using System;

using System.IO;

using Delta.Engine;

using Delta.InputSystem;

using Delta.Rendering.Basics.Drawing;

using Delta.Scenes.Enums;

using Delta.Utilities;

using Delta.Utilities.Datatypes;

using Delta.Utilities.Datatypes.Advanced;

using Delta.Utilities.Helpers;

using NUnit.Framework;



namespace Delta.Scenes.UserInterfaces.Controls

{

	/// <summary>

	/// This class represents a simple (single-line) Text box control which

	/// allows the user doing input like e.g. to enter his name and confirm it by

	/// an the 'Enter' key.

	/// </summary>

	public class TextBox : Label

	{

		#region TextCursor Class

		/// <summary>

		/// Text cursor

		/// </summary>

		private class TextCursor

		{

			#region Constants

			/// <summary>

			/// The interval time (in seconds) for change the visible state from the

			/// cursor

			/// </summary>

			private const float BlinkInterval = 0.5f; // 500 ms

			#endregion



			#region IsVisibleNow (Public)

			/// <summary>

			/// Returns 'true' if the cursor can/needs to be shown now.

			/// </summary>

			public bool IsVisibleNow

			{

				get;

				private set;

			}

			#endregion



			#region CharNumber (Public)

			/// <summary>

			/// Sets the cursor position after specified char (by its number,

			/// 1 - ...).

			/// </summary>

			public int CharNumber

			{

				get

				{

					return charNumber;

				} // get

				set

				{

					charNumber = value;



					string subText = Owner.Text.Substring(0, charNumber);

					cursorTextWidth = (subText.Length > 0)

					                  	? Owner.TextFont.Measure(subText).Width

					                  	: 0.0f;

				} // set

			}

			#endregion



			#region Private



			#region charNumber (Private)

			private int charNumber;

			#endregion



			#region Owner (Private)

			/// <summary>

			/// The Text box where the cursor belongs to.

			/// </summary>

			private readonly TextBox Owner;

			#endregion



			#region fullTextWidth (Private)

			/// <summary>

			/// The with of the whole text of the TextBox (required for setting the

			/// cursor position correctly for all text alignment modes).

			/// </summary>

			private float fullTextWidth;

			#endregion



			#region cursorTextWidth (Private)

			/// <summary>

			/// The current from the text beginning to know where to draw the final

			/// current cursor line

			/// </summary>

			private float cursorTextWidth;

			#endregion



			#region currentDrawnTime (Private)

			/// <summary>

			/// The duration (in seconds) thenceforth the cursor is shown.

			/// (-> Used for the "blinking effect")

			/// </summary>

			private float currentDrawnTime;

			#endregion



			#endregion



			#region Constructors

			/// <summary>

			/// Create text cursor

			/// </summary>

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

			public TextCursor(TextBox setOwner)

			{

				Owner = setOwner;

			}

			#endregion



			#region OnOwnerTextHasChanged (Public)

			/// <summary>

			/// Occurs every time the amount of text character changes, e.g by

			/// adding or removing one while the text editing mode is enabled.

			/// </summary>

			public void OnOwnerTextHasChanged()

			{

				string fullText = Owner.Text;

				fullTextWidth = (String.IsNullOrEmpty(fullText))

				                	? 0.0f

				                	: Owner.TextFont.Measure(fullText).Width;



				// LOOK later:

				// Currently we only support that the cursor is always located at the

				// end of the text

				CharNumber = fullText.Length;

			}

			#endregion



			#region Update (Public)

			/// <summary>

			/// Does all the magic to handle the cursor events like blinking.

			/// </summary>

			public void Update()

			{

				if (IsVisibleNow)

				{

					// Decrease by the time that the last tick needed

					currentDrawnTime += Time.Delta;

					// and check new if we have to disable the cursor drawing now (again)

					if (currentDrawnTime >= BlinkInterval)

					{

						currentDrawnTime = BlinkInterval;

						IsVisibleNow = false;

					}

				}

				else // IsVisibleNow == false

				{

					// Increase by the time that the last tick needed

					currentDrawnTime -= Time.Delta;

					// and check new if we can enable the cursor drawing now (again)

					if (currentDrawnTime <= 0.0f)

					{

						currentDrawnTime = 0.0f;

						IsVisibleNow = true;

					}

				}

			}

			#endregion



			#region Draw (Public)

			/// <summary>

			/// Visualizes the cursor.

