using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;
using Tango.Transport.Web;

namespace Tango.MachineStudio.Common.Web
{pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)

using System;
using System.Linq;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Threading;

using Tango.Scripting.Editors.Document;
using Tango.Scripting.Editors.Rendering;

namespace Tango.Scripting.Editors.Snippets
{
	/// <summary>
	/// Text element that is supposed to be replaced by the user.
	/// Will register an <see cref="IReplaceableActiveElement"/>.
	/// </summary>
	[Serializable]
	public class SnippetReplaceableTextElement : SnippetTextElement
	{
		/// <inheritdoc/>
		public override void Insert(InsertionContext context)
		{
			int start = context.InsertionPosition;
			base.Insert(context);
			int end = context.InsertionPosition;
			context.RegisterActiveElement(this, new ReplaceableActiveElement(context, start, end));
		}
		
		/// <inheritdoc/>
		public override Inline ToTextRun()
		{
			return new Italic(base.ToTextRun());
		}
	}
	
	/// <summary>
	/// Interface for active element registered by <see cref="SnippetReplaceableTextElement"/>.
	/// </summary>
	public interface IReplaceableActiveElement : IActiveElement
	{
		/// <summary>
		/// Gets the current text inside the element.
		/// </summary>
		string Text { get; }
		
		/// <summary>
		/// Occurs when the text inside the element changes.
		/// </summary>
		event EventHandler TextChanged;
	}
	
	sealed class ReplaceableActiveElement : IReplaceableActiveElement, IWeakEventListener
	{
		readonly InsertionContext context;
		readonly int startOffset, endOffset;
		TextAnchor start, end;
		
		public ReplaceableActiveElement(InsertionContext context, int startOffset, int endOffset)
		{
			this.context = context;
			this.startOffset = startOffset;
			this.endOffset = endOffset;
		}
		
		void AnchorDeleted(object sender, EventArgs e)
		{
			context.Deactivate(new SnippetEventArgs(DeactivateReason.Deleted));
		}
		
		public void OnInsertionCompleted()
		{
			// anchors must be created in OnInsertionCompleted because they should move only
			// due to user insertions, not due to insertions of other snippet parts
			start = context.Document.CreateAnchor(startOffset);
			start.MovementType = AnchorMovementType.BeforeInsertion;
			end = context.Document.CreateAnchor(endOffset);
			end.MovementType = AnchorMovementType.AfterInsertion;
			start.Deleted += AnchorDeleted;
			end.Deleted += AnchorDeleted;
			
			// Be careful with references from the document to the editing/snippet layer - use weak events
			// to prevent memory leaks when the text area control gets dropped from the UI while the snippet is active.
			// The InsertionContext will keep us alive as long as the snippet is in interactive mode.
			TextDocumentWeakEventManager.TextChanged.AddListener(context.Document, this);
			
			background = new Renderer { Layer = KnownLayer.Background, element = this };
			foreground = new Renderer { Layer = KnownLayer.Text, element = this };
			context.TextArea.TextView.BackgroundRenderers.Add(background);
			context.TextArea.TextView.BackgroundRenderers.Add(foreground);
			context.TextArea.Caret.PositionChanged += Caret_PositionChanged;
			Caret_PositionChanged(null, null);
			
			this.Text = GetText();
		}

		public void Deactivate(SnippetEventArgs e)
		{
			TextDocumentWeakEventManager.TextChanged.RemoveListener(context.Document, this);
			context.TextArea.TextView.BackgroundRenderers.Remove(background);
			context.TextArea.TextView.BackgroundRenderers.Remove(foreground);
			context.TextArea.Caret.PositionChanged -= Caret_PositionChanged;
		}
		
		bool isCaretInside;
		
		void Caret_PositionChanged(object sender, EventArgs e)
		{
			ISegment s = this.Segment;
			if (s != null) {
				bool newIsCaretInside = s.Contains(context.TextArea.Caret.Offset);
				if (newIsCaretInside != isCaretInside) {
					isCaretInside = newIsCaretInside;
					context.TextArea.TextView.InvalidateLayer(foreground.Layer);
				}
			}
		}
		
		Renderer background, foreground;
		
		public string Text { get; private set; }
		
		string GetText()
		{
			if (start.IsDeleted || end.IsDeleted)
				return string.Empty;
			else
				return context.Document.GetText(start.Offset, Math.Max(0, end.Offset - start.Offset));
		}
		
		public event EventHandler TextChanged;
		
		bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
		{
			if (managerType == typeof(TextDocumentWeakEventManager.TextChanged)) {
				string newText = GetText();
				if (this.Text != newText) {
					this.Text = newText;
					if (TextChanged != null)
						TextChanged(this, e);
				}
				return true;
			}
			return false;
		}
		
		public bool IsEditable {
			get { return true; }
		}
		
		public ISegment Segment {
			get {
				if (start.IsDeleted || end.IsDeleted)
					return null;
				else
					return new SimpleSegment(start.Offset, Math.Max(0, end.Offset - start.Offset));
			}
		}
		
		sealed class Renderer : IBackgroundRenderer
		{
			static readonly Brush backgroundBrush = CreateBackgroundBrush();
			static readonly Pen activeBorderPen = CreateBorderPen();
			
			static Brush CreateBackgroundBrush()
			{
				SolidColorBrush b = new SolidColorBrush(Colors.LimeGreen);
				b.Opacity = 0.4;
				b.Freeze();
				return b;
			}
			
			static Pen CreateBorderPen()
			{
				Pen p = new Pen(Brushes.Black, 1);
				p.DashStyle = DashStyles.Dot;
				p.Freeze();
				return p;
			}
			
			internal ReplaceableActiveElement element;
			
			public KnownLayer Layer { get; set; }
			
			public void Draw(TextView textView, System.Windows.Media.DrawingContext drawingContext)
			{
				ISegment s = element.Segment;
				if (s != null) {
					BackgroundGeometryBuilder geoBuilder = new BackgroundGeometryBuilder();
					geoBuilder.AlignToMiddleOfPixels = true;
					if (Layer == KnownLayer.Background) {
						geoBuilder.AddSegment(textView, s);
						drawingContext.DrawGeometry(backgroundBrush, null, geoBuilder.CreateGeometry());
					} else {
						// draw foreground only if active
						if (element.isCaretInside) {
							geoBuilder.AddSegment(textView, s);
							foreach (BoundActiveElement boundElement in element.context.ActiveElements.OfType<BoundActiveElement>()) {
								if (boundElement.targetElement == element) {
									geoBuilder.AddSegment(textView, boundElement.Segment);
									geoBuilder.CloseFigure();
								}
							}
							drawingContext.DrawGeometry(null, activeBorderPen, geoBuilder.CreateGeometry());
						}
					}
				}
			}
		}
	}
}