feat(iap): native Myket in-app billing plugin (AIDL) + wire purchase/consume

Implements real Myket IAB for the Capacitor app (Myket has no purchase
deep-link like Bazaar — it uses the classic Google Play IAB v3 AIDL bound to
the Myket app):

- AIDL: com.android.vending.billing.IInAppBillingService (Myket-compatible).
- MyketBillingPlugin (Capacitor): binds ir.mservices.market via
  "ir.mservices.market.InAppBillingService.BIND", runs getBuyIntent →
  startIntentSenderForResult, verifies INAPP_DATA_SIGNATURE with the RSA key
  (Security.java, SHA1withRSA), returns the purchaseToken; consume() too.
- MainActivity registers the plugin + forwards the purchase activity result.
- Manifest: ir.mservices.market.BILLING permission + <queries> for Android 11+
  package visibility.
- build.gradle: enable buildFeatures.aidl (AGP 8 disables it by default).
- storeBilling: Myket goes through the plugin (RSA key embedded); after server
  verify, BuyCoins consumes the purchase so coins can be re-bought.

Bazaar (deep-link) and web (ZarinPal) paths unchanged. Needs on-device testing
with the Myket app installed + published products.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

android/app/build.gradle

@@ -12,6 +12,10 @@ if (keystorePropsFile.exists()) {
 android {
     namespace = "com.bargevasat.app"
     compileSdk = rootProject.ext.compileSdkVersion
+    // AGP 8 disables AIDL by default; the Myket billing service needs it.
+    buildFeatures {
+        aidl true
+    }
     defaultConfig {
         applicationId "com.bargevasat.app"
         minSdkVersion rootProject.ext.minSdkVersion

android/app/src/main/AndroidManifest.xml

@@ -39,4 +39,14 @@
     <!-- Permissions -->
 
     <uses-permission android:name="android.permission.INTERNET" />
+    <!-- Myket in-app billing -->
+    <uses-permission android:name="ir.mservices.market.BILLING" />
+
+    <!-- Android 11+ package visibility: allow binding to the Myket billing service -->
+    <queries>
+        <package android:name="ir.mservices.market" />
+        <intent>
+            <action android:name="ir.mservices.market.InAppBillingService.BIND" />
+        </intent>
+    </queries>
 </manifest>

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

@@ -0,0 +1,17 @@
+// Google Play In-App Billing v3 interface. Myket implements the SAME interface
+// (bound to the Myket app via ir.mservices.market.InAppBillingService.BIND).
+package com.android.vending.billing;
+
+import android.os.Bundle;
+
+interface IInAppBillingService {
+    int isBillingSupported(int apiVersion, String packageName, String type);
+
+    Bundle getSkuDetails(int apiVersion, String packageName, String type, in Bundle skusBundle);
+
+    Bundle getBuyIntent(int apiVersion, String packageName, String sku, String type, String developerPayload);
+
+    Bundle getPurchases(int apiVersion, String packageName, String type, String continuationToken);
+
+    int consumePurchase(int apiVersion, String packageName, String purchaseToken);
+}

android/app/src/main/java/com/bargevasat/app/MainActivity.java

@@ -1,9 +1,11 @@
 package com.bargevasat.app;
 
+import android.content.Intent;
 import android.os.Bundle;
 import androidx.core.view.WindowCompat;
 import androidx.core.view.WindowInsetsCompat;
 import androidx.core.view.WindowInsetsControllerCompat;
+import com.bargevasat.app.billing.MyketBillingPlugin;
 import com.getcapacitor.BridgeActivity;
 
 /**
@@ -13,6 +15,8 @@ import com.getcapacitor.BridgeActivity;
 public class MainActivity extends BridgeActivity {
     @Override
     public void onCreate(Bundle savedInstanceState) {
+        // Register native plugins before the bridge starts.
+        registerPlugin(MyketBillingPlugin.class);
         super.onCreate(savedInstanceState);
         enableImmersive();
     }
@@ -25,6 +29,15 @@ public class MainActivity extends BridgeActivity {
         if (hasFocus) enableImmersive();
     }
 
