app: start mainchain on init if not running

lib/app.dart

@@ -1,10 +1,18 @@
+import 'dart:async';
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:get_it/get_it.dart';
+import 'package:sail_ui/sail_ui.dart';
 import 'package:sail_ui/theme/theme.dart';
 import 'package:sail_ui/theme/theme_data.dart';
+import 'package:sail_ui/widgets/core/sail_text.dart';
 import 'package:sail_ui/widgets/core/scaffold.dart';
 import 'package:sail_ui/widgets/loading_indicator.dart';
+import 'package:sidesail/logger.dart';
+import 'package:sidesail/providers/proc_provider.dart';
 import 'package:sidesail/routing/router.dart';
+import 'package:sidesail/rpc/rpc_mainchain.dart';
 import 'package:sidesail/rpc/rpc_sidechain.dart';
 import 'package:sidesail/storage/client_settings.dart';
 import 'package:sidesail/storage/sail_settings/theme_settings.dart';
@@ -34,16 +42,24 @@ class SailApp extends StatefulWidget {
 }
 
 class SailAppState extends State<SailApp> with WidgetsBindingObserver {
-  SailThemeData? theme;
   AppRouter get router => GetIt.I.get<AppRouter>();
   SidechainRPC get _sidechain => GetIt.I.get<SidechainRPC>();
+  MainchainRPC get mainchain => GetIt.I.get<MainchainRPC>();
+  ProcessProvider get processes => GetIt.I.get<ProcessProvider>();
   final settings = GetIt.I.get<ClientSettings>();
 
+  /// Unrecoverable error on startup we can't get past.
+  dynamic _initBinariesError;
+  String mainchainStartupMessage = "Checking if 'drivechaind' is started";
+  bool binariesStarted = false;
+  SailThemeData? theme;
+
   @override
   void initState() {
     super.initState();
     WidgetsBinding.instance.addObserver(this);
-    loadTheme();
+    unawaited(loadTheme());
+    unawaited(initBinaries());
   }
 
   void rebuildUI() {
@@ -64,7 +80,63 @@ class SailAppState extends State<SailApp> with WidgetsBindingObserver {
     }
   }
 
-  void loadTheme([SailThemeValues? themeToLoad]) async {
+  Future<void> initBinaries() async {
+    log.d('init binaries: checking mainchain connection');
+
+    // First, let the mainchain connection check finish.
+    await mainchain.initDone;
+
+    // If we managed to connect, we're finished here!
+    if (mainchain.connected) {
+      log.d('init binaries: mainchain is already running, not doing anything');
+      setState(() {
+        binariesStarted = true;
+      });
+      return;
+    }
+
+    // We have to start the mainchain
+    final tempDir = await Directory.systemTemp.createTemp('drivechaind');
+    final tempLogFile = await File('${tempDir.path}/drivechaind.debug.log').create(recursive: true);
+
+    if (!context.mounted) {
+      return;
+    }
+
+    final args = [
+      '-debuglogfile=${tempLogFile.path}',
+      '-regtest',
+    ];
+
+    log.d('init binaries: starting drivechaind $args');
+
+    try {
+      final pid = await processes.start(context, 'drivechaind', args);
+      log.d('init binaries: started drivechaind with PID $pid');
+      setState(() {
+        mainchainStartupMessage = "Started 'drivechaind', waiting for successful RPC connection";
+      });
+    } catch (err) {
+      log.w('init binaries: unable to start drivechaind', error: err);
+      return setState(() {
+        _initBinariesError = err;
+      });
+    }
+
+    // Add timeout?
+    log.i('init binaries: waiting for mainchain connection');
+    await waitForBoolToBeTrue(() async {
+      final (connected, _) = await mainchain.testConnection();
+      return connected;
+    });
+
+    log.i('init binaries: mainchain connected');
+    return setState(() {
+      binariesStarted = true;
+    });
+  }
+
+  Future<void> loadTheme([SailThemeValues? themeToLoad]) async {
     themeToLoad ??= (await settings.getValue(ThemeSetting())).value;
     if (themeToLoad == SailThemeValues.platform) {
       // ignore: deprecated_member_use
@@ -79,17 +151,37 @@ class SailAppState extends State<SailApp> with WidgetsBindingObserver {
     await settings.setValue(ThemeSetting(newValue: themeToLoad));
   }
 
+  bool get inInitialSetup => theme == null || !binariesStarted;
+
+  Widget loadingIndicator() {
+    if (!binariesStarted) {
+      return SailColumn(
+        crossAxisAlignment: CrossAxisAlignment.center,
+        mainAxisAlignment: MainAxisAlignment.center,
+        spacing: SailStyleValues.padding25,
+        children: [
+          SailText.primary20('Mainchain starting up: $mainchainStartupMessage'),
+          const SailCircularProgressIndicator(),
+        ],
+      );
+    }
+    return const SailCircularProgressIndicator();
+  }
+
   @override
   Widget build(BuildContext context) {
-    if (theme == null) {
+    if (inInitialSetup) {
       return MaterialApp(
         home: Material(
           color: _sidechain.chain.color,
           child: SailTheme(
             data: SailThemeData.lightTheme(_sidechain.chain.color),
-            child: const SailScaffold(
+            child: SailScaffold(
               body: Center(
-                child: SailCircularProgressIndicator(),
+                // TODO: better error message with troubleshooting tips here
+                child: _initBinariesError != null
+                    ? SailText.primary24('Ran into unrecoverable error on startup: $_initBinariesError')
+                    : loadingIndicator(),
               ),
             ),
           ),
@@ -109,3 +201,14 @@ class SailAppState extends State<SailApp> with WidgetsBindingObserver {
     super.dispose();
   }
 }
+
+Future<void> waitForBoolToBeTrue(
+  Future<bool> Function() boolGetter, {
+  Duration pollInterval = const Duration(milliseconds: 100),
+}) async {
+  bool result = await boolGetter();
+  if (!result) {
+    await Future.delayed(pollInterval);
+    await waitForBoolToBeTrue(boolGetter, pollInterval: pollInterval);
+  }
+}

lib/rpc/rpc.dart

@@ -20,6 +20,11 @@ abstract class RPCConnection extends ChangeNotifier {
   // ping method that tests whether the connection is successful
   // should throw if call is not successful
   Future<void> ping();
+
+  bool _initDone = false;
+
+  Future<void> get initDone => _initDone ? Future.value() : Future.any([]);
+
   Future<(bool, String?)> testConnection() async {
     try {
       await ping();
@@ -29,6 +34,8 @@ abstract class RPCConnection extends ChangeNotifier {
       _log.e('could not ping: ${error.toString()}!');
       connectionError = error.toString();
       connected = false;
+    } finally {
+      _initDone = true;
     }
     notifyListeners();