firebase-ios-sdk/FirebaseMessaging/Sources/FIRMessaging.m

/*
 * Copyright 2017 Google
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#if !__has_feature(objc_arc)
#error FIRMessagingLib should be compiled with ARC.
#endif

#import "FirebaseMessaging/Sources/Public/FirebaseMessaging/FIRMessaging.h"
#import <GoogleUtilities/GULAppDelegateSwizzler.h>
#import <GoogleUtilities/GULReachabilityChecker.h>
#import <GoogleUtilities/GULUserDefaults.h>
#import "Firebase/InstanceID/Private/FIRInstanceID_Private.h"
#import "Firebase/InstanceID/Public/FirebaseInstanceID.h"
#import "FirebaseCore/Sources/Private/FirebaseCoreInternal.h"
#import "FirebaseMessaging/Sources/Interop/FIRMessagingInterop.h"
#import "FirebaseMessaging/Sources/Public/FirebaseMessaging/FIRMessagingExtensionHelper.h"
#import "Interop/Analytics/Public/FIRAnalyticsInterop.h"

#import "FirebaseMessaging/Sources/FIRMessagingAnalytics.h"
#import "FirebaseMessaging/Sources/FIRMessagingConstants.h"
#import "FirebaseMessaging/Sources/FIRMessagingContextManagerService.h"
#import "FirebaseMessaging/Sources/FIRMessagingDefines.h"
#import "FirebaseMessaging/Sources/FIRMessagingLogger.h"
#import "FirebaseMessaging/Sources/FIRMessagingPubSub.h"
#import "FirebaseMessaging/Sources/FIRMessagingRemoteNotificationsProxy.h"
#import "FirebaseMessaging/Sources/FIRMessagingRmqManager.h"
#import "FirebaseMessaging/Sources/FIRMessagingSyncMessageManager.h"
#import "FirebaseMessaging/Sources/FIRMessagingUtilities.h"
#import "FirebaseMessaging/Sources/FIRMessagingVersionUtilities.h"
#import "FirebaseMessaging/Sources/FIRMessaging_Private.h"
#import "FirebaseMessaging/Sources/NSError+FIRMessaging.h"

static NSString *const kFIRMessagingMessageViaAPNSRootKey = @"aps";
static NSString *const kFIRMessagingReachabilityHostname = @"www.google.com";
static NSString *const kFIRMessagingDefaultTokenScope = @"*";
static NSString *const kFIRMessagingFCMTokenFetchAPNSOption = @"apns_token";

#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
const NSNotificationName FIRMessagingRegistrationTokenRefreshedNotification =
    @"com.firebase.messaging.notif.fcm-token-refreshed";
#else
NSString *const FIRMessagingRegistrationTokenRefreshedNotification =
    @"com.firebase.messaging.notif.fcm-token-refreshed";
#endif  // defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0

NSString *const kFIRMessagingUserDefaultsKeyAutoInitEnabled =
    @"com.firebase.messaging.auto-init.enabled";  // Auto Init Enabled key stored in NSUserDefaults

NSString *const kFIRMessagingAPNSTokenType =
    @"APNSTokenType";  // APNS Token type key stored in user info.

NSString *const kFIRMessagingPlistAutoInitEnabled =
    @"FirebaseMessagingAutoInitEnabled";  // Auto Init Enabled key stored in Info.plist

const BOOL FIRMessagingIsAPNSSyncMessage(NSDictionary *message) {
  if ([message[kFIRMessagingMessageViaAPNSRootKey] isKindOfClass:[NSDictionary class]]) {
    NSDictionary *aps = message[kFIRMessagingMessageViaAPNSRootKey];
    if (aps && [aps isKindOfClass:[NSDictionary class]]) {
      return [aps[kFIRMessagingMessageAPNSContentAvailableKey] boolValue];
    }
  }
  return NO;
}

BOOL FIRMessagingIsContextManagerMessage(NSDictionary *message) {
  return [FIRMessagingContextManagerService isContextManagerMessage:message];
}

@interface FIRMessagingMessageInfo ()

@property(nonatomic, readwrite, assign) FIRMessagingMessageStatus status;

@end

@implementation FIRMessagingMessageInfo

- (instancetype)init {
  FIRMessagingInvalidateInitializer();
}

- (instancetype)initWithStatus:(FIRMessagingMessageStatus)status {
  self = [super init];
  if (self) {
    _status = status;
  }
  return self;
}

@end

@interface FIRMessaging () <GULReachabilityDelegate>

// FIRApp properties
@property(nonatomic, readwrite, strong) NSData *apnsTokenData;
@property(nonatomic, readwrite, strong) NSString *defaultFcmToken;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
@property(nonatomic, readwrite, strong) FIRInstanceID *instanceID;
#pragma clang diagnostic pop

@property(nonatomic, readwrite, strong) FIRMessagingClient *client;
@property(nonatomic, readwrite, strong) GULReachabilityChecker *reachability;
@property(nonatomic, readwrite, strong) FIRMessagingPubSub *pubsub;
@property(nonatomic, readwrite, strong) FIRMessagingRmqManager *rmq2Manager;
@property(nonatomic, readwrite, strong) FIRMessagingSyncMessageManager *syncMessageManager;
@property(nonatomic, readwrite, strong) GULUserDefaults *messagingUserDefaults;