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+        // Forward the Myket purchase intent result to the billing plugin.
+        if (requestCode == MyketBillingPlugin.RC_BUY) {
+            MyketBillingPlugin.onPurchaseActivityResult(resultCode, data);
+        }
+    }
+
     private void enableImmersive() {
         WindowCompat.setDecorFitsSystemWindows(getWindow(), false);
         WindowInsetsControllerCompat controller =

android/app/src/main/java/com/bargevasat/app/billing/MyketBillingPlugin.java

@@ -0,0 +1,181 @@
+package com.bargevasat.app.billing;
+
+import android.app.Activity;
+import android.app.PendingIntent;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Log;
+
+import com.android.vending.billing.IInAppBillingService;
+import com.getcapacitor.JSObject;
+import com.getcapacitor.Plugin;
+import com.getcapacitor.PluginCall;
+import com.getcapacitor.PluginMethod;
+import com.getcapacitor.annotation.CapacitorPlugin;
+
+import org.json.JSONObject;
+
+/**
+ * Myket in-app billing for the Capacitor WebView. Myket implements the classic
+ * Google Play IAB v3 AIDL (IInAppBillingService), bound to the Myket app via
+ * "ir.mservices.market.InAppBillingService.BIND". The purchase intent result is
+ * delivered to MainActivity.onActivityResult, which forwards to
+ * {@link #onPurchaseActivityResult}.
+ */
+@CapacitorPlugin(name = "MyketBilling")
+public class MyketBillingPlugin extends Plugin {
+    private static final String TAG = "MyketBilling";
+    private static final String MARKET_PACKAGE = "ir.mservices.market";
+    private static final String BIND_ACTION = "ir.mservices.market.InAppBillingService.BIND";
+    private static final int API_VERSION = 3;
+    public static final int RC_BUY = 11001;
+    private static final int RESULT_OK_CODE = 0; // BILLING_RESPONSE_RESULT_OK
+
+    private static MyketBillingPlugin instance;
+
+    private IInAppBillingService service;
+    private ServiceConnection conn;
+    private boolean bound = false;
+    private String rsaKey = "";
+    private PluginCall pendingPurchase;
+
+    @Override
+    public void load() {
+        instance = this;
+    }
+
+    /** Forwarded from MainActivity.onActivityResult for RC_BUY. */
+    public static void onPurchaseActivityResult(int resultCode, Intent data) {
+        if (instance != null) instance.handlePurchaseResult(resultCode, data);
+    }
+
+    // ----------------------------- JS methods -----------------------------
+
+    @PluginMethod
+    public void isAvailable(PluginCall call) {
+        JSObject ret = new JSObject();
+        ret.put("available", isPackageInstalled(MARKET_PACKAGE));
+        call.resolve(ret);
+    }
+
+    @PluginMethod
+    public void connect(PluginCall call) {
+        rsaKey = call.getString("rsaPublicKey", rsaKey);
+        if (!isPackageInstalled(MARKET_PACKAGE)) { call.reject("myket_not_installed"); return; }
+        bind(call::resolve, call);
+    }
+
+    @PluginMethod
+    public void purchase(final PluginCall call) {
+        final String sku = call.getString("sku");
+        final String key = call.getString("rsaPublicKey", rsaKey);
+        if (key != null) rsaKey = key;
+        if (sku == null) { call.reject("missing_sku"); return; }
+        if (!isPackageInstalled(MARKET_PACKAGE)) { call.reject("myket_not_installed"); return; }
+        bind(() -> {
+            try {
+                Bundle buy = service.getBuyIntent(API_VERSION, getContext().getPackageName(), sku, "inapp", "");
+                int rc = buy.getInt("RESPONSE_CODE");
+                if (rc != RESULT_OK_CODE) { call.reject("buy_intent_failed_" + rc); return; }
+                PendingIntent pi = buy.getParcelable("BUY_INTENT");
+                if (pi == null) { call.reject("no_buy_intent"); return; }
+                pendingPurchase = call;
