Split project into seperate modules for core and android (fixes #18).

android/build.gradle

@@ -14,13 +14,18 @@ dependencies {
     compile "com.android.support:appcompat-v7:23.0.0"
     compile 'com.android.support:design:23.0.0'
     compile 'com.android.support:multidex:1.0.1'
-    androidTestCompile "com.android.support:multidex-instrumentation:1.0.1",
-                       { exclude module: "multidex" }
-    compile "org.scala-lang:scala-library:2.11.7"
+    androidTestCompile 'com.android.support:multidex-instrumentation:1.0.1',
+                       { exclude module: 'multidex' }
+    androidTestCompile project(path: ':core', configuration: 'testArtifacts')
+    compile 'org.scala-lang:scala-library:2.11.7'
     compile 'com.google.guava:guava:18.0'
     compile 'com.mobsandgeeks:adapter-kit:0.5.3'
+    compile project(path: ':core')
 }
 
+// TODO: need to import core test classes
+//assembleAndroidTest.dependsOn tasks.getByPath(':core:testClasses')
+
 // RtlHardcoded behaviour differs between target API versions. We only care about API 15.
 preBuild.doFirst {
     android.applicationVariants.each { variant ->

android/src/androidTest/scala/com/nutomic/ensichat/bluetooth/BluetoothInterfaceTest.scala

@@ -6,8 +6,7 @@ import android.test.AndroidTestCase
 
 class BluetoothInterfaceTest extends AndroidTestCase {
 
-  private lazy val adapter = new BluetoothInterface(getContext, new Handler(), Message => Unit, 
-    () => Unit, Message => false)
+  private lazy val adapter = new BluetoothInterface(getContext, new Handler(), null)
 
   /**
    * Test for issue [[https://github.com/Nutomic/ensichat/issues/3 #3]].

android/src/androidTest/scala/com/nutomic/ensichat/util/DatabaseTest.scala

@@ -1,5 +1,6 @@
 package com.nutomic.ensichat.util
 
+import java.util.GregorianCalendar
 import java.util.concurrent.CountDownLatch
 
 import android.content._
@@ -7,11 +8,10 @@ import android.database.DatabaseErrorHandler
 import android.database.sqlite.SQLiteDatabase
 import android.support.v4.content.LocalBroadcastManager
 import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.MessageTest._
-import com.nutomic.ensichat.protocol.body.CryptoData
-import com.nutomic.ensichat.protocol.header.ContentHeader
-import com.nutomic.ensichat.protocol.header.ContentHeaderTest._
-import com.nutomic.ensichat.protocol.{Address, Message, UserTest}
+import com.nutomic.ensichat.core.body.{CryptoData, Text}
+import com.nutomic.ensichat.core.header.ContentHeader
+import com.nutomic.ensichat.core.{Address, Message, User}
+import com.nutomic.ensichat.util.DatabaseTest._
 import junit.framework.Assert._
 
 import scala.collection.SortedSet
@@ -22,15 +22,33 @@ object DatabaseTest {
   /**
    * Provides a temporary database file that can be deleted easily.
    */
-  class DatabaseContext(context: Context) extends ContextWrapper(context) {
+  private class DatabaseContext(context: Context) extends ContextWrapper(context) {
     private val dbFile = "database-test.db"
     override def openOrCreateDatabase(file: String, mode: Int, factory:
-    SQLiteDatabase.CursorFactory, errorHandler: DatabaseErrorHandler): SQLiteDatabase = {
+    SQLiteDatabase.CursorFactory, errorHandler: DatabaseErrorHandler) =
       context.openOrCreateDatabase(dbFile, mode, factory, errorHandler)
-    }
     def deleteDbFile() = context.deleteDatabase(dbFile)
   }
 
+  private val a1 = new Address("A51B74475EE622C3C924DB147668F85E024CA0B44CA146B5E3D3C31A54B34C1E")
+  private val a2 = new Address("222229685A73AB8F2F853B3EA515633B7CD5A6ABDC3210BC4EF38F955A14AAF6")
+  private val a3 = new Address("3333359893F8810C4024CFC951374AABA1F4DE6347A3D7D8E44918AD1FF2BA36")
+  private val a4 = new Address("4444459893F8810C4024CFC951374AABA1F4DE6347A3D7D8E44918AD1FF2BA36")
+
+  private val h1 = new ContentHeader(a1, a2, 1234, Text.Type, Some(123),
+    Some(new GregorianCalendar(1970, 1, 1).getTime), 5)
+  private val h2 = new ContentHeader(a1, a3, 30000, Text.Type, Some(8765),
+    Some(new GregorianCalendar(2014, 6, 10).getTime), 20)
+  private val h3 = new ContentHeader(a4, a2, 250, Text.Type, Some(77),
+    Some(new GregorianCalendar(2020, 11, 11).getTime), 123)
+
+  private val m1 = new Message(h1, new Text("first"))
+  private val m2 = new Message(h2, new Text("second"))
+  private val m3 = new Message(h3, new Text("third"))
+
+  private val u1 = new User(a1, "one", "s1")
+  private val u2 = new User(a2, "two", "s2")
+
 }
 
 class DatabaseTest extends AndroidTestCase {
@@ -92,10 +110,10 @@ class DatabaseTest extends AndroidTestCase {
   }
 
   def testAddContact(): Unit = {
-    database.addContact(UserTest.u1)
+    database.addContact(u1)
     val contacts = database.getContacts
     assertEquals(1, contacts.size)
-    assertEquals(Option(UserTest.u1), database.getContact(UserTest.u1.address))
+    assertEquals(Option(u1), database.getContact(u1.address))
   }
 
   def testAddContactCallback(): Unit = {
@@ -105,17 +123,17 @@ class DatabaseTest extends AndroidTestCase {
       override def onReceive(context: Context, intent: Intent): Unit = latch.countDown()
     }
     lbm.registerReceiver(receiver, new IntentFilter(Database.ActionContactsUpdated))
-    database.addContact(UserTest.u1)
+    database.addContact(u1)
     latch.await()
     lbm.unregisterReceiver(receiver)
   }
   
   def testGetContact(): Unit = {
-    database.addContact(UserTest.u2)
-    assertTrue(database.getContact(UserTest.u1.address).isEmpty)
-    val c = database.getContact(UserTest.u2.address)
+    database.addContact(u2)
+    assertTrue(database.getContact(u1.address).isEmpty)
+    val c = database.getContact(u2.address)
     assertTrue(c.nonEmpty)
-    assertEquals(Option(UserTest.u2), c)
+    assertEquals(Option(u2), c)
   }
 
 }

android/src/main/AndroidManifest.xml

@@ -51,7 +51,7 @@
                 android:value=".activities.MainActivity" />
         </activity>
 
-        <service android:name=".protocol.ChatService" />
+        <service android:name=".service.ChatService" />
 
     </application>
 

android/src/main/res/xml/settings.xml

@@ -14,20 +14,17 @@
 
     <CheckBoxPreference
         android:title="@string/notification_sounds"
-        android:key="notification_sounds"
-        android:defaultValue="@bool/default_notification_sounds" />
+        android:key="notification_sounds" />
 
     <EditTextPreference
         android:title="@string/scan_interval_seconds"
         android:key="scan_interval_seconds"
-        android:defaultValue="@string/default_scan_interval"
         android:inputType="number"
         android:numeric="integer" />
 
     <EditTextPreference
         android:title="@string/max_connections"
         android:key="max_connections"
-        android:defaultValue="@string/default_max_connections"
         android:inputType="number"
         android:numeric="integer" />
 

android/src/main/scala/com/nutomic/ensichat/activities/ConnectionsActivity.scala

@@ -10,7 +10,7 @@ import android.view._
 import android.widget.AdapterView.OnItemClickListener
 import android.widget._
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.protocol.ChatService
+import com.nutomic.ensichat.service.CallbackHandler
 import com.nutomic.ensichat.util.Database
 import com.nutomic.ensichat.views.UsersAdapter
 
@@ -39,7 +39,7 @@ class ConnectionsActivity extends EnsichatActivity with OnItemClickListener {
     list.setEmptyView(findViewById(android.R.id.empty))
 
     val filter = new IntentFilter()
-    filter.addAction(ChatService.ActionConnectionsChanged)
+    filter.addAction(CallbackHandler.ActionConnectionsChanged)
     filter.addAction(Database.ActionContactsUpdated)
     LocalBroadcastManager.getInstance(this)
       .registerReceiver(onContactsUpdatedReceiver, filter)

android/src/main/scala/com/nutomic/ensichat/activities/EnsichatActivity.scala

@@ -3,7 +3,7 @@ package com.nutomic.ensichat.activities
 import android.content.{ComponentName, Context, Intent, ServiceConnection}
 import android.os.{Bundle, IBinder}
 import android.support.v7.app.AppCompatActivity
-import com.nutomic.ensichat.protocol.{ChatService, ChatServiceBinder}
+import com.nutomic.ensichat.service.ChatService
 
 /**
  * Connects to [[ChatService]] and provides access to it.
@@ -37,7 +37,7 @@ class EnsichatActivity extends AppCompatActivity with ServiceConnection {
    * Clears the list containing them.
    */
   override def onServiceConnected(componentName: ComponentName, iBinder: IBinder): Unit = {
-    val binder = iBinder.asInstanceOf[ChatServiceBinder]
+    val binder = iBinder.asInstanceOf[ChatService.Binder]
     chatService = Option(binder.service)
     listeners.foreach(_())
     listeners = Set.empty
@@ -60,6 +60,6 @@ class EnsichatActivity extends AppCompatActivity with ServiceConnection {
    *
    * Will only be set after [[runOnServiceConnected]].
    */
-  def service = chatService
+  def service = chatService.map(_.getConnectionHandler)
 
 }

android/src/main/scala/com/nutomic/ensichat/activities/FirstStartActivity.scala

@@ -11,7 +11,8 @@ import android.view.{KeyEvent, View}
 import android.widget.TextView.OnEditorActionListener
 import android.widget.{Button, EditText, TextView}
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.fragments.SettingsFragment
+import com.nutomic.ensichat.core.interfaces.Settings
+import com.nutomic.ensichat.core.interfaces.Settings._
 
 /**
  * Shown on first start, lets the user enter their name.
@@ -60,7 +61,7 @@ class FirstStartActivity extends AppCompatActivity with OnEditorActionListener w
   override def onClick(v: View): Unit = save()
 