/// Message ID's logged for analytics. This prevents us from logging the same message twice
/// which can happen if the user inadvertently calls `appDidReceiveMessage` along with us
/// calling it implicitly during swizzling.
@property(nonatomic, readwrite, strong) NSMutableSet *loggedMessageIDs;
@property(nonatomic, readwrite, strong) id<FIRAnalyticsInterop> _Nullable analytics;

@end

@interface FIRMessaging () <FIRMessagingInterop, FIRLibrary>
@end

@implementation FIRMessaging

+ (FIRMessaging *)messaging {
  FIRApp *defaultApp = [FIRApp defaultApp];  // Missing configure will be logged here.
  id<FIRMessagingInterop> instance = FIR_COMPONENT(FIRMessagingInterop, defaultApp.container);

  // We know the instance coming from the container is a FIRMessaging instance, cast it and move on.
  return (FIRMessaging *)instance;
}

+ (FIRMessagingExtensionHelper *)extensionHelper {
  static dispatch_once_t once;
  static FIRMessagingExtensionHelper *extensionHelper;
  dispatch_once(&once, ^{
    extensionHelper = [[FIRMessagingExtensionHelper alloc] init];
  });
  return extensionHelper;
}
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
- (instancetype)initWithAnalytics:(nullable id<FIRAnalyticsInterop>)analytics
                   withInstanceID:(FIRInstanceID *)instanceID
                 withUserDefaults:(GULUserDefaults *)defaults {
#pragma clang diagnostic pop
  self = [super init];
  if (self != nil) {
    _loggedMessageIDs = [NSMutableSet set];
    _instanceID = instanceID;
    _messagingUserDefaults = defaults;
    _analytics = analytics;
  }
  return self;
}

- (void)dealloc {
  [self.reachability stop];
  [[NSNotificationCenter defaultCenter] removeObserver:self];
  [self teardown];
}

#pragma mark - Config

+ (void)load {
  [FIRApp registerInternalLibrary:(Class<FIRLibrary>)self
                         withName:@"fire-fcm"
                      withVersion:FIRMessagingCurrentLibraryVersion()];
}

+ (nonnull NSArray<FIRComponent *> *)componentsToRegister {
  FIRDependency *analyticsDep = [FIRDependency dependencyWithProtocol:@protocol(FIRAnalyticsInterop)
                                                           isRequired:NO];
  FIRComponentCreationBlock creationBlock =
      ^id _Nullable(FIRComponentContainer *container, BOOL *isCacheable) {
    if (!container.app.isDefaultApp) {
      // Only start for the default FIRApp.
      FIRMessagingLoggerDebug(kFIRMessagingMessageCodeFIRApp001,
                              @"Firebase Messaging only works with the default app.");
      return nil;
    }

    // Ensure it's cached so it returns the same instance every time messaging is called.
    *isCacheable = YES;
    id<FIRAnalyticsInterop> analytics = FIR_COMPONENT(FIRAnalyticsInterop, container);
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    FIRMessaging *messaging =
        [[FIRMessaging alloc] initWithAnalytics:analytics
                                 withInstanceID:[FIRInstanceID instanceID]
                               withUserDefaults:[GULUserDefaults standardUserDefaults]];
#pragma clang diagnostic pop
    [messaging start];
    [messaging configureNotificationSwizzlingIfEnabled];
    return messaging;
  };
  FIRComponent *messagingProvider =
      [FIRComponent componentWithProtocol:@protocol(FIRMessagingInterop)
                      instantiationTiming:FIRInstantiationTimingEagerInDefaultApp
                             dependencies:@[ analyticsDep ]
                            creationBlock:creationBlock];

  return @[ messagingProvider ];
}

- (void)configureNotificationSwizzlingIfEnabled {
  // Swizzle remote-notification-related methods (app delegate and UNUserNotificationCenter)
  if ([FIRMessagingRemoteNotificationsProxy canSwizzleMethods]) {
    NSString *docsURLString = @"https://firebase.google.com/docs/cloud-messaging/ios/client"
                              @"#method_swizzling_in_firebase_messaging";
    FIRMessagingLoggerNotice(kFIRMessagingMessageCodeFIRApp000,
                             @"FIRMessaging Remote Notifications proxy enabled, will swizzle "
                             @"remote notification receiver handlers. If you'd prefer to manually "
                             @"integrate Firebase Messaging, add \"%@\" to your Info.plist, "
                             @"and set it to NO. Follow the instructions at:\n%@\nto ensure "
                             @"proper integration.",
                             kFIRMessagingRemoteNotificationsProxyEnabledInfoPlistKey,
                             docsURLString);
    [[FIRMessagingRemoteNotificationsProxy sharedProxy] swizzleMethodsIfPossible];
  }
}

- (void)start {
  [self setupFileManagerSubDirectory];
  [self setupNotificationListeners];
  [self setupTopics];

#if !TARGET_OS_WATCH
  // Print the library version for logging.
  NSString *currentLibraryVersion = FIRMessagingCurrentLibraryVersion();
  FIRMessagingLoggerInfo(kFIRMessagingMessageCodeMessagingPrintLibraryVersion,
                         @"FIRMessaging library version %@", currentLibraryVersion);