+                getActivity().startIntentSenderForResult(pi.getIntentSender(), RC_BUY, new Intent(), 0, 0, 0);
+            } catch (Exception e) {
+                call.reject("purchase_error", e);
+            }
+        }, call);
+    }
+
+    @PluginMethod
+    public void consume(final PluginCall call) {
+        final String token = call.getString("token");
+        if (token == null) { call.reject("missing_token"); return; }
+        bind(() -> {
+            try {
+                int rc = service.consumePurchase(API_VERSION, getContext().getPackageName(), token);
+                if (rc == RESULT_OK_CODE) call.resolve();
+                else call.reject("consume_failed_" + rc);
+            } catch (RemoteException e) {
+                call.reject("consume_error", e);
+            }
+        }, call);
+    }
+
+    // ----------------------------- internals -----------------------------
+
+    private void handlePurchaseResult(int resultCode, Intent data) {
+        PluginCall call = pendingPurchase;
+        pendingPurchase = null;
+        if (call == null) return;
+        if (data == null || resultCode != Activity.RESULT_OK) { call.reject("purchase_cancelled"); return; }
+        int rc = data.getIntExtra("RESPONSE_CODE", 0);
+        if (rc != RESULT_OK_CODE) { call.reject("purchase_failed_" + rc); return; }
+        String purchaseData = data.getStringExtra("INAPP_PURCHASE_DATA");
+        String signature = data.getStringExtra("INAPP_DATA_SIGNATURE");
+        if (purchaseData == null) { call.reject("no_purchase_data"); return; }
+        if (rsaKey != null && !rsaKey.isEmpty()
+                && !Security.verifyPurchase(rsaKey, purchaseData, signature)) {
+            call.reject("invalid_signature");
+            return;
+        }
+        try {
+            JSONObject o = new JSONObject(purchaseData);
+            JSObject ret = new JSObject();
+            ret.put("purchaseToken", o.optString("purchaseToken"));
+            ret.put("productId", o.optString("productId"));
+            ret.put("orderId", o.optString("orderId"));
+            ret.put("purchaseData", purchaseData);
+            ret.put("signature", signature == null ? "" : signature);
+            call.resolve(ret);
+        } catch (Exception e) {
+            call.reject("parse_error", e);
+        }
+    }
+
+    private void bind(final Runnable onReady, final PluginCall failCall) {
+        if (bound && service != null) { if (onReady != null) onReady.run(); return; }
+        conn = new ServiceConnection() {
+            @Override public void onServiceConnected(ComponentName name, IBinder binder) {
+                service = IInAppBillingService.Stub.asInterface(binder);
+                bound = true;
+                if (onReady != null) onReady.run();
+            }
+            @Override public void onServiceDisconnected(ComponentName name) { service = null; bound = false; }
+        };
+        Intent intent = new Intent(BIND_ACTION);
+        intent.setPackage(MARKET_PACKAGE);
+        try {
+            boolean ok = getContext().bindService(intent, conn, Context.BIND_AUTO_CREATE);
+            if (!ok && failCall != null) failCall.reject("myket_unavailable");
+        } catch (Exception e) {
+            Log.e(TAG, "bindService failed", e);
+            if (failCall != null) failCall.reject("myket_unavailable", e);
+        }
+    }
+
+    private boolean isPackageInstalled(String pkg) {
+        try {
+            getContext().getPackageManager().getPackageInfo(pkg, 0);
+            return true;
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    @Override
+    protected void handleOnDestroy() {
+        if (bound && conn != null) {
+            try { getContext().unbindService(conn); } catch (Exception ignored) {}
+        }
+        bound = false;
+        service = null;
+        if (instance == this) instance = null;
+        super.handleOnDestroy();
+    }
+}

