Moved pairing logic into dialog.

Refactor.

src/org/thoughtcrime/securesms/ApplicationPreferencesActivity.java

@@ -328,7 +328,7 @@ public class ApplicationPreferencesActivity extends PassphraseRequiredActionBarA
           QRCodeDialog.INSTANCE.show(getContext());
           break;
         case PREFERENCE_CATEGORY_LINK_DEVICE:
-          DeviceLinkingDialog.INSTANCE.show(getContext(), DeviceLinkingView.Mode.Master);
+          DeviceLinkingDialog.Companion.show(getContext(), DeviceLinkingView.Mode.Master);
           break;
         case PREFERENCE_CATEGORY_SEED:
           File languageFileDirectory = new File(getContext().getApplicationInfo().dataDir);

src/org/thoughtcrime/securesms/loki/DeviceLinkingDialog.kt

@@ -1,148 +1,61 @@
 package org.thoughtcrime.securesms.loki
 
 import android.content.Context
-import android.graphics.Color
-import android.graphics.PorterDuff
-import android.os.Handler
 import android.support.v7.app.AlertDialog
-import android.util.AttributeSet
-import android.util.Log
-import android.view.View
-import android.widget.LinearLayout
-import kotlinx.android.synthetic.main.view_device_linking.view.*
-import network.loki.messenger.R
 import org.thoughtcrime.securesms.crypto.IdentityKeyUtil
 import org.thoughtcrime.securesms.database.DatabaseFactory
-import org.thoughtcrime.securesms.util.TextSecurePreferences
+import org.thoughtcrime.securesms.logging.Log
-import org.w3c.dom.Text
 import org.whispersystems.signalservice.loki.api.LokiDeviceLinkingSession
+import org.whispersystems.signalservice.loki.api.LokiDeviceLinkingSessionListener
 import org.whispersystems.signalservice.loki.api.LokiPairingAuthorisation
 import org.whispersystems.signalservice.loki.api.LokiStorageAPI
-import org.whispersystems.signalservice.loki.crypto.MnemonicCodec
-import org.whispersystems.signalservice.loki.utilities.removing05PrefixIfNeeded
-import java.io.File
-import java.io.FileOutputStream
 
-object DeviceLinkingDialog {
+class DeviceLinkingDialog private constructor(private val context: Context, private val mode: DeviceLinkingView.Mode, private val delegate: DeviceLinkingDialogDelegate? = null): DeviceLinkingViewDelegate, LokiDeviceLinkingSessionListener {
+    private lateinit var view: DeviceLinkingView
 
-    fun show(context: Context, mode: DeviceLinkingView.Mode) {
+    private val userPrivateKey = IdentityKeyUtil.getIdentityKeyPair(context).privateKey.serialize()
-        val view = DeviceLinkingView(context, mode)
+
+    companion object {
+        fun show(context: Context, mode: DeviceLinkingView.Mode) { show(context, mode, null) }
+        fun show(context: Context, mode: DeviceLinkingView.Mode, delegate: DeviceLinkingDialogDelegate?) {
+            val dialog = DeviceLinkingDialog(context, mode, delegate)
+            dialog.show()
+        }
+    }
+
+    private fun show() {
+        view = DeviceLinkingView(context, mode, this)
         val dialog = AlertDialog.Builder(context).setView(view).show()
-        view.dismiss = { dialog.dismiss() }
+        view.dismiss = {
-    }
+            this.stopListening()
+            dialog.dismiss()
         }
 
-class DeviceLinkingView private constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int, private val mode: Mode) : LinearLayout(context, attrs, defStyleAttr) {
+        this.startListening()
-    private var delegate: DeviceLinkingDialogDelegate? = null
-    private lateinit var languageFileDirectory: File
-    var dismiss: (() -> Unit)? = null
-    private var pairingAuthorisation: LokiPairingAuthorisation? = null
-
-    // region Types
-    enum class Mode { Master, Slave }
-    // endregion
-
-    // region Lifecycle
-    constructor(context: Context, mode: Mode) : this(context, null, 0, mode)
-    private constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0, Mode.Master) // Just pass in a dummy mode
-    private constructor(context: Context) : this(context, null)
-
-    init {
-        if (mode == Mode.Slave) {
-            if (delegate == null) { throw IllegalStateException("Missing delegate for device linking dialog in slave mode.") }
     }
-        setUpLanguageFileDirectory()
+
-        setUpViewHierarchy()
+    // region Private functions
+    private fun startListening() {
         LokiDeviceLinkingSession.shared.startListeningForLinkingRequests()
+        LokiDeviceLinkingSession.shared.addListener(this)
     }
 