   /**
-   * Saves values and calls [[startMainActivity]].
+   * Saves username and default settings values, then calls [[startMainActivity]].
    */
   private def save(): Unit = {
     imm.hideSoftInputFromWindow(username.getWindowToken, 0)
@@ -68,8 +69,11 @@ class FirstStartActivity extends AppCompatActivity with OnEditorActionListener w
     preferences
       .edit()
       .putBoolean(KeyIsFirstStart, false)
-      .putString(SettingsFragment.KeyUserName, username.getText.toString.trim)
-      .putString(SettingsFragment.KeyUserStatus, getString(R.string.default_user_status))
+      .putString(Settings.KeyUserName, username.getText.toString.trim)
+      .putString(Settings.KeyUserStatus, Settings.DefaultUserStatus)
+      .putBoolean(Settings.KeyNotificationSoundsOn, DefaultNotificationSoundsOn)
+      .putString(Settings.KeyScanInterval, DefaultScanInterval.toString)
+      .putString(Settings.KeyMaxConnections, DefaultMaxConnections.toString)
       .apply()
 
     startMainActivity()

android/src/main/scala/com/nutomic/ensichat/activities/MainActivity.scala

@@ -7,8 +7,8 @@ import android.os.Bundle
 import android.view.MenuItem
 import android.widget.Toast
 import com.nutomic.ensichat.R
+import com.nutomic.ensichat.core.Address
 import com.nutomic.ensichat.fragments.{ChatFragment, ContactsFragment}
-import com.nutomic.ensichat.protocol.Address
 
 object MainActivity {
 

android/src/main/scala/com/nutomic/ensichat/bluetooth/BluetoothInterface.scala

@@ -9,10 +9,10 @@ import android.preference.PreferenceManager
 import android.util.Log
 import com.google.common.collect.HashBiMap
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.fragments.SettingsFragment
-import com.nutomic.ensichat.protocol.ChatService.InterfaceHandler
-import com.nutomic.ensichat.protocol._
-import com.nutomic.ensichat.protocol.body.ConnectionInfo
+import com.nutomic.ensichat.core.body.ConnectionInfo
+import com.nutomic.ensichat.core.interfaces.{Settings, TransmissionInterface}
+import com.nutomic.ensichat.core.{Address, ConnectionHandler, Message}
+import com.nutomic.ensichat.service.ChatService
 
 import scala.collection.immutable.HashMap
 
@@ -29,15 +29,13 @@ object BluetoothInterface {
  * Handles all Bluetooth connectivity.
  */
 class BluetoothInterface(context: Context, mainHandler: Handler,
-                         onMessageReceived: Message => Unit, callConnectionListeners: () => Unit,
-                         onConnectionOpened: (Message) => Boolean)
-  extends InterfaceHandler {
+                         connectionHandler: ConnectionHandler) extends TransmissionInterface {
 
   private val Tag = "BluetoothInterface"
 
   private lazy val btAdapter = BluetoothAdapter.getDefaultAdapter
 
-  private lazy val crypto = new Crypto(context)
+  private lazy val crypto = ChatService.newCrypto(context)
 
   private var devices = new HashMap[Device.ID, Device]()
 
@@ -108,8 +106,8 @@ class BluetoothInterface(context: Context, mainHandler: Handler,
     }
 
     val pm = PreferenceManager.getDefaultSharedPreferences(context)
-    val scanInterval = pm.getString(SettingsFragment.KeyScanInterval,
-      context.getResources.getString(R.string.default_scan_interval)).toInt * 1000
+    val scanInterval =
+      pm.getString(Settings.KeyScanInterval, Settings.DefaultScanInterval.toString).toInt * 1000
     mainHandler.postDelayed(new Runnable {
       override def run(): Unit = discover()
     }, scanInterval)
@@ -175,7 +173,7 @@ class BluetoothInterface(context: Context, mainHandler: Handler,
   def onConnectionClosed(device: Device, socket: BluetoothSocket): Unit = {
     devices -= device.id
     connections -= device.id
-    callConnectionListeners()
+    connectionHandler.onConnectionClosed()
     addressDeviceMap.inverse().remove(device.id)
   }
 
@@ -192,10 +190,10 @@ class BluetoothInterface(context: Context, mainHandler: Handler,
       val address = crypto.calculateAddress(info.key)
       // Service.onConnectionOpened sends message, so mapping already needs to be in place.
       addressDeviceMap.put(address, device)
-      if (!onConnectionOpened(msg))
+      if (!connectionHandler.onConnectionOpened(msg))
         addressDeviceMap.remove(address)
     case _ =>
-      onMessageReceived(msg)
+      connectionHandler.onMessageReceived(msg)
   }
 
   /**

android/src/main/scala/com/nutomic/ensichat/bluetooth/TransferThread.scala

@@ -3,12 +3,12 @@ package com.nutomic.ensichat.bluetooth
 import java.io._
 
 import android.bluetooth.{BluetoothDevice, BluetoothSocket}
-import android.content.{IntentFilter, Intent, Context, BroadcastReceiver}
+import android.content.{BroadcastReceiver, Context, Intent, IntentFilter}
 import android.util.Log
-import com.nutomic.ensichat.protocol._
-import com.nutomic.ensichat.protocol.body.ConnectionInfo
-import com.nutomic.ensichat.protocol.header.MessageHeader
-import Message.ReadMessageException
+import com.nutomic.ensichat.core.Message.ReadMessageException
+import com.nutomic.ensichat.core.body.ConnectionInfo
+import com.nutomic.ensichat.core.header.MessageHeader
+import com.nutomic.ensichat.core.{Address, Crypto, Message}
 
 /**
  * Transfers data between connnected devices.

android/src/main/scala/com/nutomic/ensichat/fragments/ChatFragment.scala

@@ -12,8 +12,9 @@ import android.widget.TextView.OnEditorActionListener
 import android.widget._
 import com.nutomic.ensichat.R
 import com.nutomic.ensichat.activities.EnsichatActivity
-import com.nutomic.ensichat.protocol.body.Text
-import com.nutomic.ensichat.protocol.{Address, ChatService, Message}
+import com.nutomic.ensichat.core.body.Text
+import com.nutomic.ensichat.core.{Address, ConnectionHandler, Message}
+import com.nutomic.ensichat.service.CallbackHandler
 import com.nutomic.ensichat.util.Database
 import com.nutomic.ensichat.views.{DatesAdapter, MessagesAdapter}
 
@@ -36,7 +37,7 @@ class ChatFragment extends ListFragment with OnClickListener {
 
   private var address: Address = _
 
-  private var chatService: ChatService = _
+  private var chatService: ConnectionHandler = _
 
   private var sendButton: Button = _
 
@@ -93,7 +94,7 @@ class ChatFragment extends ListFragment with OnClickListener {
       address = new Address(savedInstanceState.getByteArray("address"))
 
     LocalBroadcastManager.getInstance(getActivity)
-      .registerReceiver(onMessageReceivedReceiver, new IntentFilter(ChatService.ActionMessageReceived))
+      .registerReceiver(onMessageReceivedReceiver, new IntentFilter(CallbackHandler.ActionMessageReceived))
   }
 
   override def onSaveInstanceState(outState: Bundle): Unit = {
@@ -124,7 +125,7 @@ class ChatFragment extends ListFragment with OnClickListener {
    */
   private val onMessageReceivedReceiver = new BroadcastReceiver {
     override def onReceive(context: Context, intent: Intent): Unit = {
-      val msg = intent.getSerializableExtra(ChatService.ExtraMessage).asInstanceOf[Message]
+      val msg = intent.getSerializableExtra(CallbackHandler.ExtraMessage).asInstanceOf[Message]
       if (!Set(msg.header.origin, msg.header.target).contains(address))
         return
 

android/src/main/scala/com/nutomic/ensichat/fragments/ContactsFragment.scala

@@ -2,9 +2,8 @@ package com.nutomic.ensichat.fragments
 
 import java.io.File
 
-import android.app.{ActionBar, ListFragment}
+import android.app.ListFragment
 import android.content.{BroadcastReceiver, Context, Intent, IntentFilter}
-import android.graphics.Color
 import android.net.Uri
 import android.os.Bundle
 import android.preference.PreferenceManager
@@ -12,10 +11,11 @@ import android.support.v4.content.{ContextCompat, LocalBroadcastManager}
 import android.support.v7.widget.Toolbar
 import android.view.View.OnClickListener
 import android.view._
-import android.widget.{ListView, TextView, Toast}
+import android.widget.{ListView, TextView}
 import com.nutomic.ensichat.R
 import com.nutomic.ensichat.activities.{ConnectionsActivity, EnsichatActivity, MainActivity, SettingsActivity}
-import com.nutomic.ensichat.protocol.{ChatService, Crypto}
+import com.nutomic.ensichat.core.interfaces.Settings
+import com.nutomic.ensichat.service.{CallbackHandler, ChatService}
 import com.nutomic.ensichat.util.Database
 import com.nutomic.ensichat.views.UsersAdapter
 
@@ -43,7 +43,7 @@ class ContactsFragment extends ListFragment with OnClickListener {
     setListAdapter(adapter)
     setHasOptionsMenu(true)
     lbm.registerReceiver(onContactsUpdatedListener, new IntentFilter(Database.ActionContactsUpdated))
-    lbm.registerReceiver(onConnectionsChangedListener, new IntentFilter(ChatService.ActionConnectionsChanged))
+    lbm.registerReceiver(onConnectionsChangedListener, new IntentFilter(CallbackHandler.ActionConnectionsChanged))
   }
 
   override def onResume(): Unit = {
@@ -97,9 +97,9 @@ class ContactsFragment extends ListFragment with OnClickListener {
       val fragment = new IdenticonFragment()
       val bundle = new Bundle()
       bundle.putString(
-        IdenticonFragment.ExtraAddress, new Crypto(getActivity).localAddress.toString)
+        IdenticonFragment.ExtraAddress, ChatService.newCrypto(getActivity).localAddress.toString)
       bundle.putString(
-        IdenticonFragment.ExtraUserName, prefs.getString(SettingsFragment.KeyUserName, ""))
+        IdenticonFragment.ExtraUserName, prefs.getString(Settings.KeyUserName, ""))
       fragment.setArguments(bundle)
       fragment.show(getFragmentManager, "dialog")
       true

android/src/main/scala/com/nutomic/ensichat/fragments/IdenticonFragment.scala

@@ -2,10 +2,10 @@ package com.nutomic.ensichat.fragments
 
 import android.app.{AlertDialog, Dialog, DialogFragment}
 import android.os.Bundle
-import android.view.{LayoutInflater, View, ViewGroup}
+import android.view.LayoutInflater
 import android.widget.{ImageView, TextView}
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.protocol.Address
+import com.nutomic.ensichat.core.Address
 import com.nutomic.ensichat.util.IdenticonGenerator
 
 object IdenticonFragment {

android/src/main/scala/com/nutomic/ensichat/fragments/SettingsFragment.scala

@@ -5,34 +5,25 @@ import android.content.SharedPreferences.OnSharedPreferenceChangeListener
 import android.os.Bundle
 import android.preference.Preference.OnPreferenceChangeListener
 import android.preference.{Preference, PreferenceFragment, PreferenceManager}
-import com.nutomic.ensichat.activities.EnsichatActivity
-import com.nutomic.ensichat.fragments.SettingsFragment._
-import com.nutomic.ensichat.protocol.body.UserInfo
-import com.nutomic.ensichat.util.Database
 import com.nutomic.ensichat.{BuildConfig, R}
+import com.nutomic.ensichat.activities.EnsichatActivity
+import com.nutomic.ensichat.core.body.UserInfo
+import com.nutomic.ensichat.core.interfaces.Settings._
+import com.nutomic.ensichat.fragments.SettingsFragment._
+import com.nutomic.ensichat.util.Database
 
 object SettingsFragment {
-
-  val KeyUserName     = "user_name"
-  val KeyUserStatus   = "user_status"
-  val KeyScanInterval = "scan_interval_seconds"
-  val MaxConnections  = "max_connections"
   val Version = "version"
-
 }
 
