Initial work to support Change Number.

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/AppSettingsActivity.kt

@@ -39,6 +39,7 @@ class AppSettingsActivity : DSLSettingsActivity() {
           .setStartCategoryIndex(intent.getIntExtra(HelpFragment.START_CATEGORY_INDEX, 0))
         StartLocation.PROXY -> AppSettingsFragmentDirections.actionDirectToEditProxyFragment()
         StartLocation.NOTIFICATIONS -> AppSettingsFragmentDirections.actionDirectToNotificationsSettingsFragment()
+        StartLocation.CHANGE_NUMBER -> AppSettingsFragmentDirections.actionDirectToChangeNumberFragment()
       }
     }
 
@@ -98,6 +99,9 @@ class AppSettingsActivity : DSLSettingsActivity() {
     @JvmStatic
     fun notifications(context: Context): Intent = getIntentForStartLocation(context, StartLocation.NOTIFICATIONS)
 
+    @JvmStatic
+    fun changeNumber(context: Context): Intent = getIntentForStartLocation(context, StartLocation.CHANGE_NUMBER)
+
     private fun getIntentForStartLocation(context: Context, startLocation: StartLocation): Intent {
       return Intent(context, AppSettingsActivity::class.java)
         .putExtra(ARG_NAV_GRAPH, R.navigation.app_settings)
@@ -110,7 +114,8 @@ class AppSettingsActivity : DSLSettingsActivity() {
     BACKUPS(1),
     HELP(2),
     PROXY(3),
-    NOTIFICATIONS(4);
+    NOTIFICATIONS(4),
+    CHANGE_NUMBER(5);
 
     companion object {
       fun fromCode(code: Int?): StartLocation {

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/account/AccountSettingsFragment.kt

@@ -30,6 +30,7 @@ import org.thoughtcrime.securesms.lock.v2.CreateKbsPinActivity
 import org.thoughtcrime.securesms.lock.v2.KbsConstants
 import org.thoughtcrime.securesms.lock.v2.PinKeyboardType
 import org.thoughtcrime.securesms.pin.RegistrationLockV2Dialog
+import org.thoughtcrime.securesms.util.FeatureFlags
 import org.thoughtcrime.securesms.util.ServiceUtil
 import org.thoughtcrime.securesms.util.ThemeUtil
 
@@ -103,6 +104,15 @@ class AccountSettingsFragment : DSLSettingsFragment(R.string.AccountSettingsFrag
 
       sectionHeaderPref(R.string.AccountSettingsFragment__account)
 
+      if (FeatureFlags.changeNumber()) {
+        clickPref(
+          title = DSLSettingsText.from(R.string.AccountSettingsFragment__change_phone_number),
+          onClick = {
+            Navigation.findNavController(requireView()).navigate(R.id.action_accountSettingsFragment_to_changePhoneNumberFragment)
+          }
+        )
+      }
+
       clickPref(
         title = DSLSettingsText.from(R.string.preferences_chats__transfer_account),
         summary = DSLSettingsText.from(R.string.preferences_chats__transfer_account_to_a_new_android_device),

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberAccountLockedFragment.kt

@@ -0,0 +1,27 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.registration.fragments.BaseAccountLockedFragment
+import org.thoughtcrime.securesms.registration.viewmodel.BaseRegistrationViewModel
+
+class ChangeNumberAccountLockedFragment : BaseAccountLockedFragment(R.layout.fragment_change_number_account_locked) {
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    super.onViewCreated(view, savedInstanceState)
+
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+  }
+
+  override fun getViewModel(): BaseRegistrationViewModel {
+    return ChangeNumberUtil.getViewModel(this)
+  }
+
+  override fun onNext() {
+    findNavController().navigateUp()
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberConfirmFragment.kt

