From e94c3f1f468e05a3b80dd6ae8f04f2b79d26bd4b Mon Sep 17 00:00:00 2001
From: Javier Aranda <javier.aranda.varo@gmail.com>
Date: Mon, 10 Aug 2020 22:42:25 +0200
Subject: [PATCH] Improve Faker::Company.spanish_organisation_number

---
 lib/faker/default/company.rb             | 38 ++++++++++++++++++++++--
 test/faker/default/test_faker_company.rb | 30 +++++++++++++++++--
 2 files changed, 62 insertions(+), 6 deletions(-)

diff --git a/lib/faker/default/company.rb b/lib/faker/default/company.rb
index 1b1e486242..00e4381829 100644
--- a/lib/faker/default/company.rb
+++ b/lib/faker/default/company.rb
@@ -162,10 +162,17 @@ def profession
       # @faker.version 1.8.5
       #
       # Get a random Spanish organization number. See more here https://es.wikipedia.org/wiki/N%C3%BAmero_de_identificaci%C3%B3n_fiscal
-      def spanish_organisation_number
+      def spanish_organisation_number(organization_type: nil)
         # Valid leading character: A, B, C, D, E, F, G, H, J, N, P, Q, R, S, U, V, W
-        # 7 digit numbers
-        [sample(self::ULetters), format('%07d', rand(10**7))].join
+        # format: 1 digit letter (organization type) + 7 digit numbers + 1 digit control (letter or number based on
+        # organization type)
+        letters = %w[A B C D E F G H J N P Q R S U V W]
+
+        organization_type = sample(letters) unless letters.include?(organization_type)
+        code = format('%07d', rand(10**7))
+        control = spanish_cif_control_digit(organization_type, code)
+
+        [organization_type, code, control].join
       end
 
       ##
@@ -528,6 +535,31 @@ def inn_checksum(factor, number)
           end % 11 % 10
         ).to_s
       end
+
+      def spanish_cif_control_digit(organization_type, code)
+        letters = %w[J A B C D E F G H]
+
+        control = code.split('').each_with_index.inject(0) do |sum, (value, index)|
+          if (index + 1).even?
+            sum + value.to_i
+          else
+            sum + spanish_b_algorithm(value.to_i)
+          end
+        end
+
+        control = control.to_s[-1].to_i
+        control = control.zero? ? control : 10 - control
+
+        %w[A B C D E F G H J U V].include?(organization_type) ? control : letters[control]
+      end
+
+      def spanish_b_algorithm(value)
+        result = value.to_i * 2
+
+        return result if result < 10
+
+        result.to_s[0].to_i + result.to_s[1].to_i
+      end
     end
   end
 end
diff --git a/test/faker/default/test_faker_company.rb b/test/faker/default/test_faker_company.rb
index 87d97fddd0..e0442942a8 100644
--- a/test/faker/default/test_faker_company.rb
+++ b/test/faker/default/test_faker_company.rb
@@ -28,9 +28,8 @@ def test_type
   end
 
   def test_spanish_organisation_number
-    org_no = @tester.spanish_organisation_number
-    assert org_no.match(/\D\d{7}/)
-    assert Faker::Base::ULetters.include?(org_no[0].to_s)
+    cif = @tester.spanish_organisation_number(organization_type: 'A')
+    assert @tester.send(:spanish_cif_control_digit, 'A', cif[1..7]) == cif[-1].to_i
   end
 
   def test_swedish_organisation_number
@@ -211,6 +210,31 @@ def test_sic_code
     assert @tester.sic_code.match(/\d\d\d\d/)
   end
 
+  def test_spanish_cif_control_digit
+    assert @tester.send(:spanish_cif_control_digit, 'A', '2217680') == 4
+    assert @tester.send(:spanish_cif_control_digit, 'B', '4031315') == 7
+    assert @tester.send(:spanish_cif_control_digit, 'C', '7191088') == 9
+    assert @tester.send(:spanish_cif_control_digit, 'D', '3178686') == 6
+    assert @tester.send(:spanish_cif_control_digit, 'E', '4484441') == 3
+    assert @tester.send(:spanish_cif_control_digit, 'F', '4830511') == 4
+    assert @tester.send(:spanish_cif_control_digit, 'G', '7676903') == 3
+    assert @tester.send(:spanish_cif_control_digit, 'H', '8888075') == 2
+    assert @tester.send(:spanish_cif_control_digit, 'J', '6840041') == 5
+    assert @tester.send(:spanish_cif_control_digit, 'N', '5350867') == 'G'
+    assert @tester.send(:spanish_cif_control_digit, 'P', '5669582') == 'H'
+    assert @tester.send(:spanish_cif_control_digit, 'Q', '5182823') == 'D'
+    assert @tester.send(:spanish_cif_control_digit, 'R', '1099088') == 'E'
+    assert @tester.send(:spanish_cif_control_digit, 'S', '2210399') == 'H'
+    assert @tester.send(:spanish_cif_control_digit, 'U', '3957325') == 8
+    assert @tester.send(:spanish_cif_control_digit, 'V', '7536342') == 4
+    assert @tester.send(:spanish_cif_control_digit, 'W', '6793772') == 'B'
+  end
+
+  def test_spanish_b_algorithm
+    assert @tester.send(:spanish_b_algorithm, 2) == 4
+    assert @tester.send(:spanish_b_algorithm, 6) == 3
+  end
+
   private
 
   def czech_o_n_checksum(org_no)