# frozen-string-literal: true require_relative "levenshtein" require_relative "jaro_winkler" module DidYouMean class SpellChecker def initialize(dictionary:) @dictionary = dictionary end def correct(input) input = normalize(input) threshold = input.length > 3 ? 0.834 : 0.77 words = @dictionary.select { |word| JaroWinkler.distance(normalize(word), input) >= threshold } words.reject! { |word| input == word.to_s } words.sort_by! { |word| JaroWinkler.distance(word.to_s, input) } words.reverse! # Correct mistypes threshold = (input.length * 0.25).ceil corrections = words.select { |c| Levenshtein.distance(normalize(c), input) <= threshold } # Correct misspells if corrections.empty? corrections = words.select do |word| word = normalize(word) length = input.length < word.length ? input.length : word.length Levenshtein.distance(word, input) < length end.first(1) end corrections end private def normalize(str_or_symbol) #:nodoc: str = str_or_symbol.to_s.downcase str.tr!("@", "") str end end end