 /**
  * Settings screen.
  */
-class SettingsFragment extends PreferenceFragment with OnPreferenceChangeListener
-  with OnSharedPreferenceChangeListener {
+class SettingsFragment extends PreferenceFragment with OnSharedPreferenceChangeListener {
 
   private lazy val database = new Database(getActivity)
 
-  private lazy val name           = findPreference(KeyUserName)
-  private lazy val status         = findPreference(KeyUserStatus)
-  private lazy val scanInterval   = findPreference(KeyScanInterval)
-  private lazy val maxConnections = findPreference(MaxConnections)
+  private lazy val maxConnections       = findPreference(KeyMaxConnections)
   private lazy val version              = findPreference(Version)
 
   private lazy val prefs = PreferenceManager.getDefaultSharedPreferences(getActivity)
@@ -42,20 +33,7 @@ class SettingsFragment extends PreferenceFragment with OnPreferenceChangeListene
 
     addPreferencesFromResource(R.xml.settings)
 
-    name.setSummary(prefs.getString(KeyUserName, ""))
-    name.setOnPreferenceChangeListener(this)
-    status.setSummary(prefs.getString(KeyUserStatus, ""))
-    status.setOnPreferenceChangeListener(this)
-
-    scanInterval.setOnPreferenceChangeListener(this)
-    scanInterval.setSummary(prefs.getString(
-      KeyScanInterval, getResources.getString(R.string.default_scan_interval)))
-
-    if (BuildConfig.DEBUG) {
-      maxConnections.setOnPreferenceChangeListener(this)
-      maxConnections.setSummary(prefs.getString(
-        MaxConnections, getResources.getString(R.string.default_max_connections)))
-    } else
+    if (!BuildConfig.DEBUG)
       getPreferenceScreen.removePreference(maxConnections)
 
     val packageInfo = getActivity.getPackageManager.getPackageInfo(getActivity.getPackageName, 0)
@@ -68,14 +46,6 @@ class SettingsFragment extends PreferenceFragment with OnPreferenceChangeListene
     prefs.unregisterOnSharedPreferenceChangeListener(this)
   }
 
-  /**
-   * Updates summary, sends updated name to contacts.
-   */
-  override def onPreferenceChange(preference: Preference, newValue: AnyRef): Boolean = {
-    preference.setSummary(newValue.toString)
-    true
-  }
-
   /**
    * Sends the updated username or status to all contacts.
    */
@@ -85,6 +55,7 @@ class SettingsFragment extends PreferenceFragment with OnPreferenceChangeListene
         val service = getActivity.asInstanceOf[EnsichatActivity].service
         val ui = new UserInfo(prefs.getString(KeyUserName, ""), prefs.getString(KeyUserStatus, ""))
         database.getContacts.foreach(c => service.get.sendTo(c.address, ui))
+      case _ =>
     }
   }
 

android/src/main/scala/com/nutomic/ensichat/service/CallbackHandler.scala

@@ -0,0 +1,39 @@
+package com.nutomic.ensichat.service
+
+import android.content.{Context, Intent}
+import android.support.v4.content.LocalBroadcastManager
+import com.nutomic.ensichat.core.{ConnectionHandler, Message}
+import com.nutomic.ensichat.core.interfaces.CallbackInterface
+import com.nutomic.ensichat.service.CallbackHandler._
+
+object CallbackHandler {
+
+  val ActionMessageReceived    = "message_received"
+  val ActionConnectionsChanged = "connections_changed"
+
+  val ExtraMessage             = "extra_message"
+
+}
+
+/**
+ * Receives events from [[ConnectionHandler]] and sends them as local broadcasts.
+ */
+class CallbackHandler(context: Context, notificationHandler: NotificationHandler)
+  extends CallbackInterface {
+
+  def onMessageReceived(msg: Message): Unit = {
+    notificationHandler.onMessageReceived(msg)
+    val i = new Intent(ActionMessageReceived)
+    i.putExtra(ExtraMessage, msg)
+    LocalBroadcastManager.getInstance(context)
+      .sendBroadcast(i)
+
+  }
+
+  def onConnectionsChanged(): Unit = {
+    val i = new Intent(ActionConnectionsChanged)
+    LocalBroadcastManager.getInstance(context)
+      .sendBroadcast(i)
+  }
+
+}

android/src/main/scala/com/nutomic/ensichat/service/ChatService.scala

@@ -0,0 +1,58 @@
+package com.nutomic.ensichat.service
+
+import java.io.File
+
+import android.app.Service
+import android.content.{Context, Intent}
+import android.os.Handler
+import com.nutomic.ensichat.bluetooth.BluetoothInterface
+import com.nutomic.ensichat.core.interfaces.Log
+import com.nutomic.ensichat.core.{ConnectionHandler, Crypto}
+import com.nutomic.ensichat.util.{Database, PRNGFixes, SettingsWrapper}
+
+object ChatService {
+
+  case class Binder(service: ChatService) extends android.os.Binder
+
+  private def keyFolder(context: Context) = new File(context.getFilesDir, "keys")
+  def newCrypto(context: Context) = new Crypto(new SettingsWrapper(context), keyFolder(context))
+
+}
+
+class ChatService extends Service {
+
+  private lazy val binder = new ChatService.Binder(this)
+
+  private lazy val notificationHandler = new NotificationHandler(this)
+
+  private val callbackHandler = new CallbackHandler(this, notificationHandler)
+
+  private lazy val connectionHandler =
+    new ConnectionHandler(new SettingsWrapper(this), new Database(this), callbackHandler,
+                          ChatService.keyFolder(this))
+
+  override def onBind(intent: Intent) =  binder
+
+  override def onStartCommand(intent: Intent, flags: Int, startId: Int) = Service.START_STICKY
+
+  /**
+   * Generates keys and starts Bluetooth interface.
+   */
+  override def onCreate(): Unit = {
+    super.onCreate()
+    PRNGFixes.apply()
+    Log.setLogClass(classOf[android.util.Log])
+    notificationHandler.showPersistentNotification()
+    connectionHandler.start()
+    connectionHandler.setTransmissionInterface(new BluetoothInterface(this, new Handler(),
+                                               connectionHandler))
+  }
+
+  override def onDestroy(): Unit = {
+    notificationHandler.cancelPersistentNotification()
+    connectionHandler.stop()
+  }
+
+  def getConnectionHandler = connectionHandler
+
+}

android/src/main/scala/com/nutomic/ensichat/service/NotificationHandler.scala

@@ -0,0 +1,74 @@
+package com.nutomic.ensichat.service
+
+import android.app.{Notification, NotificationManager, PendingIntent}
+import android.content.{Context, Intent}
+import android.preference.PreferenceManager
+import android.support.v4.app.NotificationCompat
+import com.nutomic.ensichat.R
+import com.nutomic.ensichat.activities.MainActivity
+import com.nutomic.ensichat.core.Message
+import com.nutomic.ensichat.core.body.Text
+import com.nutomic.ensichat.core.interfaces.Settings
+import com.nutomic.ensichat.service.NotificationHandler._
+
+object NotificationHandler {
+
+  private val NotificationIdRunning = 1
+
+  private val NotificationIdNewMessage = 2
+
+}
+
+/**
+ * Displays notifications for new messages and while the app is running.
+ */
+class NotificationHandler(context: Context) {
+
+  private lazy val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE)
+    .asInstanceOf[NotificationManager]
+
+  def showPersistentNotification(): Unit = {
+    val intent = PendingIntent.getActivity(context, 0, new Intent(context, classOf[MainActivity]), 0)
+    val notification = new NotificationCompat.Builder(context)
+      .setSmallIcon(R.drawable.ic_launcher)
+      .setContentTitle(context.getString(R.string.app_name))
+      .setContentIntent(intent)
+      .setOngoing(true)
+      .setPriority(Notification.PRIORITY_MIN)
+      .build()
+    notificationManager.notify(NotificationIdRunning, notification)
+  }
+
+  def cancelPersistentNotification() =  notificationManager.cancel(NotificationIdRunning)
+
+  def onMessageReceived(msg: Message): Unit = msg.body match {
+    case text: Text =>
+      if (msg.header.origin == ChatService.newCrypto(context).localAddress)
+        return
+
+      val pi = PendingIntent.getActivity(context, 0, new Intent(context, classOf[MainActivity]), 0)
+      val notification = new NotificationCompat.Builder(context)
+        .setSmallIcon(R.drawable.ic_launcher)
+        .setContentTitle(context.getString(R.string.notification_message))
+        .setContentText(text.text)
+        .setDefaults(defaults())
+        .setContentIntent(pi)
+        .setAutoCancel(true)
+        .build()
+
+      notificationManager.notify(NotificationIdNewMessage, notification)
+    case _ =>
+  }
+
+  /**
+   * Returns the default notification options that should be used.
+   */
+  private def defaults(): Int = {
+    val sp = PreferenceManager.getDefaultSharedPreferences(context)
+    if (sp.getBoolean(Settings.KeyNotificationSoundsOn, Settings.DefaultNotificationSoundsOn))
+      Notification.DEFAULT_ALL
+    else
+      Notification.DEFAULT_VIBRATE | Notification.DEFAULT_LIGHTS
+  }
+
+}

android/src/main/scala/com/nutomic/ensichat/util/Database.scala

@@ -6,12 +6,10 @@ import android.content.{ContentValues, Context, Intent}
 import android.database.Cursor
 import android.database.sqlite.{SQLiteDatabase, SQLiteOpenHelper}
 import android.support.v4.content.LocalBroadcastManager
-import com.nutomic.ensichat.protocol._
-import com.nutomic.ensichat.protocol.body.Text
-import com.nutomic.ensichat.protocol.header.ContentHeader
-
-import scala.collection.SortedSet
-import scala.collection.immutable.TreeSet
+import com.nutomic.ensichat.core.body.Text
+import com.nutomic.ensichat.core.header.ContentHeader
+import com.nutomic.ensichat.core.interfaces.DatabaseInterface
+import com.nutomic.ensichat.core.{Address, Message, User}
 
 object Database {
 
@@ -55,7 +53,9 @@ object Database {
 /**
  * Stores all messages and contacts in SQL database.
  */
-class Database(context: Context)
+class Database(context: Context) extends DatabaseInterface {
+
+  private class Helper
     extends SQLiteOpenHelper(context, Database.DatabaseName, null, Database.DatabaseVersion) {
 
     override def onCreate(db: SQLiteDatabase): Unit = {
@@ -63,16 +63,28 @@ class Database(context: Context)
       db.execSQL(Database.CreateMessagesTable)
     }
 