-    private fun setUpLanguageFileDirectory() {
+    private fun stopListening() {
-        val languages = listOf( "english", "japanese", "portuguese", "spanish" )
+        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
-        val directory = File(context.applicationInfo.dataDir)
+        LokiDeviceLinkingSession.shared.removeListener(this)
-        for (language in languages) {
-            val fileName = "$language.txt"
-            if (directory.list().contains(fileName)) { continue }
-            val inputStream = context.assets.open("mnemonic/$fileName")
-            val file = File(directory, fileName)
-            val outputStream = FileOutputStream(file)
-            val buffer = ByteArray(1024)
-            while (true) {
-                val count = inputStream.read(buffer)
-                if (count < 0) { break }
-                outputStream.write(buffer, 0, count)
-            }
-            inputStream.close()
-            outputStream.close()
-        }
-        languageFileDirectory = directory
-    }
-
-    private fun setUpViewHierarchy() {
-        inflate(context, R.layout.view_device_linking, this)
-        spinner.indeterminateDrawable.setColorFilter(Color.WHITE, PorterDuff.Mode.SRC_IN)
-        val titleID = when (mode) {
-            Mode.Master -> R.string.view_device_linking_title_1
-            Mode.Slave -> R.string.view_device_linking_title_2
-        }
-        titleTextView.text = resources.getString(titleID)
-        val explanationID = when (mode) {
-            Mode.Master -> R.string.view_device_linking_explanation_1
-            Mode.Slave -> R.string.view_device_linking_explanation_2
-        }
-        explanationTextView.text = resources.getString(explanationID)
-        mnemonicTextView.visibility = if (mode == Mode.Master) View.GONE else View.VISIBLE
-        if (mode == Mode.Slave) {
-            val hexEncodedPublicKey = TextSecurePreferences.getLocalNumber(context).removing05PrefixIfNeeded()
-            mnemonicTextView.text = MnemonicCodec(languageFileDirectory).encode(hexEncodedPublicKey).split(" ").slice(0 until 3).joinToString(" ")
-        }
-        authorizeButton.visibility = View.GONE
-        authorizeButton.setOnClickListener { authorizeDeviceLink() }
-        cancelButton.setOnClickListener { cancel() }
     }
     // endregion
 
-    // region Device Linking
+    // region Dialog View Delegate
-    private fun requestUserAuthorization(authorisation: LokiPairingAuthorisation) {
+    override fun authorise(pairing: LokiPairingAuthorisation): Boolean {
-        // To be called by DeviceLinkingSession when a linking request has been received
+        val signedAuthorisation = pairing.sign(LokiPairingAuthorisation.Type.GRANT, userPrivateKey)
-        if (this.pairingAuthorisation != null) {
-            Log.e("Loki", "Received request for another pairing authorisation when one was active")
-            return
-        }
-
-        if (!authorisation.verify()) {
-            Log.w("Loki", "Received authorisation but it was not valid.")
-            return
-        }
-
-        this.pairingAuthorisation = authorisation
-
-        // Stop listening to any more requests
-        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
-
-        spinner.visibility = View.GONE
-        val titleTextViewLayoutParams = titleTextView.layoutParams as LayoutParams
-        titleTextViewLayoutParams.topMargin = toPx(16, resources)
-        titleTextView.layoutParams = titleTextViewLayoutParams
-        titleTextView.text = resources.getString(R.string.view_device_linking_title_3)
-        explanationTextView.text = resources.getString(R.string.view_device_linking_explanation_2)
-        mnemonicTextView.visibility = View.VISIBLE
-        val hexEncodedPublicKey = authorisation.secondaryDevicePubKey.removing05PrefixIfNeeded()
-        mnemonicTextView.text = MnemonicCodec(languageFileDirectory).encode(hexEncodedPublicKey).split(" ").slice(0 until 3).joinToString(" ")
-        authorizeButton.visibility = View.VISIBLE
-    }
-
-    private fun authorizeDeviceLink() {
-        if (pairingAuthorisation == null) { return; }
-
-        val authorisation = pairingAuthorisation!!
-        val userPrivateKey = IdentityKeyUtil.getIdentityKeyPair(context).privateKey.serialize()
-        val signedAuthorisation = authorisation.sign(LokiPairingAuthorisation.Type.GRANT, userPrivateKey)
         if (signedAuthorisation == null) {
             Log.e("Loki", "Failed to sign grant authorisation")
-            return
+            return false
         }
 
