Add Coupon model

lib/messages.dart

@@ -11,6 +11,7 @@ part 'src/messages/balance_transaction.dart';
 part 'src/messages/billing_details.dart';
 part 'src/messages/charge.dart';
 part 'src/messages/checkout_session.dart';
+part 'src/messages/coupon.dart';
 part 'src/messages/customer.dart';
 part 'src/messages/data_list.dart';
 part 'src/messages/event.dart';
@@ -32,8 +33,8 @@ part 'src/messages/requests/create_subscription_schedule.dart';
 part 'src/messages/requests/list_prices.dart';
 part 'src/messages/requests/list_products.dart';
 part 'src/messages/requests/list_subscription_items.dart';
-part 'src/messages/requests/list_subscriptions.dart';
 part 'src/messages/requests/list_subscription_schedules.dart';
+part 'src/messages/requests/list_subscriptions.dart';
 part 'src/messages/requests/update_customer.dart';
 part 'src/messages/requests/update_subscription.dart';
 part 'src/messages/requests/update_subscription_item.dart';

lib/src/messages/coupon.dart

@@ -0,0 +1,125 @@
+part of '../../messages.dart';
+
+enum _CouponObject { coupon }
+
+/// https://docs.stripe.com/api/coupons/object#coupon_object-duration
+enum CouponDuration {
+  /// Applies to all charges from a subscription with this coupon applied.
+  forever,
+
+  /// Applies to the first charge from a subscription with this coupon applied.
+  once,
+
+  /// Applies to charges in the first duration_in_months months from a
+  /// subscription with this coupon applied.
+  repeating,
+}
+
+/// https://docs.stripe.com/api/coupons/object#coupon_object-applies_to
+@JsonSerializable()
+class CouponAppliesTo {
+  /// A list of product IDs this coupon applies to.
+  final List<String>? products;
+
+  CouponAppliesTo({
+    this.products,
+  });
+
+  factory CouponAppliesTo.fromJson(Map<String, dynamic> json) =>
+      _$CouponAppliesToFromJson(json);
+
+  Map<String, dynamic> toJson() => _$CouponAppliesToToJson(this);
+}
+
+/// https://docs.stripe.com/api/coupons/object
+@JsonSerializable()
+class Coupon extends Message {
+  final _CouponObject object;
+
+  /// Unique identifier for the object.
+  final String id;
+
+  /// One of forever, once, and repeating. Describes how long a customer who
+  /// applies this coupon will get the discount.
+  final CouponDuration duration;
+
+  /// Time at which the object was created. Measured in seconds since the Unix
+  /// epoch.
+  final int created;
+
+  /// Has the value true if the object exists in live mode or the value false if
+  /// the object exists in test mode.
+  final bool livemode;
+
+  /// Number of times this coupon has been applied to a customer.
+  final int timesRedeemed;
+
+  /// Taking account of the above properties, whether this coupon can still be
+  /// applied to a customer.
+  final bool valid;
+
+  /// Amount (in the [currency] specified) that will be taken off the subtotal
+  /// of any invoices for this customer.
+  final int? amountOff;
+
+  /// If [amountOff] has been set, the three-letter ISO code for the currency
+  /// of the amount to take off.
+  final String? currency;
+
+  /// If [duration] is repeating, the number of months the coupon applies.
+  /// Null if coupon [duration] is forever or once.
+  final int? durationInMonths;
+
+  /// Set of key-value pairs that you can attach to an object. This can be
+  /// useful for storing additional information about the object in a structured
+  /// format.
+  final Map<String, dynamic>? metadata;
+
+  /// Name of the coupon displayed to customers on for instance invoices or
+  /// receipts.
+  final String? name;
+
+  /// Percent that will be taken off the subtotal of any invoices for this
+  /// customer for the duration of the coupon. For example, a coupon with
+  /// percent_off of 50 will make a $100 invoice $50 instead.
+  final double? percentOff;
+
+  /// Contains information about what this coupon applies to.
+  final CouponAppliesTo? appliesTo;
+
+  /// Coupons defined in each available currency option. Each key must be a
+  /// three-letter ISO currency code and a supported currency.
+  final Map<String, dynamic>? currencyOptions;
+
+  /// Maximum number of times this coupon can be redeemed, in total, across all
+  /// customers, before it is no longer valid.
+  final int? maxRedemptions;
+
+  /// Date after which the coupon can no longer be redeemed.
+  final int? redeemBy;
+
+  Coupon({
+    required this.object,
+    required this.id,
+    required this.duration,
+    required this.created,
+    required this.livemode,
+    required this.timesRedeemed,
+    required this.valid,
+    this.amountOff,
+    this.currency,
+    this.durationInMonths,
+    this.metadata,
+    this.name,
+    this.percentOff,
+    this.appliesTo,
+    this.currencyOptions,
+    this.maxRedemptions,
+    this.redeemBy,
+  });
+
+  factory Coupon.fromJson(Map<String, dynamic> json) => _$CouponFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => _$CouponToJson(this);
+}