+    override def onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int): Unit = {
+      if (oldVersion < 2) {
+        db.execSQL("ALTER TABLE contacts ADD COLUMN status TEXT")
+        val cv = new ContentValues()
+        cv.put("status", "")
+        db.update("contacts", cv, null, null)
+      }
+    }
+
+  }
+
+  private val helper = new Helper()
+
+  def close() = helper.close()
+
   def getMessagesCursor(address: Address): Cursor = {
-    getReadableDatabase.query(true,
+    helper.getReadableDatabase.query(true,
       "messages", Array("_id", "origin", "target", "message_id", "text", "date"),
       "origin = ? OR target = ?", Array(address.toString, address.toString),
       null, null, "date ASC", null)
   }
 
-  /**
-   * Inserts the given new message into the database.
-   */
   def onMessageReceived(msg: Message): Unit = msg.body match {
     case text: Text =>
       val cv =  new ContentValues()
@@ -82,14 +94,11 @@ class Database(context: Context)
       cv.put("message_id", msg.header.messageId.get.toString)
       cv.put("date",       msg.header.time.get.getTime.toString)
       cv.put("text", text.text)
-      getWritableDatabase.insert("messages", null, cv)
+      helper.getWritableDatabase.insert("messages", null, cv)
   }
 
-  /**
-   * Returns all contacts of this user.
-   */
   def getContacts: Set[User] = {
-    val c = getReadableDatabase.query(true, "contacts", Array("address", "name", "status"), "", Array(),
+    val c = helper.getReadableDatabase.query(true, "contacts", Array("address", "name", "status"), "", Array(),
       null, null, null, null)
     var contacts = Set[User]()
     while (c.moveToNext()) {
@@ -101,12 +110,9 @@ class Database(context: Context)
     contacts
   }
 
-  /**
-   * Returns the contact with the given address if it exists.
-   */
   def getContact(address: Address): Option[User] = {
-    val c = getReadableDatabase.query(true, "contacts", Array("address", "name", "status"), "address = ?",
-      Array(address.toString), null, null, null, null)
+    val c = helper.getReadableDatabase.query(true, "contacts", Array("address", "name", "status"),
+      "address = ?", Array(address.toString), null, null, null, null)
     if (c.getCount != 0) {
       c.moveToNext()
       val s = Option(new User(new Address(c.getString(c.getColumnIndex("address"))),
@@ -120,15 +126,12 @@ class Database(context: Context)
     }
   }
 
-  /**
-   * Inserts the given device into contacts.
-   */
   def addContact(contact: User): Unit = {
     val cv = new ContentValues()
     cv.put("address", contact.address.toString)
     cv.put("name", contact.name)
     cv.put("status", contact.status)
-    getWritableDatabase.insert("contacts", null, cv)
+    helper.getWritableDatabase.insert("contacts", null, cv)
     contactsUpdated()
   }
   
@@ -136,7 +139,7 @@ class Database(context: Context)
     val cv = new ContentValues()
     cv.put("name", contact.name)
     cv.put("status", contact.status)
-    getWritableDatabase.update("contacts", cv, "address = ?", Array(contact.address.toString))
+    helper.getWritableDatabase.update("contacts", cv, "address = ?", Array(contact.address.toString))
     contactsUpdated()
   }
 
@@ -145,13 +148,4 @@ class Database(context: Context)
       .sendBroadcast(new Intent(Database.ActionContactsUpdated))
   }
 
-  override def onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int): Unit = {
-    if (oldVersion < 2) {
-      db.execSQL("ALTER TABLE contacts ADD COLUMN status TEXT")
-      val cv = new ContentValues()
-      cv.put("status", "")
-      db.update("contacts", cv, null, null)
-    }
-  }
-
 }

android/src/main/scala/com/nutomic/ensichat/util/IdenticonGenerator.scala

@@ -3,7 +3,7 @@ package com.nutomic.ensichat.util
 import android.content.Context
 import android.graphics.Bitmap.Config
 import android.graphics.{Bitmap, Canvas, Color}
-import com.nutomic.ensichat.protocol.Address
+import com.nutomic.ensichat.core.Address
 
 /**
  * Calculates a unique identicon for the given hash.

android/src/main/scala/com/nutomic/ensichat/util/SettingsWrapper.scala

@@ -0,0 +1,23 @@
+package com.nutomic.ensichat.util
+
+import android.content.Context
+import android.preference.PreferenceManager
+import com.nutomic.ensichat.core.interfaces.Settings
+
+class SettingsWrapper(context: Context) extends Settings {
+
+  private val prefs = PreferenceManager.getDefaultSharedPreferences(context)
+
+  override def get[T](key: String, default: T): T = default match {
+    case s: String => prefs.getString(key, s).asInstanceOf[T]
+    case i: Int    => prefs.getInt(key, i).asInstanceOf[T]
+    case l: Long   => prefs.getLong(key, l).asInstanceOf[T]
+  }
+
+  override def put[T](key: String, value: T): Unit = value match {
+    case s: String => prefs.edit().putString(key, s).apply()
+    case i: Int    => prefs.edit().putInt(key, i).apply()
+    case l: Long   => prefs.edit().putLong(key, l).apply()
+  }
+
+}

android/src/main/scala/com/nutomic/ensichat/views/DatesAdapter.scala

@@ -1,14 +1,11 @@
 package com.nutomic.ensichat.views
 
 import java.text.DateFormat
-import java.util.Date
 
 import android.content.Context
 import android.database.Cursor
 import com.mobsandgeeks.adapters.{Sectionizer, SimpleSectionAdapter}
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.protocol.Message
-import com.nutomic.ensichat.protocol.header.ContentHeader
 import com.nutomic.ensichat.util.Database
 
 object DatesAdapter {

android/src/main/scala/com/nutomic/ensichat/views/MessagesAdapter.scala

@@ -8,8 +8,8 @@ import android.view._
 import android.widget._
 import com.mobsandgeeks.adapters.{InstantCursorAdapter, SimpleSectionAdapter, ViewHandler}
 import com.nutomic.ensichat.R
-import com.nutomic.ensichat.protocol.body.Text
-import com.nutomic.ensichat.protocol.{Address, Message}
+import com.nutomic.ensichat.core.body.Text
+import com.nutomic.ensichat.core.{Address, Message}
 import com.nutomic.ensichat.util.Database
 
 /**

android/src/main/scala/com/nutomic/ensichat/views/UsersAdapter.scala

@@ -7,8 +7,8 @@ import android.view.View.OnClickListener
 import android.view.{LayoutInflater, View, ViewGroup}
 import android.widget.{ArrayAdapter, ImageView, TextView}
 import com.nutomic.ensichat.R
+import com.nutomic.ensichat.core.User
 import com.nutomic.ensichat.fragments.IdenticonFragment
-import com.nutomic.ensichat.protocol.{Crypto, User}
 import com.nutomic.ensichat.util.IdenticonGenerator
 
 /**

app/src/androidTest/scala/com/nutomic/ensichat/activities/MainActivityTest.scala

@@ -1,39 +0,0 @@
-package com.nutomic.ensichat.activities
-
-import android.bluetooth.BluetoothAdapter
-import android.content._
-import android.test.ActivityUnitTestCase
-import junit.framework.Assert
-
-class MainActivityTest extends ActivityUnitTestCase[MainActivity](classOf[MainActivity]) {
-
-  var lastIntent: Intent = _
-
-  class ActivityContextWrapper(context: Context) extends ContextWrapper(context) {
-    override def startService(service: Intent): ComponentName = {
-      lastIntent = service
-      null
-    }
-
-    override def stopService(name: Intent): Boolean = {
-      lastIntent = name
-      true
-    }
-
-    override def bindService(service: Intent, conn: ServiceConnection, flags: Int): Boolean = false
-
-    override def unbindService(conn: ServiceConnection): Unit = {}
-  }
-
-  override def setUp(): Unit = {
-    setActivityContext(new ActivityContextWrapper(getInstrumentation.getTargetContext))
-    startActivity(new Intent(), null, null)
-  }
-
-  def testRequestBluetoothDiscoverable(): Unit = {
-    val intent: Intent = getStartedActivityIntent
-    Assert.assertEquals(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE, intent.getAction)
-    Assert.assertEquals(0, intent.getIntExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, -1))
-  }
-
-}

app/src/androidTest/scala/com/nutomic/ensichat/protocol/CryptoTest.scala

@@ -1,35 +0,0 @@
-package com.nutomic.ensichat.protocol
-
-import android.test.AndroidTestCase
-import junit.framework.Assert._
-
-class CryptoTest extends AndroidTestCase {
-
-  private lazy val crypto: Crypto = new Crypto(getContext)
-
-  override def setUp(): Unit = {
-    super.setUp()
-    if (!crypto.localKeysExist) {
-      crypto.generateLocalKeys()
-    }
-  }
-
-  def testSignVerify(): Unit = {
-    MessageTest.messages.foreach { m =>
-      val signed = crypto.sign(m)
-      assertTrue(crypto.verify(signed, crypto.getLocalPublicKey))
-      assertEquals(m.header, signed.header)
-      assertEquals(m.body, signed.body)
-    }
-  }
-
-  def testEncryptDecrypt(): Unit = {
-    MessageTest.messages.foreach{ m =>
-      val encrypted = crypto.encrypt(crypto.sign(m), crypto.getLocalPublicKey)
-      val decrypted = crypto.decrypt(encrypted)
-      assertEquals(m.body, decrypted.body)
-      assertEquals(m.header, encrypted.header)
-    }
-  }
-
-}

app/src/androidTest/scala/com/nutomic/ensichat/protocol/body/ConnectionInfoTest.scala