-        // TODO: Send authorisation message
+        // Send authorisation message
+        sendAuthorisationMessage(context, pairing.secondaryDevicePubKey, signedAuthorisation)
 
         // Add the auth to the database
         DatabaseFactory.getLokiAPIDatabase(context).insertOrUpdatePairingAuthorisation(signedAuthorisation)
@@ -150,49 +63,38 @@ class DeviceLinkingView private constructor(context: Context, attrs: AttributeSe
         // Update the api
         LokiStorageAPI.shared?.updateOurDeviceMappings()
 
-        dismiss()
+        return true
     }
 
-    private fun handleDeviceLinkAuthorized() { // TODO: deviceLink parameter
+    override fun handleDeviceLinkAuthorized() {
-        // To be called by DeviceLinkingSession when a device link has been authorized
-        // Pairings get automatically added to the database when we receive them
-        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
-
-        spinner.visibility = View.GONE
-        val titleTextViewLayoutParams = titleTextView.layoutParams as LayoutParams
-        titleTextViewLayoutParams.topMargin = toPx(8, resources)
-        titleTextView.layoutParams = titleTextViewLayoutParams
-        titleTextView.text = resources.getString(R.string.view_device_linking_title_4)
-        val explanationTextViewLayoutParams = explanationTextView.layoutParams as LayoutParams
-        explanationTextViewLayoutParams.bottomMargin = toPx(12, resources)
-        explanationTextView.layoutParams = explanationTextViewLayoutParams
-        explanationTextView.text = resources.getString(R.string.view_device_linking_explanation_3)
-        titleTextView.text = resources.getString(R.string.view_device_linking_title_4)
-        mnemonicTextView.visibility = View.GONE
-        buttonContainer.visibility = View.GONE
-
-        Handler().postDelayed({
         delegate?.handleDeviceLinkAuthorized()
-            dismiss()
-        }, 4000)
-    }
-    // endregion
-
-    // region Interaction
-    private fun dismiss() {
-        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
-        dismiss?.invoke()
     }
 
-    private fun cancel() {
+    override fun handleDeviceLinkingDialogDismissed() {
-        if (mode == Mode.Master && pairingAuthorisation != null) {
+        // If we cancelled while we were listening for requests on main device, we need to remove any pre key bundles
-            val authorisation = pairingAuthorisation!!
+        if (mode == DeviceLinkingView.Mode.Master && view.pairingAuthorisation != null) {
+            val authorisation = view.pairingAuthorisation!!
             // Remove pre key bundle from the requesting device
             DatabaseFactory.getLokiPreKeyBundleDatabase(context).removePreKeyBundle(authorisation.secondaryDevicePubKey)
         }
 
-        delegate?.handleDeviceLinkingDialogDismissed() // Only relevant in slave mode
+        delegate?.handleDeviceLinkingDialogDismissed()
-        dismiss()
+    }
+    // endregion
+
+    // region Loki Device Session Listener
+    override fun onDeviceLinkingRequestReceived(authorisation: LokiPairingAuthorisation) {
+        view.requestUserAuthorization(authorisation)
+
+        // Stop listening to any more requests
+        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
+    }
+
+    override fun onDeviceLinkRequestAccepted(authorisation: LokiPairingAuthorisation) {
+        view.onDeviceLinkAuthorized(authorisation)
+
+        // Stop listening to any more requests
+        LokiDeviceLinkingSession.shared.stopListeningForLinkingRequests()
     }
     // endregion
 }

src/org/thoughtcrime/securesms/loki/DeviceLinkingDialogDelegate.kt

@@ -1,7 +1,12 @@
 package org.thoughtcrime.securesms.loki
 
-interface DeviceLinkingDialogDelegate {
+import org.whispersystems.signalservice.loki.api.LokiPairingAuthorisation
 
