using System.Xml;

namespace PDFPatcher.Processor
{
	internal abstract class BookmarkMatcher
	{
		internal enum MatcherType
		{
			Normal, Regex, XPath
		}

		internal abstract bool Match(XmlElement item);
		internal abstract IUndoAction Replace(XmlElement item, string replacement);
		internal static BookmarkMatcher Create(string pattern, MatcherType type, bool matchCase, bool fullMatch) {
			return type == MatcherType.XPath
				? new XPathMatcher(pattern)
				: new RegexMatcher(pattern, matchCase, type == MatcherType.Regex, fullMatch);
		}
		sealed class RegexMatcher : BookmarkMatcher
		{
			readonly Model.MatchPattern.IMatcher _matcher;
			internal RegexMatcher(string pattern, bool matchCase, bool regexSearch, bool fullMatch) {
				_matcher = new Model.MatchPattern(pattern, matchCase, fullMatch, regexSearch).CreateMatcher();
			}
			internal override bool Match(XmlElement item) {
				return _matcher.Matches(item.GetAttribute(Constants.BookmarkAttributes.Title));
			}
			internal override IUndoAction Replace(XmlElement item, string replacement) {
				var a = item.GetAttributeNode(Constants.BookmarkAttributes.Title);
				if (a == null) {
					return null;
				}
				var t = a.Value;
				if (_matcher.Matches(t)) {
					var r = _matcher.Replace(t, replacement);
					return r == t ? null : (IUndoAction)UndoAttributeAction.GetUndoAction(item, Constants.BookmarkAttributes.Title, r);
				}
				return null;
			}
		}
		sealed class XPathMatcher : BookmarkMatcher
		{
			readonly System.Xml.XPath.XPathExpression _xpath;
			internal XPathMatcher(string pattern) {
				_xpath = System.Xml.XPath.XPathExpression.Compile("*[" + pattern + "]");
			}
			internal override bool Match(XmlElement item) {
				return item.CreateNavigator().Matches(_xpath);
			}
			internal override IUndoAction Replace(XmlElement item, string replacement) {
				var a = item.GetAttributeNode(Constants.BookmarkAttributes.Title);
				if (a == null) {
					return null;
				}
				var n = item.CreateNavigator().SelectSingleNode(_xpath);
				return n == null || a.Value == replacement
					? null
					: (IUndoAction)UndoAttributeAction.GetUndoAction(item, Constants.BookmarkAttributes.Title, replacement);
			}
		}
		internal sealed class SimpleReplacer : BookmarkMatcher
		{
			internal override bool Match(XmlElement item) {
				return true;
			}
			internal override IUndoAction Replace(XmlElement item, string replacement) {
				var a = item.GetAttributeNode(Constants.BookmarkAttributes.Title);
				if (a == null) {
					return null;
				}
				return a.Value != replacement
					? UndoAttributeAction.GetUndoAction(item, Constants.BookmarkAttributes.Title, replacement)
					: (IUndoAction)null;
			}
		}
	}
}