  NSString *hostname = kFIRMessagingReachabilityHostname;
  self.reachability = [[GULReachabilityChecker alloc] initWithReachabilityDelegate:self
                                                                          withHost:hostname];
  [self.reachability start];

  // setup FIRMessaging objects
  [self setupRmqManager];
  [self setupSyncMessageManager];

#endif
}

- (void)setupFileManagerSubDirectory {
  if (![[self class] hasSubDirectory:kFIRMessagingSubDirectoryName]) {
    [[self class] createSubDirectory:kFIRMessagingSubDirectoryName];
  }
}

- (void)setupNotificationListeners {
  // To prevent multiple notifications remove self as observer for all events.
  NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
  [center removeObserver:self];
  [center addObserver:self
             selector:@selector(defaultInstanceIDTokenWasRefreshed:)
                 name:kFIRMessagingRegistrationTokenRefreshNotification
               object:nil];
}

- (void)setupRmqManager {
  self.rmq2Manager = [[FIRMessagingRmqManager alloc] initWithDatabaseName:@"rmq2"];
  [self.rmq2Manager loadRmqId];
}

- (void)setupTopics {
  self.pubsub = [[FIRMessagingPubSub alloc] init];
}

- (void)setupSyncMessageManager {
  self.syncMessageManager =
      [[FIRMessagingSyncMessageManager alloc] initWithRmqManager:self.rmq2Manager];
  [self.syncMessageManager removeExpiredSyncMessages];
}

- (void)teardown {
  self.pubsub = nil;
  self.syncMessageManager = nil;
  self.rmq2Manager = nil;
  FIRMessagingLoggerDebug(kFIRMessagingMessageCodeMessaging001, @"Did successfully teardown");
}

#pragma mark - Messages

- (FIRMessagingMessageInfo *)appDidReceiveMessage:(NSDictionary *)message {
  if (!message.count) {
    return [[FIRMessagingMessageInfo alloc] initWithStatus:FIRMessagingMessageStatusUnknown];
  }

  // For downstream messages that go via MCS we should strip out this key before sending
  // the message to the device.
  BOOL isOldMessage = NO;
  NSString *messageID = message[kFIRMessagingMessageIDKey];
  if (messageID.length) {
    [self.rmq2Manager saveS2dMessageWithRmqId:messageID];

    BOOL isSyncMessage = FIRMessagingIsAPNSSyncMessage(message);
    if (isSyncMessage) {
      isOldMessage = [self.syncMessageManager didReceiveAPNSSyncMessage:message];
    }

    // Prevent duplicates by keeping a cache of all the logged messages during each session.
    // The duplicates only happen when the 3P app calls `appDidReceiveMessage:` along with
    // us swizzling their implementation to call the same method implicitly.
    // We need to rule out the contextual message because it shares the same message ID
    // as the local notification it will schedule. And because it is also a APNSSync message
    // its duplication is already checked previously.
    if (!isOldMessage && !FIRMessagingIsContextManagerMessage(message)) {
      isOldMessage = [self.loggedMessageIDs containsObject:messageID];
      if (!isOldMessage) {
        [self.loggedMessageIDs addObject:messageID];
      }
    }
  }

  if (!isOldMessage) {
    [FIRMessagingAnalytics logMessage:message toAnalytics:_analytics];
    [self handleContextManagerMessage:message];
    [self handleIncomingLinkIfNeededFromMessage:message];
  }
  return [[FIRMessagingMessageInfo alloc] initWithStatus:FIRMessagingMessageStatusNew];
}

- (BOOL)handleContextManagerMessage:(NSDictionary *)message {
  if (FIRMessagingIsContextManagerMessage(message)) {
    return [FIRMessagingContextManagerService handleContextManagerMessage:message];
  }
  return NO;
}

- (void)handleIncomingLinkIfNeededFromMessage:(NSDictionary *)message {
#if TARGET_OS_IOS || TARGET_OS_TV
  NSURL *url = [self linkURLFromMessage:message];
  if (url == nil) {
    return;
  }
  if (![NSThread isMainThread]) {
    dispatch_async(dispatch_get_main_queue(), ^{
      [self handleIncomingLinkIfNeededFromMessage:message];
    });
    return;
  }
  UIApplication *application = [GULAppDelegateSwizzler sharedApplication];
  if (!application) {
    return;
  }
  id<UIApplicationDelegate> appDelegate = application.delegate;
  SEL continueUserActivitySelector = @selector(application:
                                      continueUserActivity:restorationHandler:);

  SEL openURLWithOptionsSelector = @selector(application:openURL:options:);
  SEL openURLWithSourceApplicationSelector = @selector(application:
                                                           openURL:sourceApplication:annotation:);
#if TARGET_OS_IOS
  SEL handleOpenURLSelector = @selector(application:handleOpenURL:);
#endif
  // Due to FIRAAppDelegateProxy swizzling, this selector will most likely get chosen, whether or
  // not the actual application has implemented
  // |application:continueUserActivity:restorationHandler:|. A warning will be displayed to the user
  // if they haven't implemented it.
  if ([NSUserActivity class] != nil &&
      [appDelegate respondsToSelector:continueUserActivitySelector]) {
    NSUserActivity *userActivity =
        [[NSUserActivity alloc] initWithActivityType:NSUserActivityTypeBrowsingWeb];
    userActivity.webpageURL = url;
    [appDelegate application:application
        continueUserActivity:userActivity
          restorationHandler:^(NSArray *_Nullable restorableObjects){
              // Do nothing, as we don't support the app calling this block
          }];