@@ -1,28 +0,0 @@
-package com.nutomic.ensichat.protocol.body
-
-import android.content.Context
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.Crypto
-import junit.framework.Assert
-
-object ConnectionInfoTest {
-
-  def generateCi(context: Context) = {
-    val crypto = new Crypto(context)
-    if (!crypto.localKeysExist)
-      crypto.generateLocalKeys()
-    new ConnectionInfo(crypto.getLocalPublicKey)
-  }
-
-}
-
-class ConnectionInfoTest extends AndroidTestCase {
-
-  def testWriteRead(): Unit = {
-    val ci = ConnectionInfoTest.generateCi(getContext)
-    val bytes = ci.write
-    val body = ConnectionInfo.read(bytes)
-    Assert.assertEquals(ci.key, body.asInstanceOf[ConnectionInfo].key)
-  }
-
-}

app/src/androidTest/scala/com/nutomic/ensichat/protocol/body/UserInfoTest.scala

@@ -1,15 +0,0 @@
-package com.nutomic.ensichat.protocol.body
-
-import android.test.AndroidTestCase
-import junit.framework.Assert
-
-class UserInfoTest extends AndroidTestCase {
-
-  def testWriteRead(): Unit = {
-    val name = new UserInfo("name", "status")
-    val bytes = name.write
-    val body = UserInfo.read(bytes)
-    Assert.assertEquals(name, body.asInstanceOf[UserInfo])
-  }
-
-}

app/src/main/res/values/settings_defaults.xml

@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<resources translatable="false">
-
-    <string name="default_user_status">Let\'s chat!</string>
-
-    <string name="default_scan_interval">15</string>
-
-    <bool name="default_notification_sounds">true</bool>
-    
-    <string name="default_max_connections">1000000</string>
-    
-</resources>

app/src/main/scala/com/nutomic/ensichat/protocol/ChatService.scala

@@ -1,231 +0,0 @@
-package com.nutomic.ensichat.protocol
-
-import java.util.Date
-
-import android.app.{Notification, NotificationManager, PendingIntent, Service}
-import android.content.{Context, Intent}
-import android.os.Handler
-import android.preference.PreferenceManager
-import android.support.v4.app.NotificationCompat
-import android.support.v4.content.LocalBroadcastManager
-import android.util.Log
-import com.nutomic.ensichat.R
-import com.nutomic.ensichat.activities.MainActivity
-import com.nutomic.ensichat.bluetooth.BluetoothInterface
-import com.nutomic.ensichat.fragments.SettingsFragment
-import com.nutomic.ensichat.protocol.body.{ConnectionInfo, MessageBody, UserInfo}
-import com.nutomic.ensichat.protocol.header.ContentHeader
-import com.nutomic.ensichat.util.{Database, FutureHelper, NotificationHandler}
-
-import scala.concurrent.ExecutionContext.Implicits.global
-
-object ChatService {
-
-  val ActionStopService        = "stop_service"
-  val ActionMessageReceived    = "message_received"
-  val ActionConnectionsChanged = "connections_changed"
-
-  val ExtraMessage             = "extra_message"
-
-  abstract class InterfaceHandler {
-
-    def create(): Unit
-
-    def destroy(): Unit
-
-    def send(nextHop: Address, msg: Message): Unit
-
-  }
-
-}
-
-/**
- * High-level handling of all message transfers and callbacks.
- */
-class ChatService extends Service {
-
-  private val Tag = "ChatService"
-
-  private lazy val database = new Database(this)
-
-  private lazy val preferences = PreferenceManager.getDefaultSharedPreferences(this)
-
-  private val mainHandler = new Handler()
-
-  private lazy val binder = new ChatServiceBinder(this)
-
-  private lazy val crypto = new Crypto(this)
-
-  private lazy val btInterface = new BluetoothInterface(this, mainHandler,
-    onMessageReceived, callConnectionListeners, onConnectionOpened)
-
-  private lazy val notificationHandler = new NotificationHandler(this)
-
-  private lazy val router = new Router(connections, sendVia)
-
-  private lazy val seqNumGenerator = new SeqNumGenerator(this)
-
-  private lazy val notificationManager =
-    getSystemService(Context.NOTIFICATION_SERVICE).asInstanceOf[NotificationManager]
-
-  /**
-   * Holds all known users.
-   *
-   * This is for user names that were received during runtime, and is not persistent.
-   */
-  private var knownUsers = Set[User]()
-
-  /**
-   * Generates keys and starts Bluetooth interface.
-   */
-  override def onCreate(): Unit = {
-    super.onCreate()
-
-    showPersistentNotification()
-
-    FutureHelper {
-      crypto.generateLocalKeys()
-
-      btInterface.create()
-      Log.i(Tag, "Service started, address is " + crypto.localAddress)
-    }
-  }
-
-  def showPersistentNotification(): Unit = {
-    val openIntent = PendingIntent.getActivity(this, 0, new Intent(this, classOf[MainActivity]), 0)
-    val notification = new NotificationCompat.Builder(this)
-      .setSmallIcon(R.drawable.ic_launcher)
-      .setContentTitle(getString(R.string.app_name))
-      .setContentIntent(openIntent)
-      .setOngoing(true)
-      .setPriority(Notification.PRIORITY_MIN)
-      .build()
-    notificationManager.notify(NotificationHandler.NotificationIdRunning, notification)
-  }
-
-  override def onDestroy(): Unit = {
-    notificationManager.cancel(NotificationHandler.NotificationIdRunning)
-    btInterface.destroy()
-  }
-
-  override def onStartCommand(intent: Intent, flags: Int, startId: Int) = Service.START_STICKY
-
-  override def onBind(intent: Intent) =  binder
-
-  /**
-   * Sends a new message to the given target address.
-   */
-  def sendTo(target: Address, body: MessageBody): Unit = {
-    FutureHelper {
-      val messageId = preferences.getLong("message_id", 0)
-      val header = new ContentHeader(crypto.localAddress, target, seqNumGenerator.next(),
-        body.contentType, Some(messageId), Some(new Date()))
-      preferences.edit().putLong("message_id", messageId + 1)
-
-      val msg = new Message(header, body)
-      val encrypted = crypto.encrypt(crypto.sign(msg))
-      router.onReceive(encrypted)
-      onNewMessage(msg)
-    }
-  }
-
-  private def sendVia(nextHop: Address, msg: Message) =
-    btInterface.send(nextHop, msg)
-
-  /**
-   * Decrypts and verifies incoming messages, forwards valid ones to [[onNewMessage()]].
-   */
-  def onMessageReceived(msg: Message): Unit = {
-    if (msg.header.target == crypto.localAddress) {
-      val decrypted = crypto.decrypt(msg)
-      if (!crypto.verify(decrypted)) {
-        Log.i(Tag, "Ignoring message with invalid signature from " + msg.header.origin)
-        return
-      }
-      onNewMessage(decrypted)
-    } else {
-      router.onReceive(msg)
-    }
-  }
-
-  /**
-   * Handles all (locally and remotely sent) new messages.
-   */
-  private def onNewMessage(msg: Message): Unit = msg.body match {
-    case ui: UserInfo =>
-      val contact = new User(msg.header.origin, ui.name, ui.status)
-      knownUsers += contact
-      if (database.getContact(msg.header.origin).nonEmpty)
-        database.updateContact(contact)
-
-      callConnectionListeners()
-    case _ =>
-      val origin = msg.header.origin
-      if (origin != crypto.localAddress && database.getContact(origin).isEmpty)
-        database.addContact(getUser(origin))
-
-      database.onMessageReceived(msg)
-      notificationHandler.onMessageReceived(msg)
-      val i = new Intent(ChatService.ActionMessageReceived)
-      i.putExtra(ChatService.ExtraMessage, msg)
-      LocalBroadcastManager.getInstance(this)
-        .sendBroadcast(i)
-  }
-
-  /**
-   * Opens connection to a direct neighbor.
-   *
-   * This adds the other node's public key if we don't have it. If we do, it validates the signature
-   * with the stored key.
-   *
-   * The caller must invoke [[callConnectionListeners()]]
-   *
-   * @param msg The message containing [[ConnectionInfo]] to open the connection.
-   * @return True if the connection is valid
-   */
-  def onConnectionOpened(msg: Message): Boolean = {
-    val maxConnections = preferences.getString(SettingsFragment.MaxConnections,
-      getResources.getString(R.string.default_max_connections)).toInt
-    if (connections().size == maxConnections) {
-      Log.i(Tag, "Maximum number of connections reached")
-      return false
-    }
-
-    val info = msg.body.asInstanceOf[ConnectionInfo]
-    val sender = crypto.calculateAddress(info.key)
-    if (sender == Address.Broadcast || sender == Address.Null) {
-      Log.i(Tag, "Ignoring ConnectionInfo message with invalid sender " + sender)
-      return false
-    }
-
-    if (crypto.havePublicKey(sender) && !crypto.verify(msg, crypto.getPublicKey(sender))) {
-      Log.i(Tag, "Ignoring ConnectionInfo message with invalid signature")
-      return false
-    }
-
-    synchronized {
-      if (!crypto.havePublicKey(sender)) {
-        crypto.addPublicKey(sender, info.key)
-        Log.i(Tag, "Added public key for new device " + sender.toString)
-      }
-    }
-
-    Log.i(Tag, "Node " + sender + " connected")
-    sendTo(sender, new UserInfo(preferences.getString(SettingsFragment.KeyUserName, ""),
-                                preferences.getString(SettingsFragment.KeyUserStatus, "")))
-    callConnectionListeners()
-    true
-  }
-
-  def callConnectionListeners(): Unit = {
-    LocalBroadcastManager.getInstance(this)
-      .sendBroadcast(new Intent(ChatService.ActionConnectionsChanged))
-  }
-
-  def connections() =
-    btInterface.getConnections
-
-  def getUser(address: Address) =
-    knownUsers.find(_.address == address).getOrElse(new User(address, address.toString, ""))
-
-}

app/src/main/scala/com/nutomic/ensichat/protocol/ChatServiceBinder.scala

@@ -1,5 +0,0 @@
-package com.nutomic.ensichat.protocol
-
-import android.os.Binder
-
-case class ChatServiceBinder (service: ChatService) extends Binder

app/src/main/scala/com/nutomic/ensichat/protocol/SeqNumGenerator.scala

@@ -1,24 +0,0 @@
-package com.nutomic.ensichat.protocol
-
-import android.content.Context
-import android.preference.PreferenceManager
-import com.nutomic.ensichat.protocol.header.ContentHeader
-
-/**
- * Generates sequence numbers acorrding to protocol, which are stored persistently.
- */
-class SeqNumGenerator(context: Context) {
-
-  private val KeySequenceNumber = "sequence_number"
-
-  private val pm = PreferenceManager.getDefaultSharedPreferences(context)
-
-  private var current = pm.getInt(KeySequenceNumber, ContentHeader.SeqNumRange.head)
-
-  def next(): Int = {
-    current += 1
-    pm.edit().putInt(KeySequenceNumber, current)
-    current
-  }
-
-}

app/src/main/scala/com/nutomic/ensichat/protocol/User.scala

@@ -1,3 +0,0 @@
-package com.nutomic.ensichat.protocol
-
-case class User(address: Address, name: String, status: String)

