class Faker::Code

def asin
  fetch('code.asin')
end

def ean(base = 13)
  base == 8 ? generate_base8_ean : generate_base13_ean
end

def generate_base10_isbn
  values = regexify(/\d{9}/)
  remainder = sum(values) { |value, index| (index + 1) * value.to_i } % 11
  values << "-#{remainder == 10 ? 'X' : remainder}"
end

def generate_base13_ean
  values = regexify(/\d{12}/)
  check_digit = 10 - values.split(//).each_with_index.inject(0){ |s, (v, i)| s + v.to_i * EAN_CHECK_DIGIT13[i] } % 10
  values << (check_digit == 10 ? 0 : check_digit).to_s
end

def generate_base13_isbn
  values = regexify(/\d{12}/)
  remainder = sum(values) { |value, index| index.even? ? value.to_i : value.to_i * 3 } % 10
  values << "-#{((10 - remainder) % 10)}"
end

def generate_base8_ean
  values = regexify(/\d{7}/)
  check_digit = 10 - values.split(//).each_with_index.inject(0){ |s, (v, i)| s + v.to_i * EAN_CHECK_DIGIT8[i] } % 10
  values << (check_digit == 10 ? 0 : check_digit).to_s
end

def generate_imei
  pos = 0
  str = Array.new(15, 0)
  sum = 0
  t = 0
  len_offset = 0
  len = 15
  # Fill in the first two values of the string based with the specified prefix.
  # Reporting Body Identifier list: http://en.wikipedia.org/wiki/Reporting_Body_Identifier
  arr = sample(RBI)
  str[0] = arr[0].to_i
  str[1] = arr[1].to_i
  pos = 2
  # Fill all the remaining numbers except for the last one with random values.
  while pos < (len - 1)
    str[pos] = rand(0..9)
    pos += 1
  end
  # Calculate the Luhn checksum of the values thus far
  len_offset = (len + 1) % 2
  (0..(len - 1)).each do |position|
    if (position + len_offset) % 2 != 0
      t = str[position] * 2
      if t > 9
        t -= 9
      end
      sum += t
    else
      sum += str[position]
    end
  end
  # Choose the last digit so that it causes the entire string to pass the checksum.
  str[len - 1] = (10 - (sum % 10)) % 10
  # Output the IMEI value.
  str.join('')
end

def generate_nric_check_alphabet(values, prefix)
  weight = %w(2 7 6 5 4 3 2)
  total = values.split(//).zip(weight).collect { |a, b| a.to_i * b.to_i }.inject(:+)
  total = total + 4 if prefix == 'T'
  %w(A B C D E F G H I Z J)[10 - total % 11]
end

def imei
  generate_imei
end

def isbn(base = 10)
  base == 13 ? generate_base13_isbn : generate_base10_isbn
end

def npi
  rand(10 ** 10).to_s.rjust(10, '0')
end

def nric(min_age = 18, max_age = 65)
  birthyear = Date.birthday(min_age, max_age).year
  prefix = birthyear < 2000 ? 'S' : 'T'
  values = birthyear.to_s[-2..-1]
  values << regexify(/\d{5}/)
  check_alpha = generate_nric_check_alphabet(values, prefix)
  "#{prefix}#{values}#{check_alpha}"
end

def rut
  value = Number.number(8)
  vd = rut_verificator_digit(value)
  value << "-#{vd}"
end

def rut_verificator_digit(rut)
  total = rut.to_s.rjust(8, '0').split(//).zip(%w(3 2 7 6 5 4 3 2)).collect{|a, b| a.to_i * b.to_i}.inject(:+)
  (11 - total % 11).to_s.gsub(/10/, 'k').gsub(/11/, '0')
end

def sum(values, &block)
  values.split(//).each_with_index.inject(0) do |sum, (value, index)|
    sum + block.call(value, index)
  end
end