  } else if ([appDelegate respondsToSelector:openURLWithOptionsSelector]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability"
    [appDelegate application:application openURL:url options:@{}];
#pragma clang diagnostic pop
    // Similarly, |application:openURL:sourceApplication:annotation:| will also always be called,
    // due to the default swizzling done by FIRAAppDelegateProxy in Firebase Analytics
  } else if ([appDelegate respondsToSelector:openURLWithSourceApplicationSelector]) {
#if TARGET_OS_IOS
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    [appDelegate application:application
                     openURL:url
           sourceApplication:FIRMessagingAppIdentifier()
                  annotation:@{}];
#pragma clang diagnostic pop
  } else if ([appDelegate respondsToSelector:handleOpenURLSelector]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    [appDelegate application:application handleOpenURL:url];
#pragma clang diagnostic pop
#endif
  }
#endif
}

- (NSURL *)linkURLFromMessage:(NSDictionary *)message {
  NSString *urlString = message[kFIRMessagingMessageLinkKey];
  if (urlString == nil || ![urlString isKindOfClass:[NSString class]] || urlString.length == 0) {
    return nil;
  }
  NSURL *url = [NSURL URLWithString:urlString];
  return url;
}

#pragma mark - APNS

- (NSData *)APNSToken {
  return self.apnsTokenData;
}

- (void)setAPNSToken:(NSData *)APNSToken {
  [self setAPNSToken:APNSToken type:FIRMessagingAPNSTokenTypeUnknown];
}

- (void)setAPNSToken:(NSData *)apnsToken type:(FIRMessagingAPNSTokenType)type {
  if ([apnsToken isEqual:self.apnsTokenData]) {
    return;
  }
  self.apnsTokenData = apnsToken;

  // Notify InstanceID that APNS Token has been set.
  NSDictionary *userInfo = @{kFIRMessagingAPNSTokenType : @(type)};
  NSNotification *notification =
      [NSNotification notificationWithName:kFIRMessagingAPNSTokenNotification
                                    object:[apnsToken copy]
                                  userInfo:userInfo];
  [[NSNotificationQueue defaultQueue] enqueueNotification:notification postingStyle:NSPostASAP];
}

#pragma mark - FCM

- (BOOL)isAutoInitEnabled {
  // Defer to the class method since we're just reading from regular userDefaults and we need to
  // read this from IID without instantiating the Messaging singleton.
  return [[self class] isAutoInitEnabledWithUserDefaults:_messagingUserDefaults];
}

/// Checks if Messaging auto-init is enabled in the user defaults instance passed in. This is
/// exposed as a class property for IID to fetch the property without instantiating an instance of
/// Messaging. Since Messaging can only be used with the default FIRApp, we can have one point of
/// entry without context of which FIRApp instance is being used.
/// ** THIS METHOD IS DEPENDED ON INTERNALLY BY IID USING REFLECTION. PLEASE DO NOT CHANGE THE
///  SIGNATURE, AS IT WOULD BREAK AUTOINIT FUNCTIONALITY WITHIN IID. **
+ (BOOL)isAutoInitEnabledWithUserDefaults:(GULUserDefaults *)userDefaults {
  // Check storage
  id isAutoInitEnabledObject =
      [userDefaults objectForKey:kFIRMessagingUserDefaultsKeyAutoInitEnabled];
  if (isAutoInitEnabledObject) {
    return [isAutoInitEnabledObject boolValue];
  }

  // Check Info.plist
  isAutoInitEnabledObject =
      [[NSBundle mainBundle] objectForInfoDictionaryKey:kFIRMessagingPlistAutoInitEnabled];
  if (isAutoInitEnabledObject) {
    return [isAutoInitEnabledObject boolValue];
  }

  // If none of above exists, we default to the global switch that comes from FIRApp.
  return [[FIRApp defaultApp] isDataCollectionDefaultEnabled];
}

- (void)setAutoInitEnabled:(BOOL)autoInitEnabled {
  BOOL isFCMAutoInitEnabled = [self isAutoInitEnabled];
  [_messagingUserDefaults setBool:autoInitEnabled
                           forKey:kFIRMessagingUserDefaultsKeyAutoInitEnabled];
  [_messagingUserDefaults synchronize];
  if (!isFCMAutoInitEnabled && autoInitEnabled) {
    self.defaultFcmToken = self.instanceID.token;
  }
}

- (NSString *)FCMToken {
  NSString *token = self.defaultFcmToken;
  if (!token) {
    // We may not have received it from Instance ID yet (via NSNotification), so extract it directly
    token = self.instanceID.token;
  }
  return token;
}