@@ -0,0 +1,33 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import android.widget.TextView
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.LoggingFragment
+import org.thoughtcrime.securesms.R
+
+class ChangeNumberConfirmFragment : LoggingFragment(R.layout.fragment_change_number_confirm) {
+  private lateinit var viewModel: ChangeNumberViewModel
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    viewModel = ChangeNumberUtil.getViewModel(this)
+
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setTitle(R.string.ChangeNumberEnterPhoneNumberFragment__change_number)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+
+    val confirmMessage: TextView = view.findViewById(R.id.change_number_confirm_new_number_message)
+    confirmMessage.text = getString(R.string.ChangeNumberConfirmFragment__you_are_about_to_change_your_phone_number_from_s_to_s, viewModel.oldNumberState.fullFormattedNumber, viewModel.number.fullFormattedNumber)
+
+    val newNumber: TextView = view.findViewById(R.id.change_number_confirm_new_number)
+    newNumber.text = viewModel.number.fullFormattedNumber
+
+    val editNumber: View = view.findViewById(R.id.change_number_confirm_edit_number)
+    editNumber.setOnClickListener { findNavController().navigateUp() }
+
+    val changeNumber: View = view.findViewById(R.id.change_number_confirm_change_number)
+    changeNumber.setOnClickListener { findNavController().navigate(R.id.action_changePhoneNumberConfirmFragment_to_changePhoneNumberVerifyFragment) }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberEnterCodeFragment.kt

@@ -0,0 +1,44 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.changeNumberSuccess
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.getCaptchaArguments
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.getViewModel
+import org.thoughtcrime.securesms.registration.fragments.BaseEnterCodeFragment
+
+class ChangeNumberEnterCodeFragment : BaseEnterCodeFragment<ChangeNumberViewModel>(R.layout.fragment_change_number_enter_code) {
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    super.onViewCreated(view, savedInstanceState)
+
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.title = viewModel.number.fullFormattedNumber
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+
+    view.findViewById<View>(R.id.verify_header).setOnClickListener(null)
+  }
+
+  override fun getViewModel(): ChangeNumberViewModel {
+    return getViewModel(this)
+  }
+
+  override fun handleSuccessfulVerify() {
+    displaySuccess { changeNumberSuccess() }
+  }
+
+  override fun navigateToCaptcha() {
+    findNavController().navigate(R.id.action_changeNumberEnterCodeFragment_to_captchaFragment, getCaptchaArguments())
+  }
+
+  override fun navigateToRegistrationLock(timeRemaining: Long) {
+    findNavController().navigate(ChangeNumberEnterCodeFragmentDirections.actionChangeNumberEnterCodeFragmentToChangeNumberRegistrationLock(timeRemaining))
+  }
+
+  override fun navigateToKbsAccountLocked() {
+    findNavController().navigate(ChangeNumberEnterCodeFragmentDirections.actionChangeNumberEnterCodeFragmentToChangeNumberAccountLocked())
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberEnterPhoneNumberFragment.kt

