Added support for both ExMoney and Money

.dialyzer_ignore.exs

@@ -0,0 +1,3 @@
+[
+  {"lib/ex_double_entry/money_proxy.ex"}
+]

.github/workflows/ci.yml

@@ -6,24 +6,46 @@ jobs:
     strategy:
       matrix:
         include:
-          - elixir: 1.12.3
-            otp: 24.0
-            env: test
-          - elixir: 1.12.3
-            otp: 24.0
-            env: test_mysql
-          - elixir: 1.12.3
+
+          - elixir: 1.13.3
+            otp: 24.2
+            env: test_money
+          - elixir: 1.13.3
+            otp: 24.2
+            env: test_mysql_money
+          - elixir: 1.13.3
+            otp: 24.2
+            env: test_ex_money
+          - elixir: 1.13.3
+            otp: 24.2
+            env: test_mysql_ex_money
+
+          - elixir: 1.13.3
             otp: 23.3
-            env: test
-          - elixir: 1.12.3
+            env: test_money
+          - elixir: 1.13.3
             otp: 23.3
-            env: test_mysql
-          - elixir: 1.12.3
+            env: test_mysql_money
+          - elixir: 1.13.3
+            otp: 23.3
+            env: test_ex_money
+          - elixir: 1.13.3
+            otp: 23.3
+            env: test_mysql_ex_money
+
+          - elixir: 1.13.3
+            otp: 22.3
+            env: test_money
+          - elixir: 1.13.3
+            otp: 22.3
+            env: test_mysql_money
+          - elixir: 1.13.3
             otp: 22.3
-            env: test
-          - elixir: 1.12.3
+            env: test_ex_money
+          - elixir: 1.13.3
             otp: 22.3
-            env: test_mysql
+            env: test_mysql_ex_money
+
     services:
       postgres:
         image: postgres
@@ -51,7 +73,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Elixir
-      uses: erlef/setup-elixir@885971a72ed1f9240973bd92ab57af8c1aa68f24
+      uses: erlef/setup-beam@v1
       with:
         elixir-version: ${{ matrix.elixir }}
         otp-version: ${{ matrix.otp }}

