Merge pull request #173 from MAGICGrants/review-prompt

### .github/workflows/release.yml
@@ -150,7 +150,7 @@ jobs:
             -w /tmp/skylight \
             -e SOURCE_DATE_EPOCH \
             ghcr.io/magicgrants/skylight-wallet-builder:latest \
-            bash -c "cp -a /opt/cargo /tmp/skylight-cargo && export CARGO_HOME=/tmp/skylight-cargo && export PUB_CACHE=/tmp/skylight/.pub-cache && flutter pub get --enforce-lockfile && bash scripts/pin-rust-toolchain.sh && flutter build apk --dart-define=DEMO_MODE=true --release --split-per-abi && flutter build appbundle --dart-define=DEMO_MODE=true --release"
+            bash -c "cp -a /opt/cargo /tmp/skylight-cargo && export CARGO_HOME=/tmp/skylight-cargo && export PUB_CACHE=/tmp/skylight/.pub-cache && flutter pub get --enforce-lockfile && bash scripts/pin-rust-toolchain.sh && flutter build apk --dart-define=DEMO_MODE=true --release --split-per-abi && flutter build appbundle --dart-define=DEMO_MODE=true --release -PplayStore=true"
 
           mkdir -p dist
           cp -v build/app/outputs/flutter-apk/app-arm64-v8a-release.apk "dist/skylight-wallet-${VERSION}-arm64-v8a.apk"

### android/app/build.gradle.kts
@@ -9,6 +9,19 @@ plugins {
     id("dev.flutter.flutter-gradle-plugin")
 }
 
+// The Google Play build, and only it, links Play's in-app review library. The
+// F-Droid recipe and the GitHub APKs run `flutter build apk` without this
+// property, so they carry no Play code at all: F-Droid's reproducible build has
+// to match the published APK byte for byte, so a runtime check alone could not
+// keep the library out. The release workflow passes -PplayStore=true to
+// `flutter build appbundle` alone.
+//
+// Everything Play-specific sits in play-store.gradle and src/play/, which
+// the F-Droid recipe deletes before building (rm:), so its scanner never meets
+// a Play library -- and the APK it rebuilds is unchanged, since neither is used
+// without the property.
+val playStoreBuild = (findProperty("playStore") as String?) == "true"
+
 val keystoreProperties = Properties()
 val keystorePropertiesFile = rootProject.file("key.properties")
 if (keystorePropertiesFile.exists()) {
@@ -35,6 +48,13 @@ android {
         jvmTarget = JavaVersion.VERSION_17.toString()
     }
 
+    // One StoreReview or the other: Play's review flow, or a no-op.
+    sourceSets {
+        getByName("main") {
+            java.srcDir(if (playStoreBuild) "src/play/kotlin" else "src/foss/kotlin")
+        }
+    }
+
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "org.magicgrants.skylight"
@@ -90,6 +110,10 @@ dependencies {
     coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4")
 }
 
+if (playStoreBuild) {
+    apply(from = "play-store.gradle")
+}
+
 flutter {
     source = "../.."
 }

### android/app/play-store.gradle
@@ -0,0 +1,8 @@
+// Google Play build only: applied from build.gradle.kts under -PplayStore=true,
+// alongside the StoreReview in src/play/. The F-Droid recipe removes both.
+//
+// Groovy rather than Kotlin script: Android Lint fails on a second .gradle.kts
+// in the module ("Cannot find a KaModule for the VirtualFile"), applied or not.
+dependencies {
+    implementation 'com.google.android.play:review:2.0.2'
+}

### android/app/src/foss/kotlin/org/magicgrants/skylight/StoreReview.kt
@@ -0,0 +1,14 @@
+package org.magicgrants.skylight
+
+import android.app.Activity
+import android.content.Context
+
+// F-Droid and GitHub build: no Google Play library is compiled in, so there is
+// no store to ask and no code that could reach Play. See build.gradle.kts.
+object StoreReview {
+    @Suppress("UNUSED_PARAMETER")
+    fun isAvailable(context: Context): Boolean = false
+
+    @Suppress("UNUSED_PARAMETER")
+    fun request(activity: Activity, reply: (Boolean) -> Unit) = reply(false)
+}

