public static SearchResult SearchPage(string pageName, string textToSearch, string query)
{
//beautiful search algorithm that is worthy of becoming the new Google
var retval = new SearchResult
{
PageName = pageName,
Relevance = 0.0,
Snippet = string.Empty
};
string originalText = textToSearch;
textToSearch = textToSearch.ToLower();
string originalQuery = query;
query = query.ToLower();
var queryWords = GetQueryWords(query).ToArray();
if (!queryWords.Any())
{
return retval;
}
if (pageName.IndexOf(query, StringComparison.OrdinalIgnoreCase) > -1)
{
retval.Relevance = 1.0;
CreateSnippet(retval, originalText, 0);
}
else
{
var queryPos = textToSearch.IndexOf(query, StringComparison.OrdinalIgnoreCase);
if (queryPos > -1)
{
retval.Relevance = 0.9;
CreateSnippet(retval, originalText, queryPos);
}
else
{
var relevancePart = 0.8 / queryWords.Count();
foreach (var word in queryWords)
{
if (pageName.IndexOf(word, StringComparison.OrdinalIgnoreCase) > -1)
{
retval.Relevance += relevancePart;
if (string.IsNullOrEmpty(retval.Snippet))
{
CreateSnippet(retval, originalText, 0);
}
}
else
{
var pos = textToSearch.IndexOf(word, StringComparison.OrdinalIgnoreCase);
if (pos > -1)
{
retval.Relevance += relevancePart;
if (string.IsNullOrEmpty(retval.Snippet))
{
CreateSnippet(retval, originalText, pos);
}
}
}
}
}
}
//highlight words in snippet
foreach (var word in GetQueryWords(originalQuery))
{
var re = new Regex(word, RegexOptions.IgnoreCase);
retval.Snippet = re.Replace(retval.Snippet, HighlightWord);
}
return retval;
}
private static void CreateSnippet(SearchResult retval, string text, int foundAtPos)
{
int snippetStart = Math.Max(0, foundAtPos - 50);
int snippetStop = Math.Min(text.Length, snippetStart + 100);
retval.Snippet = text.Substring(snippetStart, snippetStop - snippetStart);
}