using System.Text; namespace Wox.Infrastructure { /// <summary> /// refer to https://github.com/mattyork/fuzzy /// </summary> public class FuzzyMatcher { private string query; private MatchOption opt; private FuzzyMatcher(string query, MatchOption opt) { this.query = query.Trim(); this.opt = opt; } public static FuzzyMatcher Create(string query) { return new FuzzyMatcher(query, new MatchOption()); } public static FuzzyMatcher Create(string query, MatchOption opt) { return new FuzzyMatcher(query, opt); } public MatchResult Evaluate(string str) { if (string.IsNullOrEmpty(str) || string.IsNullOrEmpty(query)) return new MatchResult { Success = false }; var len = str.Length; var compareString = opt.IgnoreCase ? str.ToLower() : str; var pattern = opt.IgnoreCase ? query.ToLower() : query; var sb = new StringBuilder(str.Length + (query.Length * (opt.Prefix.Length + opt.Suffix.Length))); var patternIdx = 0; var firstMatchIndex = -1; var lastMatchIndex = 0; char ch; for (var idx = 0; idx < len; idx++) { ch = str[idx]; if (compareString[idx] == pattern[patternIdx]) { if (firstMatchIndex < 0) firstMatchIndex = idx; lastMatchIndex = idx + 1; sb.Append(opt.Prefix + ch + opt.Suffix); patternIdx += 1; } else { sb.Append(ch); } // match success, append remain char if (patternIdx == pattern.Length && (idx + 1) != compareString.Length) { sb.Append(str.Substring(idx + 1)); break; } } // return rendered string if we have a match for every char if (patternIdx == pattern.Length) { return new MatchResult { Success = true, Value = sb.ToString(), Score = CalScore(str, firstMatchIndex, lastMatchIndex - firstMatchIndex) }; } return new MatchResult { Success = false }; } private int CalScore(string str, int firstIndex, int matchLen) { //a match found near the beginning of a string is scored more than a match found near the end //a match is scored more if the characters in the patterns are closer to each other, while the score is lower if they are more spread out var score = 100 * (query.Length + 1) / ((1 + firstIndex) + (matchLen + 1)); //a match with less characters assigning more weights if (str.Length - query.Length < 5) score = score + 20; else if (str.Length - query.Length < 10) score = score + 10; return score; } } public class MatchResult { public bool Success { get; set; } public int Score { get; set; } /// <summary> /// hightlight string /// </summary> public string Value { get; set; } } public class MatchOption { public MatchOption() { Prefix = ""; Suffix = ""; IgnoreCase = true; } /// <summary> /// prefix of match char, use for hightlight /// </summary> public string Prefix { get; set; } /// <summary> /// suffix of match char, use for hightlight /// </summary> public string Suffix { get; set; } public bool IgnoreCase { get; set; } } }