### android/app/src/main/kotlin/com/example/monero_light_wallet/MainActivity.kt
@@ -13,6 +13,11 @@ class MainActivity : FlutterFragmentActivity() {
     // App-neutral name shared with wallet-core's SecureClipboard (D10).
     private val secureClipboardChannel = "org.magicgrants.wallet/secure_clipboard"
 
+    // App-neutral name shared with wallet-core's StoreReview. Which StoreReview
+    // this resolves to -- Play's review flow or a no-op -- is chosen at build
+    // time; see build.gradle.kts.
+    private val storeReviewChannel = "org.magicgrants.wallet/store_review"
+
     override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
         super.configureFlutterEngine(flutterEngine)
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, secureClipboardChannel)
@@ -31,6 +36,14 @@ class MainActivity : FlutterFragmentActivity() {
                     else -> result.notImplemented()
                 }
             }
+        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, storeReviewChannel)
+            .setMethodCallHandler { call, result ->
+                when (call.method) {
+                    "isAvailable" -> result.success(StoreReview.isAvailable(this))
+                    "requestReview" -> StoreReview.request(this) { result.success(it) }
+                    else -> result.notImplemented()
+                }
+            }
     }
 
     // Copies [text] flagged as sensitive so keyboards/clipboard UIs don't show a

### android/app/src/play/kotlin/org/magicgrants/skylight/StoreReview.kt
@@ -0,0 +1,46 @@
+package org.magicgrants.skylight
+
+import android.app.Activity
+import android.content.Context
+import android.os.Build
+import com.google.android.play.core.review.ReviewManagerFactory
+
+// Google Play build: the in-app review flow, for installs Google Play made.
+// Compiled in only when the build passes -PplayStore=true; see build.gradle.kts.
+object StoreReview {
+    private const val PLAY_STORE = "com.android.vending"
+
+    // Whether Google Play installed this app. A local package-manager lookup:
+    // nothing here talks to Play, and everything that would is gated on it. The
+    // same bundle is attached to GitHub releases, so a copy installed by hand
+    // lands here too -- and must not reach Play.
+    fun isAvailable(context: Context): Boolean = installerOf(context) == PLAY_STORE
+
+    // Replies true once Play has been asked, whatever it then showed: Play
+    // reports neither whether the card appeared nor whether the user rated.
+    fun request(activity: Activity, reply: (Boolean) -> Unit) {
+        if (!isAvailable(activity)) {
+            reply(false)
+            return
+        }
+        val manager = ReviewManagerFactory.create(activity)
+        manager.requestReviewFlow().addOnCompleteListener { request ->
+            if (!request.isSuccessful) {
+                reply(true)
+                return@addOnCompleteListener
+            }
+            manager.launchReviewFlow(activity, request.result).addOnCompleteListener { reply(true) }
+        }
+    }
+
+    @Suppress("DEPRECATION")
+    private fun installerOf(context: Context): String? = try {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            context.packageManager.getInstallSourceInfo(context.packageName).installingPackageName
+        } else {
+            context.packageManager.getInstallerPackageName(context.packageName)
+        }
+    } catch (_: Exception) {
+        null
+    }
+}

### ios/Runner/AppDelegate.swift
@@ -1,10 +1,12 @@
 import Flutter
+import StoreKit
 import UIKit
 import workmanager_apple
 
 @main
 @objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate {
   private var secureClipboardChannel: FlutterMethodChannel?
+  private var storeReviewChannel: FlutterMethodChannel?
 
