react-native NativeModule for interacting with gmail objc google rest apis

Thing.m

//
//  RNGmailAPI.m
//  astroboy
//
//  Created by Eric Lewis on 4/9/19.
//  Copyright © 2019 Eric Lewis. All rights reserved.
//

#import "RNGmailAPI.h"
#import "RNPromiseWrapper.h"

#import <GTLRGmail.h>

@interface RNGmailAPI ()

@property (nonatomic) RNPromiseWrapper *promiseWrapper;
@property (nonatomic) GTLRGmailService *gmail;
@property (nonatomic) GTLRBatchQuery *batchQuery;
@property (nonatomic) GIDSignIn *signIn;

@end

@implementation RNGmailAPI

RCT_EXPORT_MODULE();

- (instancetype)init
{
  self = [super init];
  if (self) {
    self.promiseWrapper = [[RNPromiseWrapper alloc] init];
    self.gmail = [[GTLRGmailService alloc] init];
    self.signIn = [GIDSignIn sharedInstance];
    self.signIn.delegate = self;
  }
  return self;
}

- (NSDictionary *)constantsToExport
{
  return @{ @"initialIsLoggedIn": @(self.signIn.hasAuthInKeychain) };
}

+ (BOOL)requiresMainQueueSetup
{
  return NO;
}

RCT_EXPORT_METHOD(initialize:(RCTPromiseResolveBlock)resolve
                    rejecter:(RCTPromiseRejectBlock)reject)
{
  if (self.signIn.currentUser == nil) {
    NSString *methodName = @"initialize";
    [self.promiseWrapper setPromiseWithInProgressCheck:resolve rejecter:nil fromCallSite:methodName];
    dispatch_async(dispatch_get_main_queue(), ^{
      [[GIDSignIn sharedInstance] signInSilently];
    });
  } else {
    resolve(self.signIn.currentUser);
  }
}
 
RCT_EXPORT_METHOD(executeQueries:(NSArray<NSDictionary *> *)queries
                  resolver:(RCTPromiseResolveBlock)resolve
                  rejecter:(RCTPromiseRejectBlock)reject)
{
  [self execute:[self createBatchQuery:queries] resolver:resolve rejecter:reject];
}

- (void)execute:(GTLRBatchQuery *)query
  resolver:(RCTPromiseResolveBlock)resolve
                 rejecter:(RCTPromiseRejectBlock)reject
{
  [self.gmail executeQuery:query
   completionHandler:^(GTLRServiceTicket *ticket, GTLRBatchResult *batchResult, NSError *error) {
     if (error == nil) {
       // reset the global batcher (maybe there is a better way?) also, maybe we don't want to on error?
       
       NSDictionary *successes = batchResult.successes;
       NSMutableArray *successResponse = [[NSMutableArray alloc] initWithCapacity:successes.count];
       for (NSString *requestID in successes) {
         GTLRObject *list = [successes objectForKey:requestID];
         [successResponse addObject:list.JSON];
       }
       
       NSDictionary *failures = batchResult.failures;
       NSMutableArray *failuresResponse = [[NSMutableArray alloc] initWithCapacity:failures.count];
       for (NSString *requestID in failures) {
         GTLRErrorObject *errorObj = [failures objectForKey:requestID];
         [failuresResponse addObject:errorObj.JSON];
       }
       
       resolve(@{ @"results": successResponse, @"errors": failuresResponse });
     } else {
       reject(@"gmail_error", @"Something went wrong, yo.", error);
     }
   }];
}

- (GTLRBatchQuery *)createBatchQuery:(NSArray<NSDictionary *> *)queries
{
  __block GTLRBatchQuery *batch = [GTLRBatchQuery batchQuery];
  
  [queries enumerateObjectsUsingBlock:^(NSDictionary *query, NSUInteger idx, BOOL * _Nonnull stop) {
    [batch addQuery:[self createQueryFromDictionary:query]];
  }];
  
  return batch;
}

- (id)createQueryFromDictionary:(NSDictionary*)queryDict
{
  NSString *type = queryDict[@"type"];
  Class theClass = NSClassFromString([NSString stringWithFormat:@"GTLRGmailQuery_%@", type]);
  id query       = (   [type containsString:@"Trash"]
                    || [type containsString:@"Untrash"]
                    || [type containsString:@"Delete"]
                    || [type containsString:@"Get"])
                      ? [theClass queryWithUserId:self.signIn.currentUser.userID identifier:queryDict[@"id"]]
                      : [theClass queryWithUserId:self.signIn.currentUser.userID];
  
  NSMutableDictionary *queryDictCopy = [queryDict mutableCopy];
  
  // clean off some things we don't wanna attach
  [queryDictCopy removeObjectForKey:@"type"];
  [queryDictCopy removeObjectForKey:@"id"];
  
  [query setValuesForKeysWithDictionary:queryDictCopy];

  return query;
}

- (void)signIn:(GIDSignIn *)signIn didSignInForUser:(GIDGoogleUser *)user
     withError:(NSError *)error
{
  if (error) {
    [self.promiseWrapper reject:@"Error when revoking access." withError:error];
    return;
  }
  
  self.gmail.authorizer = [[user authentication] fetcherAuthorizer];
  [self.promiseWrapper resolve:(user)];
}

- (void)signIn:(GIDSignIn *)signIn didDisconnectWithUser:(GIDGoogleUser *)user
     withError:(NSError *)error
{
  if (error) {
    [self.promiseWrapper reject:@"Error when disconnecting user." withError:error];
    return;
  }
  
  [self.promiseWrapper resolve:(user)];
}

@end