// <developer>niklas@protocol7.com</developer>
// <completed>80</completed>

using System;
using System.Xml;
using System.Net;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using SharpVectors.Dom.Stylesheets;

namespace SharpVectors.Dom.Css
{
	/// <summary>
	/// The CSSStyleSheet interface is a concrete interface used to represent a CSS style sheet i.e., a style sheet whose content type is "text/css".
	/// </summary>
	public class CssStyleSheet : StyleSheet, ICssStyleSheet
	{
		#region Constructors
		/// <summary>
		/// Constructor for CssStyleSheet
		/// </summary>
		/// <param name="pi">The XML processing instruction that references the stylesheet</param>
		/// <param name="origin">The type of stylesheet</param>
		internal CssStyleSheet(XmlProcessingInstruction pi, CssStyleSheetType origin) : base(pi)
		{
			Origin = origin;
		}

		/// <summary>
		/// Constructor for CssStyleSheet
		/// </summary>
		/// <param name="styleElement">The XML style element that references the stylesheet</param>
		/// <param name="origin">The type of stylesheet</param>
		internal CssStyleSheet(XmlElement styleElement, CssStyleSheetType origin) : base(styleElement)
		{
			Origin = origin;
		}

		/// <summary>
		/// Constructor for CssStyleSheet
		/// </summary>
		/// <param name="ownerNode">The node that owns this stylesheet. E.g. used for getting the BaseUri</param>
		/// <param name="href">The URL of the stylesheet</param>
		/// <param name="title">The title of the stylesheet</param>
		/// <param name="media">List of medias for the stylesheet</param>
		/// <param name="ownerRule">The rule (e.g. ImportRule) that referenced this stylesheet</param>
		/// <param name="origin">The type of stylesheet</param>
		public CssStyleSheet(XmlNode ownerNode, string href, string title, string media, 
            CssRule ownerRule, CssStyleSheetType origin) 
            : base(ownerNode, href, "text/css", title, media)
		{
			Origin = origin;
			this.ownerRule = ownerRule;
		}
		#endregion

		#region Public methods
		/// <summary>
		/// Used to find matching style rules in the cascading order
		/// </summary>
		/// <param name="elt">The element to find styles for</param>
		/// <param name="pseudoElt">The pseudo-element to find styles for</param>
		/// <param name="ml">The medialist that the document is using</param>
		/// <param name="csd">A CssStyleDeclaration that holds the collected styles</param>
		protected internal override void GetStylesForElement(XmlElement elt, string pseudoElt, MediaList ml, CssCollectedStyleDeclaration csd)
		{
			if(((MediaList)Media).Matches(ml))
			{
				((CssRuleList)CssRules).GetStylesForElement(elt, pseudoElt, ml, csd);
			}
		}
		#endregion

		#region Private methods

		private string StringReplaceEvaluator(Match match)
		{
			alReplacedStrings.Add(match.Value);

			return "\"<<<" + (alReplacedStrings.Count - 1) + ">>>\"";
		}

		private string PreProcessContent()
		{
			if (SheetContent != null && SheetContent.Length > 0)
			{
				// "escape" strings, eg: "foo" => "<<<number>>>"			
				Regex re = new Regex(@"(""(.|\n)*?[^\\]"")|('(.|\n)*?[^\\]')");
                alReplacedStrings.Clear();
				string s = re.Replace(SheetContent, new MatchEvaluator(StringReplaceEvaluator));
			
				//ReplacedStrings = alReplacedStrings.ToArray();
				//alReplacedStrings.Clear();

				// remove comments
				Regex reComment = new Regex(@"(//.*)|(/\*(.|\n)*?\*/)");
				s = reComment.Replace(s, String.Empty);
				return s;
			}
			else
			{
				return "";
			}
		}

		#endregion

		#region Private fields
		private readonly CssStyleSheetType Origin;
        private List<string> alReplacedStrings = new List<string>();
		//private string[] ReplacedStrings;
		#endregion

		#region Implementation of ICssStyleSheet
		/// <summary>
		/// Used to delete a rule from the style sheet.
		/// </summary>
		/// <param name="index">The index within the style sheet's rule list of the rule to remove.</param>
		/// <exception cref="DomException">INDEX_SIZE_ERR: Raised if the specified index does not correspond to a rule in the style sheet's rule list.</exception>
		/// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this style sheet is readonly.</exception>
		public void DeleteRule(ulong index)
		{
			((CssRuleList)CssRules).DeleteRule(index);
		}

		/// <summary>
		/// Used to insert a new rule into the style sheet. The new rule now becomes part of the cascade.
		/// </summary>
		/// <param name="rule">The parsable text representing the rule. For rule sets this contains both the selector and the style declaration. For at-rules, this specifies both the at-identifier and the rule content.</param>
		/// <param name="index">The index within the style sheet's rule list of the rule before which to insert the specified rule. If the specified index is equal to the length of the style sheet's rule collection, the rule will be added to the end of the style sheet.</param>
		/// <returns>The index within the style sheet's rule collection of the newly inserted rule.</returns>
		/// <exception cref="DomException">INDEX_SIZE_ERR: Raised if the specified index does not correspond to a rule in the style sheet's rule list.</exception>
		/// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this style sheet is readonly.</exception>
		/// <exception cref="DomException">HIERARCHY_REQUEST_ERR: Raised if the rule cannot be inserted at the specified index e.g. if an @import rule is inserted after a standard rule set or other at-rule.</exception>
		/// <exception cref="DomException">SYNTAX_ERR: Raised if the specified rule has a syntax error and is unparsable.</exception>
		public ulong InsertRule(string rule, ulong index)
		{
			throw new NotImplementedException("CssStyleSheet.InsertRule()");
			//return ((CssRuleList)CssRules).InsertRule(rule, index);
		}

		private CssRuleList cssRules = null;
		/// <summary>
		/// The list of all CSS rules contained within the style sheet. This includes both rule sets and at-rules.
		/// </summary>
		public ICssRuleList CssRules
		{
			get
			{
				if (cssRules == null)
				{
					string css = PreProcessContent();
                    cssRules = new CssRuleList(ref css, this, alReplacedStrings, Origin);
				}

				return cssRules;
			}
			set
			{
				throw new NotImplementedException();
			}
		}

		private CssRule ownerRule;
		/// <summary>
		/// If this style sheet comes from an @import rule, the ownerRule attribute will contain the CSSImportRule. In that case, the ownerNode attribute in the StyleSheet interface will be null. If the style sheet comes from an element or a processing instruction, the ownerRule attribute will be null and the ownerNode attribute will contain the Node.
		/// </summary>
		public ICssRule OwnerRule
		{
			get
			{
				return ownerRule;
			}
		}
		#endregion
	}
}