private MatchScore FindEndOfMatch(string targetString, string chars, int score, int firstIndex, ImmutableHashSet <int> matchSet)
{
var lastIndex = firstIndex;
var lastMatch = MatchType.Undefined;
if (firstIndex == 0 || !char.IsLetterOrDigit(targetString[firstIndex - 1]))
{
lastMatch = MatchType.Boundary;
}
foreach (var c in chars)
{
var index = targetString.IndexOf(c, lastIndex + 1);
if (index == -1)
{
return(null);
}
if (index == lastIndex + 1)
{
if (lastMatch != MatchType.Sequential)
{
score += 1;
lastMatch = MatchType.Sequential;
}
}
else if (!char.IsLetterOrDigit(targetString[index - 1]))
{
if (lastMatch != MatchType.Boundary)
{
score += 1;
lastMatch = MatchType.Boundary;
}
}
else
{
score += index - lastIndex;
lastMatch = MatchType.Normal;
}
lastIndex = index;
matchSet = matchSet.Add(index);
}
return(MatchScore.Create(score, new Range(firstIndex, lastIndex), matchSet));
}
private static MatchScore GetBestMatch(string searchString, string targetString, int?lastIndex, int score, ImmutableHashSet <int> matchedIndexes, MatchType lastMatch)
{
if (searchString.Length == 0)
{
return(MatchScore.Create(score, new Range(0, 0), matchedIndexes));
}
var searchChar = char.ToLowerInvariant(searchString.First());
var bestMatch = NoMatch;
for (var i = lastIndex + 1 ?? 0; i < targetString.Length; i++)
{
if (char.ToLowerInvariant(targetString[i]) == searchChar)
{
MatchType matchType;
var nextScore = score;
if (i == lastIndex + 1)
{
matchType = MatchType.Sequential;
}
else if (i == 0 || !char.IsLetterOrDigit(targetString[i - 1]) || !char.IsLetterOrDigit(targetString[i]))
{
matchType = MatchType.Boundary;
}
else if (char.IsLower(targetString[i - 1]) && char.IsUpper(targetString[i]))
{
matchType = MatchType.Boundary;
}
else
{
matchType = MatchType.Normal;
}
if (lastMatch == MatchType.Normal)
{
if (lastIndex.HasValue)
{
nextScore += i - lastIndex.Value;
}
}
else if (lastMatch == MatchType.Boundary || lastMatch == MatchType.Sequential)
{
if (matchType == MatchType.Normal)
{
if (lastIndex.HasValue)
{
nextScore += i - lastIndex.Value;
}
}
}
if (Mode == SelectaMode.Strict && matchType == MatchType.Normal)
{
continue;
}
var match = GetBestMatch(searchString.Substring(1), targetString, i, nextScore, matchedIndexes.Add(i), matchType);
if (match.Score < bestMatch.Score)
{
bestMatch = match;
}
}
}
return(bestMatch);
}
