Fix over 200 nullability warnings - 600 left to go

src/Mollie.Api/Client/BaseMollieClient.cs

@@ -64,11 +64,11 @@ protected async Task<T> GetAsync<T>(UrlObjectLink<T> urlObject) {
             return await this.GetAsync<T>(urlObject.Href).ConfigureAwait(false);
         }
 
-        protected async Task<T> PostAsync<T>(string relativeUri, object data) {
+        protected async Task<T> PostAsync<T>(string relativeUri, object? data) {
             return await this.SendHttpRequest<T>(HttpMethod.Post, relativeUri, data).ConfigureAwait(false);
         }
 
-        protected async Task<T> PatchAsync<T>(string relativeUri, object data) {
+        protected async Task<T> PatchAsync<T>(string relativeUri, object? data) {
             return await this.SendHttpRequest<T>(new HttpMethod("PATCH"), relativeUri, data).ConfigureAwait(false);
         }
 

src/Mollie.Api/Framework/Factories/BalanceReportResponseFactory.cs

@@ -1,3 +1,4 @@
+using System;
 using Mollie.Api.Models.Balance.Response.BalanceReport;
 using Mollie.Api.Models.Balance.Response.BalanceReport.Specific.StatusBalance;
 using Mollie.Api.Models.Balance.Response.BalanceReport.Specific.TransactionCategories;
@@ -7,11 +8,11 @@ public class BalanceReportResponseFactory {
         public BalanceReportResponse Create(string reportGrouping) {
             switch (reportGrouping) {
                 case ReportGrouping.StatusBalances:
-                    return new StatusBalanceReportResponse();
+                    return Activator.CreateInstance<StatusBalanceReportResponse>();
                 case ReportGrouping.TransactionCategories:
-                    return new TransactionCategoriesReportResponse();
+                    return Activator.CreateInstance<TransactionCategoriesReportResponse>();
                 default: 
-                    return new BalanceReportResponse();
+                    return Activator.CreateInstance<BalanceReportResponse>();
             }
         }
     }

src/Mollie.Api/Framework/Factories/BalanceTransactionFactory.cs

@@ -1,4 +1,5 @@
-using Mollie.Api.Models.Balance.Response.BalanceTransaction;
+using System;
+using Mollie.Api.Models.Balance.Response.BalanceTransaction;
 using Mollie.Api.Models.Balance.Response.BalanceTransaction.Specific;
 
 namespace Mollie.Api.Framework.Factories {
@@ -11,24 +12,24 @@ public BalanceTransaction Create(string type) {
                 case BalanceTransactionContextType.ChargebackReversal:
                 case BalanceTransactionContextType.ApplicationFee:
                 case BalanceTransactionContextType.SplitPayment:
-                    return new PaymentBalanceTransaction();
+                    return Activator.CreateInstance<PaymentBalanceTransaction>();
                 case BalanceTransactionContextType.Capture:
-                    return new CaptureBalanceTransaction();
+                    return Activator.CreateInstance<CaptureBalanceTransaction>();
                 case BalanceTransactionContextType.Refund:
                 case BalanceTransactionContextType.ReturnedRefund:
                 case BalanceTransactionContextType.PlatformPaymentRefund:
-                    return new RefundBalanceTransaction();
+                    return Activator.CreateInstance<RefundBalanceTransaction>();
                 case BalanceTransactionContextType.Chargeback:
                 case BalanceTransactionContextType.PlatformPaymentChargeback:
-                    return new ChargebackBalanceTransaction();
+                    return Activator.CreateInstance<ChargebackBalanceTransaction>();
                 case BalanceTransactionContextType.OutgoingTransfer:
                 case BalanceTransactionContextType.CanceledOutgoingTransfer:
                 case BalanceTransactionContextType.ReturnedTransfer:
-                    return new SettlementBalanceTransaction();
+                    return Activator.CreateInstance<SettlementBalanceTransaction>();
                 case BalanceTransactionContextType.InvoiceCompensation:
-                    return new InvoiceBalanceTransaction();
+                    return Activator.CreateInstance<InvoiceBalanceTransaction>();
                 default: 
-                    return new BalanceTransaction();
+                    return Activator.CreateInstance<BalanceTransaction>();
             }
         }
     }