@@ -0,0 +1,174 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.text.TextUtils
+import android.view.View
+import android.widget.ScrollView
+import android.widget.Spinner
+import android.widget.Toast
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import org.thoughtcrime.securesms.LoggingFragment
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.LabeledEditText
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.getViewModel
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberViewModel.ContinueStatus
+import org.thoughtcrime.securesms.registration.fragments.CountryPickerFragment
+import org.thoughtcrime.securesms.registration.fragments.CountryPickerFragmentArgs
+import org.thoughtcrime.securesms.registration.util.RegistrationNumberInputController
+import org.thoughtcrime.securesms.util.Dialogs
+
+private const val OLD_NUMBER_COUNTRY_SELECT = "old_number_country"
+private const val NEW_NUMBER_COUNTRY_SELECT = "new_number_country"
+
+class ChangeNumberEnterPhoneNumberFragment : LoggingFragment(R.layout.fragment_change_number_enter_phone_number) {
+
+  private lateinit var scrollView: ScrollView
+
+  private lateinit var oldNumberCountrySpinner: Spinner
+  private lateinit var oldNumberCountryCode: LabeledEditText
+  private lateinit var oldNumber: LabeledEditText
+
+  private lateinit var newNumberCountrySpinner: Spinner
+  private lateinit var newNumberCountryCode: LabeledEditText
+  private lateinit var newNumber: LabeledEditText
+
+  private lateinit var viewModel: ChangeNumberViewModel
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    viewModel = getViewModel(this)
+
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setTitle(R.string.ChangeNumberEnterPhoneNumberFragment__change_number)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+
+    view.findViewById<View>(R.id.change_number_enter_phone_number_continue).setOnClickListener {
+      onContinue()
+    }
+
+    scrollView = view.findViewById(R.id.change_number_enter_phone_number_scroll)
+
+    oldNumberCountrySpinner = view.findViewById(R.id.change_number_enter_phone_number_old_number_spinner)
+    oldNumberCountryCode = view.findViewById(R.id.change_number_enter_phone_number_old_number_country_code)
+    oldNumber = view.findViewById(R.id.change_number_enter_phone_number_old_number_number)
+
+    val oldController = RegistrationNumberInputController(
+      requireContext(),
+      oldNumberCountryCode,
+      oldNumber,
+      oldNumberCountrySpinner,
+      false,
+      object : RegistrationNumberInputController.Callbacks {
+        override fun onNumberFocused() {
+          scrollView.postDelayed({ scrollView.smoothScrollTo(0, oldNumber.bottom) }, 250)
+        }
+
+        override fun onNumberInputNext(view: View) {
+          newNumberCountryCode.requestFocus()
+        }
+
+        override fun onNumberInputDone(view: View) = Unit
+
+        override fun onPickCountry(view: View) {
+          val arguments: CountryPickerFragmentArgs = CountryPickerFragmentArgs.Builder().setResultKey(OLD_NUMBER_COUNTRY_SELECT).build()
+
+          findNavController().navigate(R.id.action_enterPhoneNumberChangeFragment_to_countryPickerFragment, arguments.toBundle())
+        }
+
+        override fun setNationalNumber(number: String) {
+          viewModel.setOldNationalNumber(number)
+        }
+
+        override fun setCountry(countryCode: Int) {
+          viewModel.setOldCountry(countryCode)
+        }
+      }
+    )
+
+    newNumberCountrySpinner = view.findViewById(R.id.change_number_enter_phone_number_new_number_spinner)
+    newNumberCountryCode = view.findViewById(R.id.change_number_enter_phone_number_new_number_country_code)
+    newNumber = view.findViewById(R.id.change_number_enter_phone_number_new_number_number)
+
+    val newController = RegistrationNumberInputController(
+      requireContext(),
+      newNumberCountryCode,
+      newNumber,
+      newNumberCountrySpinner,
+      true,
+      object : RegistrationNumberInputController.Callbacks {
+        override fun onNumberFocused() {
+          scrollView.postDelayed({ scrollView.smoothScrollTo(0, newNumber.bottom) }, 250)
+        }
+
+        override fun onNumberInputNext(view: View) = Unit
+
+        override fun onNumberInputDone(view: View) {
+          onContinue()
+        }
+
+        override fun onPickCountry(view: View) {
+          val arguments: CountryPickerFragmentArgs = CountryPickerFragmentArgs.Builder().setResultKey(NEW_NUMBER_COUNTRY_SELECT).build()
+
+          findNavController().navigate(R.id.action_enterPhoneNumberChangeFragment_to_countryPickerFragment, arguments.toBundle())
+        }
+
+        override fun setNationalNumber(number: String) {
+          viewModel.setNewNationalNumber(number)
+        }
+
+        override fun setCountry(countryCode: Int) {
+          viewModel.setNewCountry(countryCode)
+        }
+      }
+    )
+
+    parentFragmentManager.setFragmentResultListener(OLD_NUMBER_COUNTRY_SELECT, this) { _, bundle ->
+      viewModel.setOldCountry(bundle.getInt(CountryPickerFragment.KEY_COUNTRY_CODE), bundle.getString(CountryPickerFragment.KEY_COUNTRY))
+    }
+
+    parentFragmentManager.setFragmentResultListener(NEW_NUMBER_COUNTRY_SELECT, this) { _, bundle ->
+      viewModel.setNewCountry(bundle.getInt(CountryPickerFragment.KEY_COUNTRY_CODE), bundle.getString(CountryPickerFragment.KEY_COUNTRY))
+    }
+
+    viewModel.getLiveOldNumber().observe(viewLifecycleOwner, oldController::updateNumber)
+    viewModel.getLiveNewNumber().observe(viewLifecycleOwner, newController::updateNumber)
+  }
+
+  private fun onContinue() {
+    if (TextUtils.isEmpty(oldNumberCountryCode.text)) {
+      Toast.makeText(context, getString(R.string.ChangeNumberEnterPhoneNumberFragment__you_must_specify_your_old_number_country_code), Toast.LENGTH_LONG).show()
+      return
+    }
+
+    if (TextUtils.isEmpty(oldNumber.text)) {
+      Toast.makeText(context, getString(R.string.ChangeNumberEnterPhoneNumberFragment__you_must_specify_your_old_phone_number), Toast.LENGTH_LONG).show()
+      return
+    }
+
+    if (TextUtils.isEmpty(newNumberCountryCode.text)) {
+      Toast.makeText(context, getString(R.string.ChangeNumberEnterPhoneNumberFragment__you_must_specify_your_new_number_country_code), Toast.LENGTH_LONG).show()
+      return
+    }
+
+    if (TextUtils.isEmpty(newNumber.text)) {
+      Toast.makeText(context, getString(R.string.ChangeNumberEnterPhoneNumberFragment__you_must_specify_your_new_phone_number), Toast.LENGTH_LONG).show()
+      return
+    }
+
+    when (viewModel.canContinue()) {
+      ContinueStatus.CAN_CONTINUE -> findNavController().navigate(R.id.action_enterPhoneNumberChangeFragment_to_changePhoneNumberConfirmFragment)
+      ContinueStatus.INVALID_NUMBER -> {
+        Dialogs.showAlertDialog(
+          context, getString(R.string.RegistrationActivity_invalid_number), String.format(getString(R.string.RegistrationActivity_the_number_you_specified_s_is_invalid), viewModel.number.e164Number)
+        )
+      }
+      ContinueStatus.OLD_NUMBER_DOESNT_MATCH -> {
+        MaterialAlertDialogBuilder(requireContext())
+          .setMessage(R.string.ChangeNumberEnterPhoneNumberFragment__the_phone_number_you_entered_doesnt_match_your_accounts)
+          .setPositiveButton(android.R.string.ok, null)
+          .show()
+      }
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberFragment.kt

