Feature/validate descriptive record

lib/aba_file_validator.ex

@@ -1,8 +1,81 @@
 defmodule AbaFileValidator do
+  import __MODULE__.Utils, only: [correct_length?: 2, string_empty?: 1, valid_date?: 1]
+
   @moduledoc """
   Documentation for `AbaFileValidator`.
   """
 
+  @spec get_descriptive_record(binary) ::
+          {:error, :incorrect_length | :incorrect_starting_code | :invalid_format}
+          | {:ok, binary(), binary(), binary(), binary(), binary(), binary()}
+  @doc """
+  Get the entries as part of the descriptiive record
+
+  ## Examples
+
+      iex> AbaFileValidator.get_descriptive_record(1)
+      {:error, :invalid_input}
+
+      iex> AbaFileValidator.get_descriptive_record("11")
+      {:error, :incorrect_length}
+
+      iex> AbaFileValidator.get_descriptive_record("01")
+      {:error, :incorrect_length}
+
+      iex> AbaFileValidator.get_descriptive_record("1                 01CBA       test                      301500221212121227121222                                        ")
+      {:error, :incorrect_starting_code}
+
+      iex> AbaFileValidator.get_descriptive_record("0                   CBA       test                      301500221212121227121222                                        ")
+      {:error, :invalid_format}
+
+      iex> AbaFileValidator.get_descriptive_record("0                 01CBA       test                      301500221212121227121222                                        ")
+      {:ok, "01", "CBA", "test                      ", "301500", "221212121227", "121222"}
+
+  """
+  def get_descriptive_record(entry) when not is_binary(entry) do
+    {:error, :invalid_input}
+  end
+
+  def get_descriptive_record(entry) do
+    if not correct_length?(entry, 120) do
+      {:error, :incorrect_length}
+    else
+      {code, entry} = String.split_at(entry, 1)
+
+      if code != "0" do
+        {:error, :incorrect_starting_code}
+      else
+        {first_blank, entry} = String.split_at(entry, 17)
+        {reel_sequence_number, entry} = String.split_at(entry, 2)
+        {bank_abbreviation, entry} = String.split_at(entry, 3)
+        {mid_blank, entry} = String.split_at(entry, 7)
+        {user_preferred_specification, entry} = String.split_at(entry, 26)
+        {user_id_number, entry} = String.split_at(entry, 6)
+        {description, entry} = String.split_at(entry, 12)
+        {date, last_blank} = String.split_at(entry, 6)
+
+        with true <- code == "0",
+             true <- correct_length?(first_blank, 17),
+             true <- correct_length?(mid_blank, 7),
+             true <- correct_length?(last_blank, 40),
+             false <- string_empty?(reel_sequence_number),
+             false <- string_empty?(bank_abbreviation),
+             false <- string_empty?(user_preferred_specification),
+             false <- string_empty?(user_id_number),
+             false <- string_empty?(description),
+             true <- valid_date?(date),
+             false <- string_empty?(date) do
+          {:ok, reel_sequence_number, bank_abbreviation, user_preferred_specification,
+           user_id_number, description, date}
+        else
+          _error ->
+            {:error, :invalid_format}
+        end
+      end
+    end
+  end
+
+  @spec get_transaction_code_description(any) :: :error | binary()
   @doc """
   Get a description for a given transaction code
 
@@ -17,8 +90,13 @@ defmodule AbaFileValidator do
   """
   def get_transaction_code_description(13), do: "Externally initiated debit items"
   def get_transaction_code_description("13"), do: "Externally initiated debit items"
-  def get_transaction_code_description(50), do: "Externally initiated credit items with the exception of those bearing Transaction Codes"
-  def get_transaction_code_description("50"), do: "Externally initiated credit items with the exception of those bearing Transaction Codes"
+
+  def get_transaction_code_description(50),
+    do: "Externally initiated credit items with the exception of those bearing Transaction Codes"
+
+  def get_transaction_code_description("50"),
+    do: "Externally initiated credit items with the exception of those bearing Transaction Codes"
+
   def get_transaction_code_description(51), do: "Australian Government Security Interest"
   def get_transaction_code_description("51"), do: "Australian Government Security Interest"
   def get_transaction_code_description(52), do: "Family Allowance"

