✨ Add Coupon support

lib/stripe/coupon.ex

@@ -0,0 +1,82 @@
+defmodule Stripe.Coupon do
+  @moduledoc """
+  Work with Stripe coupon objects.
+
+  You can:
+
+  - Create a coupon
+  - Retrieve a coupon
+  - Update a coupon
+  - Delete a coupon
+  - list all coupons
+
+  Stripe API reference: https://stripe.com/docs/api#coupons
+  """
+
+  @type t :: %__MODULE__{}
+
+  defstruct [
+    :id, :object, :amount_off, :created, :currency, :duration, :duration_in_months,
+    :livemode, :max_redemptions, :metadata, :percent_off, :redeem_by, :times_redeemed
+  ]
+
+  @plural_endpoint "coupons"
+
+  @schema %{
+    id: [:retrieve, :create],
+    object: [:retrieve],
+    amount_off: [:create, :retrieve],
+    created: [:retrieve],
+    currency: [:create, :retrieve],
+    duration: [:create, :retrieve],
+    duration_in_months: [:create, :retrieve],
+    livemode: [:retrieve],
+    max_redemptions: [:create, :retrieve],
+    metadata: [:create, :retrieve, :update],
+    percent_off: [:create, :retrieve],
+    redeem_by: [:create, :retrieve],
+    times_redeemed: [:create, :retrieve]
+  }
+
+  @nullable_keys [
+    :amount_off, :currency, :duration_in_months, :max_redemptions,
+    :metadata, :percent_off, :redeem_by, :times_redeemed
+  ]
+
+  @doc """
+  Create a coupon.
+  """
+  @spec create(map, Keyword.t) :: {:ok, t} | {:error, Stripe.api_error_struct}
+  def create(changes, opts \\ []) do
+    Stripe.Request.create(@plural_endpoint, changes, @schema, opts)
+  end
+
+  @doc """
+  Retrieve a coupon.
+  """
+  @spec retrieve(binary, Keyword.t) :: {:ok, t} | {:error, Stripe.api_error_struct}
+  def retrieve(id, opts \\ []) do
+    endpoint = @plural_endpoint <> "/" <> id
+    Stripe.Request.retrieve(endpoint, opts)
+  end
+
+  @doc """
+  Update a coupon.
+
+  Takes the `id` and a map of changes.
+  """
+  @spec update(binary, map, list) :: {:ok, t} | {:error, Stripe.api_error_struct}
+  def update(id, changes, opts \\ []) do
+    endpoint = @plural_endpoint <> "/" <> id
+    Stripe.Request.update(endpoint, changes, @schema, @nullable_keys, opts)
+  end
+
+  @doc """
+  Delete a coupon.
+  """
+  @spec delete(binary, list) :: :ok | {:error, Stripe.api_error_struct}
+  def delete(id, opts \\ []) do
+    endpoint = @plural_endpoint <> "/" <> id
+    Stripe.Request.delete(endpoint, %{}, opts)
+  end
+end

test/stripe/util_test.exs

@@ -8,6 +8,7 @@ defmodule Stripe.UtilTest do
       assert object_name_to_module("account") == Stripe.Account
       assert object_name_to_module("bank_account") == Stripe.ExternalAccount
       assert object_name_to_module("card") == Stripe.Card
+      assert object_name_to_module("coupon") == Stripe.Coupon
       assert object_name_to_module("customer") == Stripe.Customer
       assert object_name_to_module("event") == Stripe.Event
       assert object_name_to_module("external_account") == Stripe.ExternalAccount