src/Mollie.Api/Framework/Factories/PaymentResponseFactory.cs

@@ -1,43 +1,48 @@
-using Mollie.Api.Models.Payment;
+using System;
+using Mollie.Api.Models.Payment;
 using Mollie.Api.Models.Payment.Response;
 using Mollie.Api.Models.Payment.Response.Specific;
 
 namespace Mollie.Api.Framework.Factories {
     public class PaymentResponseFactory {
-        public PaymentResponse Create(string paymentMethod) {
+        public PaymentResponse Create(string? paymentMethod) {
+            if (string.IsNullOrEmpty(paymentMethod)) {
+                return Activator.CreateInstance<PaymentResponse>();
+            }
+
             switch (paymentMethod) {
                 case PaymentMethod.BankTransfer:
-                    return new BankTransferPaymentResponse();
+                    return Activator.CreateInstance<BankTransferPaymentResponse>();
                 case PaymentMethod.CreditCard:
-                    return new CreditCardPaymentResponse();
+                    return Activator.CreateInstance<CreditCardPaymentResponse>();
                 case PaymentMethod.Ideal:
-                    return new IdealPaymentResponse();
+                    return Activator.CreateInstance<IdealPaymentResponse>();
                 case PaymentMethod.Giropay:
-                    return new GiropayPaymentResponse();
+                    return Activator.CreateInstance<GiropayPaymentResponse>();
                 case PaymentMethod.Eps:
-                    return new EpsPaymentResponse();
+                    return Activator.CreateInstance<EpsPaymentResponse>();
                 case PaymentMethod.Bancontact:
-                    return new BancontactPaymentResponse();
+                    return Activator.CreateInstance<BancontactPaymentResponse>();
                 case PaymentMethod.PayPal:
-                    return new PayPalPaymentResponse();
+                    return Activator.CreateInstance<PayPalPaymentResponse>();
                 case PaymentMethod.PaySafeCard:
-                    return new PaySafeCardPaymentResponse();
+                    return Activator.CreateInstance<PaySafeCardPaymentResponse>();
                 case PaymentMethod.Sofort:
-                    return new SofortPaymentResponse();
+                    return Activator.CreateInstance<SofortPaymentResponse>();
                 case PaymentMethod.Belfius:
-                    return new BelfiusPaymentResponse();
+                    return Activator.CreateInstance<BelfiusPaymentResponse>();
                 case PaymentMethod.DirectDebit:
-                    return new SepaDirectDebitResponse();
+                    return Activator.CreateInstance<SepaDirectDebitResponse>();
                 case PaymentMethod.Kbc:
-                    return new KbcPaymentResponse();
+                    return Activator.CreateInstance<KbcPaymentResponse>();
                 case PaymentMethod.GiftCard:
-                    return new GiftcardPaymentResponse();
+                    return Activator.CreateInstance<GiftcardPaymentResponse>();
                 case PaymentMethod.IngHomePay:
-                    return new IngHomePayPaymentResponse();
+                    return Activator.CreateInstance<IngHomePayPaymentResponse>();
                 case PaymentMethod.PointOfSale:
-                    return new PointOfSalePaymentResponse();
+                    return Activator.CreateInstance<PointOfSalePaymentResponse>();
                 default:
-                    return new PaymentResponse();
+                    return Activator.CreateInstance<PaymentResponse>();
             }
         }
     }

src/Mollie.Api/JsonConverters/PaymentResponseConverter.cs

@@ -12,14 +12,14 @@ public PaymentResponseConverter(PaymentResponseFactory paymentResponseFactory) {
         }
 
         protected override PaymentResponse Create(Type objectType, JObject jObject) {
-            string paymentMethod = this.GetPaymentMethod(jObject);
+            string? paymentMethod = GetPaymentMethod(jObject);
 
             return this._paymentResponseFactory.Create(paymentMethod);
         }
 
-        private string GetPaymentMethod(JObject jObject) {
+        private string? GetPaymentMethod(JObject jObject) {
             if (this.FieldExists("method", jObject)) {
-                string paymentMethodValue = (string) jObject["method"];
+                string paymentMethodValue = (string) jObject["method"]!;
                 if (!string.IsNullOrEmpty(paymentMethodValue)) {
                     return paymentMethodValue;
                 }

src/Mollie.Api/Models/Amount.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
+using Newtonsoft.Json;
 
 namespace Mollie.Api.Models {
     public class Amount {
@@ -20,6 +21,7 @@ public class Amount {
         /// </summary>
         public string Value { get; set; }
 
