked(input, isInsideControl);



			// Accept a click only if it is occurring inside the control

			if (isInsideControl)

			{

				// We want to change the 'IsChecked' value on every click event

				IsChecked = !IsChecked;

				input.IsHandled = true;

			} // if

		}

		#endregion



		#region OnIsCheckedChanging

		/// <summary>

		/// On is checked changing

		/// </summary>

		/// <param name="oldIsChecked">Old value</param>

		/// <returns>

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

		/// aborted.

		/// </returns>

		protected virtual bool OnIsCheckedChanging(bool oldIsChecked)

		{

			return true;

		}

		#endregion



		#region DetectChanges

		/// <summary>

		/// This method implements the checks of the changes which are should be

		/// detected in this element. It also cares about triggering the events and

		/// the event handler methods.

		/// </summary>

		protected override void DetectChanges()

		{

			base.DetectChanges();



			// Detect 'IsChecked' changes

			if (IsChecked != lastIsChecked)

			{

				// Check now if the new value should be set

				if (OnIsCheckedChanging(lastIsChecked))

				{

					lastIsChecked = IsChecked;



					// After setting the new value also inform all external listeners

					// about the change

					if (CheckedChanged != null &&

					    // but only if it isn't just the value initialization

					    isRuntimeValueChange)

					{

						CheckedChanged.Invoke(this);

					} // if

				} // if

				else

				{

					IsChecked = lastIsChecked;

				} // else

			} // if

		}

		#endregion



		#region ShortElementInfo

		/// <summary>

		/// Short element info

		/// </summary>

		protected override string ShortElementInfo()

		{

			return base.ShortElementInfo() + ", IsChecked='" + IsChecked + "'";

		}

		#endregion



		#endregion



		/// <summary>

		/// Tests for Checkbox controls

		/// </summary>

		[Category("Visual")]

		internal class CheckboxTests

		{

			#region DisplayCheckbox (Static)

			/// <summary>

			/// Display checkbox

			/// </summary>

			[Test]

			public static void DisplayCheckbox()

			{

				Checkbox testCheckbox = new Checkbox

				{

					LocalArea = new Rectangle(0.2f, 0.3f, 0.4f, 0.05f),

					//Size = new Size(0.6f, 0.1f),

					IsChecked = true,

					Text = "DisplayCheckbox",

				};



				Screen testScene = new Screen();

				testScene.Add(testCheckbox);



				// Open now the scene to "activate" for the test

				Scene.Open(testScene);



				// We just call here Application.Start() to display the image, but we

				// don't need to call the "Image.Draw()" explicitely, because this

				// already handled automatically by the UI manager.

				Application.Start();

			}

			#endregion



			#region DisabledCheckbox (Static)

			/// <summary>

			/// Disabled checkbox

			/// </summary>

			[Test]

			public static void DisabledCheckbox()

			{

				Checkbox testCheckbox = new Checkbox

				{

					LocalArea = new Rectangle(0.2f, 0.3f, 0.4f, 0.05f),

					IsChecked = true,

					Text = "Enabled",

				};



				Screen testScene = new Screen();

				testScene.Add(testCheckbox);



				// Open now the scene to "activate" for the test

				testScene.Open();



				Application.Start(delegate

				{

					// Disable/enable the Checkbox by pressing the keyboard "Space" button

					if (Input.Keyboard.SpaceReleased)

					{

						testCheckbox.State = (testCheckbox.State >= ElementState.Enabled)

						                     	? ElementState.Disabled

						                     	: ElementState.Enabled;

						testCheckbox.Text = testCheckbox.State.ToString();

					}

				});

			}

			#endregion

		}

	}

}