- (void)tokenWithCompletion:(FIRMessagingFCMTokenFetchCompletion)completion {
  FIROptions *options = FIRApp.defaultApp.options;
  [self retrieveFCMTokenForSenderID:options.GCMSenderID completion:completion];
}
- (void)deleteTokenWithCompletion:(FIRMessagingDeleteFCMTokenCompletion)completion {
  FIROptions *options = FIRApp.defaultApp.options;
  [self deleteFCMTokenForSenderID:options.GCMSenderID completion:completion];
}

- (void)retrieveFCMTokenForSenderID:(nonnull NSString *)senderID
                         completion:(nonnull FIRMessagingFCMTokenFetchCompletion)completion {
  if (!senderID.length) {
    NSString *description = @"Couldn't fetch token because a Sender ID was not supplied. A valid "
                            @"Sender ID is required to fetch an FCM token";
    FIRMessagingLoggerError(kFIRMessagingMessageCodeSenderIDNotSuppliedForTokenFetch, @"%@",
                            description);
    if (completion) {
      NSError *error = [NSError messagingErrorWithCode:kFIRMessagingErrorCodeInvalidRequest
                                         failureReason:description];
      completion(nil, error);
    }
    return;
  }
  NSDictionary *options = nil;
  if (self.APNSToken) {
    options = @{kFIRMessagingFCMTokenFetchAPNSOption : self.APNSToken};
  } else {
    FIRMessagingLoggerWarn(kFIRMessagingMessageCodeAPNSTokenNotAvailableDuringTokenFetch,
                           @"APNS device token not set before retrieving FCM Token for Sender ID "
                           @"'%@'. Notifications to this FCM Token will not be delivered over APNS."
                           @"Be sure to re-retrieve the FCM token once the APNS device token is "
                           @"set.",
                           senderID);
  }
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  [self.instanceID tokenWithAuthorizedEntity:senderID
                                       scope:kFIRMessagingDefaultTokenScope
                                     options:options
                                     handler:completion];
#pragma clang diagnostic pop
}

- (void)deleteFCMTokenForSenderID:(nonnull NSString *)senderID
                       completion:(nonnull FIRMessagingDeleteFCMTokenCompletion)completion {
  if (!senderID.length) {
    NSString *description = @"Couldn't delete token because a Sender ID was not supplied. A "
                            @"valid Sender ID is required to delete an FCM token";
    FIRMessagingLoggerError(kFIRMessagingMessageCodeSenderIDNotSuppliedForTokenDelete, @"%@",
                            description);
    if (completion) {
      NSError *error = [NSError messagingErrorWithCode:kFIRMessagingErrorCodeInvalidRequest
                                         failureReason:description];
      completion(error);
    }
    return;
  }
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  [self.instanceID deleteTokenWithAuthorizedEntity:senderID
                                             scope:kFIRMessagingDefaultTokenScope
                                           handler:completion];
#pragma clang diagnostic pop
}

- (void)deleteDataWithCompletion:(void (^)(NSError *_Nullable))completion {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  FIRMessaging_WEAKIFY(self);
  [self.instanceID
      deleteTokenWithAuthorizedEntity:@"*"
                                scope:@"*"
                              handler:^(NSError *_Nonnull error) {
                                FIRMessaging_STRONGIFY(self);
                                if (error) {
                                  completion(error);
                                  return;
                                }
                                [self.instanceID
                                    deleteCheckinWithHandler:^(NSError *_Nullable error) {
                                      if (error) {
                                        completion(error);
                                        return;
                                      }
                                      // Only request new token if FCM auto initialization is
                                      // enabled.
                                      if ([self isAutoInitEnabled]) {
                                        // Deletion succeeds! Requesting new checkin, IID and token.
                                        [self tokenWithCompletion:^(NSString *_Nullable token,
                                                                    NSError *_Nullable error) {
                                          completion(error);
                                        }];
                                        return;
                                      }
                                      completion(nil);
                                    }];
                              }];
#pragma clang diagnostic pop
}

#pragma mark - FIRMessagingDelegate helper methods
- (void)setDelegate:(id<FIRMessagingDelegate>)delegate {
  _delegate = delegate;
  [self validateDelegateConformsToTokenAvailabilityMethods];
}

// Check if the delegate conforms to |didReceiveRegistrationToken:|
// and display a warning to the developer if not.
// NOTE: Once |didReceiveRegistrationToken:| can be made a required method, this
// check can be removed.
- (void)validateDelegateConformsToTokenAvailabilityMethods {
  if (self.delegate && ![self.delegate respondsToSelector:@selector(messaging:
                                                              didReceiveRegistrationToken:)]) {
    FIRMessagingLoggerWarn(kFIRMessagingMessageCodeTokenDelegateMethodsNotImplemented,
                           @"The object %@ does not respond to "
                           @"-messaging:didReceiveRegistrationToken:. Please implement "
                           @"-messaging:didReceiveRegistrationToken: to be provided with an FCM "
                           @"token.",
                           self.delegate.description);
  }
}

