NSString+Emojize.m

//
//  NSString+Emojize.m
//  Field Recorder
//
//  Created by Jonathan Beilin on 11/5/12.
//  Copyright (c) 2014 DIY. All rights reserved.
//

#import "NSString+Emojize.h"

@implementation NSString (Emojize)

- (NSString *)emojizedString
{
    return [NSString emojizedStringWithString:self];
}

+ (NSString *)emojizedStringWithString:(NSString *)text
{
    static dispatch_once_t onceToken;
    static NSRegularExpression *regex = nil;
    dispatch_once(&onceToken, ^{
        regex = [[NSRegularExpression alloc] initWithPattern:@"(:[a-z0-9-+_]+:)" options:NSRegularExpressionCaseInsensitive error:NULL];
    });
    
    __block NSString *resultText = text;

    NSRange matchingRange = NSMakeRange(0, [resultText length]);
     
    [regex enumerateMatchesInString:resultText options:NSMatchingReportCompletion range:matchingRange usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
         if (result && ([result resultType] == NSTextCheckingTypeRegularExpression) && !(flags & NSMatchingInternalError)) {
             NSRange range = result.range;
             if (range.location != NSNotFound) {
                 NSString *code = [text substringWithRange:range];
                 
                 Boolean found = false;
                 NSString *unicode = nil;
                 // search through JSON for emoji
                 for (NSString* type in self.emojiAliases){
                     for(NSDictionary* emojiObject in [self.emojiAliases objectForKey:type]) {
                         for(NSString* name in [emojiObject objectForKey:@"names"]) {
                             if ([[NSString stringWithFormat:@":%@:", name] isEqualToString:code]) {
                                 
                                 found = true;
                                 unicode = [emojiObject objectForKey:@"surrogates"];
                                 break;
                             }
                         }
                         if (found) break;
                     }
                     if (found) break;
                 }
                 
                 if (found) {
                     resultText = [resultText stringByReplacingOccurrencesOfString:code withString:unicode];
                 }
             }
         }
     }];
    
    return resultText;
}

+ (NSDictionary *)emojiAliases {
    static NSDictionary *_emojiAliases;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        NSString *path = [[NSBundle mainBundle] pathForResource:@"emoji" ofType:@"json"];
        NSData *data = [NSData dataWithContentsOfFile:path];
        _emojiAliases = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
    });
    return _emojiAliases;
}

@end