feat: ios fund created channel

Author: Jasonvdb

example/utils/helpers.ts

@@ -240,3 +240,18 @@ export const ldkNetwork = (network: TAvailableNetworks): ENetworks => {
 			return ENetworks.signet;
 	}
 };
+
+
+export const scriptToAddress = (outputScript: string): string => {
+	if (!outputScript.startsWith('0020')) {
+		throw new Error('Invalid output script, currently example app only supports P2WSH');
+	}
+
+	outputScript = outputScript.slice(4);
+
+	const scriptPubKey = Buffer.from(outputScript, 'hex');
+	const network = getNetwork(selectedNetwork);
+	const address = bitcoin.payments.p2wsh({ hash: scriptPubKey, network }).address;
+
+	return address ?? "";
+}

lib/ios/Ldk.m

@@ -91,6 +91,11 @@ @interface RCT_EXTERN_MODULE(Ldk, NSObject)
                   pushSats:(NSInteger *)pushSats
                   resolve:(RCTPromiseResolveBlock)resolve
                   reject:(RCTPromiseRejectBlock)reject)
+RCT_EXTERN_METHOD(fundChannel:(NSString *)temporaryChannelId
+                  counterpartyNodeId:(NSString *)counterpartyNodeId
+                  fundingTransaction:(NSString *)fundingTransaction
+                  resolve:(RCTPromiseResolveBlock)resolve
+                  reject:(RCTPromiseRejectBlock)reject)
 RCT_EXTERN_METHOD(forceCloseAllChannels:(BOOL *)broadcastLatestTx
                   resolve:(RCTPromiseResolveBlock)resolve
                   reject:(RCTPromiseRejectBlock)reject)

lib/ios/Ldk.swift

@@ -59,6 +59,7 @@ enum LdkErrors: String {
     case channel_close_fail
     case channel_accept_fail
     case start_create_channel_fail
+    case fund_channel_fail
     case spend_outputs_fail
     case failed_signing_request
     case write_fail
@@ -104,6 +105,7 @@ enum LdkCallbackResponses: String {
     case accept_channel_success
     case close_channel_success
     case start_create_channel_success
+    case fund_channel_success
     case file_write_success
     case abandon_payment_success
     case backup_client_setup_success
@@ -935,6 +937,25 @@ class Ldk: NSObject {
         handleReject(reject, .start_create_channel_fail)
     }
 
+    @objc
+    func fundChannel(_ temporaryChannelId: NSString, counterpartyNodeId: NSString, fundingTransaction: NSString, resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
+        guard let channelManager = channelManager else {
+            return handleReject(reject, .init_channel_manager)
+        }
+        
+        let res = channelManager.fundingTransactionGenerated(
+            temporaryChannelId: .initWith(aArg: String(temporaryChannelId).hexaBytes),
+            counterpartyNodeId: String(counterpartyNodeId).hexaBytes,
+            fundingTransaction: String(fundingTransaction).hexaBytes
+        )
+        
+        if res.isOk() {
+            return handleResolve(resolve, .fund_channel_success)
+        }
+        
+        handleReject(reject, .fund_channel_fail)
+    }
+    
     @objc
     func forceCloseAllChannels(_ broadcastLatestTx: Bool, resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
         guard let channelManager = channelManager else {

lib/src/ldk.ts

@@ -40,6 +40,7 @@ import {
 	TSpendRecoveredForceCloseOutputsReq,
 	TChannelMonitor,
 	TCreateChannelReq,
+	TFundChannelReq,
 } from './utils/types';
 import { extractPaymentRequest } from './utils/helpers';
 
@@ -500,6 +501,25 @@ class LDK {
 		}
 	}
 
+	/**
+	 * Funds an already created channel with a signed transaction.
+	 * https://docs.rs/lightning/latest/lightning/ln/channelmanager/struct.ChannelManager.html#method.funding_transaction_generated
+	 * @param temporaryChannelId
+	 * @param counterPartyNodeId
+	 * @param fundingTransaction
+	 * @returns {Promise<Err<unknown> | Ok<Ok<string> | Err<string>>>}
+	 */
+	async fundChannel({temporaryChannelId, counterPartyNodeId, fundingTransaction}: TFundChannelReq): Promise<Result<string>> {
+		try {
+			const res = await NativeLDK.fundChannel(temporaryChannelId, counterPartyNodeId, fundingTransaction);
+			this.writeDebugToLog('fundChannel');
+			return ok(res);
+		} catch (e) {
+			this.writeErrorToLog('fundChannel', e);
+			return err(e);
+		}
+	}
+
 	/**
 	 * Force close all channels
 	 * @param broadcastLatestTx

lib/src/utils/types.ts

@@ -287,6 +287,12 @@ export type TCreateChannelReq = {
 	pushSats: number;
 };
 
+export type TFundChannelReq = {
+	temporaryChannelId: string;
+	counterPartyNodeId: string;
+	fundingTransaction: string;
+};
+
 export type TAcceptChannelReq = {
 	temporaryChannelId: string;
 	counterPartyNodeId: string;