- (void)notifyDelegateOfFCMTokenAvailability {
  __weak FIRMessaging *weakSelf = self;
  if (![NSThread isMainThread]) {
    dispatch_async(dispatch_get_main_queue(), ^{
      [weakSelf notifyDelegateOfFCMTokenAvailability];
    });
    return;
  }
  if ([self.delegate respondsToSelector:@selector(messaging:didReceiveRegistrationToken:)]) {
    [self.delegate messaging:self didReceiveRegistrationToken:self.defaultFcmToken];
  }
  // Should always trigger the token refresh notification when the delegate method is called
  NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
  [center postNotificationName:FIRMessagingRegistrationTokenRefreshedNotification
                        object:self.defaultFcmToken];
}

#pragma mark - Topics

+ (NSString *)normalizeTopic:(NSString *)topic {
  if (!topic.length) {
    return nil;
  }
  if (![FIRMessagingPubSub hasTopicsPrefix:topic]) {
    topic = [FIRMessagingPubSub addPrefixToTopic:topic];
  }
  if ([FIRMessagingPubSub isValidTopicWithPrefix:topic]) {
    return [topic copy];
  }
  return nil;
}

- (void)subscribeToTopic:(NSString *)topic {
  [self subscribeToTopic:topic completion:nil];
}

- (void)subscribeToTopic:(NSString *)topic
              completion:(nullable FIRMessagingTopicOperationCompletion)completion {
  if ([FIRMessagingPubSub hasTopicsPrefix:topic]) {
    FIRMessagingLoggerWarn(kFIRMessagingMessageCodeTopicFormatIsDeprecated,
                           @"Format '%@' is deprecated. Only '%@' should be used in "
                           @"subscribeToTopic.",
                           topic, [FIRMessagingPubSub removePrefixFromTopic:topic]);
  }
  __weak FIRMessaging *weakSelf = self;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  [self.instanceID instanceIDWithHandler:^(FIRInstanceIDResult *_Nullable result,
                                           NSError *_Nullable error) {
    if (error) {
      FIRMessagingLoggerError(
          kFIRMessagingMessageCodeMessaging010,
          @"The subscription operation failed due to an error getting the FCM token: %@.", error);
      if (completion) {
        completion(error);
      }
      return;
    }
    FIRMessaging *strongSelf = weakSelf;
    NSString *normalizeTopic = [[strongSelf class] normalizeTopic:topic];
    if (normalizeTopic.length) {
      [strongSelf.pubsub subscribeToTopic:normalizeTopic handler:completion];
      return;
    }
    NSString *failureReason =
        [NSString stringWithFormat:@"Cannot parse topic name: '%@'. Will not subscribe.", topic];
    FIRMessagingLoggerError(kFIRMessagingMessageCodeMessaging009, @"%@", failureReason);
    if (completion) {
      completion([NSError messagingErrorWithCode:kFIRMessagingErrorCodeInvalidTopicName
                                   failureReason:failureReason]);
    }
  }];
#pragma clang diagnostic pop
}

- (void)unsubscribeFromTopic:(NSString *)topic {
  [self unsubscribeFromTopic:topic completion:nil];
}

- (void)unsubscribeFromTopic:(NSString *)topic
                  completion:(nullable FIRMessagingTopicOperationCompletion)completion {
  if ([FIRMessagingPubSub hasTopicsPrefix:topic]) {
    FIRMessagingLoggerWarn(kFIRMessagingMessageCodeTopicFormatIsDeprecated,
                           @"Format '%@' is deprecated. Only '%@' should be used in "
                           @"unsubscribeFromTopic.",
                           topic, [FIRMessagingPubSub removePrefixFromTopic:topic]);
  }
  __weak FIRMessaging *weakSelf = self;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  [self.instanceID instanceIDWithHandler:^(FIRInstanceIDResult *_Nullable result,
                                           NSError *_Nullable error) {
    if (error) {
      FIRMessagingLoggerError(
          kFIRMessagingMessageCodeMessaging012,
          @"The unsubscription operation failed due to an error getting the FCM token: %@.", error);
      if (completion) {
        completion(error);
      }
      return;
    }
    FIRMessaging *strongSelf = weakSelf;
    NSString *normalizeTopic = [[strongSelf class] normalizeTopic:topic];
    if (normalizeTopic.length) {
      [strongSelf.pubsub unsubscribeFromTopic:normalizeTopic handler:completion];
      return;
    }
    NSString *failureReason =
        [NSString stringWithFormat:@"Cannot parse topic name: '%@'. Will not unsubscribe.", topic];
    FIRMessagingLoggerError(kFIRMessagingMessageCodeMessaging011, @"%@", failureReason);
    if (completion) {
      completion([NSError messagingErrorWithCode:kFIRMessagingErrorCodeInvalidTopicName
                                   failureReason:failureReason]);
    }
  }];
#pragma clang diagnostic pop
}

#pragma mark - IID dependencies

+ (NSString *)FIRMessagingSDKVersion {
  return FIRMessagingCurrentLibraryVersion();
}

+ (NSString *)FIRMessagingSDKCurrentLocale {
  return [self currentLocale];
}

#pragma mark - GULReachabilityDelegate

- (void)reachability:(GULReachabilityChecker *)reachability
       statusChanged:(GULReachabilityStatus)status {
  [self onNetworkStatusChanged];
}

#pragma mark - Network

- (void)onNetworkStatusChanged {
  if ([self isNetworkAvailable]) {
    [self.pubsub scheduleSync:YES];
  }
}