-    fun handleDeviceLinkAuthorized() // TODO: Device link
+interface DeviceLinkingDialogDelegate {
-    fun handleDeviceLinkingDialogDismissed()
+    fun handleDeviceLinkAuthorized() {}
+    fun handleDeviceLinkingDialogDismissed() {}
+}
+
+interface DeviceLinkingViewDelegate: DeviceLinkingDialogDelegate {
+    fun authorise(pairing: LokiPairingAuthorisation): Boolean { return false }
 }

src/org/thoughtcrime/securesms/loki/DeviceLinkingView.kt

@@ -0,0 +1,165 @@
+package org.thoughtcrime.securesms.loki
+
+import android.content.Context
+import android.graphics.Color
+import android.graphics.PorterDuff
+import android.os.Handler
+import android.os.Looper
+import android.util.AttributeSet
+import android.util.Log
+import android.view.View
+import android.widget.LinearLayout
+import kotlinx.android.synthetic.main.view_device_linking.view.*
+import network.loki.messenger.R
+import org.thoughtcrime.securesms.ApplicationContext
+import org.thoughtcrime.securesms.database.DatabaseFactory
+import org.thoughtcrime.securesms.util.TextSecurePreferences
+import org.whispersystems.libsignal.util.guava.Optional
+import org.whispersystems.signalservice.api.crypto.UnidentifiedAccessPair
+import org.whispersystems.signalservice.api.messages.SignalServiceDataMessage
+import org.whispersystems.signalservice.api.push.SignalServiceAddress
+import org.whispersystems.signalservice.loki.api.LokiDeviceLinkingSession
+import org.whispersystems.signalservice.loki.api.LokiPairingAuthorisation
+import org.whispersystems.signalservice.loki.crypto.MnemonicCodec
+import org.whispersystems.signalservice.loki.utilities.removing05PrefixIfNeeded
+import java.io.File
+import java.io.FileOutputStream
+
+class DeviceLinkingView private constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int, private val mode: Mode, private var delegate: DeviceLinkingViewDelegate) : LinearLayout(context, attrs, defStyleAttr) {
+    private lateinit var languageFileDirectory: File
+    var dismiss: (() -> Unit)? = null
+    var pairingAuthorisation: LokiPairingAuthorisation? = null
+        private set
+
+    // region Types
+    enum class Mode { Master, Slave }
+    // endregion
+
+    // region Lifecycle
+    constructor(context: Context, mode: Mode, delegate: DeviceLinkingViewDelegate) : this(context, null, 0, mode, delegate)
+    private constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0, Mode.Master, object : DeviceLinkingViewDelegate {}) // Just pass in a dummy mode
+    private constructor(context: Context) : this(context, null)
+
+    init {
+        setUpLanguageFileDirectory()
+        setUpViewHierarchy()
+    }
+
+    private fun setUpLanguageFileDirectory() {
+        val languages = listOf( "english", "japanese", "portuguese", "spanish" )
+        val directory = File(context.applicationInfo.dataDir)
+        for (language in languages) {
+            val fileName = "$language.txt"
+            if (directory.list().contains(fileName)) { continue }
+            val inputStream = context.assets.open("mnemonic/$fileName")
+            val file = File(directory, fileName)
+            val outputStream = FileOutputStream(file)
+            val buffer = ByteArray(1024)
+            while (true) {
+                val count = inputStream.read(buffer)
+                if (count < 0) { break }
+                outputStream.write(buffer, 0, count)
+            }
+            inputStream.close()
+            outputStream.close()
+        }
+        languageFileDirectory = directory
+    }
+
+    private fun setUpViewHierarchy() {
+        inflate(context, R.layout.view_device_linking, this)
+        spinner.indeterminateDrawable.setColorFilter(Color.WHITE, PorterDuff.Mode.SRC_IN)
+        val titleID = when (mode) {
+            Mode.Master -> R.string.view_device_linking_title_1
+            Mode.Slave -> R.string.view_device_linking_title_2
+        }
+        titleTextView.text = resources.getString(titleID)
+        val explanationID = when (mode) {
+            Mode.Master -> R.string.view_device_linking_explanation_1