@@ -0,0 +1,19 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.LoggingFragment
+import org.thoughtcrime.securesms.R
+
+class ChangeNumberFragment : LoggingFragment(R.layout.fragment_change_phone_number) {
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+
+    view.findViewById<View>(R.id.change_phone_number_continue).setOnClickListener {
+      findNavController().navigate(R.id.action_changePhoneNumberFragment_to_enterPhoneNumberChangeFragment)
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberPinDiffersFragment.kt

@@ -0,0 +1,43 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import androidx.activity.OnBackPressedCallback
+import androidx.activity.result.contract.ActivityResultContracts
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import org.thoughtcrime.securesms.LoggingFragment
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.changeNumberSuccess
+import org.thoughtcrime.securesms.lock.v2.CreateKbsPinActivity
+
+class ChangeNumberPinDiffersFragment : LoggingFragment(R.layout.fragment_change_number_pin_differs) {
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    view.findViewById<View>(R.id.change_number_pin_differs_keep_old_pin).setOnClickListener {
+      changeNumberSuccess()
+    }
+
+    val changePin = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
+      if (result.resultCode == CreateKbsPinActivity.RESULT_OK) {
+        changeNumberSuccess()
+      }
+    }
+
+    view.findViewById<View>(R.id.change_number_pin_differs_update_pin).setOnClickListener {
+      changePin.launch(CreateKbsPinActivity.getIntentForPinChangeFromSettings(requireContext()))
+    }
+
+    requireActivity().onBackPressedDispatcher.addCallback(
+      viewLifecycleOwner,
+      object : OnBackPressedCallback(true) {
+        override fun handleOnBackPressed() {
+          MaterialAlertDialogBuilder(requireContext())
+            .setMessage(R.string.ChangeNumberPinDiffersFragment__keep_old_pin_question)
+            .setPositiveButton(android.R.string.ok) { _, _ -> changeNumberSuccess() }
+            .setNegativeButton(android.R.string.cancel, null)
+            .show()
+        }
+      }
+    )
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberRegistrationLockFragment.kt

