class Grape::Validations::Validators::LengthValidator

def build_message
  if options_key?(:message)
    @option[:message]
  elsif @min && @max
    format I18n.t(:length, scope: 'grape.errors.messages'), min: @min, max: @max
  elsif @min
    format I18n.t(:length_min, scope: 'grape.errors.messages'), min: @min
  elsif @max
    format I18n.t(:length_max, scope: 'grape.errors.messages'), max: @max
  else
    format I18n.t(:length_is, scope: 'grape.errors.messages'), is: @is
  end
end

def initialize(attrs, options, required, scope, opts)
  @min = options[:min]
  @max = options[:max]
  @is = options[:is]
  super
  raise ArgumentError, 'min must be an integer greater than or equal to zero' if !@min.nil? && (!@min.is_a?(Integer) || @min.negative?)
  raise ArgumentError, 'max must be an integer greater than or equal to zero' if !@max.nil? && (!@max.is_a?(Integer) || @max.negative?)
  raise ArgumentError, "min #{@min} cannot be greater than max #{@max}" if !@min.nil? && !@max.nil? && @min > @max
  return if @is.nil?
  raise ArgumentError, 'is must be an integer greater than zero' if !@is.is_a?(Integer) || !@is.positive?
  raise ArgumentError, 'is cannot be combined with min or max' if !@min.nil? || !@max.nil?
end

def validate_param!(attr_name, params)
  param = params[attr_name]
  return unless param.respond_to?(:length)
  return unless (!@min.nil? && param.length < @min) || (!@max.nil? && param.length > @max) || (!@is.nil? && param.length != @is)
  raise Grape::Exceptions::Validation.new(params: [@scope.full_name(attr_name)], message: build_message)
end