app/src/main/scala/com/nutomic/ensichat/util/NotificationHandler.scala

@@ -1,58 +0,0 @@
-package com.nutomic.ensichat.util
-
-import android.app.{Notification, NotificationManager, PendingIntent}
-import android.content.{Context, Intent}
-import android.preference.PreferenceManager
-import android.support.v4.app.NotificationCompat
-import com.nutomic.ensichat.R
-import com.nutomic.ensichat.activities.MainActivity
-import com.nutomic.ensichat.protocol.body.Text
-import com.nutomic.ensichat.protocol.{Crypto, Message}
-
-object NotificationHandler {
-
-  val NotificationIdRunning = 1
-
-  val NotificationIdNewMessage = 2
-
-}
-
-/**
- * Displays notifications for new messages.
- */
-class NotificationHandler(context: Context) {
-
-  def onMessageReceived(msg: Message): Unit = msg.body match {
-    case text: Text =>
-      if (msg.header.origin == new Crypto(context).localAddress)
-        return
-
-      val pi = PendingIntent.getActivity(context, 0, new Intent(context, classOf[MainActivity]), 0)
-      val notification = new NotificationCompat.Builder(context)
-        .setSmallIcon(R.drawable.ic_launcher)
-        .setContentTitle(context.getString(R.string.notification_message))
-        .setContentText(text.text)
-        .setDefaults(defaults())
-        .setContentIntent(pi)
-        .setAutoCancel(true)
-        .build()
-
-      val nm = context.getSystemService(Context.NOTIFICATION_SERVICE)
-        .asInstanceOf[NotificationManager]
-      nm.notify(NotificationHandler.NotificationIdNewMessage, notification)
-    case _ =>
-  }
-
-  /**
-   * Returns the default notification options that should be used.
-   */
-  def defaults(): Int = {
-    val sp = PreferenceManager.getDefaultSharedPreferences(context)
-    val defaultSounds = context.getResources.getBoolean(R.bool.default_notification_sounds)
-    if (sp.getBoolean("notification_sounds", defaultSounds))
-      Notification.DEFAULT_ALL
-    else
-      Notification.DEFAULT_VIBRATE | Notification.DEFAULT_LIGHTS
-  }
-
-}

build.gradle

@@ -1,4 +1,3 @@
-// Top-level build file where you can add configuration options common to all sub-projects/modules.
 apply plugin: 'com.github.ben-manes.versions'
 
 buildscript {
@@ -8,14 +7,12 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:1.3.1'
         classpath 'com.github.ben-manes:gradle-versions-plugin:0.11.3'
-
-        // NOTE: Do not place your application dependencies here; they belong
-        // in the individual module build.gradle files
     }
 }
 
 allprojects {
     repositories {
         jcenter()
+        mavenCentral()
     }
 }

core/.gitignore

@@ -0,0 +1 @@
+/build

core/build.gradle

@@ -0,0 +1,23 @@
+apply plugin: 'scala'
+
+dependencies {
+    compile 'org.scala-lang:scala-library:2.11.7'
+    testCompile 'junit:junit:4.12'
+    testCompile 'commons-io:commons-io:2.4'
+}
+
+test {
+    systemProperty "testDir", new File(buildDir, "/test/").toString()
+}
+
+task myTestsJar(type: Jar) {
+    from sourceSets.test.output, sourceSets.main.output
+}
+
+configurations {
+    testArtifacts
+}
+
+artifacts {
+    testArtifacts myTestsJar
+}

core/src/main/scala/com/nutomic/ensichat/core/Address.scala

@@ -1,6 +1,4 @@
-package com.nutomic.ensichat.protocol
-
-import java.util
+package com.nutomic.ensichat.core
 
 object Address {
 
@@ -41,7 +39,7 @@ case class Address(bytes: Array[Byte]) {
       .toArray)
   }
 
-  override def hashCode = util.Arrays.hashCode(bytes)
+  override def hashCode = java.util.Arrays.hashCode(bytes)
 
   override def equals(a: Any) = a match {
     case o: Address => bytes.deep == o.bytes.deep

core/src/main/scala/com/nutomic/ensichat/core/ConnectionHandler.scala

@@ -0,0 +1,160 @@
+package com.nutomic.ensichat.core
+
+import java.io.File
+import java.util.Date
+
+import com.nutomic.ensichat.core.body.{ConnectionInfo, MessageBody, UserInfo}
+import com.nutomic.ensichat.core.header.ContentHeader
+import com.nutomic.ensichat.core.interfaces._
+import com.nutomic.ensichat.core.util.FutureHelper
+
+import scala.concurrent.ExecutionContext.Implicits.global
+
+/**
+ * High-level handling of all message transfers and callbacks.
+ */
+class ConnectionHandler(settings: Settings, database: DatabaseInterface,
+                        callbacks: CallbackInterface, keyFolder: File) {
+
+  private val Tag = "ConnectionHandler"
+
+  private lazy val crypto = new Crypto(settings, keyFolder)
+
+  private var transmissionInterface: TransmissionInterface = _
+
+  private lazy val router = new Router(connections, sendVia)
+
+  private lazy val seqNumGenerator = new SeqNumGenerator(settings)
+
+  /**
+   * Holds all known users.
+   *
+   * This is for user names that were received during runtime, and is not persistent.
+   */
+  private var knownUsers = Set[User]()
+
+  /**
+   * Generates keys and starts Bluetooth interface.
+   */
+  def start(): Unit = {
+    FutureHelper {
+      crypto.generateLocalKeys()
+      Log.i(Tag, "Service started, address is " + crypto.localAddress)
+    }
+  }
+
+  def stop(): Unit = {
+    transmissionInterface.destroy()
+  }
+
+  def setTransmissionInterface(interface: TransmissionInterface) = {
+    transmissionInterface = interface
+    transmissionInterface.create()
+  }
+
+  /**
+   * Sends a new message to the given target address.
+   */
+  def sendTo(target: Address, body: MessageBody): Unit = {
+    FutureHelper {
+      val messageId = settings.get("message_id", 0L)
+      val header = new ContentHeader(crypto.localAddress, target, seqNumGenerator.next(),
+        body.contentType, Some(messageId), Some(new Date()))
+      settings.put("message_id", messageId + 1)
+
+      val msg = new Message(header, body)
+      val encrypted = crypto.encrypt(crypto.sign(msg))
+      router.onReceive(encrypted)
+      onNewMessage(msg)
+    }
+  }
+
+  private def sendVia(nextHop: Address, msg: Message) =
+    transmissionInterface.send(nextHop, msg)
+
+  /**
+   * Decrypts and verifies incoming messages, forwards valid ones to [[onNewMessage()]].
+   */
+  def onMessageReceived(msg: Message): Unit = {
+    if (msg.header.target == crypto.localAddress) {
+      val decrypted = crypto.decrypt(msg)
+      if (!crypto.verify(decrypted)) {
+        Log.i(Tag, "Ignoring message with invalid signature from " + msg.header.origin)
+        return
+      }
+      onNewMessage(decrypted)
+    } else {
+      router.onReceive(msg)
+    }
+  }
+
+  /**
+   * Handles all (locally and remotely sent) new messages.
+   */
+  private def onNewMessage(msg: Message): Unit = msg.body match {
+    case ui: UserInfo =>
+      val contact = new User(msg.header.origin, ui.name, ui.status)
+      knownUsers += contact
+      if (database.getContact(msg.header.origin).nonEmpty)
+        database.updateContact(contact)
+
+      callbacks.onConnectionsChanged()
+    case _ =>
+      val origin = msg.header.origin
+      if (origin != crypto.localAddress && database.getContact(origin).isEmpty)
+        database.addContact(getUser(origin))
+
+      database.onMessageReceived(msg)
+      callbacks.onMessageReceived(msg)
+  }
+
+  /**
+   * Opens connection to a direct neighbor.
+   *
+   * This adds the other node's public key if we don't have it. If we do, it validates the signature
+   * with the stored key.
+   *
+   * @param msg The message containing [[ConnectionInfo]] to open the connection.
+   * @return True if the connection is valid
+   */
+  def onConnectionOpened(msg: Message): Boolean = {
+    val maxConnections = settings.get(Settings.KeyMaxConnections, Settings.DefaultMaxConnections.toString).toInt
+    if (connections().size == maxConnections) {
+      Log.i(Tag, "Maximum number of connections reached")
+      return false
+    }
+
+    val info = msg.body.asInstanceOf[ConnectionInfo]
+    val sender = crypto.calculateAddress(info.key)
+    if (sender == Address.Broadcast || sender == Address.Null) {
+      Log.i(Tag, "Ignoring ConnectionInfo message with invalid sender " + sender)
+      return false
+    }
+
+    if (crypto.havePublicKey(sender) && !crypto.verify(msg, crypto.getPublicKey(sender))) {
+      Log.i(Tag, "Ignoring ConnectionInfo message with invalid signature")
+      return false
+    }
+
+    synchronized {
+      if (!crypto.havePublicKey(sender)) {
+        crypto.addPublicKey(sender, info.key)
+        Log.i(Tag, "Added public key for new device " + sender.toString)
+      }
+    }
+
+    Log.i(Tag, "Node " + sender + " connected")
+    sendTo(sender, new UserInfo(settings.get(Settings.KeyUserName, ""),
+                                settings.get(Settings.KeyUserStatus, "")))
+    callbacks.onConnectionsChanged()
+    true
+  }
+
+  def onConnectionClosed() = callbacks.onConnectionsChanged()
+
+  def connections() = transmissionInterface.getConnections
+
+  def getUser(address: Address) =
+    knownUsers.find(_.address == address).getOrElse(new User(address, address.toString, ""))
+
+}

core/src/main/scala/com/nutomic/ensichat/core/Crypto.scala

@@ -1,4 +1,4 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
 import java.io._
 import java.security._
@@ -6,13 +6,10 @@ import java.security.spec.{PKCS8EncodedKeySpec, X509EncodedKeySpec}
 import javax.crypto.spec.SecretKeySpec
 import javax.crypto.{Cipher, CipherOutputStream, KeyGenerator, SecretKey}
 
-import android.content.Context
-import android.preference.PreferenceManager
-import android.util.Log
-import com.nutomic.ensichat.protocol.Crypto._
-import com.nutomic.ensichat.protocol.body._
-import com.nutomic.ensichat.protocol.header.ContentHeader
-import com.nutomic.ensichat.util.PRNGFixes
+import com.nutomic.ensichat.core.Crypto._
+import com.nutomic.ensichat.core.body._
+import com.nutomic.ensichat.core.header.ContentHeader
+import com.nutomic.ensichat.core.interfaces.{Log, Settings}
 
 object Crypto {
 
@@ -39,7 +36,12 @@ object Crypto {
   /**
    * Algorithm used for symmetric message encryption.
    */
-  val SymmetricKeyAlgorithm = "AES/CBC/PKCS5Padding"
+  val SymmetricKeyAlgorithm = "AES"
+
+  /**
+   * Length of the symmetric message encryption key in bits.
+   */
+  val SymmetricKeyLength = 128
 