@@ -0,0 +1,63 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.changeNumberSuccess
+import org.thoughtcrime.securesms.keyvalue.SignalStore
+import org.thoughtcrime.securesms.lock.PinHashing
+import org.thoughtcrime.securesms.registration.fragments.BaseRegistrationLockFragment
+import org.thoughtcrime.securesms.registration.viewmodel.BaseRegistrationViewModel
+import org.thoughtcrime.securesms.util.CircularProgressButtonUtil.cancelSpinning
+import org.thoughtcrime.securesms.util.CommunicationActions
+import org.thoughtcrime.securesms.util.SupportEmailUtil
+
+class ChangeNumberRegistrationLockFragment : BaseRegistrationLockFragment(R.layout.fragment_change_number_registration_lock) {
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    super.onViewCreated(view, savedInstanceState)
+
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+  }
+
+  override fun getViewModel(): BaseRegistrationViewModel {
+    return ChangeNumberUtil.getViewModel(this)
+  }
+
+  override fun navigateToAccountLocked() {
+    findNavController().navigate(ChangeNumberRegistrationLockFragmentDirections.actionChangeNumberRegistrationLockToChangeNumberAccountLocked())
+  }
+
+  override fun handleSuccessfulPinEntry(pin: String) {
+    val pinsDiffer: Boolean = SignalStore.kbsValues().localPinHash?.let { !PinHashing.verifyLocalPinHash(it, pin) } ?: false
+
+    cancelSpinning(pinButton)
+
+    if (pinsDiffer) {
+      findNavController().navigate(ChangeNumberRegistrationLockFragmentDirections.actionChangeNumberRegistrationLockToChangeNumberPinDiffers())
+    } else {
+      changeNumberSuccess()
+    }
+  }
+
+  override fun sendEmailToSupport() {
+    val subject = R.string.ChangeNumberRegistrationLockFragment__signal_change_number_need_help_with_pin_for_android_v2_pin
+
+    val body: String = SupportEmailUtil.generateSupportEmailBody(
+      requireContext(),
+      subject,
+      null,
+      null
+    )
+
+    CommunicationActions.openEmail(
+      requireContext(),
+      SupportEmailUtil.getSupportEmailAddress(requireContext()),
+      getString(subject),
+      body
+    )
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberRepository.kt

@@ -0,0 +1,86 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.content.Context
+import androidx.annotation.WorkerThread
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.schedulers.Schedulers
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.database.DatabaseFactory
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
+import org.thoughtcrime.securesms.keyvalue.CertificateType
+import org.thoughtcrime.securesms.keyvalue.SignalStore
+import org.thoughtcrime.securesms.pin.KbsRepository
+import org.thoughtcrime.securesms.pin.KeyBackupSystemWrongPinException
+import org.thoughtcrime.securesms.pin.TokenData
+import org.thoughtcrime.securesms.registration.VerifyAccountRepository
+import org.thoughtcrime.securesms.util.TextSecurePreferences
+import org.whispersystems.signalservice.api.KbsPinData
+import org.whispersystems.signalservice.api.KeyBackupSystemNoDataException
+import org.whispersystems.signalservice.internal.ServiceResponse
+import org.whispersystems.signalservice.internal.push.VerifyAccountResponse
+
+private val TAG: String = Log.tag(ChangeNumberRepository::class.java)
+
+class ChangeNumberRepository(private val context: Context) {
+
+  private val accountManager = ApplicationDependencies.getSignalServiceAccountManager()
+
+  fun changeNumber(code: String, newE164: String): Single<ServiceResponse<VerifyAccountResponse>> {
+    return Single.fromCallable { accountManager.changeNumber(code, newE164, null) }
+      .subscribeOn(Schedulers.io())
+  }
+
+  fun changeNumber(
+    code: String,
+    newE164: String,
+    pin: String,
+    tokenData: TokenData
+  ): Single<ServiceResponse<VerifyAccountRepository.VerifyAccountWithRegistrationLockResponse>> {
+    return Single.fromCallable {
+      try {
+        val kbsData: KbsPinData = KbsRepository.restoreMasterKey(pin, tokenData.enclave, tokenData.basicAuth, tokenData.tokenResponse)!!
+        val registrationLock: String = kbsData.masterKey.deriveRegistrationLock()
+
+        val response: ServiceResponse<VerifyAccountResponse> = accountManager.changeNumber(code, newE164, registrationLock)
+        VerifyAccountRepository.VerifyAccountWithRegistrationLockResponse.from(response, kbsData)
+      } catch (e: KeyBackupSystemWrongPinException) {
+        ServiceResponse.forExecutionError(e)
+      } catch (e: KeyBackupSystemNoDataException) {
+        ServiceResponse.forExecutionError(e)
+      }
+    }.subscribeOn(Schedulers.io())
+  }
+
+  @WorkerThread
+  fun changeLocalNumber(e164: String): Single<Unit> {
+    TextSecurePreferences.setLocalNumber(context, e164)
+
+    DatabaseFactory.getRecipientDatabase(context).updateSelfPhone(e164)
+
+    ApplicationDependencies.closeConnections()
+    ApplicationDependencies.getIncomingMessageObserver()
+
+    return rotateCertificates()
+  }
+
+  @Suppress("UsePropertyAccessSyntax")
+  private fun rotateCertificates(): Single<Unit> {
+    val certificateTypes = SignalStore.phoneNumberPrivacy().allCertificateTypes
+
+    Log.i(TAG, "Rotating these certificates $certificateTypes")
+
+    return Single.fromCallable {
+      for (certificateType in certificateTypes) {
+        val certificate: ByteArray? = when (certificateType) {
+          CertificateType.UUID_AND_E164 -> accountManager.getSenderCertificate()
+          CertificateType.UUID_ONLY -> accountManager.getSenderCertificateForPhoneNumberPrivacy()
+          else -> throw AssertionError()
+        }
+
+        Log.i(TAG, "Successfully got $certificateType certificate")
+
+        SignalStore.certificateValues().setUnidentifiedAccessCertificate(certificateType, certificate)
+      }
+    }.subscribeOn(Schedulers.io())
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberUtil.kt

