feat: add payment notifications and entitlement fulfillment

Tiku.Infrastructure/Commerce/WechatPayProvider.cs

@@ -1,4 +1,6 @@
 using System.Text.Json;
+using SKIT.FlurlHttpClient.Wechat.TenpayV3.Models;
+using SKIT.FlurlHttpClient.Wechat.TenpayV3.Events;
 using SKIT.FlurlHttpClient.Wechat.TenpayV3;
 using SKIT.FlurlHttpClient.Wechat.TenpayV3.Settings;
 using Tiku.Application.Commerce;
@@ -25,10 +27,35 @@ internal sealed class WechatPayProvider : IPaymentProvider
         PaymentNotificationRequest request,
         CancellationToken cancellationToken = default)
     {
-        _ = BuildClient(account);
-        throw new PaymentProviderException(
-            "WeChat Pay SDK is configured; notification parsing is enabled in the notification batch.",
-            "wechat_pay_notification_not_enabled");
+        var client = BuildClient(account);
+        var signatureValid = TryGetHeader(request.Headers, "Wechatpay-Timestamp", out var timestamp) &&
+                             TryGetHeader(request.Headers, "Wechatpay-Nonce", out var nonce) &&
+                             TryGetHeader(request.Headers, "Wechatpay-Signature", out var signature) &&
+                             TryGetHeader(request.Headers, "Wechatpay-Serial", out var serial) &&
+                             client.VerifyEventSignature(timestamp, nonce, request.RawBody, signature, serial);
+        var payload = TryDecryptTransactionResource(client, request.Body, out var decrypted)
+            ? decrypted
+            : request.Body;
+        var eventId = GetString(request.Body, "id") ?? GetString(payload, "transaction_id") ?? Guid.NewGuid().ToString("N");
+        var orderNo = GetString(payload, "out_trade_no", "outTradeNo")
+                      ?? throw new PaymentProviderException("WeChat Pay notification order number is missing.", "wechat_pay_notify_order_missing");
+        var tradeNo = GetString(payload, "transaction_id", "transactionId");
+        var tradeState = GetString(payload, "trade_state", "tradeState") ?? GetString(request.Body, "event_type");
+        var amount = GetInt(payload, "amount", "total") ?? GetInt(payload, "amountCents") ?? 0;
+        var paidAt = GetDateTimeOffset(payload, "success_time", "successTime");
+
+        return Task.FromResult(new PaymentNotificationResult(
+            Provider,
+            GetString(request.Body, "event_type") ?? "TRANSACTION.SUCCESS",
+            eventId,
+            orderNo,
+            tradeNo,
+            amount,
+            string.Equals(tradeState, "SUCCESS", StringComparison.OrdinalIgnoreCase) ||
+            string.Equals(tradeState, "TRANSACTION.SUCCESS", StringComparison.OrdinalIgnoreCase),
+            signatureValid,
+            paidAt,
+            payload));
     }
 
     private static WechatTenpayClient BuildClient(PaymentProviderAccount account)
@@ -65,4 +92,101 @@ internal sealed class WechatPayProvider : IPaymentProvider
             "WeChat Pay provider configuration is incomplete.",
             "wechat_pay_config_incomplete");
     }
+
+    private static bool TryDecryptTransactionResource(
+        WechatTenpayClient client,
+        JsonElement body,
+        out JsonElement payload)
+    {
+        payload = default;
+        try
+        {
+            if (body.ValueKind != JsonValueKind.Object ||
+                !body.TryGetProperty("resource", out var resource))
+            {
+                return false;
+            }
+
+            var webhookEvent = JsonSerializer.Deserialize<WechatTenpayEvent>(body.GetRawText());
+            if (webhookEvent?.Resource is null)
+            {
+                return false;
+            }
+
+            var decrypted = client.DecryptEventResource<TransactionResource>(webhookEvent);
+            payload = JsonSerializer.SerializeToElement(decrypted);
+            _ = resource;
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static bool TryGetHeader(
+        IReadOnlyDictionary<string, string> headers,
+        string name,
+        out string value)
+    {
+        foreach (var pair in headers)
+        {
+            if (string.Equals(pair.Key, name, StringComparison.OrdinalIgnoreCase))
+            {
+                value = pair.Value;
+                return true;
+            }
+        }
+
+        value = string.Empty;
+        return false;
+    }
+
+    private static string? GetString(JsonElement element, params string[] keys)
+    {
+        if (element.ValueKind != JsonValueKind.Object)
+        {
+            return null;
+        }
+
+        foreach (var key in keys)
+        {
+            if (element.TryGetProperty(key, out var property) &&
+                property.ValueKind == JsonValueKind.String)
+            {
+                return property.GetString();
+            }
+        }
+
+        return null;
+    }
+
+    private static int? GetInt(JsonElement element, string parentKey, string childKey)
+    {
+        if (element.ValueKind == JsonValueKind.Object &&
+            element.TryGetProperty(parentKey, out var parent) &&
+            parent.ValueKind == JsonValueKind.Object &&
+            parent.TryGetProperty(childKey, out var child) &&
+            child.TryGetInt32(out var value))
+        {
+            return value;
+        }
+
+        return null;
+    }
+
+    private static int? GetInt(JsonElement element, string key)
+    {
+        return element.ValueKind == JsonValueKind.Object &&
+               element.TryGetProperty(key, out var property) &&
+               property.TryGetInt32(out var value)
+            ? value
+            : null;
+    }
+
+    private static DateTimeOffset? GetDateTimeOffset(JsonElement element, params string[] keys)
+    {
+        var value = GetString(element, keys);
+        return DateTimeOffset.TryParse(value, out var parsed) ? parsed : null;
+    }
 }