   /**
    * Algorithm used to hash PublicKey and get the address.
@@ -57,15 +59,12 @@ object Crypto {
 /**
  * Handles all cryptography related operations.
  *
- * @note We can't use [[KeyStore]], because it requires certificates, and does not work for
- *       private keys
+ * @param keyFolder Folder where private and public keys are stored.
  */
-class Crypto(context: Context) {
+class Crypto(settings: Settings, keyFolder: File) {
 
   private val Tag = "Crypto"
 
-  PRNGFixes.apply()
-
   /**
    * Generates a new key pair using [[KeyAlgorithm]] with [[KeySize]] bits and stores the keys.
    *
@@ -87,10 +86,7 @@ class Crypto(context: Context) {
       // The hash must have at least one bit set to not collide with the broadcast address.
     } while(address == Address.Broadcast || address == Address.Null)
 
-    PreferenceManager.getDefaultSharedPreferences(context)
-      .edit()
-      .putString(Crypto.LocalAddressKey, address.toString)
-      .commit()
+    settings.put(LocalAddressKey, address.toString)
 
     saveKey(PrivateKeyAlias, keyPair.getPrivate)
     saveKey(PublicKeyAlias, keyPair.getPublic)
@@ -169,7 +165,7 @@ class Crypto(context: Context) {
         ", aborting")
     }
 
-    keyFolder.mkdir()
+    keyFolder.mkdirs()
     var fos: Option[FileOutputStream] = None
     try {
       fos = Option(new FileOutputStream(path))
@@ -218,11 +214,6 @@ class Crypto(context: Context) {
     }
   }
 
-  /**
-   * Returns the folder where keys are stored.
-   */
-  private def keyFolder = new File(context.getFilesDir, "keys")
-
   def encrypt(msg: Message, key: PublicKey = null): Message = {
     assert(msg.crypto.signature.isDefined, "Message must be signed before encryption")
 
@@ -287,7 +278,7 @@ class Crypto(context: Context) {
    */
   private def makeSecretKey(): SecretKey = {
     val kgen = KeyGenerator.getInstance(SymmetricCipherAlgorithm)
-    kgen.init(256)
+    kgen.init(SymmetricKeyLength)
     val key = kgen.generateKey()
     new SecretKeySpec(key.getEncoded, SymmetricKeyAlgorithm)
   }
@@ -304,7 +295,6 @@ class Crypto(context: Context) {
   /**
    * Returns the address of the local node.
    */
-  def localAddress = new Address(
-    PreferenceManager.getDefaultSharedPreferences(context).getString(LocalAddressKey, null))
+  def localAddress = new Address(settings.get(LocalAddressKey, ""))
 
 }

core/src/main/scala/com/nutomic/ensichat/core/Message.scala

@@ -1,10 +1,10 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
 import java.io.InputStream
 import java.security.spec.InvalidKeySpecException
 
-import com.nutomic.ensichat.protocol.body._
-import com.nutomic.ensichat.protocol.header.{AbstractHeader, ContentHeader, MessageHeader}
+import com.nutomic.ensichat.core.body.{ConnectionInfo, CryptoData, EncryptedBody, MessageBody}
+import com.nutomic.ensichat.core.header.{AbstractHeader, ContentHeader, MessageHeader}
 
 object Message {
 

core/src/main/scala/com/nutomic/ensichat/core/Router.scala

@@ -1,6 +1,6 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
-import com.nutomic.ensichat.protocol.header.{MessageHeader, ContentHeader}
+import com.nutomic.ensichat.core.header.{ContentHeader, MessageHeader}
 
 /**
  * Forwards messages to all connected devices.

core/src/main/scala/com/nutomic/ensichat/core/SeqNumGenerator.scala

@@ -0,0 +1,21 @@
+package com.nutomic.ensichat.core
+
+import com.nutomic.ensichat.core.header.ContentHeader
+import com.nutomic.ensichat.core.interfaces.Settings
+
+/**
+ * Generates sequence numbers according to protocol, which are stored persistently.
+ */
+class SeqNumGenerator(preferences: Settings) {
+
+  private val KeySequenceNumber = "sequence_number"
+
+  private var current = preferences.get(KeySequenceNumber, ContentHeader.SeqNumRange.head)
+
+  def next(): Int = {
+    current += 1
+    preferences.put(KeySequenceNumber, current)
+    current
+  }
+
+}

core/src/main/scala/com/nutomic/ensichat/core/User.scala

@@ -0,0 +1,3 @@
+package com.nutomic.ensichat.core
+
+case class User(address: Address, name: String, status: String)

core/src/main/scala/com/nutomic/ensichat/core/body/ConnectionInfo.scala

@@ -1,11 +1,11 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 import java.nio.ByteBuffer
 import java.security.spec.X509EncodedKeySpec
 import java.security.{KeyFactory, PublicKey}
 
-import com.nutomic.ensichat.protocol.Crypto
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.Crypto
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object ConnectionInfo {
 

core/src/main/scala/com/nutomic/ensichat/core/body/CryptoData.scala

@@ -1,9 +1,9 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 import java.nio.ByteBuffer
 import java.util
 
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object CryptoData {
 

core/src/main/scala/com/nutomic/ensichat/core/body/EncryptedBody.scala

@@ -1,4 +1,4 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 /**
  * Represents the data in an encrypted message body.

core/src/main/scala/com/nutomic/ensichat/core/body/MessageBody.scala

@@ -1,4 +1,4 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 /**
  * Holds the actual message content.

core/src/main/scala/com/nutomic/ensichat/core/body/Text.scala

@@ -1,9 +1,9 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 import java.nio.ByteBuffer
 
-import com.nutomic.ensichat.protocol.Message
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.Message
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object Text {
 

core/src/main/scala/com/nutomic/ensichat/core/body/UserInfo.scala

@@ -1,8 +1,9 @@
-package com.nutomic.ensichat.protocol.body
+package com.nutomic.ensichat.core.body
 
 import java.nio.ByteBuffer
-import com.nutomic.ensichat.protocol.Message
-import com.nutomic.ensichat.util.BufferUtils
+
+import com.nutomic.ensichat.core.Message
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object UserInfo {
 

core/src/main/scala/com/nutomic/ensichat/core/header/AbstractHeader.scala

@@ -1,10 +1,10 @@
-package com.nutomic.ensichat.protocol.header
+package com.nutomic.ensichat.core.header
 
 import java.nio.ByteBuffer
 import java.util.Date
 
-import com.nutomic.ensichat.protocol.Address
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.Address
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object AbstractHeader {
 

core/src/main/scala/com/nutomic/ensichat/core/header/ContentHeader.scala

@@ -1,10 +1,10 @@
-package com.nutomic.ensichat.protocol.header
+package com.nutomic.ensichat.core.header
 
 import java.nio.ByteBuffer
 import java.util.Date
 
-import com.nutomic.ensichat.protocol.Address
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.Address
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object ContentHeader {
 

core/src/main/scala/com/nutomic/ensichat/core/header/MessageHeader.scala

@@ -1,10 +1,10 @@
-package com.nutomic.ensichat.protocol.header
+package com.nutomic.ensichat.core.header
 
 import java.nio.ByteBuffer
 
-import com.nutomic.ensichat.protocol.{Message, Address}
-import Message.ParseMessageException
-import com.nutomic.ensichat.util.BufferUtils
+import com.nutomic.ensichat.core.Address
+import com.nutomic.ensichat.core.Message.ParseMessageException
+import com.nutomic.ensichat.core.util.BufferUtils
 
 object MessageHeader {
 

core/src/main/scala/com/nutomic/ensichat/core/interfaces/CallbackInterface.scala

@@ -0,0 +1,10 @@
+package com.nutomic.ensichat.core.interfaces
+
+import com.nutomic.ensichat.core.Message
+
+trait CallbackInterface {
+
+  def onMessageReceived(msg: Message): Unit
+
+  def onConnectionsChanged(): Unit
+}

core/src/main/scala/com/nutomic/ensichat/core/interfaces/DatabaseInterface.scala

@@ -0,0 +1,29 @@
+package com.nutomic.ensichat.core.interfaces
+
+import com.nutomic.ensichat.core.{Address, Message, User}
+
+trait DatabaseInterface {
+
+  /**
+   * Inserts the given new message into the database.
+   */
+  def onMessageReceived(msg: Message): Unit
+
+  /**
+   * Returns all contacts of this user.
+   */
+  def getContacts: Set[User]
+
+  /**
+   * Returns the contact with the given address if it exists.
+   */
+  def getContact(address: Address): Option[User]
+
+  /**
+   * Inserts the given device into contacts.
+   */
+  def addContact(contact: User): Unit
+
+  def updateContact(contact: User): Unit
+
+}

core/src/main/scala/com/nutomic/ensichat/core/interfaces/Log.scala

@@ -0,0 +1,29 @@
+package com.nutomic.ensichat.core.interfaces
+
+object Log {
+
+  def setLogClass[T](logClass: Class[T]) = {
+    this.logClass = Option(logClass)
+  }
+
+  private var logClass: Option[Class[_]] = None
+
+  def v(tag: String, message: String, tr: Throwable = null) = log("v", tag, message, tr)
+
+  def d(tag: String, message: String, tr: Throwable = null) = log("d", tag, message, tr)
+
+  def i(tag: String, message: String, tr: Throwable = null) = log("i", tag, message, tr)
+
+  def w(tag: String, message: String, tr: Throwable = null) = log("w", tag, message, tr)
+
+  def e(tag: String, message: String, tr: Throwable = null) = log("e", tag, message, tr)
+
+  private def log(level: String, tag: String, message: String, throwable: Throwable) = logClass match {
+    case Some(l) =>
+      l.getMethod(level, classOf[String], classOf[String], classOf[Throwable])
+        .invoke(null, tag, message, throwable)
+    case None =>
+      System.out.println(level + tag + message + throwable)
+  }
+
+}

core/src/main/scala/com/nutomic/ensichat/core/interfaces/Settings.scala

@@ -0,0 +1,36 @@
+package com.nutomic.ensichat.core.interfaces
+
+object Settings {
+
+  val KeyUserName             = "user_name"
+  val KeyUserStatus           = "user_status"
+  val KeyNotificationSoundsOn = "notification_sounds"
+
+  /**
+   * NOTE: Stored as string in settings.
+   */
+  val KeyScanInterval         = "scan_interval_seconds"
+
+  /**
+   * NOTE: Stored as string in settings.
+   */
+  val KeyMaxConnections       = "max_connections"
+
+  val DefaultUserStatus           = "Let's chat!"
+  val DefaultScanInterval         = 15
+  val DefaultNotificationSoundsOn = true
+  val DefaultMaxConnections       = 1000000
+
+}
+
+/**
+ * Interface for persistent storage of key value pairs.
+ *
+ * Must support at least storage of strings and integers.
+ */
+trait Settings {
+
+  def put[T](key: String, value: T): Unit
+  def get[T](key: String, default: T): T
+
+}

core/src/main/scala/com/nutomic/ensichat/core/interfaces/TransmissionInterface.scala