@@ -0,0 +1,41 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.widget.Toast
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModelProvider
+import androidx.navigation.fragment.NavHostFragment
+import androidx.navigation.fragment.findNavController
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.registration.fragments.CaptchaFragment
+import org.thoughtcrime.securesms.registration.viewmodel.BaseRegistrationViewModel
+
+/**
+ * Helpers for various aspects of the change number flow.
+ */
+object ChangeNumberUtil {
+  @JvmStatic
+  fun getViewModel(fragment: Fragment): ChangeNumberViewModel {
+    val navController = NavHostFragment.findNavController(fragment)
+    return ViewModelProvider(
+      navController.getViewModelStoreOwner(R.id.app_settings_change_number),
+      ChangeNumberViewModel.Factory(navController.getBackStackEntry(R.id.app_settings_change_number))
+    ).get(ChangeNumberViewModel::class.java)
+  }
+
+  fun getCaptchaArguments(): Bundle {
+    return Bundle().apply {
+      putSerializable(
+        CaptchaFragment.EXTRA_VIEW_MODEL_PROVIDER,
+        object : CaptchaFragment.CaptchaViewModelProvider {
+          override fun get(fragment: CaptchaFragment): BaseRegistrationViewModel = getViewModel(fragment)
+        }
+      )
+    }
+  }
+
+  fun Fragment.changeNumberSuccess() {
+    findNavController().navigate(R.id.action_pop_app_settings_change_number)
+    Toast.makeText(requireContext(), R.string.ChangeNumber__your_phone_number_has_been_changed, Toast.LENGTH_SHORT).show()
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberVerifyFragment.kt

