Added Faker::Code.imei

README.md

@@ -83,7 +83,9 @@ Faker::Business.credit_card_type #=> "visa"
 
 ```crystal
 
-Faker::Code.isbn #=> 640354399-7
+Faker::Code.isbn #=> "640354399-7"
+
+Faker::Code.imei #=> "531691246033652"
 
 ```
 

spec/code_spec.cr

@@ -9,9 +9,14 @@ describe Faker::Code do
     Faker::Code.isbn(13).match(/^\d{12}-\d$/).should_not eq nil
   end
 
+  it "imei" do
+    Faker::Code.imei.match(/\A[\d.:\-\s]+\z/i).should_not eq nil
+  end
+
   it "should return deterministic results when seeded" do
     Faker.seed 123456
     Faker::Code.isbn.should eq "394314441-0"
     Faker::Code.isbn(13).should eq "205982563728-9"
+    Faker::Code.imei.should eq "860839366575918"
   end
 end

src/faker/code.cr

@@ -1,5 +1,7 @@
 module Faker
   class Code < Base
+    RBI = %w[01 10 30 33 35 44 45 49 50 51 52 53 54 86 91 98 99]
+
     def self.isbn(base : Int32 = 10)
       case base
       when 10 then generate_base10_isbn
@@ -8,6 +10,41 @@ module Faker
       end
     end
 
+    def self.imei
+      str = Array.new(15, 0)
+      sum = 0
+      len = 15
+
+      # Fill in the first two values of the string based with the specified prefix.
+      arr = RBI.sample(Faker.rng)
+      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] = Faker.rng.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).odd?
+          t = str[position] * 2
+
+          t -= 9 if t > 9
+
+          sum += t
+        else
+          sum += str[position]
+        end
+      end
+      str[len - 1] = (10 - (sum % 10)) % 10
+
+      str.join("")
+    end
+
     private def self.generate_base10_isbn
       values = Faker.regexify(/\d{9}/)
       remainder = sum(values) { |value, index| (index + 1) * value.to_i } % 11