README.md

@@ -20,6 +20,9 @@ def deps do
     # pick one DB package
     {:postgrex, ">= 0.0.0"},
     {:myxql, ">= 0.0.0"},
+    # pick one money package
+    {:money, "~> 1.9"},
+    {:ex_money, "~> 5.9"},
   ]
 end
 ```

config/test_ex_money.exs

@@ -0,0 +1,18 @@
+import Config
+
+config :ex_double_entry,
+  db: :postgres,
+  money: :ex_money
+
+config :ex_double_entry, ExDoubleEntry.Repo,
+  username: System.get_env("POSTGRES_DB_USERNAME", "postgres"),
+  password: System.get_env("POSTGRES_DB_PASSWORD", "postgres"),
+  database: System.get_env("POSTGRES_DB_NAME", "ex_double_entry_test"),
+  hostname: System.get_env("POSTGRES_DB_HOST", "localhost"),
+  pool: Ecto.Adapters.SQL.Sandbox,
+  show_sensitive_data_on_connection_error: true,
+  timeout: :infinity,
+  queue_target: 200,
+  queue_interval: 10
+
+config :logger, level: :info

config/test.exs → config/test_money.exs

@@ -1,7 +1,8 @@
 import Config
 
 config :ex_double_entry,
-  db: :postgres
+  db: :postgres,
+  money: :money
 
 config :ex_double_entry, ExDoubleEntry.Repo,
   username: System.get_env("POSTGRES_DB_USERNAME", "postgres"),

config/test_mysql_ex_money.exs

@@ -0,0 +1,18 @@
+import Config
+
+config :ex_double_entry,
+  db: :mysql,
+  money: :ex_money
+
+config :ex_double_entry, ExDoubleEntry.Repo,
+  username: System.get_env("MYSQL_DB_USERNAME", "root"),
+  password: System.get_env("MYSQL_DB_PASSWORD", ""),
+  database: System.get_env("MYSQL_DB_NAME", "ex_double_entry_test"),
+  hostname: System.get_env("MYSQL_DB_HOST", "localhost"),
+  pool: Ecto.Adapters.SQL.Sandbox,
+  show_sensitive_data_on_connection_error: true,
+  timeout: :infinity,
+  queue_target: 200,
+  queue_interval: 10
+
+config :logger, level: :info

config/test_mysql.exs → config/test_mysql_money.exs

@@ -1,7 +1,8 @@
 import Config
 
 config :ex_double_entry,
-  db: :mysql
+  db: :mysql,
+  money: :money
 
 config :ex_double_entry, ExDoubleEntry.Repo,
   username: System.get_env("MYSQL_DB_USERNAME", "root"),

lib/ex_double_entry.ex

@@ -34,9 +34,9 @@ defmodule ExDoubleEntry do
   ## Examples
 
   iex> %ExDoubleEntry.Transfer{
-  iex>   money: Money.new(42, :USD),
-  iex>   from: %ExDoubleEntry.Account{identifier: :checking, currency: :USD, balance: Money.new(42, :USD), positive_only?: false},
-  iex>   to: %ExDoubleEntry.Account{identifier: :savings, currency: :USD, balance: Money.new(0, :USD)},
+  iex>   money: MoneyProxy.new(42, :USD),
+  iex>   from: %ExDoubleEntry.Account{identifier: :checking, currency: :USD, balance: MoneyProxy.new(42, :USD), positive_only?: false},
+  iex>   to: %ExDoubleEntry.Account{identifier: :savings, currency: :USD, balance: MoneyProxy.new(0, :USD)},
   iex>   code: :deposit
   iex> }
   iex> |> ExDoubleEntry.transfer!()

lib/ex_double_entry/ecto_types/amount.ex

@@ -0,0 +1,21 @@
+if Code.ensure_loaded?(Ecto.Type) do
+  defmodule ExDoubleEntry.EctoType.Amount do
+    if macro_exported?(Ecto.Type, :__using__, 1) do
+      use Ecto.Type
+    else
+      @behaviour Ecto.Type
+    end
+
+    def type, do: :integer
+
+    def cast(val) when is_integer(val), do: {:ok, val}
+    def cast(%Decimal{} = val), do: {:ok, Decimal.to_integer(val)}
+    def cast(_), do: :error
+
+    def load(val) when is_integer(val), do: {:ok, val}
+
+    def dump(val) when is_integer(val), do: {:ok, val}
+    def dump(%Decimal{} = val), do: {:ok, Decimal.to_integer(val)}
+    def dump(_), do: :error
+  end
+end

lib/ex_double_entry/ecto_types/currency.ex

@@ -10,7 +10,7 @@ if Code.ensure_loaded?(Ecto.Type) do
 
     def cast(val)
 
-    def cast(%Money{currency: currency}), do: {:ok, currency}
+    def cast(%{currency: currency}), do: {:ok, currency}
 
     def cast(atom) when is_atom(atom), do: {:ok, atom}
 

lib/ex_double_entry/money_proxy.ex

@@ -0,0 +1,49 @@
+defmodule ExDoubleEntry.MoneyProxy do
+  @moduledoc """
+  The `Money` and `ExMoney` packages both claim the `Money` module namespace,
+  therefore this proxy module normalises the function uses so that ExDoubleEntry
