Primer paso de la investigacion. Se aportan el .apk, las carpetas con el apk extraido y el apk descompilado. El archivo API_DOCUMENTATION.md es un archivo donde se anotaran los descubrimientos del funcionamiento de la API, y los .py son scripts para probar la funcionalidad de la API con los métodos que vayamos encontrando. Finalmente, los archivos .js son scripts de Frida para extraer informacion de la APP durante la ejecucion.

apk_decompiled/sources/com/google/firebase/messaging/SharedPreferencesQueue.java

@@ -0,0 +1,174 @@
+package com.google.firebase.messaging;
+
+import android.content.SharedPreferences;
+import android.text.TextUtils;
+import android.util.Log;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.Executor;
+
+/* loaded from: classes3.dex */
+final class SharedPreferencesQueue {
+    private final String itemSeparator;
+    private final String queueName;
+    private final SharedPreferences sharedPreferences;
+    private final Executor syncExecutor;
+    final ArrayDeque<String> internalQueue = new ArrayDeque<>();
+    private boolean bulkOperation = false;
+
+    private SharedPreferencesQueue(SharedPreferences sharedPreferences, String str, String str2, Executor executor) {
+        this.sharedPreferences = sharedPreferences;
+        this.queueName = str;
+        this.itemSeparator = str2;
+        this.syncExecutor = executor;
+    }
+
+    private String checkAndSyncState(String str) {
+        checkAndSyncState(str != null);
+        return str;
+    }
+
+    public static SharedPreferencesQueue createInstance(SharedPreferences sharedPreferences, String str, String str2, Executor executor) {
+        SharedPreferencesQueue sharedPreferencesQueue = new SharedPreferencesQueue(sharedPreferences, str, str2, executor);
+        sharedPreferencesQueue.initQueue();
+        return sharedPreferencesQueue;
+    }
+
+    private void initQueue() {
+        synchronized (this.internalQueue) {
+            try {
+                this.internalQueue.clear();
+                String string = this.sharedPreferences.getString(this.queueName, "");
+                if (!TextUtils.isEmpty(string) && string.contains(this.itemSeparator)) {
+                    String[] split = string.split(this.itemSeparator, -1);
+                    if (split.length == 0) {
+                        Log.e(Constants.TAG, "Corrupted queue. Please check the queue contents and item separator provided");
+                    }
+                    for (String str : split) {
+                        if (!TextUtils.isEmpty(str)) {
+                            this.internalQueue.add(str);
+                        }
+                    }
+                }
+            } finally {
+            }
+        }
+    }
+
+    /* JADX INFO: Access modifiers changed from: private */
+    public void syncState() {
+        synchronized (this.internalQueue) {
+            this.sharedPreferences.edit().putString(this.queueName, serialize()).commit();
+        }
+    }
+
+    private void syncStateAsync() {
+        this.syncExecutor.execute(new n(this, 0));
+    }
+
+    public boolean add(String str) {
+        boolean checkAndSyncState;
+        if (TextUtils.isEmpty(str) || str.contains(this.itemSeparator)) {
+            return false;
+        }
+        synchronized (this.internalQueue) {
+            checkAndSyncState = checkAndSyncState(this.internalQueue.add(str));
+        }
+        return checkAndSyncState;
+    }
+
+    public void beginTransaction() {
+        this.bulkOperation = true;
+    }
+
+    public void beginTransactionSync() {
+        synchronized (this.internalQueue) {
+            beginTransaction();
+        }
+    }
+
+    public void clear() {
+        synchronized (this.internalQueue) {
+            this.internalQueue.clear();
+            checkAndSyncState(true);
+        }
+    }
+
+    public void commitTransaction() {
+        this.bulkOperation = false;
+        syncStateAsync();
+    }
+
+    public void commitTransactionSync() {
+        synchronized (this.internalQueue) {
+            commitTransaction();
+        }
+    }
+
+    public String peek() {
+        String peek;
+        synchronized (this.internalQueue) {
+            peek = this.internalQueue.peek();
+        }
+        return peek;
+    }
+
+    public boolean remove(Object obj) {
+        boolean checkAndSyncState;
+        synchronized (this.internalQueue) {
+            checkAndSyncState = checkAndSyncState(this.internalQueue.remove(obj));
+        }
+        return checkAndSyncState;
+    }
+
+    public String serialize() {
+        StringBuilder sb = new StringBuilder();
+        Iterator<String> it = this.internalQueue.iterator();
+        while (it.hasNext()) {
+            sb.append(it.next());
+            sb.append(this.itemSeparator);
+        }
+        return sb.toString();
+    }
+
+    public String serializeSync() {
+        String serialize;
+        synchronized (this.internalQueue) {
+            serialize = serialize();
+        }
+        return serialize;
+    }
+
+    public int size() {
+        int size;
+        synchronized (this.internalQueue) {
+            size = this.internalQueue.size();
+        }
+        return size;
+    }
+
+    public List<String> toList() {
+        ArrayList arrayList;
+        synchronized (this.internalQueue) {
+            arrayList = new ArrayList(this.internalQueue);
+        }
+        return arrayList;
+    }
+
+    private boolean checkAndSyncState(boolean z3) {
+        if (z3 && !this.bulkOperation) {
+            syncStateAsync();
+        }
+        return z3;
+    }
+
+    public String remove() {
+        String checkAndSyncState;
+        synchronized (this.internalQueue) {
+            checkAndSyncState = checkAndSyncState(this.internalQueue.remove());
+        }
+        return checkAndSyncState;
+    }
+}