From c620a5e23a9a7e1012f91d996450bdd558942408 Mon Sep 17 00:00:00 2001
From: sneurlax <sneurlax@gmail.com>
Date: Sun, 6 Aug 2023 22:57:34 -0500
Subject: [PATCH] WIP nextChangeAddress

WIP move reserve_change_addresses(int addresses) to fusion interface
---
 fusiondart                                    |  2 +-
 .../coins/bitcoincash/bitcoincash_wallet.dart | 28 +++++++++++++++----
 lib/services/mixins/fusion_interface.dart     | 12 ++++++++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/fusiondart b/fusiondart
index b4209c152..ad107a683 160000
--- a/fusiondart
+++ b/fusiondart
@@ -1 +1 @@
-Subproject commit b4209c1523cf53d9db805ce0924e6902c716c0f3
+Subproject commit ad107a683cfdf72040270921062fc6f43ae63f6b
diff --git a/lib/services/coins/bitcoincash/bitcoincash_wallet.dart b/lib/services/coins/bitcoincash/bitcoincash_wallet.dart
index ea2341ffd..e0e6b095c 100644
--- a/lib/services/coins/bitcoincash/bitcoincash_wallet.dart
+++ b/lib/services/coins/bitcoincash/bitcoincash_wallet.dart
@@ -26,7 +26,8 @@ import 'package:stackwallet/db/isar/main_db.dart';
 import 'package:stackwallet/electrumx_rpc/cached_electrumx.dart';
 import 'package:stackwallet/electrumx_rpc/electrumx.dart';
 import 'package:stackwallet/models/balance.dart';
-import 'package:stackwallet/models/isar/models/blockchain_data/address.dart';
+import 'package:stackwallet/models/isar/models/blockchain_data/address.dart'
+    as stack_address;
 import 'package:stackwallet/models/isar/models/isar_models.dart' as isar_models;
 import 'package:stackwallet/models/paymint/fee_object_model.dart';
 import 'package:stackwallet/models/signing_data.dart';
@@ -197,8 +198,25 @@ class BitcoinCashWallet extends CoinServiceAPI
           .findFirst()) ??
       await _generateAddressForChain(0, 0, DerivePathTypeExt.primaryFor(coin));
 
-  Future<String> get currentChangeAddress async =>
-      (await _currentChangeAddress).value;
+  Future<String> get currentChangeAddress async => (await _currentChangeAddress)
+      .value; // could return Address to cast Stack's Address to Fusiondart's Address like `(await _currentChangeAddress).toFusionAddress();`
+
+  Future<String> get nextChangeAddress async {
+    // get change <Address>
+    final currentChange = await _currentChangeAddress;
+    // use <Address>.derivationmIndex + 1 to get next change address derivation path
+    final int nextChangeIndex = currentChange.derivationIndex + 1;
+    // generate next change address
+    final stack_address.Address newChangeAddress =
+        await _generateAddressForChain(
+            1,
+            nextChangeIndex,
+            DerivePathTypeExt.primaryFor(
+                coin)); // may need to pick other derive path type, eg 44, 49, 84
+
+    return newChangeAddress
+        .value; // could return Address to cast Stack's Address to Fusiondart's Address like `newChangeAddress.toFusionAddress();`
+  }
 
   Future<isar_models.Address> get _currentChangeAddress async =>
       (await db
@@ -2147,10 +2165,10 @@ class BitcoinCashWallet extends CoinServiceAPI
             walletId: walletId,
             value: possible,
             publicKey: [],
-            type: AddressType.nonWallet,
+            type: stack_address.AddressType.nonWallet,
             derivationIndex: -1,
             derivationPath: null,
-            subType: AddressSubType.nonWallet,
+            subType: stack_address.AddressSubType.nonWallet,
           );
         }
       } else {
diff --git a/lib/services/mixins/fusion_interface.dart b/lib/services/mixins/fusion_interface.dart
index fc721d781..dcab0096e 100644
--- a/lib/services/mixins/fusion_interface.dart
+++ b/lib/services/mixins/fusion_interface.dart
@@ -30,6 +30,18 @@ mixin FusionInterface {
     _getCurrentChangeAddress = getCurrentChangeAddress;
   }
 
+  static List<Address> reserve_change_addresses(int number_addresses) {
+    // TODO
+    // get current change address
+    // get int number_addresses next addresses
+    return [];
+  }
+
+  static List<Address> unreserve_change_address(Address addr) {
+    //implement later based on wallet.
+    return [];
+  }
+
   void fuse() async {
     // Initial attempt for CashFusion integration goes here.
     Fusion mainFusionObject = Fusion();