+        [JsonConstructor]
         public Amount(string currency, string value) {
             this.Currency = currency;
             this.Value = value;
@@ -35,8 +37,6 @@ public Amount(string currency, decimal value) {
             this.Value = ConvertDecimalAmountToStringAmount(currency, value);
         }
 
-        public Amount() { }
-
         /// <summary>
         /// Implicit cast operator from Amount to decimal.
         /// </summary>
@@ -54,20 +54,20 @@ private static string ConvertDecimalAmountToStringAmount(string currency, decima
         }
 
         public override string ToString() {
-            return $"{this.Value} {this.Currency}";
+            return $"{Value} {Currency}";
         }
 
-        public override bool Equals(object obj) {
+        public override bool Equals(object? obj) {
             if (obj is Amount amount) {
-                return this.Currency == amount.Currency && this.Value == amount.Value;
+                return Currency == amount.Currency && Value == amount.Value;
             }
 
             return false;
         }
 
         public override int GetHashCode() {
             unchecked {
-                return ((Currency != null ? Currency.GetHashCode() : 0) * 397) ^ (Value != null ? Value.GetHashCode() : 0);
+                return (Currency.GetHashCode() * 397) ^ Value.GetHashCode();
             }
         }
     }

src/Mollie.Api/Models/Balance/Response/BalanceReport/BalanceReportResponse.cs

@@ -6,7 +6,7 @@ public class BalanceReportResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains a balance report object. Will always contain balance-report for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The ID of a Balance this report is generated for.

src/Mollie.Api/Models/Balance/Response/BalanceResponse.cs

@@ -7,12 +7,12 @@ public class BalanceResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains a balance object. Will always contain balance for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The identifier uniquely referring to this balance. Mollie assigns this identifier at balance creation time. For example bal_gVMhHKqSSRYJyPsuoPNFH.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// The balance’s date and time of creation, in ISO 8601 format.

src/Mollie.Api/Models/Balance/Response/BalanceTransaction/BalanceTransaction.cs

@@ -6,13 +6,13 @@ public class BalanceTransaction {
         /// Indicates the response contains a balance transaction object. Will always contain balance_transaction
         /// for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The identifier uniquely referring to this balance transaction. Mollie assigns this identifier at
         /// transaction creation time. For example baltr_QM24QwzUWR4ev4Xfgyt29d.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// The type of movement, for example payment or refund. See Mollie docs for a full list of values

src/Mollie.Api/Models/Capture/Response/CaptureResponse.cs

@@ -8,12 +8,12 @@ public class CaptureResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains a capture object. Will always contain capture for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The capture’s unique identifier, for example cpt_4qqhO89gsT.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// The mode used to create this capture.

src/Mollie.Api/Models/ClientLink/Response/ClientLinkResponse.cs

@@ -4,9 +4,9 @@ namespace Mollie.Api.Models.ClientLink.Response
 {
     public class ClientLinkResponse
     {
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         [JsonProperty("_links")]
         public ClientLinkResponseLinks Links { get; set; }

src/Mollie.Api/Models/Customer/CustomerResponse.cs

@@ -10,13 +10,13 @@ public class CustomerResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains a customer object. Will always contain customer for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The customer's unique identifier, for example cst_4pmbK7CqtT.
         /// Store this identifier for later recurring payments.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// The mode used to create this payment. Mode determines whether a payment is real or a test payment.
@@ -63,8 +63,8 @@ public class CustomerResponse : IResponseObject {
         [JsonProperty("_links")]
         public CustomerResponseLinks Links { get; set; }
 