lib/util.ex

@@ -0,0 +1,13 @@
+defmodule AbaFileValidator.Utils do
+  def correct_length?(entry,n) when is_binary(entry), do: String.length(entry) == n
+  def string_empty?(entry) when is_binary(entry), do: String.trim(entry) |> String.length() == 0
+
+  def valid_date?(<<dd::binary-2, mm::binary-2, yy::binary-2>>) do
+    [yy, mm, dd] = for i <- [yy, mm, dd], do: String.to_integer(i)
+    NaiveDateTime.new(yy, mm, dd, 0, 0, 0)
+    |> case do
+      {:ok, _} -> true
+      {:error, _} -> false
+    end
+  end
+end

test/aba_file_validator_test.exs

@@ -2,14 +2,27 @@ defmodule AbaFileValidatorTest do
   use ExUnit.Case
   doctest AbaFileValidator
 
-  test "transaction code description" do
+  test "AbaFileValidator.get_transaction_code_description/1" do
     assert AbaFileValidator.get_transaction_code_description(11) == :error
-    assert AbaFileValidator.get_transaction_code_description(13) == "Externally initiated debit items"
-    assert AbaFileValidator.get_transaction_code_description("13") == "Externally initiated debit items"
-    assert AbaFileValidator.get_transaction_code_description(50) == "Externally initiated credit items with the exception of those bearing Transaction Codes"
-    assert AbaFileValidator.get_transaction_code_description("50") == "Externally initiated credit items with the exception of those bearing Transaction Codes"
-    assert AbaFileValidator.get_transaction_code_description(51) == "Australian Government Security Interest"
-    assert AbaFileValidator.get_transaction_code_description("51") == "Australian Government Security Interest"
+
+    assert AbaFileValidator.get_transaction_code_description(13) ==
+             "Externally initiated debit items"
+
+    assert AbaFileValidator.get_transaction_code_description("13") ==
+             "Externally initiated debit items"
+
+    assert AbaFileValidator.get_transaction_code_description(50) ==
+             "Externally initiated credit items with the exception of those bearing Transaction Codes"
+
+    assert AbaFileValidator.get_transaction_code_description("50") ==
+             "Externally initiated credit items with the exception of those bearing Transaction Codes"
+
+    assert AbaFileValidator.get_transaction_code_description(51) ==
+             "Australian Government Security Interest"
+
+    assert AbaFileValidator.get_transaction_code_description("51") ==
+             "Australian Government Security Interest"
+
     assert AbaFileValidator.get_transaction_code_description(52) == "Family Allowance"
     assert AbaFileValidator.get_transaction_code_description("52") == "Family Allowance"
     assert AbaFileValidator.get_transaction_code_description(53) == "Pay"
@@ -23,4 +36,37 @@ defmodule AbaFileValidatorTest do
     assert AbaFileValidator.get_transaction_code_description(57) == "Debenture/Note Interest"
     assert AbaFileValidator.get_transaction_code_description("57") == "Debenture/Note Interest"
   end
+
+  describe "AbaFileValidator.get_descriptive_record/1" do
+    test "validates succesfully" do
+      entry =
+        "0                 01CBA       test                      301500221212121227121222                                        "
+
+      assert AbaFileValidator.get_descriptive_record(entry) == {:ok, "01", "CBA", "test                      ", "301500", "221212121227", "121222"}
+    end
+
+    test "returns an error if incorrect length with correct starting code" do
+      assert AbaFileValidator.get_descriptive_record("0") == {:error, :incorrect_length}
+    end
+
+    test "returns an error if incorrect length with incorrect starting code" do
+      assert AbaFileValidator.get_descriptive_record("1") == {:error, :incorrect_length}
+    end
+
+    test "returns an error if incorrect starting code" do
+      entry =
+        "1                 01CBA       test                      301500221212121227121222                                        "
+
+      assert AbaFileValidator.get_descriptive_record(entry) ==
+               {:error, :incorrect_starting_code}
+    end
+
+    test "returns an error if invalid string" do
+      entry =
+        "0                   CBA       test                      301500221212121227121222                                        "
+
+      assert AbaFileValidator.get_descriptive_record(entry) ==
+               {:error, :invalid_format}
+    end
+  end
 end