+  can be used by either.
+  """
+
+  defdelegate new(amount, currency), to: Money
+
+  def add(a, b) do
+    if function_exported?(Money, :add!, 2) do
+      apply(Money, :add!, [a, b])
+    else
+      apply(Money, :add, [a, b])
+    end
+  end
+
+  def subtract(a, b) do
+    if function_exported?(Money, :sub!, 2) do
+      apply(Money, :sub!, [a, b])
+    else
+      apply(Money, :subtract, [a, b])
+    end
+  end
+
+  def cmp(a, b) do
+    if function_exported?(Money, :compare!, 2) do
+      apply(Money, :compare!, [a, b])
+    else
+      apply(Money, :cmp, [a, b])
+    end
+  end
+
+  def neg(money) do
+    if function_exported?(Money, :neg, 1) do
+      apply(Money, :neg, [money])
+    else
+      apply(Money, :mult!, [money, -1])
+    end
+  end
+
+  def positive?(money) do
+    if function_exported?(Money, :positive?, 1) do
+      apply(Money, :positive?, [money])
+    else
+      apply(Money, :cmp!, [money, Money.new(0, money.currency)]) >= 0
+    end
+  end
+end

lib/ex_double_entry/schemas/account_balance.ex

@@ -2,13 +2,13 @@ defmodule ExDoubleEntry.AccountBalance do
   use Ecto.Schema
   import Ecto.{Changeset, Query}
 
-  alias ExDoubleEntry.{Account, AccountBalance}
+  alias ExDoubleEntry.{Account, AccountBalance, EctoType}
 
   schema "#{ExDoubleEntry.db_table_prefix()}account_balances" do
-    field(:identifier, ExDoubleEntry.EctoType.Identifier)
-    field(:currency, ExDoubleEntry.EctoType.Currency)
-    field(:scope, ExDoubleEntry.EctoType.Scope)
-    field(:balance_amount, :integer)
+    field(:identifier, EctoType.Identifier)
+    field(:currency, EctoType.Currency)
+    field(:scope, EctoType.Scope)
+    field(:balance_amount, EctoType.Amount)
 
     timestamps(type: :utc_datetime_usec)
   end

lib/ex_double_entry/schemas/line.ex

@@ -2,17 +2,17 @@ defmodule ExDoubleEntry.Line do
   use Ecto.Schema
   import Ecto.Changeset
 
-  alias ExDoubleEntry.{AccountBalance, Line}
+  alias ExDoubleEntry.{AccountBalance, EctoType, Line, MoneyProxy}
 
   schema "#{ExDoubleEntry.db_table_prefix()}lines" do
-    field(:account_identifier, ExDoubleEntry.EctoType.Identifier)
-    field(:account_scope, ExDoubleEntry.EctoType.Scope)
-    field(:currency, ExDoubleEntry.EctoType.Currency)
-    field(:amount, :integer)
-    field(:balance_amount, :integer)
-    field(:code, ExDoubleEntry.EctoType.Identifier)
-    field(:partner_identifier, ExDoubleEntry.EctoType.Identifier)
-    field(:partner_scope, ExDoubleEntry.EctoType.Scope)
+    field(:account_identifier, EctoType.Identifier)
+    field(:account_scope, EctoType.Scope)
+    field(:currency, EctoType.Currency)
+    field(:amount, EctoType.Amount)
+    field(:balance_amount, EctoType.Amount)
+    field(:code, EctoType.Identifier)
+    field(:partner_identifier, EctoType.Identifier)
+    field(:partner_scope, EctoType.Scope)
     field(:metadata, :map)
 
     belongs_to(:partner_line, Line)
@@ -55,7 +55,7 @@ defmodule ExDoubleEntry.Line do
       currency: money.currency,
       code: code,
       amount: money.amount,
-      balance_amount: Money.add(account.balance, money).amount,
+      balance_amount: MoneyProxy.add(account.balance, money).amount,
       partner_identifier: partner.identifier,
       partner_scope: partner.scope,
       metadata: metadata,

lib/ex_double_entry/services/account.ex

@@ -1,8 +1,10 @@
 defmodule ExDoubleEntry.Account do
+  @type t() :: %__MODULE__{}
+
   @enforce_keys [:identifier, :currency]
   defstruct [:id, :identifier, :scope, :currency, :balance, :positive_only?]
 
-  alias ExDoubleEntry.{Account, AccountBalance}
+  alias ExDoubleEntry.{Account, AccountBalance, MoneyProxy}
 
   def present(nil), do: nil
 
@@ -13,7 +15,7 @@ defmodule ExDoubleEntry.Account do
       currency: params.currency,
       scope: params.scope,
       positive_only?: positive_only?(params.identifier),
-      balance: Money.new(params.balance_amount, params.currency)
+      balance: MoneyProxy.new(params.balance_amount, params.currency)
     }
   end