@@ -0,0 +1,75 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.os.Bundle
+import android.view.View
+import android.widget.TextView
+import android.widget.Toast
+import androidx.appcompat.widget.Toolbar
+import androidx.navigation.fragment.findNavController
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.LoggingFragment
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.getCaptchaArguments
+import org.thoughtcrime.securesms.components.settings.app.changenumber.ChangeNumberUtil.getViewModel
+import org.thoughtcrime.securesms.registration.VerifyAccountRepository
+import org.thoughtcrime.securesms.util.LifecycleDisposable
+
+private val TAG: String = Log.tag(ChangeNumberVerifyFragment::class.java)
+
+class ChangeNumberVerifyFragment : LoggingFragment(R.layout.fragment_change_phone_number_verify) {
+  private lateinit var viewModel: ChangeNumberViewModel
+
+  private var requestingCaptcha: Boolean = false
+
+  private val lifecycleDisposable: LifecycleDisposable = LifecycleDisposable()
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    lifecycleDisposable.bindTo(lifecycle)
+    viewModel = getViewModel(this)
+  }
+
+  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+    val toolbar: Toolbar = view.findViewById(R.id.toolbar)
+    toolbar.setTitle(R.string.ChangeNumberVerifyFragment__change_number)
+    toolbar.setNavigationOnClickListener { findNavController().navigateUp() }
+
+    val status: TextView = view.findViewById(R.id.change_phone_number_verify_status)
+    status.text = getString(R.string.ChangeNumberVerifyFragment__verifying_s, viewModel.number.fullFormattedNumber)
+
+    if (!requestingCaptcha || viewModel.hasCaptchaToken()) {
+      requestCode()
+    } else {
+      Toast.makeText(requireContext(), R.string.ChangeNumberVerifyFragment__captcha_required, Toast.LENGTH_SHORT).show()
+      findNavController().navigateUp()
+    }
+  }
+
+  private fun requestCode() {
+    lifecycleDisposable.add(
+      viewModel.requestVerificationCode(VerifyAccountRepository.Mode.SMS_WITHOUT_LISTENER)
+        .observeOn(AndroidSchedulers.mainThread())
+        .subscribe { processor ->
+          if (processor.hasResult()) {
+            findNavController().navigate(R.id.action_changePhoneNumberVerifyFragment_to_changeNumberEnterCodeFragment)
+          } else if (processor.localRateLimit()) {
+            Log.i(TAG, "Unable to request sms code due to local rate limit")
+            findNavController().navigate(R.id.action_changePhoneNumberVerifyFragment_to_changeNumberEnterCodeFragment)
+          } else if (processor.captchaRequired()) {
+            Log.i(TAG, "Unable to request sms code due to captcha required")
+            findNavController().navigate(R.id.action_changePhoneNumberVerifyFragment_to_captchaFragment, getCaptchaArguments())
+            requestingCaptcha = true
+          } else if (processor.rateLimit()) {
+            Log.i(TAG, "Unable to request sms code due to rate limit")
+            Toast.makeText(requireContext(), R.string.RegistrationActivity_rate_limited_to_service, Toast.LENGTH_LONG).show()
+            findNavController().navigateUp()
+          } else {
+            Log.w(TAG, "Unable to request sms code", processor.error)
+            Toast.makeText(requireContext(), R.string.RegistrationActivity_unable_to_connect_to_service, Toast.LENGTH_LONG).show()
+            findNavController().navigateUp()
+          }
+        }
+    )
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/changenumber/ChangeNumberViewModel.kt