+            Mode.Slave -> R.string.view_device_linking_explanation_2
+        }
+        explanationTextView.text = resources.getString(explanationID)
+        mnemonicTextView.visibility = if (mode == Mode.Master) View.GONE else View.VISIBLE
+        if (mode == Mode.Slave) {
+            val hexEncodedPublicKey = TextSecurePreferences.getLocalNumber(context).removing05PrefixIfNeeded()
+            mnemonicTextView.text = MnemonicCodec(languageFileDirectory).encode(hexEncodedPublicKey).split(" ").slice(0 until 3).joinToString(" ")
+        }
+        authorizeButton.visibility = View.GONE
+        authorizeButton.setOnClickListener { authorize() }
+        cancelButton.setOnClickListener { cancel() }
+    }
+    // endregion
+
+    // region Device Linking
+    fun requestUserAuthorization(authorisation: LokiPairingAuthorisation) {
+        // To be called when a linking request has been received
+        if (mode != Mode.Master) {
+            Log.w("Loki", "Received request for pairing authorisation on a slave device")
+            return
+        }
+
+        if (authorisation.type != LokiPairingAuthorisation.Type.REQUEST) {
+            Log.w("Loki", "Received request for GRANT pairing authorisation! It shouldn't be possible!!")
+            return
+        }
+
+        if (this.pairingAuthorisation != null) {
+            Log.e("Loki", "Received request for another pairing authorisation when one was active")
+            return
+        }
+
+        this.pairingAuthorisation = authorisation
+
+        spinner.visibility = View.GONE
+        val titleTextViewLayoutParams = titleTextView.layoutParams as LayoutParams
+        titleTextViewLayoutParams.topMargin = toPx(16, resources)
+        titleTextView.layoutParams = titleTextViewLayoutParams
+        titleTextView.text = resources.getString(R.string.view_device_linking_title_3)
+        explanationTextView.text = resources.getString(R.string.view_device_linking_explanation_2)
+        mnemonicTextView.visibility = View.VISIBLE
+        val hexEncodedPublicKey = authorisation.secondaryDevicePubKey.removing05PrefixIfNeeded()
+        mnemonicTextView.text = MnemonicCodec(languageFileDirectory).encode(hexEncodedPublicKey).split(" ").slice(0 until 3).joinToString(" ")
+        authorizeButton.visibility = View.VISIBLE
+    }
+
+    private fun authorize() {
+        if (pairingAuthorisation == null || mode != Mode.Master ) { return; }
+
+        // Pass authorisation to delegate and only dismiss if it succeeded
+        if (delegate.authorise(pairingAuthorisation!!)) {
+            delegate.handleDeviceLinkAuthorized()
+            dismiss?.invoke()
+        }
+    }
+
+    fun onDeviceLinkAuthorized(authorisation: LokiPairingAuthorisation) {
+        // To be called when a device link was accepted by the primary device
+        if (mode == Mode.Master || authorisation != pairingAuthorisation) { return }
+
+        spinner.visibility = View.GONE
+        val titleTextViewLayoutParams = titleTextView.layoutParams as LayoutParams
+        titleTextViewLayoutParams.topMargin = toPx(8, resources)
+        titleTextView.layoutParams = titleTextViewLayoutParams
+        titleTextView.text = resources.getString(R.string.view_device_linking_title_4)
+        val explanationTextViewLayoutParams = explanationTextView.layoutParams as LayoutParams
+        explanationTextViewLayoutParams.bottomMargin = toPx(12, resources)
+        explanationTextView.layoutParams = explanationTextViewLayoutParams
+        explanationTextView.text = resources.getString(R.string.view_device_linking_explanation_3)
+        titleTextView.text = resources.getString(R.string.view_device_linking_title_4)
+        mnemonicTextView.visibility = View.GONE
+        buttonContainer.visibility = View.GONE
+
+        Handler().postDelayed({
+            delegate.handleDeviceLinkAuthorized()
+            dismiss?.invoke()
+        }, 4000)
+    }
+    // endregion
+
+    // region Interaction
+    private fun cancel() {
+        delegate.handleDeviceLinkingDialogDismissed()
+        dismiss?.invoke()
+    }
+    // endregion
+}

