module ISO3166
  def ISO3166::Country(country_data_or_country)
    case country_data_or_country
    when ISO3166::Country
      country_data_or_country
    when String, Symbol
      ISO3166::Country.search(country_data_or_country)
    else
      fail TypeError, "can't convert #{country_data_or_country.class.name} into ISO3166::Country"
    end
  end

  module CountryClassMethods
    def new(country_data)
      super if country_data.is_a?(Hash) || codes.include?(country_data.to_s.upcase)
    end

    def codes
      ISO3166::Data.codes
    end

    def all(&blk)
      blk ||= proc { |_alpha2, d| ISO3166::Country.new(d) }
      ISO3166::Data.cache.map(&blk)
    end

    alias_method :countries, :all

    def all_translated(locale = 'en')
      translations(locale).values
    end

    def all_names_with_codes(locale = 'en')
      ISO3166::Country.all.map do |c|
        [(c.translation(locale) || c.name).html_safe, c.alpha2]
      end.sort_by { |d| d[0] }
    end

    def translations(locale = 'en')
      I18nData.countries(locale.upcase)
    end

    def search(query)
      country = new(query.to_s.upcase)
      (country && country.valid?) ? country : nil
    end

    def [](query)
      search(query)
    end

    def method_missing(*m)
      regex = m.first.to_s.match(/^find_(all_)?(country_|countries_)?by_(.+)/)
      super unless regex

      countries = find_by(Regexp.last_match[3], m[1], Regexp.last_match[2])
      Regexp.last_match[1] ? countries : countries.last
    end

    def find_all_by(attribute, val)
      attributes, value = parse_attributes(attribute, val)

      ISO3166::Data.cache.select do |_, v|
        attributes.map do |attr|
          Array(Country.new(v).send(attr)).any? { |n| value === sterlize_value(n)}
        end.include?(true)
      end
    end

    def sterlize_value(v)
      if v.is_a?(Regexp)
        Regexp.new(v.source.unaccent, 'i')
      else
        UnicodeUtils.downcase(v.to_s.unaccent)
      end
    end

    protected

    def parse_attributes(attribute, val)
      fail "Invalid attribute name '#{attribute}'" unless instance_methods.include?(attribute.to_sym)

      attributes = Array(attribute.to_s)
      if attributes == ['name']
        attributes << 'unofficial_names'
        # TODO: Revisit when better data from i18n_data
        # attributes << 'translated_names'
      end

      [attributes, sterlize_value(val)]
    end

    def find_by(attribute, value, obj = nil)
      find_all_by(attribute.downcase, value).map do |country|
        obj.nil? ? country : new(country.last)
      end
    end
  end

end