using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.Core;
usingpre { 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.Globalization;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Media;
using System.Xml;
using System.Xml.Schema;

using ICSharpCode.AvalonEdit.Utils;

namespace ICSharpCode.AvalonEdit.Highlighting.Xshd
{
	/// <summary>
	/// Loads .xshd files, version 1.0.
	/// </summary>
	sealed class V1Loader
	{
		static XmlSchemaSet schemaSet;
		
		static XmlSchemaSet SchemaSet {
			get {
				if (schemaSet == null) {
					schemaSet = HighlightingLoader.LoadSchemaSet(new XmlTextReader(
						Resources.OpenStream("ModeV1.xsd")));
				}
				return schemaSet;
			}
		}
		
		public static XshdSyntaxDefinition LoadDefinition(XmlReader reader, bool skipValidation)
		{
			reader = HighlightingLoader.GetValidatingReader(reader, false, skipValidation ? null : SchemaSet);
			XmlDocument document = new XmlDocument();
			document.Load(reader);
			V1Loader loader = new V1Loader();
			return loader.ParseDefinition(document.DocumentElement);
		}
		
		XshdSyntaxDefinition ParseDefinition(XmlElement syntaxDefinition)
		{
			XshdSyntaxDefinition def = new XshdSyntaxDefinition();
			def.Name = syntaxDefinition.GetAttributeOrNull("name");
			if (syntaxDefinition.HasAttribute("extensions")) {
				def.Extensions.AddRange(syntaxDefinition.GetAttribute("extensions").Split(';', '|'));
			}
			
			XshdRuleSet mainRuleSetElement = null;
			foreach (XmlElement element in syntaxDefinition.GetElementsByTagName("RuleSet")) {
				XshdRuleSet ruleSet = ImportRuleSet(element);
				def.Elements.Add(ruleSet);
				if (ruleSet.Name == null)
					mainRuleSetElement = ruleSet;
				
				if (syntaxDefinition["Digits"] != null) {
					// create digit highlighting rule
					
					const string optionalExponent = @"([eE][+-]?[0-9]+)?";
					const string floatingPoint = @"\.[0-9]+";
					ruleSet.Elements.Add(
						new XshdRule {
							ColorReference = GetColorReference(syntaxDefinition["Digits"]),
							RegexType = XshdRegexType.IgnorePatternWhitespace,
							Regex = @"\b0[xX][0-9a-fA-F]+"
								+ @"|"
								+ @"(\b\d+(" + floatingPoint + ")?"
								+ @"|" + floatingPoint + ")"
								+ optionalExponent
						});
				}
			}
			
			if (syntaxDefinition.HasAttribute("extends") && mainRuleSetElement != null) {
				// convert 'extends="HTML"' to '<Import ruleSet="HTML/" />' in main rule set.
				mainRuleSetElement.Elements.Add(
					new XshdImport { RuleSetReference = new XshdReference<XshdRuleSet>(
						syntaxDefinition.GetAttribute("extends"), string.Empty
					) });
			}
			return def;
		}
		
		static XshdColor GetColorFromElement(XmlElement element)
		{
			if (!element.HasAttribute("bold") && !element.HasAttribute("italic") && !element.HasAttribute("color") && !element.HasAttribute("bgcolor"))
				return null;
			XshdColor color = new XshdColor();
			if (element.HasAttribute("bold"))
				color.FontWeight = XmlConvert.ToBoolean(element.GetAttribute("bold")) ? FontWeights.Bold : FontWeights.Normal;
			if (element.HasAttribute("italic"))
				color.FontStyle = XmlConvert.ToBoolean(element.GetAttribute("italic")) ? FontStyles.Italic : FontStyles.Normal;
			if (element.HasAttribute("color"))
				color.Foreground = ParseColor(element.GetAttribute("color"));
			if (element.HasAttribute("bgcolor"))
				color.Background = ParseColor(element.GetAttribute("bgcolor"));
			return color;
		}
		
