#import <Foundation/Foundation.h>
#import <AppKit/AppKit.h>

/* --- Address ----------------------------------------- */

@interface Address : NSObject {
    NSString* street;
    NSNumber* zipCode;
    NSString* city;
}

@property(retain) NSString* street;
@property(retain) NSNumber* zipCode;
@property(retain) NSString* city;

@end

@implementation Address

@synthesize street, zipCode, city;

-(id)init {
    if( !( self = [super init] ) ) { return nil; }
    
    self.street  = @"Elm Street";
    self.zipCode = @"12345";
    self.city    = @"Crashington";
    
    return self;
}

-(void) modifyStreet {
    self.street = @"Main Street";
}

-(void)dealloc { 
    [street release]; [zipCode release]; [city release]; 
    [super dealloc];
}
@end

/* --- Person ----------------------------------------- */

@interface Person : NSObject {
    NSString* name;
    Address* address;
}
@property(retain) NSString* name;
@property(retain) Address* address;
@end

@implementation Person

@synthesize address, name;

-(id)init {
    if( !( self = [super init] ) ) { return nil; }
    
    self.name = @"Tom";
    self.address = [[Address new] autorelease];
    
    return self;
}

- (void)modifyAddress {
    Address* a = [[Address new] autorelease];
    a.street  = @"Jump Street";
    a.zipCode = @"54321";
    a.city    = @"Memleakville";
    self.address = a;
}

- (void)dealloc { [address release]; [name release]; [super dealloc]; }

@end

/* --- Bridge ----------------------------------------- */

@interface Bridge : NSObject {
    NSMutableDictionary* observedKeys;
    NSObject* obj;
}

@property(retain) NSObject* obj;

@end

@implementation Bridge

@synthesize obj;

- (id)init {
    if( !( self = [super init] ) ) { return nil; }
    observedKeys = [NSMutableDictionary new];
    return self;
}
- (void)forwardInvocation:(NSInvocation*)inv {
    [inv invokeWithTarget:obj];
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector {
    return [obj methodSignatureForSelector:aSelector];
}

- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    NSLog( @">>>> Detected Change in keyPath: %@", keyPath );
    [self willChangeValueForKey:keyPath];
    [self didChangeValueForKey:keyPath];    
}

-(id)valueForUndefinedKey:(NSString*)key {
    if( ![observedKeys objectForKey:key] ) {
        [observedKeys setObject:[NSNumber numberWithBool:YES] forKey:key];
        [obj addObserver:self forKeyPath:key options:NSKeyValueObservingOptionNew context:nil];
    } 
    return [obj valueForKey:key];
}

- (void)dealloc {
    for( NSString* key in [observedKeys allKeys] ) {
        [obj removeObserver:self forKeyPath:key];
    }
    [obj release];
    [observedKeys release];
    [super dealloc];
}

@end

/* --- MyObserver ------------------------------------ */

@interface MyObserver : NSObject {
    Address* address;
    NSString* street;
}

@property(retain) Address* address;
@property(retain) NSString* street;
@end

@implementation MyObserver

@synthesize street, address;

-(void)dealloc { [street release]; [super dealloc]; }

@end


/* This works fine */
void testBindingToAddress() {
    NSLog( @"Testing Binding to 'address' --------------" );
     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
    Bridge* b = [[Bridge new] autorelease];
    b.obj = [Person new];
    MyObserver* o = [[MyObserver new] autorelease];
    [o bind:@"address" toObject:b withKeyPath:@"address"
        options:nil];
    NSLog( @"Before modifyStreet: %@", o.address.street );    
    [[b valueForKey:@"address"] performSelector:@selector(modifyStreet)];
    NSLog( @"After modifyStreet: %@", o.address.street );        

    [b performSelector:@selector(modifyAddress)];
    NSLog( @"After modifyAdress:  %@", o.address.street );

    [pool drain];   
}

/* This produces an exception */
void testBindingToStreet() {
    NSLog( @"Testing Binding to 'address.street' --------------" );    
     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
    Bridge* b = [[Bridge new] autorelease];
    b.obj = [Person new];
    MyObserver* o = [[MyObserver new] autorelease];
    [o bind:@"street" toObject:b withKeyPath:@"address.street"
        options:nil];

    NSLog( @"Before modifyStreet: %@", o.street );    
    [[b valueForKey:@"address"] performSelector:@selector(modifyStreet)];
    NSLog( @"After modifyStreet: %@", o.street );        

    [b performSelector:@selector(modifyAddress)];
    NSLog( @"After modifyAdress:  %@", o.street );

    [pool drain];   
}

/* --- main() ------------------------------------ */
int main (int argc, const char * argv[]) {
    testBindingToAddress();
    testBindingToStreet();    
    return 0;
}