- (BOOL)isNetworkAvailable {
  GULReachabilityStatus status = self.reachability.reachabilityStatus;
  return (status == kGULReachabilityViaCellular || status == kGULReachabilityViaWifi);
}

- (FIRMessagingNetworkStatus)networkType {
  GULReachabilityStatus status = self.reachability.reachabilityStatus;
  if (![self isNetworkAvailable]) {
    return kFIRMessagingReachabilityNotReachable;
  } else if (status == kGULReachabilityViaCellular) {
    return kFIRMessagingReachabilityReachableViaWWAN;
  } else {
    return kFIRMessagingReachabilityReachableViaWiFi;
  }
}

#pragma mark - Notifications

- (void)defaultInstanceIDTokenWasRefreshed:(NSNotification *)notification {
  if (notification.object && ![notification.object isKindOfClass:[NSString class]]) {
    FIRMessagingLoggerDebug(kFIRMessagingMessageCodeMessaging015,
                            @"Invalid default FCM token type %@",
                            NSStringFromClass([notification.object class]));
    return;
  }
  // Retrieve the Instance ID default token, and should notify delegate and
  // trigger notification as long as the token is different from previous state.
  NSString *oldToken = self.defaultFcmToken;
  self.defaultFcmToken = [(NSString *)notification.object copy];
  if ((self.defaultFcmToken.length && oldToken.length &&
       ![self.defaultFcmToken isEqualToString:oldToken]) ||
      self.defaultFcmToken.length != oldToken.length) {
    [self notifyDelegateOfFCMTokenAvailability];
    [self.pubsub scheduleSync:YES];
  }
}

#pragma mark - Application Support Directory

+ (BOOL)hasSubDirectory:(NSString *)subDirectoryName {
  NSString *subDirectoryPath = [self pathForSubDirectory:subDirectoryName];
  BOOL isDirectory;
  if (![[NSFileManager defaultManager] fileExistsAtPath:subDirectoryPath
                                            isDirectory:&isDirectory]) {
    return NO;
  } else if (!isDirectory) {
    return NO;
  }
  return YES;
}

+ (NSString *)pathForSubDirectory:(NSString *)subDirectoryName {
  NSArray *directoryPaths =
      NSSearchPathForDirectoriesInDomains(FIRMessagingSupportedDirectory(), NSUserDomainMask, YES);
  NSString *dirPath = directoryPaths.lastObject;
  NSArray *components = @[ dirPath, subDirectoryName ];
  return [NSString pathWithComponents:components];
}

+ (BOOL)createSubDirectory:(NSString *)subDirectoryName {
  NSString *subDirectoryPath = [self pathForSubDirectory:subDirectoryName];
  BOOL hasSubDirectory;

  if (![[NSFileManager defaultManager] fileExistsAtPath:subDirectoryPath
                                            isDirectory:&hasSubDirectory]) {
    NSError *error;
    [[NSFileManager defaultManager] createDirectoryAtPath:subDirectoryPath
                              withIntermediateDirectories:YES
                                               attributes:nil
                                                    error:&error];
    if (error) {
      FIRMessagingLoggerError(kFIRMessagingMessageCodeMessaging017,
                              @"Cannot create directory %@, error: %@", subDirectoryPath, error);
      return NO;
    }
  } else {
    if (!hasSubDirectory) {
      FIRMessagingLoggerError(kFIRMessagingMessageCodeMessaging018,
                              @"Found file instead of directory at %@", subDirectoryPath);
      return NO;
    }
  }
  return YES;
}

#pragma mark - Locales

+ (NSString *)currentLocale {
  NSArray *locales = [self firebaseLocales];
  NSArray *preferredLocalizations =
      [NSBundle preferredLocalizationsFromArray:locales
                                 forPreferences:[NSLocale preferredLanguages]];
  NSString *legalDocsLanguage = [preferredLocalizations firstObject];
  // Use en as the default language
  return legalDocsLanguage ? legalDocsLanguage : @"en";
}

+ (NSArray *)firebaseLocales {
  NSMutableArray *locales = [NSMutableArray array];
  NSDictionary *localesMap = [self firebaselocalesMap];
  for (NSString *key in localesMap) {
    [locales addObjectsFromArray:localesMap[key]];
  }
  return locales;
}