-        public T GetMetadata<T>(JsonSerializerSettings jsonSerializerSettings = null) {
-            return JsonConvert.DeserializeObject<T>(this.Metadata, jsonSerializerSettings);
+        public T? GetMetadata<T>(JsonSerializerSettings? jsonSerializerSettings = null) {
+            return JsonConvert.DeserializeObject<T>(Metadata, jsonSerializerSettings);
         }
     }
 }

src/Mollie.Api/Models/Invoice/InvoiceResponse.cs

@@ -7,7 +7,7 @@ public class InvoiceResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains an invoice object. Will always contain invoice for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
 		/// <summary>
 		/// The invoice's unique identifier, for example inv_FrvewDA3Pr.

src/Mollie.Api/Models/Issuer/IssuerResponse.cs

@@ -3,14 +3,14 @@ public class IssuerResponse : IResponseObject {
         /// <summary>
         /// Contains "issuer"
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         ///     The issuer's unique identifier, for example ideal_ABNANL2A. When creating a payment, specify this ID as the issuer
         ///     parameter to forward
         ///     the consumer to their banking environment directly.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         ///     The issuer's full name, for example 'ABN AMRO'.

src/Mollie.Api/Models/Mandate/MandateResponse.cs

@@ -7,12 +7,12 @@ public class MandateResponse : IResponseObject {
         /// <summary>
         /// Indicates the response contains a mandate object. Will always contain mandate for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// Unique identifier of you mandate.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// Current status of mandate - See the Mollie.Api.Models.Mandate.MandateStatus class for a full 

src/Mollie.Api/Models/Onboarding/Response/OnboardingStatusResponse.cs

@@ -6,7 +6,7 @@ public class OnboardingStatusResponse {
         /// <summary>
         /// Indicates the response contains an onboarding object. Will always contain onboarding for this endpoint.
         /// </summary>
-        public string Resource { get; set; }
+        public required string Resource { get; init; }
 
         /// <summary>
         /// The name of the organization.

src/Mollie.Api/Models/Order/Request/ManageOrderLines/ManageOrderLinesUpdateOperationData.cs

@@ -1,5 +1,5 @@
 namespace Mollie.Api.Models.Order.Request.ManageOrderLines {
     public class ManageOrderLinesUpdateOperationData : OrderLineUpdateRequest {
-        public string Id { get; set; } 
+        public required string Id { get; init; } 
     }
 }

src/Mollie.Api/Models/Order/Request/OrderLineDetails.cs

@@ -1,6 +1,6 @@
 namespace Mollie.Api.Models.Order {
     public class OrderLineDetails {
-        public string Id { get; set; }
+        public required string Id { get; init; }
         public int? Quantity { get; set; }
         public Amount Amount { get; set; }
     }

src/Mollie.Api/Models/Order/Request/OrderLineUpdateRequest.cs

@@ -70,7 +70,7 @@ public class OrderLineUpdateRequest {
         /// </summary>
         public bool? Testmode { get; set; }
 
-        public void SetMetadata(object metadataObj, JsonSerializerSettings jsonSerializerSettings = null) {
+        public void SetMetadata(object metadataObj, JsonSerializerSettings? jsonSerializerSettings = null) {
             this.Metadata = JsonConvert.SerializeObject(metadataObj, jsonSerializerSettings);
         }
     }

src/Mollie.Api/Models/Order/Request/OrderRequest.cs

@@ -141,7 +141,7 @@ public string Method {
         /// </summary>
         public bool? Testmode { get; set; }
 
-        public void SetMetadata(object metadataObj, JsonSerializerSettings jsonSerializerSettings = null) {
+        public void SetMetadata(object metadataObj, JsonSerializerSettings? jsonSerializerSettings = null) {
             this.Metadata = JsonConvert.SerializeObject(metadataObj, jsonSerializerSettings);
         }
     }

src/Mollie.Api/Models/Order/Response/OrderLineResponse.cs

@@ -7,7 +7,7 @@ public class OrderLineResponse {
         /// <summary>
         /// The order line’s unique identifier, for example odl_dgtxyl.
         /// </summary>
-        public string Id { get; set; }
+        public required string Id { get; init; }
 
         /// <summary>
         /// The ID of the order the line belongs too, for example ord_kEn1PlbGa.