Add billing module, provide a separate build for Google Play

client/android/billing/build.gradle.kts

@@ -0,0 +1,18 @@
+plugins {
+    id(libs.plugins.android.library.get().pluginId)
+    id(libs.plugins.kotlin.android.get().pluginId)
+}
+
+kotlin {
+    jvmToolchain(17)
+}
+
+android {
+    namespace = "org.amnezia.vpn.billing"
+}
+
+dependencies {
+    implementation(libs.androidx.core)
+    implementation(libs.kotlinx.coroutines)
+    implementation(libs.android.billing)
+}

client/android/build.gradle.kts

@@ -43,14 +43,12 @@ android {
         ndk.abiFilters += qtTargetAbiList.split(",")
     }
 
-    sourceSets {
-        getByName("main") {
-            manifest.srcFile("AndroidManifest.xml")
-            java.setSrcDirs(listOf("src"))
-            res.setSrcDirs(listOf("res"))
-            // androyddeployqt creates the folders below
-            assets.setSrcDirs(listOf("assets"))
-            jniLibs.setSrcDirs(listOf("libs"))
+    signingConfigs {
+        register("release") {
+            storeFile = providers.environmentVariable("ANDROID_KEYSTORE_PATH").orNull?.let { file(it) }
+            storePassword = providers.environmentVariable("ANDROID_KEYSTORE_KEY_PASS").orNull
+            keyAlias = providers.environmentVariable("ANDROID_KEYSTORE_KEY_ALIAS").orNull
+            keyPassword = providers.environmentVariable("ANDROID_KEYSTORE_KEY_PASS").orNull
         }
     }
 
@@ -60,6 +58,65 @@ android {
             packaging {
                 resources.excludes += "DebugProbesKt.bin"
             }
+            signingConfig = signingConfigs["release"]
+        }
+
+        create("fdroid") {
+            initWith(getByName("release"))
+            signingConfig = null
+            matchingFallbacks += "release"
+        }
+    }
+
+    flavorDimensions += "billing"
+
+    productFlavors {
+        create("oss") {
+            dimension = "billing"
+        }
+        create("play") {
+            dimension = "billing"
+        }
+    }
+
+    sourceSets {
+        getByName("main") {
+            manifest.srcFile("AndroidManifest.xml")
+            java.setSrcDirs(listOf("src"))
+            res.setSrcDirs(listOf("res"))
+            // androyddeployqt creates the folders below
+            assets.setSrcDirs(listOf("assets"))
+            jniLibs.setSrcDirs(listOf("libs"))
+        }
+
+        getByName("oss") {
+            java.setSrcDirs(listOf("oss"))
+        }
+
+        getByName("play") {
+            java.setSrcDirs(listOf("play"))
+        }
+    }
+
+    splits {
+        abi {
+            isEnable = true
+            reset()
+            include(*qtTargetAbiList.split(',').toTypedArray())
+            isUniversalApk = false
+        }
+    }
+
+    // fix for Qt Creator to allow deploying the application to a device
+    // to enable this fix, add the line outputBaseName=android-build to local.properties
+    if (outputBaseName.isNotEmpty()) {
+        applicationVariants.all {
+            outputs.map { it as BaseVariantOutputImpl }
+                .forEach { output ->
+                    if (output.outputFileName.endsWith(".apk")) {
+                        output.outputFileName = "$outputBaseName-${buildType.name}.apk"
+                    }
+                }
         }
     }
 
@@ -85,5 +142,9 @@ dependencies {
     implementation(libs.google.mlkit)
     implementation(libs.androidx.datastore)
     implementation(libs.androidx.biometric)
-    implementation(libs.android.billing)
+
+    playImplementation(project(":billing"))
 }
+
+fun DependencyHandler.playImplementation(dependency: Any): Dependency? =
+    add("playImplementation", dependency)

client/android/oss/org/amnezia/vpn/BillingProvider.kt

@@ -0,0 +1,7 @@
+package org.amnezia.vpn
+
+class BillingProvider {
+    fun type(): String {
+        return "OSS"
+    }
+}

client/android/play/org/amnezia/vpn/BillingProvider.kt

@@ -0,0 +1,7 @@
+package org.amnezia.vpn
+
+class BillingProvider {
+    fun type(): String {
+        return "PLAY"
+    }
+}

client/android/settings.gradle.kts

@@ -30,6 +30,7 @@ rootProject.buildFileName = "build.gradle.kts"
 
 include(":qt")
 include(":utils")
+include(":billing")
 include(":protocolApi")
 include(":wireguard")
 include(":awg")

client/android/src/org/amnezia/vpn/AmneziaActivity.kt

@@ -182,6 +182,7 @@ class AmneziaActivity : QtActivity() {
      * Activity overloaded methods
      */
     override fun onCreate(savedInstanceState: Bundle?) {
+        Log.d(TAG, "Billing provider: ${BillingProvider().type()}")
         super.onCreate(savedInstanceState)
         Log.d(TAG, "Create Amnezia activity")
         loadLibs()