// 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.ComponentModel;

namespace Tango.Scripting.Editors.Utils
{
	/// <summary>
	/// WeakEventManager for INotifyPropertyChanged.PropertyChanged.
	/// </summary>
	public sealed class PropertyChangedWeakEventManager : WeakEventManagerBase<PropertyChangedWeakEventManager, INotifyPropertyChanged>
	{
		/// <inheritdoc/>
		protected override void StartListening(INotifyPropertyChanged source)
		{
			source.PropertyChanged += DeliverEvent;
		}
		
		/// <inheritdoc/>
		protectedpre { 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.Collections.Generic;
using System.Text;
using System.Windows;
using Tango.Scripting.Editors.Document;
using Tango.Scripting.Editors.Highlighting;
using Tango.Scripting.Editors.Utils;

namespace Tango.Scripting.Editors.Editing
{
	/// <summary>
	/// Base class for selections.
	/// </summary>
	public abstract class Selection
	{
		/// <summary>
		/// Creates a new simple selection that selects the text from startOffset to endOffset.
		/// </summary>
		public static Selection Create(TextArea textArea, int startOffset, int endOffset)
		{
			if (textArea == null)
				throw new ArgumentNullException("textArea");
			if (startOffset == endOffset)
				return textArea.emptySelection;
			else
				return new SimpleSelection(textArea,
				                           new TextViewPosition(textArea.Document.GetLocation(startOffset)),
				                           new TextViewPosition(textArea.Document.GetLocation(endOffset)));
		}
		
		internal static Selection Create(TextArea textArea, TextViewPosition start, TextViewPosition end)
		{
			if (textArea == null)
				throw new ArgumentNullException("textArea");
			if (textArea.Document.GetOffset(start.Location) == textArea.Document.GetOffset(end.Location) && start.VisualColumn == end.VisualColumn)
				return textArea.emptySelection;
			else
				return new SimpleSelection(textArea, start, end);
		}
		
		/// <summary>
		/// Creates a new simple selection that selects the text in the specified segment.
		/// </summary>
		public static Selection Create(TextArea textArea, ISegment segment)
		{
			if (segment == null)
				throw new ArgumentNullException("segment");
			return Create(textArea, segment.Offset, segment.EndOffset);
		}
		
		internal readonly TextArea textArea;
		
		/// <summary>
		/// Constructor for Selection.
		/// </summary>
		protected Selection(TextArea textArea)
		{
			if (textArea == null)
				throw new ArgumentNullException("textArea");
			this.textArea = textArea;
		}
		
		/// <summary>
		/// Gets the start position of the selection.
		/// </summary>
		public abstract TextViewPosition StartPosition { get; }
		
		/// <summary>
		/// Gets the end position of the selection.
		/// </summary>
		public abstract TextViewPosition EndPosition { get; }
		
		/// <summary>
		/// Gets the selected text segments.
		/// </summary>
		public abstract IEnumerable<SelectionSegment> Segments { get; }
		
		/// <summary>
		/// Gets the smallest segment that contains all segments in this selection.
		/// May return null if the selection is empty.
		/// </summary>
		public abstract ISegment SurroundingSegment { get; }
		
		/// <summary>
		/// Replaces the selection with the specified text.
		/// </summary>
		public abstract void ReplaceSelectionWithText(string newText);
		
		internal string AddSpacesIfRequired(string newText, TextViewPosition start, TextViewPosition end)
		{
			if (EnableVirtualSpace && InsertVirtualSpaces(newText, start, end)) {
				var line = textArea.Document.GetLineByNumber(start.Line);
				string lineText = textArea.Document.GetText(line);
				var vLine = textArea.TextView.GetOrConstructVisualLine(line);
				int colDiff = start.VisualColumn - vLine.VisualLengthWithEndOfLineMarker;
				if (colDiff > 0) {
					string additionalSpaces = "";
					if (!textArea.Options.ConvertTabsToSpaces && lineText.Trim('\t').Length == 0) {
						int tabCount = (int)(colDiff / textArea.Options.IndentationSize);
						additionalSpaces = new string('\t', tabCount);
						colDiff -= tabCount * textArea.Options.IndentationSize;
					}
					additionalSpaces += new string(' ', colDiff);
					return additionalSpaces + newText;
				}
			}
			return newText;
		}
		
		bool InsertVirtualSpaces(string newText, TextViewPosition start, TextViewPosition end)
		{
			return (!string.IsNullOrEmpty(newText) || !(IsInVirtualSpace(start) && IsInVirtualSpace(end)))
				&& newText != "\r\n"
				&& newText != "\n" 
				&& newText != "\r";
		}
		
		bool IsInVirtualSpace(TextViewPosition pos)
		{
			return pos.VisualColumn > textArea.TextView.GetOrConstructVisualLine(textArea.Document.GetLineByNumber(pos.Line)).VisualLength;
		}
		
