From 1b9eb3c572963814b949593427099c018f3f0354 Mon Sep 17 00:00:00 2001
From: Matthew Chen <matthew@signal.org>
Date: Fri, 15 Mar 2019 09:16:19 -0400
Subject: [PATCH] Ensure Callkit is enabled for locale.

---
 .../PrivacySettingsTableViewController.m      |  4 +++-
 .../call/UserInterface/CallUIAdapter.swift    | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Signal/src/ViewControllers/AppSettings/PrivacySettingsTableViewController.m b/Signal/src/ViewControllers/AppSettings/PrivacySettingsTableViewController.m
index 90978af3b..061796827 100644
--- a/Signal/src/ViewControllers/AppSettings/PrivacySettingsTableViewController.m
+++ b/Signal/src/ViewControllers/AppSettings/PrivacySettingsTableViewController.m
@@ -207,7 +207,9 @@ static NSString *const kSealedSenderInfoURL = @"https://signal.org/blog/sealed-s
                                 selector:@selector(didToggleCallsHideIPAddressSwitch:)]];
     [contents addSection:callingSection];
 
-    if (@available(iOS 11, *)) {
+    if (CallUIAdapter.isCallkitDisabledForLocale) {
+        // Hide all CallKit-related prefs; CallKit is disabled.
+    } else if (@available(iOS 11, *)) {
         OWSTableSection *callKitSection = [OWSTableSection new];
         [callKitSection
             addItem:[OWSTableItem switchItemWithText:NSLocalizedString(
diff --git a/Signal/src/call/UserInterface/CallUIAdapter.swift b/Signal/src/call/UserInterface/CallUIAdapter.swift
index d2a2ba0b5..c998b475b 100644
--- a/Signal/src/call/UserInterface/CallUIAdapter.swift
+++ b/Signal/src/call/UserInterface/CallUIAdapter.swift
@@ -100,6 +100,9 @@ extension CallUIAdaptee {
             // So we use the non-CallKit call UI.
             Logger.info("choosing non-callkit adaptee for simulator.")
             adaptee = NonCallKitCallUIAdaptee(callService: callService, notificationPresenter: notificationPresenter)
+        } else if CallUIAdapter.isCallkitDisabledForLocale {
+            Logger.info("choosing non-callkit adaptee due to locale.")
+            adaptee = NonCallKitCallUIAdaptee(callService: callService, notificationPresenter: notificationPresenter)
         } else if #available(iOS 11, *) {
             Logger.info("choosing callkit adaptee for iOS11+")
             let showNames = Environment.shared.preferences.notificationPreviewType() != .noNameNoPreview
@@ -129,6 +132,22 @@ extension CallUIAdaptee {
         callService.addObserverAndSyncState(observer: self)
     }
 
+    @objc
+    public static var isCallkitDisabledForLocale: Bool {
+        let locale = Locale.current
+        guard let regionCode = locale.regionCode else {
+            owsFailDebug("Missing region code.")
+            return false
+        }
+
+        // Apple has stopped approving apps that use CallKit functionality in mainland China.
+        // When the "CN" region is enabled, this check simply switches to the same pre-CallKit
+        // interface that is still used by everyone on iOS 9.
+        //
+        // For further reference: https://forums.developer.apple.com/thread/103083
+        return regionCode == "CN"
+    }
+
     // MARK: Dependencies
 
     var audioSession: OWSAudioSession {