/// <summary>
/// Utility method for evaluating the Regex Matches in ReplaceVariations()
/// </summary>
private static async Task <string> EvaluateVariation(Match match, string caseSensitiveOldValue, string caseSensitiveNewValue, StringConflictHandler conflictHandler)
{
if (match.Value == caseSensitiveOldValue.ToUpper())
{
return(caseSensitiveNewValue.ToUpper());
}
if (match.Value == caseSensitiveOldValue.FirstCharacterToLower())
{
if (match.Value == caseSensitiveOldValue.ToLower())
{
// resolve conflict (e.g. should dissolve => foofilter or dissolve => fooFilter)
return(await conflictHandler(match.Value, caseSensitiveNewValue.ToLower(), caseSensitiveNewValue.FirstCharacterToLower()));
}
else
{
return(caseSensitiveNewValue.FirstCharacterToLower());
}
}
if (match.Value == caseSensitiveOldValue.ToLower())
{
return(caseSensitiveOldValue.ToLower());
}
return(caseSensitiveNewValue);
}
/// <summary>
/// Using case-insensitive regex matching, determines the variation of the match, and replaces it with the appropriate variation of the desired result
/// e.g. ReplaceVariations("Hello WORLD", "hello", "goodbye") == "Goodbye WORLD", and ReplaceVariations("Hello WORLD", "world", "friend") == "Hello FRIEND"
/// </summary>
/// <param name="string">unadultered string to replace</param>
/// <param name="caseSensitiveOldValue">the old value to replace, in desired case, e.g. "OldFilter"</param>
/// <param name="caseSensitiveNewValue">the new value, in desired case, e.g. "NewFilter"</param>
/// <param name="conflictHandler">an async callback for optionally getting user feedback from the main thread</param>
/// <returns>a string with all variation replacements applied</returns>
public static string ReplaceVariations(this string @string, string caseSensitiveOldValue, string caseSensitiveNewValue, StringConflictHandler conflictHandler)
{
return(Regex.Replace(
input: @string,
pattern: caseSensitiveOldValue,
evaluator: (Match match) =>
{
var task = EvaluateVariation(match, caseSensitiveOldValue, caseSensitiveNewValue, conflictHandler);
task.Wait();
return task.Result;
},
options: RegexOptions.IgnoreCase));
}