			/// </summary>

			public void Draw(Color cursorColor)

			{

				Rectangle textArea = Owner.TextContentElement.DrawArea;



				// Compute the quad space offset from text start

				float cursorTextOffset;



				#region Compute the offset based on the current text alignment mode

				switch (Owner.TextFont.HorizontalAlignment)

				{

					case HorizontalAlignment.Left:

						cursorTextOffset = cursorTextWidth;

						break;



					case HorizontalAlignment.Centered:

						cursorTextOffset = (textArea.Width / 2) - (fullTextWidth / 2) +

						                   cursorTextWidth;

						break;



					case HorizontalAlignment.Right:

						cursorTextOffset = textArea.Right - fullTextWidth +

						                   cursorTextWidth;

						break;



					default:

						cursorTextOffset = 0.01f;

						Log.Warning("The set text alignment mode which is set by the " +

						            "Font isn't supported by the TextBox yet, so can't show the. " +

						            "text cursor at the right position.");

						break;

				}

				#endregion



				// inclusive the current max. text height (based on the current font)

				float halfFontHeight = Owner.TextFont.LineHeight / 2;



				// to specify the top

				Point topCurorPos = new Point(textArea.Left + cursorTextOffset,

					textArea.Center.Y - halfFontHeight);

				// and the bottom point

				Point bottumCurorPos = new Point(topCurorPos.X,

					textArea.Center.Y + halfFontHeight);



				// of the cursor line we want to draw

				Line.Draw(topCurorPos, bottumCurorPos, cursorColor);

			}

			#endregion



			#region StartBlinking (Public)

			/// <summary>

			/// Starts the blinking of the cursor.

			/// </summary>

			public void StartBlinking()

			{

				IsVisibleNow = true;

				currentDrawnTime = 0.0f;

			}

			#endregion



			#region StopBlinking (Public)

			/// <summary>

			/// Stops the blinking of the cursor.

			/// </summary>

			public void StopBlinking()

			{

				IsVisibleNow = false;

				currentDrawnTime = BlinkInterval;

			}

			#endregion

		}

		#endregion



		#region Constants

		/// <summary>

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

		/// </summary>

		private const int VersionNumber = 1;

		#endregion



		#region MaxCharacters (Public)

		/// <summary>

		/// Maximum characters

		/// </summary>

		public int MaxCharacters

		{

			get;

			set;

		}

		#endregion



		#region IsReadOnly (Public)

		/// <summary>

		/// Is the Text box read only

		/// </summary>

		public bool IsReadOnly

		{

			get;

			set;

		}

		#endregion



		#region Protected



		#region FallbackDesign (Protected)

		/// <summary>

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

		/// explicitely.

		/// </summary>

		protected override ControlDesign FallbackDesign

		{

			get

			{

				return Theme.Current.TextboxDesign;

			} // get

		}

		#endregion



		///// <summary>

		///// 'True' if the user wishes to enable text editing on this text box.

		///// If the editing will be really enabled depends on the current state of

		///// the text box.

		///// </summary>

		//private bool isTextEditingWished;



		///// <summary>

		///// Is text editing on

		///// </summary>

		//protected bool IsTextEditingOn

		//{

		//  get

		//  {

		//    return isTextEditingWished &&

		//      IsReadOnly == false &&

		//      State >= ElementState.Enabled;

		//  } // get

		//  set

		//  {

		//    if (isTextEditingWished != value)

		//    {

		//      isTextEditingWished = value;



		//      if (isTextEditingWished)

		//      {

		//        // Inform the cursor that he can start with blinking now (at the

		//        // end of the text)

		//        textCursor.CharNumber = Text.Length;

		//        textCursor.StartBlinking();

		//        // and start showing an On-Screen-Keyboard (if no physical keyboard

		//        // is connected)

		//        Input.Keyboard.ShowOnScreenKeyboard();

		//      } // if

		//      else

		//      {

		//        // Inform the cursor that he can stop with blinking now

		//        textCursor.StopBlinking();

		//        // and also hide the On-Screen-Keaboard again (if there was one)

		//        Input.Keyboard.HideOnScreenKeyboard();

		//      } // else

		//    } // if

		//  } // set

		//}



		#region IsTextEditingOn (Protected)

		/// <summary>

		/// Is text editing on

		/// </summary>

		protected bool IsTextEditingOn

		{

			get

			{

				return State == ElementState.Active &&

				       IsReadOnly == false;

			} // get

			set

			{

				// If the editing mode is wished

				if (value &&

				    // but is still not enabled

				    State != ElementState.Active)

				{

					// then do it now

					State = ElementState.Active;



					// Inform the cursor that he can start with blinking now (at the

					// end of the text)

					textCursor.CharNumber = Text.Length;

					textCursor.StartBlinking();

					// and start showing an On-Screen-Keyboard (if no physical keyboard

					// is connected)

					Input.Keyboard.ShowOnScreenKeyboard();

				} // if



					// otherwise the editing mode should be disabled now

				else if (value == false &&

				         // and the control is still in there

				         State == ElementState.Active)

				{

					// then deactivate it now

					State = ElementState.Enabled;



					// Inform the cursor that he can stop with blinking now

					textCursor.StopBlinking();

					// and also hide the On-Screen-Keaboard again (if there was one)

					Input.Keyboard.HideOnScreenKeyboard();

				} // else

			} // set

		}

		#endregion



		#endregion



		#region Private



		#region textCursor (Private)

		/// <summary>

		/// The instance of the text cursor we show if the text editing mode is

		/// enabled.

		/// </summary>

		private readonly TextCursor textCursor;

		#endregion



		#endregion



		#region Constructors

		/// <summary>

		/// Creates a Text box instance.

