Add a very basic purchase screen

Along with a 'Go Pro' option in the sidebar. This is extremely ugly and
is therefore disabled by default right now.

lib/app.dart

@@ -4,6 +4,7 @@ import 'package:device_info/device_info.dart';
 import 'package:firebase_analytics/firebase_analytics.dart';
 import 'package:firebase_analytics/observer.dart';
 import 'package:flutter/material.dart';
+import 'package:gitjournal/screens/purchase_screen.dart';
 import 'package:gitjournal/utils/logger.dart';
 import 'package:provider/provider.dart';
 import 'package:path/path.dart' as p;
@@ -135,6 +136,7 @@ class JournalApp extends StatelessWidget {
             GitHostSetupScreen(stateContainer.completeGitHostSetup),
         '/onBoarding': (context) =>
             OnBoardingScreen(stateContainer.completeOnBoarding),
+        '/purchase': (context) => PurchaseScreen(),
       },
       debugShowCheckedModeBanner: false,
       //debugShowMaterialGrid: true,

lib/features.dart

@@ -1,3 +1,4 @@
 class Features {
   static bool perFolderConfig = false;
+  static bool purchaseProModeAvailable = false;
 }

lib/screens/purchase_screen.dart

@@ -0,0 +1,153 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:gitjournal/analytics.dart';
+
+import 'package:flutter/services.dart';
+import 'package:flutter_inapp_purchase/flutter_inapp_purchase.dart';
+
+class PurchaseScreen extends StatefulWidget {
+  @override
+  _PurchaseScreenState createState() => _PurchaseScreenState();
+}
+
+class _PurchaseScreenState extends State<PurchaseScreen> {
+  String _platformVersion = 'Unknown';
+  var _skus = ['sku_monthly_min'];
+  List<IAPItem> _iapItems = [];
+
+  StreamSubscription _purchaseUpdatedSubscription;
+  StreamSubscription _purchaseErrorSubscription;
+  StreamSubscription _conectionSubscription;
+
+  @override
+  void initState() {
+    super.initState();
+    initPlatformState();
+  }
+
+  Future<void> initPlatformState() async {
+    // prepare
+    var result = await FlutterInappPurchase.instance.initConnection;
+    print('result: $result');
+
+    // If the widget was removed from the tree while the asynchronous platform
+    // message was in flight, we want to discard the reply rather than calling
+    // setState to update our non-existent appearance.
+    if (!mounted) return;
+
+    try {
+      _iapItems = await FlutterInappPurchase.instance.getSubscriptions(_skus);
+      setState(() {});
+      print("IAP ITEMS $_iapItems");
+    } catch (err) {
+      print('getSubscriptions error: $err');
+    }
+
+    _conectionSubscription =
+        FlutterInappPurchase.connectionUpdated.listen((connected) {
+      print('connected: $connected');
+    });
+
+    _purchaseUpdatedSubscription =
+        FlutterInappPurchase.purchaseUpdated.listen((productItem) {
+      print('purchase-updated: $productItem');
+    });
+
+    _purchaseErrorSubscription =
+        FlutterInappPurchase.purchaseError.listen((purchaseError) {
+      print('purchase-error: $purchaseError');
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    var theme = Theme.of(context);
+    var textTheme = theme.textTheme;
+
+    if (_iapItems.isEmpty) {
+      return const PurchaseLoadingScreen();
+    }
+    var iap = _iapItems[0];
+
+    // FIXME: This screen needs to be made way way more beautiful
+    //        It's an extrememly important screen
+
+    Widget w = Column(
+      children: <Widget>[
+        Text('Pro Version', style: textTheme.display2),
+        Text('Support GitJournal by going Pro', style: textTheme.subhead),
+        RaisedButton(
+          child: Text('Subscribe for ${iap.localizedPrice} / month'),
+          onPressed: () {
+            FlutterInappPurchase.instance.requestSubscription(_skus[0]);
+          },
+        ),
+      ],
+      mainAxisAlignment: MainAxisAlignment.spaceAround,
+    );
+
+    w = Container(
+      child: SafeArea(child: w),
+      color: theme.scaffoldBackgroundColor,
+      padding: const EdgeInsets.all(16.0),
+    );
+
+    return WillPopScope(child: w, onWillPop: _onWillPop);
+  }
+
+  Future<bool> _onWillPop() async {
+    getAnalytics().logEvent(
+      name: "purchase_screen_close",
+    );
+    return true;
+  }
+}
+
+class PurchaseLoadingScreen extends StatelessWidget {
+  const PurchaseLoadingScreen({Key key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    var theme = Theme.of(context);
+    var children = <Widget>[
+      Padding(
+        padding: const EdgeInsets.all(8.0),
+        child: Text(
+          "Loading",
+          textAlign: TextAlign.center,
+          style: Theme.of(context).textTheme.display1,
+        ),
+      ),
+      const SizedBox(height: 8.0),
+      const Padding(
+        padding: EdgeInsets.all(8.0),
+        child: CircularProgressIndicator(
+          value: null,
+        ),
+      ),
+    ];
+
+    var w = Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      crossAxisAlignment: CrossAxisAlignment.center,
+      children: children,
+    );
+
+    return WillPopScope(
+      onWillPop: _onWillPopLoading,
+      child: Container(
+        child: SafeArea(child: w),
+        color: theme.scaffoldBackgroundColor,
+        padding: const EdgeInsets.all(16.0),
+      ),
+    );
+  }
+
+  Future<bool> _onWillPopLoading() async {
+    getAnalytics().logEvent(
+      name: "purchase_screen_close_loading",
+    );
+    return true;
+  }
+}

lib/widgets/app_drawer.dart

@@ -2,6 +2,7 @@ import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_email_sender/flutter_email_sender.dart';
+import 'package:gitjournal/features.dart';
 import 'package:launch_review/launch_review.dart';
 import 'package:provider/provider.dart';
 import 'package:share/share.dart';
@@ -64,6 +65,21 @@ class AppDrawer extends StatelessWidget {
             ),
           ),
           if (setupGitButton != null) ...[setupGitButton, divider],
+          if (Features.purchaseProModeAvailable)
+            _buildDrawerTile(
+              context,
+              icon: Icons.power,
+              title: "Go Pro",
+              onTap: () {
+                Navigator.pop(context);
+                Navigator.pushNamed(context, "/purchase");
+
+                getAnalytics().logEvent(
+                  name: "purchase_screen_open",
+                );
+              },
+            ),
+          if (Features.purchaseProModeAvailable) divider,
           _buildDrawerTile(
             context,
             icon: Icons.note,

pubspec.lock

@@ -207,6 +207,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.2.1+1"
+  flutter_inapp_purchase:
+    dependency: "direct main"
+    description:
+      name: flutter_inapp_purchase
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.4"
   flutter_launcher_icons:
     dependency: "direct dev"
     description:

pubspec.yaml

@@ -41,6 +41,7 @@ dependencies:
   font_awesome_flutter: ^8.7.0
   sentry: ">=3.0.0 <4.0.0"
   equatable: ^1.1.0
+  flutter_inapp_purchase: ^2.1.4
 
 dev_dependencies:
   flutter_launcher_icons: "^0.7.2"