@@ -0,0 +1,18 @@
+package com.nutomic.ensichat.core.interfaces
+
+import com.nutomic.ensichat.core.{Address, Message}
+
+/**
+ * Transfers data to another node over a certain medium (eg Internet or Bluetooth).
+ */
+trait TransmissionInterface {
+
+  def create(): Unit
+
+  def destroy(): Unit
+
+  def send(nextHop: Address, msg: Message): Unit
+
+  def getConnections: Set[Address]
+
+}

core/src/main/scala/com/nutomic/ensichat/core/util/BufferUtils.scala

@@ -1,4 +1,4 @@
-package com.nutomic.ensichat.util
+package com.nutomic.ensichat.core.util
 
 import java.nio.ByteBuffer
 

core/src/main/scala/com/nutomic/ensichat/core/util/FutureHelper.scala

@@ -1,6 +1,4 @@
-package com.nutomic.ensichat.util
-
-import android.os.{Looper, Handler}
+package com.nutomic.ensichat.core.util
 
 import scala.concurrent.{ExecutionContext, Future}
 
@@ -12,13 +10,10 @@ import scala.concurrent.{ExecutionContext, Future}
 object FutureHelper {
 
   def apply[A](action: => A)(implicit executor: ExecutionContext): Future[A] = {
-    val handler = new Handler(Looper.getMainLooper)
     val f = Future(action)
     f.onFailure {
       case e =>
-        handler.post(new Runnable {
-          override def run(): Unit = throw e
-        })
+        throw e
     }
     f
   }

core/src/test/scala/com/nutomic/ensichat/core/AddressTest.scala

@@ -1,8 +1,8 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.AddressTest._
-import junit.framework.Assert._
+import com.nutomic.ensichat.core.AddressTest._
+import junit.framework.TestCase
+import org.junit.Assert._
 
 object AddressTest {
 
@@ -24,7 +24,7 @@ object AddressTest {
 
 }
 
-class AddressTest extends AndroidTestCase {
+class AddressTest extends TestCase {
 
   def testEncode(): Unit = {
     Addresses.foreach{a =>

core/src/test/scala/com/nutomic/ensichat/core/CryptoTest.scala

@@ -0,0 +1,50 @@
+package com.nutomic.ensichat.core
+
+import java.io.File
+
+import com.nutomic.ensichat.core.interfaces.Settings
+import junit.framework.TestCase
+import org.junit.Assert._
+
+object CryptoTest {
+
+  class TestSettings extends Settings {
+    private var map = Map[String, Any]()
+    override def get[T](key: String, default: T): T = map.getOrElse(key, default).asInstanceOf[T]
+    override def put[T](key: String, value: T): Unit = map += (key -> value)
+  }
+
+  def getCrypto: Crypto = {
+    val tempFolder = new File(System.getProperty("testDir"), "/crypto/")
+    val crypto = new Crypto(new TestSettings(), tempFolder)
+    if (!crypto.localKeysExist) {
+      crypto.generateLocalKeys()
+    }
+    crypto
+  }
+
+}
+
+class CryptoTest extends TestCase {
+
+  private lazy val crypto = CryptoTest.getCrypto
+
+  def testSignVerify(): Unit = {
+    MessageTest.messages.foreach { m =>
+      val signed = crypto.sign(m)
+      assertTrue(crypto.verify(signed, crypto.getLocalPublicKey))
+      assertEquals(m.header, signed.header)
+      assertEquals(m.body, signed.body)
+    }
+  }
+
+  def testEncryptDecrypt(): Unit = {
+    MessageTest.messages.foreach{ m =>
+      val encrypted = crypto.encrypt(crypto.sign(m), crypto.getLocalPublicKey)
+      val decrypted = crypto.decrypt(encrypted)
+      assertEquals(m.body, decrypted.body)
+      assertEquals(m.header, encrypted.header)
+    }
+  }
+
+}

core/src/test/scala/com/nutomic/ensichat/core/MessageTest.scala

@@ -1,13 +1,13 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
 import java.io.ByteArrayInputStream
 
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.MessageTest._
-import com.nutomic.ensichat.protocol.body.{ConnectionInfo, ConnectionInfoTest, Text}
-import com.nutomic.ensichat.protocol.header.ContentHeaderTest._
-import com.nutomic.ensichat.protocol.header.MessageHeader
-import junit.framework.Assert._
+import com.nutomic.ensichat.core.MessageTest._
+import com.nutomic.ensichat.core.body.{ConnectionInfo, ConnectionInfoTest, Text}
+import com.nutomic.ensichat.core.header.ContentHeaderTest._
+import com.nutomic.ensichat.core.header.MessageHeader
+import junit.framework.TestCase
+import org.junit.Assert._
 
 import scala.collection.immutable.TreeSet
 
@@ -23,16 +23,9 @@ object MessageTest {
 
 }
 
-class MessageTest extends AndroidTestCase {
+class MessageTest extends TestCase {
 
-  private lazy val crypto: Crypto = new Crypto(getContext)
-
-  override def setUp(): Unit = {
-    super.setUp()
-    if (!crypto.localKeysExist) {
-      crypto.generateLocalKeys()
-    }
-  }
+  private lazy val crypto = CryptoTest.getCrypto
 
   def testOrder(): Unit = {
     var messages = new TreeSet[Message]()(Message.Ordering)
@@ -48,7 +41,7 @@ class MessageTest extends AndroidTestCase {
 
   def testSerializeSigned(): Unit = {
     val header = new MessageHeader(ConnectionInfo.Type, AddressTest.a4, AddressTest.a2, 0)
-    val m = new Message(header, ConnectionInfoTest.generateCi(getContext))
+    val m = new Message(header, ConnectionInfoTest.generateCi())
 
     val signed = crypto.sign(m)
     val bytes = signed.write

core/src/test/scala/com/nutomic/ensichat/core/RouterTest.scala

@@ -1,13 +1,13 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
 import java.util.{Date, GregorianCalendar}
 
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.body.{Text, UserInfo}
-import com.nutomic.ensichat.protocol.header.ContentHeader
-import junit.framework.Assert._
+import com.nutomic.ensichat.core.body.{Text, UserInfo}
+import com.nutomic.ensichat.core.header.ContentHeader
+import junit.framework.TestCase
+import org.junit.Assert._
 
-class RouterTest extends AndroidTestCase {
+class RouterTest extends TestCase {
 
   private def neighbors() = Set[Address](AddressTest.a1, AddressTest.a2, AddressTest.a3)
 

core/src/test/scala/com/nutomic/ensichat/core/UserTest.scala

@@ -1,4 +1,4 @@
-package com.nutomic.ensichat.protocol
+package com.nutomic.ensichat.core
 
 object UserTest {
 

core/src/test/scala/com/nutomic/ensichat/core/body/ConnectionInfoTest.scala

@@ -0,0 +1,27 @@
+package com.nutomic.ensichat.core.body
+
+import com.nutomic.ensichat.core.CryptoTest
+import junit.framework.TestCase
+import org.junit.Assert._
+
+object ConnectionInfoTest {
+
+  def generateCi() = {
+    val crypto = CryptoTest.getCrypto
+    if (!crypto.localKeysExist)
+      crypto.generateLocalKeys()
+    new ConnectionInfo(crypto.getLocalPublicKey)
+  }
+
+}
+
+class ConnectionInfoTest extends TestCase {
+
+  def testWriteRead(): Unit = {
+    val ci = ConnectionInfoTest.generateCi()
+    val bytes = ci.write
+    val body = ConnectionInfo.read(bytes)
+    assertEquals(ci.key, body.asInstanceOf[ConnectionInfo].key)
+  }
+
+}

core/src/test/scala/com/nutomic/ensichat/core/body/UserInfoTest.scala

@@ -0,0 +1,15 @@
+package com.nutomic.ensichat.core.body
+
+import junit.framework.TestCase
+import org.junit.Assert._
+
+class UserInfoTest extends TestCase {
+
+  def testWriteRead(): Unit = {
+    val name = new UserInfo("name", "status")
+    val bytes = name.write
+    val body = UserInfo.read(bytes)
+    assertEquals(name, body.asInstanceOf[UserInfo])
+  }
+
+}

core/src/test/scala/com/nutomic/ensichat/core/header/ContentHeaderTest.scala

@@ -1,11 +1,11 @@
-package com.nutomic.ensichat.protocol.header
+package com.nutomic.ensichat.core.header
 
-import java.util.{GregorianCalendar, Date}
+import java.util.{Date, GregorianCalendar}
 
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.body.Text
-import com.nutomic.ensichat.protocol.{Address, AddressTest}
-import junit.framework.Assert._
+import com.nutomic.ensichat.core.body.Text
+import com.nutomic.ensichat.core.{Address, AddressTest}
+import junit.framework.TestCase
+import org.junit.Assert._
 
 object ContentHeaderTest {
 
@@ -28,7 +28,7 @@ object ContentHeaderTest {
 
 }
 
-class ContentHeaderTest extends AndroidTestCase {
+class ContentHeaderTest extends TestCase {
 
   def testSerialize(): Unit = {
     ContentHeaderTest.headers.foreach{h =>

core/src/test/scala/com/nutomic/ensichat/core/header/MessageHeaderTest.scala

@@ -1,9 +1,9 @@
-package com.nutomic.ensichat.protocol.header
+package com.nutomic.ensichat.core.header
 
-import android.test.AndroidTestCase
-import com.nutomic.ensichat.protocol.header.MessageHeaderTest._
-import com.nutomic.ensichat.protocol.{Address, AddressTest}
-import junit.framework.Assert._
+import com.nutomic.ensichat.core.header.MessageHeaderTest._
+import com.nutomic.ensichat.core.{Address, AddressTest}
+import junit.framework.TestCase
+import org.junit.Assert._
 
 object MessageHeaderTest {
 
@@ -19,7 +19,7 @@ object MessageHeaderTest {
 
 }
 
-class MessageHeaderTest extends AndroidTestCase {
+class MessageHeaderTest extends TestCase {
 
   def testSerialize(): Unit = {
     headers.foreach{h =>

settings.gradle

@@ -1 +1 @@
-include ':app'
+include ':android', ':core'