		/// </summary>

		public TextBox()

		{

			textCursor = new TextCursor(this);

		}

		#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 it current working version

			dataWriter.Write(VersionNumber);



			dataWriter.Write(MaxCharacters);

			dataWriter.Write(IsReadOnly);

		}

		#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);



			int version = dataReader.ReadInt32();

			switch (version)

			{

				case 1:

					MaxCharacters = dataReader.ReadInt32();

					IsReadOnly = dataReader.ReadBoolean();

					// ...done

					break;



				default:

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

					break;

			} // switch

		}

		#endregion



		#region Methods (Private)



		#region OnInputEvent

		/// <summary>

		/// On input event

		/// </summary>

		/// <param name="input">Input data</param>

		protected override void OnInputEvent(CommandTrigger input)

		{

			switch (input.CommandName)

			{

				case Command.UIClick:

					// Only allow text editing if the user has clicked inside the control

					if (IsInControl(input.Position))

					{

						// If the text editing mode is already enabled then we assume the

						// user wants to set the cursor at a specific position

						if (IsTextEditingOn)

						{

							// removing text (by BackSpace/Del) by us or telling it the

							// char index in the string where to start editing

							//textCursor.DetermineCharNumber(inputData.Position -

							//  TextArea.Position);

						} // if



							// otherwise if the text editing is not enabled yet then do it now

						else

						{

							IsTextEditingOn = true;

						} // else

					} // if



						// if the click was outside the text editing mode will be disabled

						// again (if it was enabled before)

					else if (IsTextEditingOn &&

					         input.Button != InputButton.Space)

					{

						IsTextEditingOn = false;

					} // if

					break;



				default:

					base.OnInputEvent(input);

					break;

			} // switch

		}

		#endregion



		#region OnTextChanging

		/// <summary>

		/// On text changing

		/// </summary>

		/// <param name="oldText">Old text</param>

		/// <returns>

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

		/// aborted.

		/// </returns>

		protected override bool OnTextChanging(string oldText)

		{

			if (base.OnTextChanging(oldText))

			{

				if (MaxCharacters > 0)

				{

					Text = Text.MaxStringLength(MaxCharacters,

						StringHelper.CutModes.End);

				} // if



				// and also inform the text cursor about the new text size to let it

				// readjust the current cursor position (currently always at the end) 

				textCursor.OnOwnerTextHasChanged();



				return true;

			} // if



			return false;

		}

		#endregion



		#region UpdateDrawData

		/// <summary>

		/// Updates all data of this element which are required for the following

		/// draw call.

		/// </summary>

		/// <remarks>

		/// This method will only be called if the element is in an enabled state.

		/// </remarks>

		protected override void UpdateDrawData()

		{

			base.UpdateDrawData();



			if (IsTextEditingOn)

			{

				string newText = Text;

				Input.Keyboard.HandleInput(ref newText);

				if (newText != Text)

				{

					// If we pressed the "Enter" key then just finish the text editing

					// mode

					if (newText.EndsWith("\n"))

					{

						IsTextEditingOn = false;

						return;

					} // if



					Text = newText;

				} // if



				textCursor.Update();

			} // if

		}

		#endregion



		#region DrawData

		/// <summary>

		/// Draws all data of this TextBox which needs to be visualized.

		/// </summary>

		/// <remarks>

		/// This method will only be called if the TextBox is in a visible state.

		/// </remarks>

		protected override void DrawData()

		{

			base.DrawData();



			// If the text editing mode is enabled

			if (IsTextEditingOn)

			{

				// draw the cursor

				if (textCursor.IsVisibleNow)

				{

					textCursor.Draw(TextFont.Color);

				} // if

			} // if

		}

		#endregion



		#region DrawDebugInfo

		/// <summary>

		/// Draw debug info

		/// </summary>

		protected override void DrawDebugInfo()

		{

			base.DrawDebugInfo();



			float gap = 0.01f;

			Point startPos = new Point(DrawArea.Center.X, DrawArea.Bottom);

			startPos.Y += gap;



			TextFont.Draw("IsTextEditingOn '" + IsTextEditingOn + "'",

				Rectangle.FromCenter(startPos, new Size(0.5f, TextFont.LineHeight)));

			startPos.Y += gap;

		}

		#endregion



		#endregion



		/// <summary>

		/// Tests for TextBox controls

		/// </summary>

		[Category("Visual")]

		internal class Tests

		{

			#region DisplayTextbox (Static)

			/// <summary>

			/// Display text box

			/// </summary>

			[Test]

			public static void DisplayTextbox()

			{

				TextBox testTextBox = new TextBox

				{

					LocalArea = new Rectangle(0.2f, 0.2f, 0.5f, 0.1f),

					//Design = new TextControlDesign

					//{

					//  //Background = currentTheme.LabelDesign.Background,

					//  Background = null,

					//  DisabledBackground = currentTheme.LabelDesign.DisabledBackground,

					//  TextFont = currentTheme.LabelDesign.TextFont.Clone(Color.Green),

					//},

					Text = "Text.........Text",

					//Text = "T",

				};



				Screen testScreen = new Screen();

				testScreen.Add(testTextBox);



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

				testScreen.Open();



				Application.Start(delegate

				{

				});

			}

			#endregion

		}

	}

}