IAP: add billing init method (#3332)

Co-authored-by: Marvin W <git@larma.de>

Author: DaVinci9196

vending-app/src/main/aidl/com/android/vending/billing/IInAppBillingInitializeCallback.aidl

@@ -0,0 +1,11 @@
+/*
+ * SPDX-FileCopyrightText: 2026 microG Project Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.android.vending.billing;
+
+import android.os.Bundle;
+
+interface IInAppBillingInitializeCallback {
+    void callback(in Bundle bundle);
+}

vending-app/src/main/aidl/com/android/vending/billing/IInAppBillingService.aidl

@@ -10,6 +10,7 @@ import com.android.vending.billing.IInAppBillingGetBillingConfigCallback;
 import com.android.vending.billing.IInAppBillingGetExternalPaymentDialogIntentCallback;
 import com.android.vending.billing.IInAppBillingIsAlternativeBillingOnlyAvailableCallback;
 import com.android.vending.billing.IInAppBillingIsExternalPaymentAvailableCallback;
+import com.android.vending.billing.IInAppBillingInitializeCallback;
 
 
 /**
@@ -441,4 +442,14 @@ interface IInAppBillingService {
     void showExternalOfferInformationDialog(int apiVersion, String packageName, in Bundle extraParams, IInAppBillingGetExternalPaymentDialogIntentCallback callback) = 1900;
 
     void delegateToBackend(in Bundle bundle, IInAppBillingDelegateToBackendCallback callback) = 2000;
-}
+
+    /**
+     * @param apiVersion billing API version that the app is using, must be 22 or later
+     * @param packageName package name of the calling app
+     * @param extraParams a Bundle with the following optional keys:
+     *        "callingPackage" - String
+     *        "enablePendingPurchases" - Boolean
+     * @param callback callback that is invoked with the result, see IInAppBillingInitializeCallback.aidl for details
+     */
+    void initialize(int apiVersion, String packageName, in Bundle extraParams, IInAppBillingInitializeCallback callback) = 2100;
+}

vending-app/src/main/java/org/microg/vending/billing/InAppBillingServiceImpl.kt

@@ -10,6 +10,7 @@ import android.app.PendingIntent.FLAG_CANCEL_CURRENT
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import android.os.Parcel
 import android.util.Log
 import androidx.annotation.RequiresApi
 import androidx.core.app.PendingIntentCompat
@@ -23,6 +24,7 @@ import com.android.vending.billing.IInAppBillingDelegateToBackendCallback
 import com.android.vending.billing.IInAppBillingGetAlternativeBillingOnlyDialogIntentCallback
 import com.android.vending.billing.IInAppBillingGetBillingConfigCallback
 import com.android.vending.billing.IInAppBillingGetExternalPaymentDialogIntentCallback
+import com.android.vending.billing.IInAppBillingInitializeCallback
 import com.android.vending.billing.IInAppBillingIsAlternativeBillingOnlyAvailableCallback
 import com.android.vending.billing.IInAppBillingIsExternalPaymentAvailableCallback
 import com.android.vending.billing.IInAppBillingService
@@ -36,6 +38,7 @@ import kotlinx.coroutines.async
 import kotlinx.coroutines.runBlocking
 import org.json.JSONObject
 import org.microg.gms.utils.toHexString
+import org.microg.gms.utils.warnOnTransactionIssues
 import org.microg.vending.billing.core.*
 import java.util.Locale
 
@@ -707,4 +710,20 @@ class InAppBillingServiceImpl(private val context: Context) : IInAppBillingServi
     override fun delegateToBackend(bundle: Bundle?, callback: IInAppBillingDelegateToBackendCallback?) {
         Log.d(TAG, "delegateToBackend Not yet implemented")
     }
-}
+
+    override fun initialize(
+        apiVersion: Int,
+        packageName: String?,
+        extraParams: Bundle?,
+        callback: IInAppBillingInitializeCallback?
+    ) {
+        extraParams?.keySet()
+        Log.w(TAG, "initialize: apiVersion: $apiVersion packageName:$packageName params:$extraParams")
+        callback?.callback(resultBundle(BillingResponseCode.OK, "", bundleOf(
+            "BILLING_API_VERSION_KEY" to apiVersion
+        )))
+    }
+
+    override fun onTransact(code: Int, data: Parcel, reply: Parcel?, flags: Int): Boolean =
+        warnOnTransactionIssues(code, reply, flags, TAG) { super.onTransact(code, data, reply, flags) }
+}