module Faker
  module Char
    def self.prepare(string)
      result = romanize_cyrillic string
      result = fix_umlauts result
      result.gsub(/\W/, '').downcase
    end

    def self.fix_umlauts(string)
      string.gsub(/[äöüß]/i) do |match|
        case match.downcase
        when 'ä' then 'ae'
        when 'ö' then 'oe'
        when 'ü' then 'ue'
        when 'ß' then 'ss'
        end
      end
    end

    def self.romanize_cyrillic(string)
      if Faker::Config.locale == 'uk'
        # Based on conventions abopted by BGN/PCGN for Ukrainian
        uk_chars = {
          'а' => 'a',  'б' => 'b',  'в' => 'v',  'г' => 'h',  'ґ' => 'g',  'д' => 'd',
          'е' => 'e',  'є' => 'ye', 'ж' => 'zh', 'з' => 'z',  'и' => 'y',  'і' => 'i',
          'ї' => 'yi', 'й' => 'y',  'к' => 'k',  'л' => 'l',  'м' => 'm',  'н' => 'n',
          'о' => 'o',  'п' => 'p',  'р' => 'r',  'с' => 's',  'т' => 't',  'у' => 'u',
          'ф' => 'f',  'х' => 'kh', 'ц' => 'ts', 'ч' => 'ch', 'ш' => 'sh', 'щ' => 'shch',
          'ю' => 'yu', 'я' => 'ya',
          'А' => 'a',  'Б' => 'b',  'В' => 'v',  'Г' => 'h',  'Ґ' => 'g',  'Д' => 'd',
          'Е' => 'e',  'Є' => 'ye', 'Ж' => 'zh', 'З' => 'z',  'И' => 'y',  'І' => 'i',
          'Ї' => 'yi', 'Й' => 'y',  'К' => 'k',  'Л' => 'l',  'М' => 'm',  'Н' => 'n',
          'О' => 'o',  'П' => 'p',  'Р' => 'r',  'С' => 's',  'Т' => 't',  'У' => 'u',
          'Ф' => 'f',  'Х' => 'kh', 'Ц' => 'ts', 'Ч' => 'ch', 'Ш' => 'sh', 'Щ' => 'shch',
          'Ю' => 'yu', 'Я' => 'ya',
          'ь' => '' # Ignore symbol, because its standard presentation is not allowed in URLs
        }
        return string.gsub(/[а-яА-ЯіїєґІЇЄҐ]/, uk_chars)
      end

      if Faker::Config.locale == 'ru'
        # Based on conventions abopted by BGN/PCGN for Russian
        ru_chars = {
          'а' => 'a', 'б' => 'b', 'в' => 'v', 'г' => 'h', 'д' => 'd', 'е' => 'e',
          'ё' => 'ye', 'ж' => 'zh', 'з' => 'z',    'и' => 'i',  'й' => 'y',  'к' => 'k',
          'л' => 'l',  'м' => 'm',  'н' => 'n',    'о' => 'o',  'п' => 'p',  'р' => 'r',
          'с' => 's',  'т' => 't',  'у' => 'u',    'ф' => 'f',  'х' => 'kh', 'ц' => 'ts',
          'ч' => 'ch', 'ш' => 'sh', 'щ' => 'shch', 'ы' => 'у',  'э' => 'e',  'ю' => 'yu',
          'я' => 'ya',
          'А' => 'a',  'Б' => 'b',  'В' => 'v',    'Г' => 'h',  'Д' => 'd',  'Е' => 'e',
          'Ё' => 'ye', 'Ж' => 'zh', 'З' => 'z',    'И' => 'i',  'Й' => 'y',  'К' => 'k',
          'Л' => 'l',  'М' => 'm',  'Н' => 'n',    'О' => 'o',  'П' => 'p',  'Р' => 'r',
          'С' => 's',  'Т' => 't',  'У' => 'u',    'Ф' => 'f',  'Х' => 'kh', 'Ц' => 'ts',
          'Ч' => 'ch', 'Ш' => 'sh', 'Щ' => 'shch', 'Ы' => 'у',  'Э' => 'e',  'Ю' => 'yu',
          'Я' => 'ya',
          'ь' => '', 'ъ' => '' # Ignore symbols, because its standard presentation is not allowed in URLs
        }
        return string.gsub(/[а-яА-Я]/, ru_chars)
      end

      string
    end
  end
end