french_ssn.rb

require 'pry'
require 'date'
require 'frenchdepartments'

# The way to stop the program and land in a console in the middle of a run
# Put in any right place of your choosing
# binding.pry

# Gender (1 == man, 2 == woman)
# Year of birth (84)
# Month of birth (12)
# Department of birth (76, basically included between 01 and 99)
# 6 random digits (451 089)
# A 2 digits key (46, equal to the remainder of the division of (97 - ssn_without_key) by 97.)

REGEX = /^(?<gender>[1-2])(?<year_of_birth>\d{2})(?<month_of_birth>(0[1-9]|1[0-2]))(?<department>(0[1-9]|[1-9]\d))(?<random>\d{6})(?<key>\d{2})/

def french_ssn_info(str)
  str = str.delete(" ")
  result = str.match(REGEX) # MatchData
  # Guard statement
  return "The number is invalid" if result.nil?

  # We extract captures from matchdata and compose a sentence
  # Implementation part0
  gender = result[:gender] == 1 ? "woman" : "man"
  month_name = Date::MONTHNAMES[result[:month_of_birth].to_i] # 01 - 12
  year = "19#{result[:year_of_birth]}"
  region = FrenchDepartments.all_departments_names[result[:department].to_i] # "01-99"
  return "a #{gender}, born in #{month_name}, #{year} in #{region}."
end

#               # String
# p french_ssn_info("1 84 12 76 451 089 46") # API application programming interface
# # "a man, born in December, 1984 in Seine-Maritime." # Str
# p french_ssn_info("123")
# # "The number is invalid" # Str

french_ssn_spec.rb

require_relative "../french_ssn.rb"

describe "#french_ssn_info" do
  it "should print a message if the number is invalid" do
    actual = french_ssn_info("123")
    expected = "The number is invalid"
    expect(actual).to eq(expected)
  end

  it "should print invalid if passed a non-numeric string" do
    actual = french_ssn_info("YOLO")
    expected = "The number is invalid"
    expect(actual).to eq(expected)
  end

  it "should compose a sentence if the number is valid" do
    actual = french_ssn_info("1 84 12 76 451 089 46")
    expected = "a man, born in December, 1984 in Seine-Maritime."
    expect(actual).to eq(expected)
  end
end