Added releasePaymentPreimage functions to all 3 kotlin clients

lightspark-sdk/src/commonJvmAndroidMain/kotlin/com/lightspark/sdk/LightsparkFuturesClient.kt

@@ -21,6 +21,7 @@ import com.lightspark.sdk.model.InvoiceType
 import com.lightspark.sdk.model.OutgoingPayment
 import com.lightspark.sdk.model.PaymentDirection
 import com.lightspark.sdk.model.RegionCode
+import com.lightspark.sdk.model.ReleasePaymentPreimageOutput
 import com.lightspark.sdk.model.RiskRating
 import com.lightspark.sdk.model.TransactionStatus
 import com.lightspark.sdk.model.UmaInvitation
@@ -116,6 +117,23 @@ class LightsparkFuturesClient(config: ClientConfig) {
     ): CompletableFuture<WalletDashboard?> =
         coroutineScope.future { coroutinesClient.getSingleNodeDashboard(nodeId, numTransactions, bitcoinNetwork) }
 
+    /**
+     * Marks a payment preimage as released. To be used when the recipient has received the payment.
+     *
+     * @param invoiceId The invoice the preimage belongs to.
+     * @param paymentPreimage The preimage to release.
+     */
+    fun releasePaymentPreimage(
+        invoiceId: String,
+        paymentPreimage: String
+    ): CompletableFuture<ReleasePaymentPreimageOutput?> =
+        coroutineScope.future {
+            coroutinesClient.releasePaymentPreimage(
+                invoiceId,
+                paymentPreimage
+            )
+        }
+
     /**
      * Creates a lightning invoice for the given node.
      *

lightspark-sdk/src/commonMain/kotlin/com/lightspark/sdk/LightsparkCoroutinesClient.kt

@@ -172,6 +172,30 @@ class LightsparkCoroutinesClient private constructor(
         )
     }
 
+    /**
+     * Marks a payment preimage as released. To be used when the recipient has received the payment.
+     *
+     * @param invoiceId The invoice the preimage belongs to.
+     * @param paymentPreimage The preimage to release.
+     */
+    suspend fun releasePaymentPreimage(invoiceId: String, paymentPreimage: String): ReleasePaymentPreimageOutput {
+        requireValidAuth()
+
+        return executeQuery(
+            Query(
+                ReleasePaymentPreimageMutation,
+                {
+                    add("invoice_id", invoiceId)
+                    add("payment_preimage", paymentPreimage)
+                },
+            ) {
+                val releasePaymentPreimageJson =
+                    requireNotNull(it["release_payment_preimage"]) { "Invalid response for payment preimage release" }
+                serializerFormat.decodeFromJsonElement<ReleasePaymentPreimageOutput>(releasePaymentPreimageJson)
+            },
+        )
+    }
+
     /**
      * Creates a lightning invoice for the given node.
      *

lightspark-sdk/src/commonMain/kotlin/com/lightspark/sdk/LightsparkSyncClient.kt

@@ -98,6 +98,22 @@ class LightsparkSyncClient constructor(config: ClientConfig) {
         bitcoinNetwork: BitcoinNetwork = defaultBitcoinNetwork,
     ): WalletDashboard? = runBlocking { asyncClient.getSingleNodeDashboard(nodeId, numTransactions, bitcoinNetwork) }
 
+    /**
+     * Marks a payment preimage as released. To be used when the recipient has received the payment.
+     *
+     * @param invoiceId The invoice the preimage belongs to.
+     * @param paymentPreimage The preimage to release.
+     */
+    fun releasePaymentPreimage(
+        invoiceId: String,
+        paymentPreimage: String
+    ): ReleasePaymentPreimageOutput = runBlocking {
+        asyncClient.releasePaymentPreimage(
+            invoiceId,
+            paymentPreimage
+        )
+    }
+
     /**
      * Creates a lightning invoice for the given node.
      *