#import "NSObject+SPInvocationGrabbing.h"
#import <execinfo.h>

#pragma mark Invocation grabbing
@interface SPInvocationGrabber ()
@property (readwrite, retain, nonatomic) id object;
@property (readwrite, retain, nonatomic) NSInvocation *invocation;

@end

@implementation SPInvocationGrabber
- (id)initWithObject:(id)obj;
{
       return [self initWithObject:obj stacktraceSaving:YES];
}

-(id)initWithObject:(id)obj stacktraceSaving:(BOOL)saveStack;
{
       self.object = obj;

       if(saveStack)
              [self saveBacktrace];

       return self;
}
-(void)dealloc;
{
       free(frameStrings);
       self.object = nil;
       self.invocation = nil;
}
@synthesize invocation = _invocation, object = _object;

@synthesize backgroundAfterForward, onMainAfterForward, waitUntilDone;
- (void)runInBackground;
{
    [self invoke];
}


- (void)forwardInvocation:(NSInvocation *)anInvocation {
       [anInvocation retainArguments];
       anInvocation.target = _object;
       self.invocation = anInvocation;

       if(backgroundAfterForward)
              [NSThread detachNewThreadSelector:@selector(runInBackground) toTarget:self withObject:nil];
       else if(onMainAfterForward)
        [self performSelectorOnMainThread:@selector(invoke) withObject:nil waitUntilDone:waitUntilDone];
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)inSelector {
       NSMethodSignature *signature = [super methodSignatureForSelector:inSelector];
       if (signature == NULL)
              signature = [_object methodSignatureForSelector:inSelector];

       return signature;
}

- (void)invoke;
{

       @try {
              [_invocation invoke];
       }
       @catch (NSException * e) {
              NSLog(@"SPInvocationGrabber's target raised %@:\n\t%@\nInvocation was originally scheduled at:", e.name, e);
              [self printBacktrace];
              printf("\n");
              [e raise];
       }

       self.invocation = nil;
       self.object = nil;
}

-(void)saveBacktrace;
{
  void *backtraceFrames[128];
  frameCount = backtrace(&backtraceFrames[0], 128);
  frameStrings = backtrace_symbols(&backtraceFrames[0], frameCount);
}
-(void)printBacktrace;
{
       for(int x = 3; x < frameCount; x++) {
              if(frameStrings[x] == NULL) { break; }
              printf("%s\n", frameStrings[x]);
       }
}
@end

@implementation NSObject (SPInvocationGrabbing)
-(id)grab;
{
       return [[SPInvocationGrabber alloc] initWithObject:self];
}
-(id)invokeAfter:(NSTimeInterval)delta;
{
       id grabber = [self grab];
       [NSTimer scheduledTimerWithTimeInterval:delta target:grabber selector:@selector(invoke) userInfo:nil repeats:NO];
       return grabber;
}
- (id)nextRunloop;
{
       return [self invokeAfter:0];
}
-(id)inBackground;
{
    SPInvocationGrabber *grabber = [self grab];
       grabber.backgroundAfterForward = YES;
       return grabber;
}
-(id)onMainAsync:(BOOL)async;
{
    SPInvocationGrabber *grabber = [self grab];
       grabber.onMainAfterForward = YES;
    grabber.waitUntilDone = !async;
       return grabber;
}

@end