MKiCloudSync.m

//
//  MKiCloudSync.m
//  iCloud1
//
//  Created by Mugunth Kumar (@mugunthkumar) on 20/11/11.
//  Copyright (C) 2011-2020 by Steinlogic

//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.

//  As a side note, you might also consider
//	1) tweeting about this mentioning @mugunthkumar
//	2) A paypal donation to mugunth.kumar@gmail.com


#import "MKiCloudSync.h"

static NSString *prefix;
@implementation MKiCloudSync

+(void) updateToiCloud:(NSNotification*) notificationObject {

  NSDictionary *dict = [[NSUserDefaults standardUserDefaults] dictionaryRepresentation];

  [dict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {

    if([key hasPrefix:prefix]) {
      [[NSUbiquitousKeyValueStore defaultStore] setObject:obj forKey:key];
    }
  }];

  [[NSUbiquitousKeyValueStore defaultStore] synchronize];
}

+(void) updateFromiCloud:(NSNotification*) notificationObject {

  NSUbiquitousKeyValueStore *iCloudStore = [NSUbiquitousKeyValueStore defaultStore];
  NSDictionary *dict = [iCloudStore dictionaryRepresentation];

  // prevent NSUserDefaultsDidChangeNotification from being posted while we update from iCloud

  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                  name:NSUserDefaultsDidChangeNotification
                                                object:nil];

  [dict enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {

    if([key hasPrefix:prefix]) {
      [[NSUserDefaults standardUserDefaults] setObject:obj forKey:key];
    }
  }];

  [[NSUserDefaults standardUserDefaults] synchronize];

  // enable NSUserDefaultsDidChangeNotification notifications again

  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(updateToiCloud:)
                                               name:NSUserDefaultsDidChangeNotification
                                             object:nil];

  [[NSNotificationCenter defaultCenter] postNotificationName:kMKiCloudSyncNotification object:nil];
}

+(void) startWithPrefix:(NSString*) prefixToSync {

  prefix = prefixToSync;
  if([NSUbiquitousKeyValueStore defaultStore]) {  // is iCloud enabled

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(updateFromiCloud:)
                                                 name:NSUbiquitousKeyValueStoreDidChangeExternallyNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(updateToiCloud:)
                                                 name:NSUserDefaultsDidChangeNotification                                                    object:nil];
  } else {
    DLog(@"iCloud not enabled");
  }
}

+ (void) dealloc {

  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                  name:NSUbiquitousKeyValueStoreDidChangeExternallyNotification
                                                object:nil];

  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                  name:NSUserDefaultsDidChangeNotification
                                                object:nil];
}
@end