class ActiveModel::Type::Decimal

def apply_scale(value)
  if scale
    value.round(scale)
  else
    value
  end
end

def cast_value(value)
  casted_value = \
    case value
    when ::Float
      convert_float_to_big_decimal(value)
    when ::Numeric
      BigDecimal(value, precision || BIGDECIMAL_PRECISION)
    when ::String
      begin
        value.to_d
      rescue ArgumentError
        BigDecimal(0)
      end
    else
      if value.respond_to?(:to_d)
        value.to_d
      else
        cast_value(value.to_s)
      end
    end
  apply_scale(casted_value)
end

def convert_float_to_big_decimal(value)
  if precision
    BigDecimal(apply_scale(value), float_precision)
  else
    value.to_d
  end
end

def float_precision
  if precision.to_i > ::Float::DIG + 1
    ::Float::DIG + 1
  else
    precision.to_i
  end
end

def type
  :decimal
end

def type_cast_for_schema(value)
  value.to_s.inspect
end