+ (NSDictionary *)firebaselocalesMap {
  return @{
    // Albanian
    @"sq" : @[ @"sq_AL" ],
    // Belarusian
    @"be" : @[ @"be_BY" ],
    // Bulgarian
    @"bg" : @[ @"bg_BG" ],
    // Catalan
    @"ca" : @[ @"ca", @"ca_ES" ],
    // Croatian
    @"hr" : @[ @"hr", @"hr_HR" ],
    // Czech
    @"cs" : @[ @"cs", @"cs_CZ" ],
    // Danish
    @"da" : @[ @"da", @"da_DK" ],
    // Estonian
    @"et" : @[ @"et_EE" ],
    // Finnish
    @"fi" : @[ @"fi", @"fi_FI" ],
    // Hebrew
    @"he" : @[ @"he", @"iw_IL" ],
    // Hindi
    @"hi" : @[ @"hi_IN" ],
    // Hungarian
    @"hu" : @[ @"hu", @"hu_HU" ],
    // Icelandic
    @"is" : @[ @"is_IS" ],
    // Indonesian
    @"id" : @[ @"id", @"in_ID", @"id_ID" ],
    // Irish
    @"ga" : @[ @"ga_IE" ],
    // Korean
    @"ko" : @[ @"ko", @"ko_KR", @"ko-KR" ],
    // Latvian
    @"lv" : @[ @"lv_LV" ],
    // Lithuanian
    @"lt" : @[ @"lt_LT" ],
    // Macedonian
    @"mk" : @[ @"mk_MK" ],
    // Malay
    @"ms" : @[ @"ms_MY" ],
    // Maltese
    @"mt" : @[ @"mt_MT" ],
    // Polish
    @"pl" : @[ @"pl", @"pl_PL", @"pl-PL" ],
    // Romanian
    @"ro" : @[ @"ro", @"ro_RO" ],
    // Russian
    @"ru" : @[ @"ru_RU", @"ru", @"ru_BY", @"ru_KZ", @"ru-RU" ],
    // Slovak
    @"sk" : @[ @"sk", @"sk_SK" ],
    // Slovenian
    @"sl" : @[ @"sl_SI" ],
    // Swedish
    @"sv" : @[ @"sv", @"sv_SE", @"sv-SE" ],
    // Turkish
    @"tr" : @[ @"tr", @"tr-TR", @"tr_TR" ],
    // Ukrainian
    @"uk" : @[ @"uk", @"uk_UA" ],
    // Vietnamese
    @"vi" : @[ @"vi", @"vi_VN" ],
    // The following are groups of locales or locales that sub-divide a
    // language).
    // Arabic
    @"ar" : @[
      @"ar",    @"ar_DZ", @"ar_BH", @"ar_EG", @"ar_IQ", @"ar_JO", @"ar_KW",
      @"ar_LB", @"ar_LY", @"ar_MA", @"ar_OM", @"ar_QA", @"ar_SA", @"ar_SD",
      @"ar_SY", @"ar_TN", @"ar_AE", @"ar_YE", @"ar_GB", @"ar-IQ", @"ar_US"
    ],
    // Simplified Chinese
    @"zh_Hans" : @[ @"zh_CN", @"zh_SG", @"zh-Hans" ],
    // Traditional Chinese
    @"zh_Hant" : @[ @"zh_HK", @"zh_TW", @"zh-Hant", @"zh-HK", @"zh-TW" ],
    // Dutch
    @"nl" : @[ @"nl", @"nl_BE", @"nl_NL", @"nl-NL" ],
    // English
    @"en" : @[
      @"en",    @"en_AU", @"en_CA", @"en_IN", @"en_IE", @"en_MT", @"en_NZ", @"en_PH",
      @"en_SG", @"en_ZA", @"en_GB", @"en_US", @"en_AE", @"en-AE", @"en_AS", @"en-AU",
      @"en_BD", @"en-CA", @"en_EG", @"en_ES", @"en_GB", @"en-GB", @"en_HK", @"en_ID",
      @"en-IN", @"en_NG", @"en-PH", @"en_PK", @"en-SG", @"en-US"
    ],
    // French

    @"fr" :
        @[ @"fr", @"fr_BE", @"fr_CA", @"fr_FR", @"fr_LU", @"fr_CH", @"fr-CA", @"fr-FR", @"fr_MA" ],
    // German
    @"de" : @[ @"de", @"de_AT", @"de_DE", @"de_LU", @"de_CH", @"de-DE" ],
    // Greek
    @"el" : @[ @"el", @"el_CY", @"el_GR" ],
    // Italian
    @"it" : @[ @"it", @"it_IT", @"it_CH", @"it-IT" ],
    // Japanese
    @"ja" : @[ @"ja", @"ja_JP", @"ja_JP_JP", @"ja-JP" ],
    // Norwegian
    @"no" : @[ @"nb", @"no_NO", @"no_NO_NY", @"nb_NO" ],
    // Brazilian Portuguese
    @"pt_BR" : @[ @"pt_BR", @"pt-BR" ],
    // European Portuguese
    @"pt_PT" : @[ @"pt", @"pt_PT", @"pt-PT" ],
    // Serbian
    @"sr" : @[ @"sr_BA", @"sr_ME", @"sr_RS", @"sr_Latn_BA", @"sr_Latn_ME", @"sr_Latn_RS" ],
    // European Spanish
    @"es_ES" : @[ @"es", @"es_ES", @"es-ES" ],
    // Mexican Spanish
    @"es_MX" : @[ @"es-MX", @"es_MX", @"es_US", @"es-US" ],
    // Latin American Spanish
    @"es_419" : @[
      @"es_AR", @"es_BO", @"es_CL", @"es_CO", @"es_CR", @"es_DO", @"es_EC",
      @"es_SV", @"es_GT", @"es_HN", @"es_NI", @"es_PA", @"es_PY", @"es_PE",
      @"es_PR", @"es_UY", @"es_VE", @"es-AR", @"es-CL", @"es-CO"
    ],
    // Thai
    @"th" : @[ @"th", @"th_TH", @"th_TH_TH" ],
  };
}

@end