   override func application(
     _ application: UIApplication,
@@ -68,5 +70,41 @@ import workmanager_apple
       }
       secureClipboardChannel = channel
     }
+
+    let reviewRegistrar = engineBridge.pluginRegistry.registrar(forPlugin: "StoreReview")
+    if let messenger = reviewRegistrar?.messenger() {
+      // App-neutral name shared with wallet-core's StoreReview. iOS builds only
+      // ship through App Store Connect, and in TestFlight the request is a
+      // no-op by Apple's design, so there is no install source to check.
+      let channel = FlutterMethodChannel(
+        name: "org.magicgrants.wallet/store_review",
+        binaryMessenger: messenger
+      )
+      channel.setMethodCallHandler { call, reply in
+        switch call.method {
+        case "isAvailable":
+          reply(true)
+        case "requestReview":
+          reply(Self.requestReview())
+        default:
+          reply(FlutterMethodNotImplemented)
+        }
+      }
+      storeReviewChannel = channel
+    }
+  }
+
+  /// Hands the request to StoreKit's own prompt, which decides whether to show
+  /// it (at most three times a year) and never says whether it did.
+  private static func requestReview() -> Bool {
+    let scene = UIApplication.shared.connectedScenes
+      .first { $0.activationState == .foregroundActive } as? UIWindowScene
+    guard let scene else { return false }
+    if #available(iOS 16.0, *) {
+      AppStore.requestReview(in: scene)
+    } else {
+      SKStoreReviewController.requestReview(in: scene)
+    }
+    return true
   }
 }

### lib/screens/send.dart
@@ -1,8 +1,11 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:provider/provider.dart';
 import 'package:wallet_domain/wallet_domain.dart' show baseUnitsToDecimalString, decimalToBaseUnits;
+import 'package:wallet_infra/wallet_infra.dart' show StoreReview;
 
 import 'package:skylight_wallet/consts.dart' as consts;
 import 'package:skylight_wallet/l10n/app_localizations.dart';
@@ -537,6 +540,10 @@ class _SendScreenState extends State<SendScreen> {
       onConfirm: () => _commitTx(tx, destinationAddress),
     );
 
+    if (committed == true) {
+      // The send went through: ask for a store review on a later launch.
+      unawaited(StoreReview.markEligible());
+    }
     if (committed == true && mounted) {
       Navigator.pushNamed(context, '/wallet_home', arguments: {'showTxSuccessToast': true});
     }

### lib/screens/wallet_home.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:intl/intl.dart';
@@ -15,6 +17,7 @@ import 'package:skylight_wallet/wallet_core_glue.dart';
 import 'package:skylight_wallet/widgets/ui/ui.dart';
 import 'package:skylight_wallet/widgets/wallet_navigation_bar.dart';
 import 'package:wallet_domain/wallet_domain.dart' show TxDetails;
+import 'package:wallet_infra/wallet_infra.dart' show StoreReview;
 
 /// The balance hero's big number style, mirroring Spice's `coin_home.dart`.
 TextStyle get _balanceStyle => TextStyle(
@@ -95,9 +98,20 @@ class _WalletHomeScreenState extends State<WalletHomeScreen> {
       if (args != null && args['showTxSuccessToast'] == true) {
         _showTxSuccessToast();
       }
+
+      // Opening the app after a send is when a store review is asked for;
+      // StoreReview decides whether one is due, once per launch.
+      unawaited(StoreReview.requestIfDue(stillAppropriate: _stillOnHome));
     });
   }
 
+  // Still the screen in front, with the app in the foreground: the review
+  // dialog must not land on a send or receive the user has already opened.
+  bool _stillOnHome() =>
+      mounted &&
+      (ModalRoute.of(context)?.isCurrent ?? false) &&
+      WidgetsBinding.instance.lifecycleState == AppLifecycleState.resumed;
+
   void _showTxDetails(TxDetails txDetails) {
     showTxDetailsDialog(context, txDetails);
   }