remove spvwallet, make some libdcrwallet fns async, light refactor

cw_decred/lib/api/libdcrwallet.dart

@@ -0,0 +1,108 @@
+import 'dart:convert';
+import 'dart:ffi';
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+import 'package:cw_decred/api/libdcrwallet_bindings.dart';
+import 'package:cw_decred/api/util.dart';
+
+final String libraryName =
+    Platform.isAndroid || Platform.isLinux // TODO: Linux.
+        ? 'libdcrwallet.so'
+        : 'cw_decred.framework/cw_decred';
+
+final dcrwalletApi = libdcrwallet(DynamicLibrary.open(libraryName));
+
+/// initLibdcrwallet initializes libdcrwallet using the provided logDir and gets
+/// it ready for use. This must be done before attempting to create, load or use
+/// a wallet.
+void initLibdcrwallet(String logDir) {
+  final cLogDIr = logDir.toCString();
+  handleErrorAndPointers(
+    fn: () => dcrwalletApi.initialize(cLogDIr),
+    ptrsToFree: [cLogDIr],
+  );
+}
+
+/// createWalletAsync calls the libdcrwallet's createWallet function
+/// asynchronously.
+Future<void> createWalletAsync(
+    {required String name, required String dataDir, required String password}) {
+  final args = <String, String>{
+    "name": name,
+    "dataDir": dataDir,
+    "password": password,
+  };
+  return compute(createWalletSync, args);
+}
+
+/// createWalletSync calls the libdcrwallet's createWallet function
+/// synchronously.
+void createWalletSync(Map<String, String> args) {
+  final name = args["name"]!.toCString();
+  final dataDir = args["dataDir"]!.toCString();
+  final password = args["password"]!.toCString();
+  final network = "testnet".toCString();
+
+  handleErrorAndPointers(
+    fn: () => dcrwalletApi.createWallet(name, dataDir, network, password),
+    ptrsToFree: [name, dataDir, network, password],
+  );
+}
+
+/// loadWalletAsync calls the libdcrwallet's loadWallet function asynchronously.
+Future<void> loadWalletAsync({required String name, required String dataDir}) {
+  final args = <String, String>{
+    "name": name,
+    "dataDir": dataDir,
+  };
+  return compute(loadWalletSync, args);
+}
+
+/// loadWalletSync calls the libdcrwallet's loadWallet function synchronously.
+void loadWalletSync(Map<String, String> args) {
+  final name = args["name"]!.toCString();
+  final dataDir = args["dataDir"]!.toCString();
+  final network = "testnet".toCString();
+
+  handleErrorAndPointers(
+    fn: () => dcrwalletApi.loadWallet(name, dataDir, network),
+    ptrsToFree: [name, dataDir, network],
+  );
+}
+
+void closeWallet(String walletName) {
+  // TODO.
+}
+
+Future<void> changeWalletPassword(
+    String walletName, String currentPassword, String newPassword) async {
+  // TODO.
+}
+
+String? walletSeed(String walletName, String walletPassword) {
+  final cName = walletName.toCString();
+  final pass = walletPassword.toCString();
+  final seed = dcrwalletApi.walletSeed(cName, pass);
+  freePointers([cName, pass]);
+  return seed.toDartString();
+}
+
+String? currentReceiveAddress(String walletName) {
+  final cName = walletName.toCString();
+  final currentAddress = dcrwalletApi.currentReceiveAddress(cName);
+  cName.free();
+  return currentAddress.toDartString();
+}
+
+Map balance(String walletName) {
+  final cName = walletName.toCString();
+  final balJson = dcrwalletApi.walletBalance(cName).toDartString();
+  cName.free();
+  return jsonDecode(balJson!);
+}
+
+int calculateEstimatedFeeWithFeeRate(int feeRate, int amount) {
+  // Ideally we create a tx with wallet going to this amount and just return
+  // the fee we get back. TODO.
+  return 123000;
+}

cw_decred/lib/balance.dart

@@ -5,6 +5,8 @@ class DecredBalance extends Balance {
   const DecredBalance({required this.confirmed, required this.unconfirmed})
       : super(confirmed, unconfirmed);
 
+  factory DecredBalance.zero() => DecredBalance(confirmed: 0, unconfirmed: 0);
+
   final int confirmed;
   final int unconfirmed;
 

cw_decred/lib/pending_transaction.dart

@@ -1,16 +1,13 @@
 import 'package:cw_core/pending_transaction.dart';
 import 'package:cw_decred/amount_format.dart';
-import 'package:cw_decred/api/spvwallet.dart';
 
 class DecredPendingTransaction with PendingTransaction {
   DecredPendingTransaction(
-      {required this.spv,
-      required this.txid,
+      {required this.txid,
       required this.amount,
       required this.fee,
       required this.rawHex});
 
-  final SPVWallet spv;
   final int amount;
   final int fee;
   final String txid;
@@ -30,6 +27,6 @@ class DecredPendingTransaction with PendingTransaction {
 
   @override
   Future<void> commit() async {
-    this.spv.sendRawTransaction(this.rawHex);
+    // TODO: Submit rawHex using libdcrwallet.
   }
 }