		/// <summary>
		/// Updates the selection when the document changes.
		/// </summary>
		public abstract Selection UpdateOnDocumentChange(DocumentChangeEventArgs e);
		
		/// <summary>
		/// Gets whether the selection is empty.
		/// </summary>
		public virtual bool IsEmpty {
			get { return Length == 0; }
		}
		
		/// <summary>
		/// Gets whether virtual space is enabled for this selection.
		/// </summary>
		public virtual bool EnableVirtualSpace {
			get { return textArea.Options.EnableVirtualSpace; }
		}
		
		/// <summary>
		/// Gets the selection length.
		/// </summary>
		public abstract int Length { get; }
		
		/// <summary>
		/// Returns a new selection with the changed end point.
		/// </summary>
		/// <exception cref="NotSupportedException">Cannot set endpoint for empty selection</exception>
		public abstract Selection SetEndpoint(TextViewPosition endPosition);
		
		/// <summary>
		/// If this selection is empty, starts a new selection from <paramref name="startPosition"/> to
		/// <paramref name="endPosition"/>, otherwise, changes the endpoint of this selection.
		/// </summary>
		public abstract Selection StartSelectionOrSetEndpoint(TextViewPosition startPosition, TextViewPosition endPosition);
		
		/// <summary>
		/// Gets whether the selection is multi-line.
		/// </summary>
		public virtual bool IsMultiline {
			get {
				ISegment surroundingSegment = this.SurroundingSegment;
				if (surroundingSegment == null)
					return false;
				int start = surroundingSegment.Offset;
				int end = start + surroundingSegment.Length;
				var document = textArea.Document;
				if (document == null)
					throw ThrowUtil.NoDocumentAssigned();
				return document.GetLineByOffset(start) != document.GetLineByOffset(end);
			}
		}
		
		/// <summary>
		/// Gets the selected text.
		/// </summary>
		public virtual string GetText()
		{
			var document = textArea.Document;
			if (document == null)
				throw ThrowUtil.NoDocumentAssigned();
			StringBuilder b = null;
			string text = null;
			foreach (ISegment s in Segments) {
				if (text != null) {
					if (b == null)
						b = new StringBuilder(text);
					else
						b.Append(text);
				}
				text = document.GetText(s);
			}
			if (b != null) {
				if (text != null) b.Append(text);
				return b.ToString();
			} else {
				return text ?? string.Empty;
			}
		}
		
		/// <summary>
		/// Creates a HTML fragment for the selected text.
		/// </summary>
		public string CreateHtmlFragment(HtmlOptions options)
		{
			if (options == null)
				throw new ArgumentNullException("options");
			IHighlighter highlighter = textArea.GetService(typeof(IHighlighter)) as IHighlighter;
			StringBuilder html = new StringBuilder();
			bool first = true;
			foreach (ISegment selectedSegment in this.Segments) {
				if (first)
					first = false;
				else
					html.AppendLine("<br>");
				html.Append(HtmlClipboard.CreateHtmlFragment(textArea.Document, highlighter, selectedSegment, options));
			}
			return html.ToString();
		}
		
		/// <inheritdoc/>
		public abstract override bool Equals(object obj);
		
		/// <inheritdoc/>
		public abstract override int GetHashCode();
		
		/// <summary>
		/// Gets whether the specified offset is included in the selection.
		/// </summary>
		/// <returns>True, if the selection contains the offset (selection borders inclusive);
		/// otherwise, false.</returns>
		public virtual bool Contains(int offset)
		{
			if (this.IsEmpty)
				return false;
			if (this.SurroundingSegment.Contains(offset)) {
				foreach (ISegment s in this.Segments) {
					if (s.Contains(offset)) {
						return true;
					}
				}
			}
			return false;
		}
		
		/// <summary>
		/// Creates a data object containing the selection's text.
		/// </summary>
		public virtual DataObject CreateDataObject(TextArea textArea)
		{
			string text = GetText();
			// Ensure we use the appropriate newline sequence for the OS
			DataObject data = new DataObject(TextUtilities.NormalizeNewLines(text, Environment.NewLine));
			// we cannot use DataObject.SetText - then we cannot drag to SciTe
			// (but dragging to Word works in both cases)
			
			// Also copy text in HTML format to clipboard - good for pasting text into Word
			// or to the SharpDevelop forums.
			HtmlClipboard.SetHtml(data, CreateHtmlFragment(new HtmlOptions(textArea.Options)));
			return data;
		}
	}
}