		static XshdReference<XshdColor> GetColorReference(XmlElement element)
		{
			XshdColor color = GetColorFromElement(element);
			if (color != null)
				return new XshdReference<XshdColor>(color);
			else
				return new XshdReference<XshdColor>();
		}
		
		static HighlightingBrush ParseColor(string c)
		{
			if (c.StartsWith("#", StringComparison.Ordinal)) {
				int a = 255;
				int offset = 0;
				if (c.Length > 7) {
					offset = 2;
					a = Int32.Parse(c.Substring(1,2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
				}
				
				int r = Int32.Parse(c.Substring(1 + offset,2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
				int g = Int32.Parse(c.Substring(3 + offset,2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
				int b = Int32.Parse(c.Substring(5 + offset,2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
				return new SimpleHighlightingBrush(Color.FromArgb((byte)a, (byte)r, (byte)g, (byte)b));
			} else if (c.StartsWith("SystemColors.", StringComparison.Ordinal)) {
				return V2Loader.GetSystemColorBrush(null, c);
			} else {
				return new SimpleHighlightingBrush((Color)V2Loader.ColorConverter.ConvertFromInvariantString(c));
			}
		}
		
		char ruleSetEscapeCharacter;
		
		XshdRuleSet ImportRuleSet(XmlElement element)
		{
			XshdRuleSet ruleSet = new XshdRuleSet();
			ruleSet.Name = element.GetAttributeOrNull("name");
			
			if (element.HasAttribute("escapecharacter")) {
				ruleSetEscapeCharacter = element.GetAttribute("escapecharacter")[0];
			} else {
				ruleSetEscapeCharacter = '\0';
			}
			
			if (element.HasAttribute("reference")) {
				ruleSet.Elements.Add(
					new XshdImport { RuleSetReference = new XshdReference<XshdRuleSet>(
						element.GetAttribute("reference"), string.Empty
					) });
			}
			ruleSet.IgnoreCase = element.GetBoolAttribute("ignorecase");
			
			foreach (XmlElement el in element.GetElementsByTagName("KeyWords")) {
				XshdKeywords keywords = new XshdKeywords();
				keywords.ColorReference = GetColorReference(el);
				// we have to handle old syntax highlighting definitions that contain
				// empty keywords or empty keyword groups
				foreach (XmlElement node in el.GetElementsByTagName("Key")) {
					string word = node.GetAttribute("word");
					if (!string.IsNullOrEmpty(word))
						keywords.Words.Add(word);
				}
				if (keywords.Words.Count > 0) {
					ruleSet.Elements.Add(keywords);
				}
			}
			
			foreach (XmlElement el in element.GetElementsByTagName("Span")) {
				ruleSet.Elements.Add(ImportSpan(el));
			}
			
			foreach (XmlElement el in element.GetElementsByTagName("MarkPrevious")) {
				ruleSet.Elements.Add(ImportMarkPrevNext(el, false));
			}
			foreach (XmlElement el in element.GetElementsByTagName("MarkFollowing")) {
				ruleSet.Elements.Add(ImportMarkPrevNext(el, true));
			}
			
			return ruleSet;
		}
		
		static XshdRule ImportMarkPrevNext(XmlElement el, bool markFollowing)
		{
			bool markMarker = el.GetBoolAttribute("markmarker") ?? false;
			string what = Regex.Escape(el.InnerText);
			const string identifier = @"[\d\w_]+";
			const string whitespace = @"\s*";
			
			string regex;
			if (markFollowing) {
				if (markMarker) {
					regex = what + whitespace + identifier;
				} else {
					regex = "(?<=(" + what + whitespace + "))" + identifier;
				}
			} else {
				if (markMarker) {
					regex = identifier + whitespace + what;
				} else {
					regex = identifier + "(?=(" + whitespace + what + "))";
				}
			}
			return new XshdRule {
				ColorReference = GetColorReference(el),
				Regex = regex,
				RegexType = XshdRegexType.IgnorePatternWhitespace
			};
		}
		