src/org/thoughtcrime/securesms/loki/SeedActivity.kt

@@ -16,10 +16,12 @@ import org.thoughtcrime.securesms.crypto.IdentityKeyUtil
 import org.thoughtcrime.securesms.database.Address
 import org.thoughtcrime.securesms.database.DatabaseFactory
 import org.thoughtcrime.securesms.database.IdentityDatabase
+import org.thoughtcrime.securesms.logging.Log
 import org.thoughtcrime.securesms.util.Hex
 import org.thoughtcrime.securesms.util.TextSecurePreferences
 import org.whispersystems.curve25519.Curve25519
 import org.whispersystems.libsignal.util.KeyHelper
+import org.whispersystems.signalservice.loki.api.LokiPairingAuthorisation
 import org.whispersystems.signalservice.loki.crypto.MnemonicCodec
 import org.whispersystems.signalservice.loki.utilities.Analytics
 import org.whispersystems.signalservice.loki.utilities.PublicKeyValidation
@@ -36,8 +38,6 @@ class SeedActivity : BaseActionBarActivity() {
     private var mnemonic: String? = null
         set(newValue) { field = newValue; updateMnemonicTextView() }
 
-    private var dialog: ProgressDialog? = null
-
     // region Types
     enum class Mode { Register, Restore, Link }
     // endregion
@@ -177,7 +177,7 @@ class SeedActivity : BaseActionBarActivity() {
         }
         val hexEncodedSeed = Hex.toStringCondensed(seed)
         IdentityKeyUtil.save(this, IdentityKeyUtil.lokiSeedKey, hexEncodedSeed)
-        if (seed.count() == 16) seed = seed + seed
+        if (seed.count() == 16) seed += seed
         if (mode == Mode.Restore) {
             IdentityKeyUtil.generateIdentityKeyPair(this, seed)
         }
@@ -197,18 +197,46 @@ class SeedActivity : BaseActionBarActivity() {
         if (mode == Mode.Link) {
             TextSecurePreferences.setHasSeenWelcomeScreen(this, true)
             TextSecurePreferences.setPromptedPushRegistration(this, true)
+
+            // Build the pairing request
+            val primaryDevicePublicKey = publicKeyEditText.text.trim().toString()
+            val authorisation = LokiPairingAuthorisation(primaryDevicePublicKey, hexEncodedPublicKey).sign(LokiPairingAuthorisation.Type.REQUEST, keyPair.privateKey.serialize())
+            if (authorisation == null) {
+                Log.w("Loki", "Failed to sign outgoing pairing request :(")
+                resetRegistration()
+                return Toast.makeText(application, "Failed to initialise device pairing", Toast.LENGTH_SHORT).show()
+            }
+
             val application = ApplicationContext.getInstance(this)
             application.startLongPollingIfNeeded()
             application.setUpStorageAPIIfNeeded()
 
-            // TODO: Show activity view here?
+            // Show the dialog
+            DeviceLinkingDialog.show(this, DeviceLinkingView.Mode.Slave, object: DeviceLinkingDialogDelegate {
+                override fun handleDeviceLinkAuthorized() {
+                    showAccountDetailsView()
+                }
 
-            // TODO: Also need to reset on registration
+                override fun handleDeviceLinkingDialogDismissed() {
+                    resetRegistration()
+                    Toast.makeText(application, "Cancelled Device Linking", Toast.LENGTH_SHORT).show()
+                }
+            })
 
+            // Send the request to the other user
+            sendAuthorisationMessage(this, authorisation.primaryDevicePubKey, authorisation)
         } else {
+            showAccountDetailsView()
+        }
+    }
+
+    private fun showAccountDetailsView() {
         startActivity(Intent(this, AccountDetailsActivity::class.java))
         finish()
     }
+
+    private fun resetRegistration() {
+
     }
     // endregion
 }

src/org/thoughtcrime/securesms/loki/Utilities.kt

@@ -0,0 +1,25 @@
+package org.thoughtcrime.securesms.loki
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import org.thoughtcrime.securesms.ApplicationContext
+import org.thoughtcrime.securesms.logging.Log
+import org.whispersystems.libsignal.util.guava.Optional
+import org.whispersystems.signalservice.api.crypto.UnidentifiedAccessPair
+import org.whispersystems.signalservice.api.messages.SignalServiceDataMessage
+import org.whispersystems.signalservice.api.push.SignalServiceAddress
+import org.whispersystems.signalservice.loki.api.LokiPairingAuthorisation
+
+fun sendAuthorisationMessage(context: Context, contactHexEncodedPublicKey: String, authorisation: LokiPairingAuthorisation) {
+  Handler(Looper.getMainLooper()).post {
+    val messageSender = ApplicationContext.getInstance(context).communicationModule.provideSignalMessageSender()
+    val address = SignalServiceAddress(contactHexEncodedPublicKey)
+    val message = SignalServiceDataMessage.newBuilder().withBody("").withPairingAuthorisation(authorisation).build()
+    try {
+      messageSender.sendMessage(0, address, Optional.absent<UnidentifiedAccessPair>(), message) // The message ID doesn't matter
+    } catch (e: Exception) {
+      Log.d("Loki", "Failed to send authorisation message to: $contactHexEncodedPublicKey.")
+    }
+  }
+}