@@ -0,0 +1,159 @@
+package org.thoughtcrime.securesms.components.settings.app.changenumber
+
+import android.app.Application
+import androidx.annotation.WorkerThread
+import androidx.lifecycle.AbstractSavedStateViewModelFactory
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import androidx.savedstate.SavedStateRegistryOwner
+import com.google.i18n.phonenumbers.NumberParseException
+import com.google.i18n.phonenumbers.PhoneNumberUtil
+import io.reactivex.rxjava3.core.Single
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
+import org.thoughtcrime.securesms.pin.KbsRepository
+import org.thoughtcrime.securesms.pin.TokenData
+import org.thoughtcrime.securesms.registration.VerifyAccountRepository
+import org.thoughtcrime.securesms.registration.VerifyAccountResponseProcessor
+import org.thoughtcrime.securesms.registration.VerifyAccountResponseWithoutKbs
+import org.thoughtcrime.securesms.registration.VerifyCodeWithRegistrationLockResponseProcessor
+import org.thoughtcrime.securesms.registration.viewmodel.BaseRegistrationViewModel
+import org.thoughtcrime.securesms.registration.viewmodel.NumberViewState
+import org.thoughtcrime.securesms.util.DefaultValueLiveData
+import org.thoughtcrime.securesms.util.TextSecurePreferences
+import org.whispersystems.signalservice.internal.ServiceResponse
+import org.whispersystems.signalservice.internal.push.VerifyAccountResponse
+
+private val TAG: String = Log.tag(ChangeNumberViewModel::class.java)
+
+class ChangeNumberViewModel(
+  private val localNumber: String,
+  private val changeNumberRepository: ChangeNumberRepository,
+  savedState: SavedStateHandle,
+  password: String,
+  verifyAccountRepository: VerifyAccountRepository,
+  kbsRepository: KbsRepository,
+) : BaseRegistrationViewModel(savedState, verifyAccountRepository, kbsRepository, password) {
+
+  var oldNumberState: NumberViewState = NumberViewState.Builder().build()
+    private set
+
+  private val liveOldNumberState = DefaultValueLiveData(oldNumberState)
+  private val liveNewNumberState = DefaultValueLiveData(number)
+
+  init {
+    try {
+      val countryCode: Int = PhoneNumberUtil.getInstance()
+        .parse(localNumber, null)
+        .countryCode
+
+      setOldCountry(countryCode)
+      setNewCountry(countryCode)
+    } catch (e: NumberParseException) {
+      Log.i(TAG, "Unable to parse number for default country code")
+    }
+  }
+
+  fun getLiveOldNumber(): LiveData<NumberViewState> {
+    return liveOldNumberState
+  }
+
+  fun getLiveNewNumber(): LiveData<NumberViewState> {
+    return liveNewNumberState
+  }
+
+  fun setOldNationalNumber(number: String) {
+    oldNumberState = oldNumberState.toBuilder()
+      .nationalNumber(number)
+      .build()
+
+    liveOldNumberState.value = oldNumberState
+  }
+
+  fun setOldCountry(countryCode: Int, country: String? = null) {
+    oldNumberState = oldNumberState.toBuilder()
+      .selectedCountryDisplayName(country)
+      .countryCode(countryCode)
+      .build()
+
+    liveOldNumberState.value = oldNumberState
+  }
+
+  fun setNewNationalNumber(number: String) {
+    setNationalNumber(number)
+
+    liveNewNumberState.value = this.number
+  }
+
+  fun setNewCountry(countryCode: Int, country: String? = null) {
+    onCountrySelected(country, countryCode)
+
+    liveNewNumberState.value = this.number
+  }
+
+  fun canContinue(): ContinueStatus {
+    return if (oldNumberState.e164Number == localNumber) {
+      if (number.isValid) {
+        ContinueStatus.CAN_CONTINUE
+      } else {
+        ContinueStatus.INVALID_NUMBER
+      }
+    } else {
+      ContinueStatus.OLD_NUMBER_DOESNT_MATCH
+    }
+  }
+
+  override fun verifyAccountWithoutRegistrationLock(): Single<ServiceResponse<VerifyAccountResponse>> {
+    return changeNumberRepository.changeNumber(textCodeEntered, number.e164Number)
+  }
+
+  override fun verifyAccountWithRegistrationLock(pin: String, kbsTokenData: TokenData): Single<ServiceResponse<VerifyAccountRepository.VerifyAccountWithRegistrationLockResponse>> {
+    return changeNumberRepository.changeNumber(textCodeEntered, number.e164Number, pin, kbsTokenData)
+  }
+
+  @WorkerThread
+  override fun onVerifySuccess(processor: VerifyAccountResponseProcessor): Single<VerifyAccountResponseProcessor> {
+    return changeNumberRepository.changeLocalNumber(number.e164Number)
+      .map { processor }
+      .onErrorReturn { t ->
+        Log.w(TAG, "Error attempting to change local number", t)
+        VerifyAccountResponseWithoutKbs(ServiceResponse.forUnknownError(t))
+      }
+  }
+
+  override fun onVerifySuccessWithRegistrationLock(processor: VerifyCodeWithRegistrationLockResponseProcessor, pin: String): Single<VerifyCodeWithRegistrationLockResponseProcessor> {
+    return changeNumberRepository.changeLocalNumber(number.e164Number)
+      .map { processor }
+      .onErrorReturn { t ->
+        Log.w(TAG, "Error attempting to change local number", t)
+        VerifyCodeWithRegistrationLockResponseProcessor(ServiceResponse.forUnknownError(t), processor.token)
+      }
+  }
+
+  class Factory(owner: SavedStateRegistryOwner) : AbstractSavedStateViewModelFactory(owner, null) {
+
+    override fun <T : ViewModel?> create(key: String, modelClass: Class<T>, handle: SavedStateHandle): T {
+      val context: Application = ApplicationDependencies.getApplication()
+      val localNumber: String = TextSecurePreferences.getLocalNumber(context)
+      val password: String = TextSecurePreferences.getPushServerPassword(context)
+
+      val viewModel = ChangeNumberViewModel(
+        localNumber = localNumber,
+        changeNumberRepository = ChangeNumberRepository(context),
+        savedState = handle,
+        password = password,
+        verifyAccountRepository = VerifyAccountRepository(context),
+        kbsRepository = KbsRepository()
+      )
+
+      return requireNotNull(modelClass.cast(viewModel))
+    }
+  }
+
+  enum class ContinueStatus {
+    CAN_CONTINUE,
+    INVALID_NUMBER,
+    OLD_NUMBER_DOESNT_MATCH
+  }
+}