NSObject+classSwitch.m

//
//  NSObject+classSwitch.m
//
//  Created by Jonathan Annett on 30/10/13.
//  Copyright (c) 2013 Sophtwhere. All rights reserved.
//

#import "NSObject+classSwitch.h"
#import "NSObject+arcAgnostics.h"


/////////////////////////////////
#define DEF_OBJ_CODE(NSObject)\
NSString *_is##NSObject##_ = @#NSObject;
DEFINE_OBECTS()
#undef DEF_OBJ_CODE
/////////////////////////////////
NSString *_isUndefinedObject_ = @"isUndefinedObject";


#define DEF_OBJ_CODE(NSObject)\
@implementation NSObject (classSwitch)\
-(enum nsObjectSwitchCode) classSwitchCode {\
/**/return is##NSObject;\
}\
+(enum nsObjectSwitchCode) classSwitchCode {\
/**/return is##NSObject;\
}\
-(BOOL)isUndefinedObject {\
/**/return NO;\
}\
-(NSObject*) as##NSObject {\
/**/return self;\
}\
-(BOOL) is##NSObject{\
/**/return YES;\
}\
@end

DEFINE_OBECTS()

#undef DEF_OBJ_CODE





@implementation NSObject(classSwitchDefaults)

-(dispatch_block_t) class_specific_block_copy:(NSDictionary*) blocks{

    id element = nil;

    switch (self.classSwitchCode) {
        case isUndefinedObject :
            element = blocks[_isUndefinedObject_];\
            break;

#define DEF_OBJ_CODE(NSObject)\
/**/    case is##NSObject:\
/**/        element = blocks[_is##NSObject##_];\
/**/        break;\


            DEFINE_OBECTS()

#undef DEF_OBJ_CODE

        default:
            break;
    }

    dispatch_block_t result =
    element==nil ? ^{} :
    (dispatch_block_t) ([element isNSString] ? blocks[element] : element);


    return Block_copy(result);

}

#define DEF_OBJ_CODE(NSObject)\
-(BOOL) is##NSObject{\
/**/return NO;\
}\
-(NSObject*) as##NSObject{\
/**/return nil;\
}\

DEFINE_OBECTS()
#undef DEF_OBJ_CODE

-(void) class_specific_block_dispatch:(NSDictionary*) blocks{
    if (blocks){
        dispatch_block_t block = [self class_specific_block_copy:blocks];
        block();
        Block_release(block);
    }
}

-(void) class_specific_block_dispatch_async:(dispatch_queue_t) queue
                                     blocks:(NSDictionary*) blocks {
    if (blocks){
        dispatch_block_t block = [self class_specific_block_copy:blocks];
        dispatch_async(queue, ^{
            block();
            Block_release(block);
        });
    }
}


-(enum nsObjectSwitchCode) classSwitchCode {
    return isUndefinedObject;
}

+(enum nsObjectSwitchCode) classSwitchCode {
    return isUndefinedObject;
}

-(BOOL)isUndefinedObject {
    return YES;
}

+(enum nsObjectSwitchCode) classSwitchCodeFromNSString:(NSString*) string decoder:(NSDictionary*) decode{
    NSNumber *decoded = decode ? decode[string] : nil;
    return decoded ? (enum nsObjectSwitchCode) decoded.unsignedIntegerValue : isUndefinedObject;
}


+(enum nsObjectSwitchCode) classSwitchCodeFromClassName:(NSString*) classname{
    static NSDictionary *decode = nil;

    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{

       decode = [@{

#define DEF_OBJ_CODE(NSObject)\
_is##NSObject##_ :  @(is##NSObject),

                                 DEFINE_OBECTS()
#undef DEF_OBJ_CODE


                                 } retain];
    });
    return [self classSwitchCodeFromNSString:classname decoder:decode];
}


@end



@implementation NSObject(testClassSwitch)



+(void ) test {





    NSArray *hello_world = @[@"hello",@"world"];

    NSString *hello = [hello_world componentsJoinedByString:@" "];

    NSDictionary *message = @{@"message" : hello};

    NSMutableDictionary *greeting = [[@{@"howdie" : hello_world} mutableCopy] autorelease];


    NSArray *checker = @[hello,hello_world,message,greeting];



    NSDictionary *checkerBlocks = @{

                                    _isUndefinedObject_ : ^{

                                        NSLog(@"don't know what to do with this");

                                    },

                                    // use same handler for NSDictionary and NSMutableDictionary
                                   _isNSMutableDictionary_ : _isNSDictionary_,
                                   _isNSDictionary_ :
                                       ^{
                                           NSLog(@"this is a block for a dictionary");
                                       },

                                    // treat NSURL as undefined.
                                    _isNSURL_ : _isUndefinedObject_,

                                   _isNSArray_ :
                                       ^{
                                           NSLog(@"this is a block for an array");
                                       },

                                   _isNSString_ :
                                       ^{
                                           NSLog(@"this is a block for a string - success");
                                       }

                                   };



    dispatch_block_t myblock = [hello   class_specific_block_copy:checkerBlocks];
    myblock();
    Block_release(myblock);

    [hello_world class_specific_block_dispatch:checkerBlocks];

    [greeting class_specific_block_dispatch_async:dispatch_get_main_queue() blocks:checkerBlocks];




    [[[[UIView alloc] init] autorelease ]class_specific_block_dispatch:checkerBlocks];

    [[NSURL URLWithString:@"http://www.google.com" ] class_specific_block_dispatch:checkerBlocks];

    for (NSObject *testme in checker) {


        if (testme.isNSArray) {
            NSLog(@"yes ! testme is an array");
        }

        switch (testme.classSwitchCode) {
            case isNSString:
                NSLog(@"%@ is a string!",testme);
                break;
            case isNSArray:
                NSLog(@"%@ is an array with %d elements!",testme,[(NSArray*) testme count]);

                break;
            case isNSMutableArray:
                NSLog(@"%@ is a mutable array with %d elements!",testme,[(NSArray*) testme count]);

                break;
            case isNSDictionary:

                NSLog(@"%@ is an dictionary with these keys: %@!",testme,[(NSDictionary*) testme allKeys]);

                break;

            default:
                break;
        }
    }


}

@end