android/app/src/main/java/com/bargevasat/app/billing/Security.java

@@ -0,0 +1,71 @@
+package com.bargevasat.app.billing;
+
+import android.text.TextUtils;
+import android.util.Base64;
+import android.util.Log;
+
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.PublicKey;
+import java.security.SignatureException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.X509EncodedKeySpec;
+
+/**
+ * Verifies that a Myket purchase payload was signed by the store, using the
+ * app's RSA public key (from the Myket developer panel). Mirrors Google Play
+ * IAB v3 "Security" — Myket uses the same SHA1withRSA signing.
+ */
+public final class Security {
+    private static final String TAG = "MyketSecurity";
+    private static final String KEY_FACTORY_ALGORITHM = "RSA";
+    private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
+
+    private Security() {}
+
+    /** @return true if signedData was signed by the private key matching base64PublicKey. */
+    public static boolean verifyPurchase(String base64PublicKey, String signedData, String signature) {
+        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey) || TextUtils.isEmpty(signature)) {
+            Log.w(TAG, "Purchase verification failed: missing data.");
+            return false;
+        }
+        try {
+            PublicKey key = generatePublicKey(base64PublicKey);
+            return verify(key, signedData, signature);
+        } catch (Exception e) {
+            Log.e(TAG, "Verification error", e);
+            return false;
+        }
+    }
+
+    private static PublicKey generatePublicKey(String encodedPublicKey)
+            throws NoSuchAlgorithmException, InvalidKeySpecException {
+        byte[] decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT);
+        KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
+        return keyFactory.generatePublic(new X509EncodedKeySpec(decodedKey));
+    }
+
+    private static boolean verify(PublicKey publicKey, String signedData, String signature) {
+        byte[] signatureBytes;
+        try {
+            signatureBytes = Base64.decode(signature, Base64.DEFAULT);
+        } catch (IllegalArgumentException e) {
+            Log.e(TAG, "Base64 decoding failed.");
+            return false;
+        }
+        try {
+            java.security.Signature sig = java.security.Signature.getInstance(SIGNATURE_ALGORITHM);
+            sig.initVerify(publicKey);
+            sig.update(signedData.getBytes());
+            if (!sig.verify(signatureBytes)) {
+                Log.e(TAG, "Signature verification failed.");
+                return false;
+            }
+            return true;
+        } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
+            Log.e(TAG, "Signature exception", e);
+        }
+        return false;
+    }
+}

src/components/screens/BuyCoinsScreen.tsx

@@ -6,7 +6,7 @@ import { ScreenHeader, ScreenShell } from "@/components/online/ScreenHeader";
 import { useSessionStore } from "@/lib/session-store";
 import { useI18n } from "@/lib/i18n";
 import { getService } from "@/lib/online/service";
-import { isStoreBilling, purchaseViaStore } from "@/lib/storeBilling";
+import { consumeStorePurchase, isStoreBilling, purchaseViaStore } from "@/lib/storeBilling";
 import { sound } from "@/lib/sound";
 import { CoinPack } from "@/lib/online/types";
 import { cn } from "@/lib/cn";
@@ -47,6 +47,8 @@ export function BuyCoinsScreen() {
         if (r.kind === "token") {
           const v = await getService().verifyIab(r.store, r.productId, r.token);
           if (v.ok && v.profile) {
+            // Consumable: let the store mark it consumed so it can be re-bought.
+            await consumeStorePurchase(r.store, r.token);
             setProfile(v.profile);
             sound.play("purchase");
             setGained(v.coins);

src/lib/storeBilling.ts

@@ -4,13 +4,14 @@
 //   `bazaar://in_app?...&sku=...&redirect_url=...`; Bazaar processes payment and
 //   reopens the app at redirect_url with `?purchaseToken=...`. We stash the SKU
 //   first, then on return POST the token to `/api/coins/iab/verify`.
-// - **Myket**: native AIDL billing. A Capacitor plugin must inject
-//   `window.MyketBilling` (see ANDROID.md). We call `.purchase(sku)` and POST the
-//   returned token to verify. Without the bridge, Myket is "unavailable".
+// - **Myket**: native AIDL billing via the `MyketBilling` Capacitor plugin
+//   (android/.../billing/MyketBillingPlugin.java). We call `.purchase({sku})`,
+//   POST the returned token to verify, then `.consume({token})` so the
+//   consumable can be bought again.
 //
-// The active store is the build flavor `NEXT_PUBLIC_STORE` (bazaar|myket|web),
-// overridden at runtime if the Myket native bridge is present.
+// The active store is the build flavor `NEXT_PUBLIC_STORE` (bazaar|myket|web).
 