		XshdSpan ImportSpan(XmlElement element)
		{
			XshdSpan span = new XshdSpan();
			if (element.HasAttribute("rule")) {
				span.RuleSetReference = new XshdReference<XshdRuleSet>(null, element.GetAttribute("rule"));
			}
			char escapeCharacter = ruleSetEscapeCharacter;
			if (element.HasAttribute("escapecharacter")) {
				escapeCharacter = element.GetAttribute("escapecharacter")[0];
			}
			span.Multiline = !(element.GetBoolAttribute("stopateol") ?? false);
			
			span.SpanColorReference = GetColorReference(element);
			
			span.BeginRegexType = XshdRegexType.IgnorePatternWhitespace;
			span.BeginRegex = ImportRegex(element["Begin"].InnerText,
			                              element["Begin"].GetBoolAttribute("singleword") ?? false,
			                              element["Begin"].GetBoolAttribute("startofline"));
			span.BeginColorReference = GetColorReference(element["Begin"]);
			
			string endElementText = string.Empty;
			if (element["End"] != null) {
				span.EndRegexType = XshdRegexType.IgnorePatternWhitespace;
				endElementText = element["End"].InnerText;
				span.EndRegex = ImportRegex(endElementText,
				                            element["End"].GetBoolAttribute("singleword") ?? false,
				                            null);
				span.EndColorReference = GetColorReference(element["End"]);
			}
			
			if (escapeCharacter != '\0') {
				XshdRuleSet ruleSet = new XshdRuleSet();
				if (endElementText.Length == 1 && endElementText[0] == escapeCharacter) {
					// ""-style escape
					ruleSet.Elements.Add(new XshdSpan {
					                     	BeginRegex = Regex.Escape(endElementText + endElementText),
					                     	EndRegex = ""
					                     });
				} else {
					// \"-style escape
					ruleSet.Elements.Add(new XshdSpan {
					                     	BeginRegex = Regex.Escape(escapeCharacter.ToString()),
					                     	EndRegex = "."
					                     });
				}
				if (span.RuleSetReference.ReferencedElement != null) {
					ruleSet.Elements.Add(new XshdImport { RuleSetReference = span.RuleSetReference });
				}
				span.RuleSetReference = new XshdReference<XshdRuleSet>(ruleSet);
			}
			return span;
		}
		
		static string ImportRegex(string expr, bool singleWord, bool? startOfLine)
		{
			StringBuilder b = new StringBuilder();
			if (startOfLine != null) {
				if (startOfLine.Value) {
					b.Append(@"(?<=(^\s*))");
				} else {
					b.Append(@"(?<!(^\s*))");
				}
			} else {
				if (singleWord)
					b.Append(@"\b");
			}
			for (int i = 0; i < expr.Length; i++) {
				char c = expr[i];
				if (c == '@') {
					++i;
					if (i == expr.Length)
						throw new HighlightingDefinitionInvalidException("Unexpected end of @ sequence, use @@ to look for a single @.");
					switch (expr[i]) {
						case 'C': // match whitespace or punctuation
							b.Append(@"[^\w\d_]");
							break;
						case '!': // negative lookahead
							{
								StringBuilder whatmatch = new StringBuilder();
								++i;
								while (i < expr.Length && expr[i] != '@') {
									whatmatch.Append(expr[i++]);
								}
								b.Append("(?!(");
								b.Append(Regex.Escape(whatmatch.ToString()));
								b.Append("))");
							}
							break;
						case '-': // negative lookbehind
							{
								StringBuilder whatmatch = new StringBuilder();
								++i;
								while (i < expr.Length && expr[i] != '@') {
									whatmatch.Append(expr[i++]);
								}
								b.Append("(?<!(");
								b.Append(Regex.Escape(whatmatch.ToString()));
								b.Append("))");
							}
							break;
						case '@':
							b.Append("@");
							break;
						default:
							throw new HighlightingDefinitionInvalidException("Unknown character in @ sequence.");
					}
				} else {
					b.Append(Regex.Escape(c.ToString()));
				}
			}
			if (singleWord)
				b.Append(@"\b");
			return b.ToString();
		}
	}
}