public FlagsStringMatcher(ProjectTreeFlags flags, RegexOptions options = RegexOptions.Compiled)
{
switch (flags.Count)
{
case 0:
// We are testing against the empty set of flags, which always returns true
_regex = null;
break;
case 1:
// Find the single flag, using full-word search
_regex = new Regex($@"\b({flags.First()})\b", options);
break;
default:
// Find all flags, in any order, using full-word search
// https://regex101.com/r/LPVGgB/1
var pattern = new StringBuilder("^");
foreach (string flagName in flags)
{
pattern.AppendFormat(@"(?=.*\b({0})\b)", flagName);
}
pattern.Append(".*$");
_regex = new Regex(pattern.ToString(), options);
break;
}
}