+import { registerPlugin } from "@capacitor/core";
 import { CoinPack } from "./online/types";
 
 export type StoreId = "bazaar" | "myket" | "web";
@@ -19,24 +20,30 @@ const ENV_STORE = ((process.env.NEXT_PUBLIC_STORE as StoreId | undefined) ?? "we
 const PACKAGE = process.env.NEXT_PUBLIC_APP_PACKAGE ?? "com.bargevasat.app";
 const PENDING_SKU_KEY = "iab_pending_sku";
 
-/** Native bridge contract a Myket Capacitor plugin must fulfil. */
-interface MyketBridge {
-  available?: boolean;
-  purchase: (sku: string) => Promise<{ purchaseToken: string; productId?: string }>;
-  consume?: (token: string) => Promise<void>;
+// Myket in-app billing RSA public key (Myket developer panel). Public, not secret.
+const MYKET_RSA_PUBLIC_KEY =
+  "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCbUBKRU4g1AQrbOO8GkcBn79ol0hbs5PZVd5vPP6za98BTc9leqvyGE+DwSg7lbsXTZxCzPRBS3m0qB9LShe70WG+RQapG9Q2lodszYkauicPkJSpbXWh/nfrziTWNqEHqUfCsC4+lkKSEkxDNa1Po7uZzbwaJ+Kf1+d8wSWYpxwIDAQAB";
+
+interface MyketBillingPlugin {
+  isAvailable(): Promise<{ available: boolean }>;
+  connect(opts: { rsaPublicKey: string }): Promise<void>;
+  purchase(opts: { sku: string; rsaPublicKey: string }): Promise<{
+    purchaseToken: string;
+    productId?: string;
+  }>;
+  consume(opts: { token: string }): Promise<void>;
 }
+const MyketBilling = registerPlugin<MyketBillingPlugin>("MyketBilling");
+
 declare global {
   interface Window {
-    MyketBilling?: MyketBridge;
     Capacitor?: { isNativePlatform?: () => boolean; getPlatform?: () => string };
   }
 }
 
 export function getStore(): StoreId {
   if (typeof window === "undefined") return ENV_STORE;
-  // Myket's native bridge wins when present (a Myket-flavored build).
-  if (window.MyketBilling?.available) return "myket";
-  // Honor an explicit build flavor.
+  // Honor an explicit build flavor (bazaar | myket).
   if (ENV_STORE !== "web") return ENV_STORE;
   // Otherwise, inside the Android app shell (Capacitor) default to Cafe Bazaar
   // IAB — the APK ships to Bazaar, which requires its own billing. The web build
@@ -77,14 +84,32 @@ export async function purchaseViaStore(pack: CoinPack): Promise<PurchaseStart> {
     return { kind: "redirect" };
   }
 
-  if (store === "myket" && window.MyketBilling) {
-    const res = await window.MyketBilling.purchase(sku);
+  if (store === "myket") {
+    try {
+      const res = await MyketBilling.purchase({ sku, rsaPublicKey: MYKET_RSA_PUBLIC_KEY });
       return { kind: "token", store: "myket", productId: res.productId ?? sku, token: res.purchaseToken };
+    } catch {
+      return { kind: "unavailable" };
+    }
   }
 
   return { kind: "unavailable" };
 }
 
+/**
+ * Finalize a verified store purchase. Coin packs are consumable, so on Myket we
+ * must consume the purchase (after the server credited it) to allow re-buying.
+ * Bazaar consumables are handled server-side; this is a no-op there.
+ */
+export async function consumeStorePurchase(store: StoreId, token: string): Promise<void> {
+  if (store !== "myket" || !token) return;
+  try {
+    await MyketBilling.consume({ token });
+  } catch {
+    /* best-effort; the server already credited */
+  }
+}
+
 /**
  * On app load, capture a Bazaar redirect (`?purchaseToken=...`). Returns the
  * pending purchase to verify, or null. Also clears the stashed SKU.