feat: Export settings migration activity (#1308)

android/app/src/main/AndroidManifest.xml

@@ -42,6 +42,10 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+       <activity
+           android:name=".ExportSettingsActivity"
+           android:exported="true">
+       </activity>
         <meta-data
             android:name="flutterEmbedding"
             android:value="2" />

android/app/src/main/kotlin/app/revanced/manager/flutter/ExportSettingsActivity.kt

@@ -0,0 +1,87 @@
+package app.revanced.manager.flutter
+
+import android.app.Activity
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageInfo
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.util.Base64
+import org.json.JSONObject
+import java.io.ByteArrayInputStream
+import java.io.File
+import java.security.cert.CertificateFactory
+import java.security.cert.X509Certificate
+import java.security.MessageDigest
+
+class ExportSettingsActivity : Activity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val callingPackageName = getCallingPackage()!!
+
+        if (getFingerprint(callingPackageName) == getFingerprint(getPackageName())) {
+            // Create JSON Object
+            val json = JSONObject()
+
+            // Default Data
+            json.put("keystorePassword", "s3cur3p@ssw0rd")
+
+            // Load Shared Preferences
+            val sharedPreferences = getSharedPreferences("FlutterSharedPreferences", Context.MODE_PRIVATE)
+            val allEntries: Map<String, *> = sharedPreferences.getAll()
+            for ((key, value) in allEntries.entries) {
+                json.put(
+                    key.replace("flutter.", ""),
+                    if (value is Boolean) if (value) 1 else 0 else value
+                )
+            }
+
+            // Load keystore
+            val keystoreFile = File(getExternalFilesDir(null), "/revanced-manager.keystore")
+            if (keystoreFile.exists()) {
+                val keystoreBytes = keystoreFile.readBytes()
+                val keystoreBase64 =
+                    Base64.encodeToString(keystoreBytes, Base64.DEFAULT).replace("\n", "")
+                json.put("keystore", keystoreBase64)
+            }
+
+            // Load saved patches
+            val storedPatchesFile = File(filesDir.parentFile.absolutePath, "/app_flutter/selected-patches.json")
+            if (storedPatchesFile.exists()) {
+                val patchesBytes = storedPatchesFile.readBytes()
+                val patches = String(patchesBytes, Charsets.UTF_8)
+                json.put("patches", patches)
+            }
+
+            // Send data back
+            val resultIntent = Intent()
+            resultIntent.putExtra("data", json.toString())
+            setResult(Activity.RESULT_OK, resultIntent)
+            finish()
+        } else {
+            val resultIntent = Intent()
+            setResult(Activity.RESULT_CANCELED)
+            finish()
+        }
+    }
+
+    fun getFingerprint(packageName: String): String {
+        // Get the signature of the app that matches the package name
+        val packageInfo = packageManager.getPackageInfo(packageName, PackageManager.GET_SIGNATURES)
+        val signature = packageInfo.signatures[0]
+
+        // Get the raw certificate data
+        val rawCert = signature.toByteArray()
+
+        // Generate an X509Certificate from the data
+        val certFactory = CertificateFactory.getInstance("X509")
+        val x509Cert = certFactory.generateCertificate(ByteArrayInputStream(rawCert)) as X509Certificate
+
+        // Get the SHA256 fingerprint
+        val fingerprint = MessageDigest.getInstance("SHA256").digest(x509Cert.encoded).joinToString("") {
+            "%02x".format(it)
+        }
+
+        return fingerprint
+    }
+}