/*

 File: Reachability.m
 Abstract: Basic demonstration of how to use the SystemConfiguration Reachablity APIs.

 Version: 2.2

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*/

#import <sys/socket.h>
#import <netinet/in.h>
#import <netinet6/in6.h>
#import <arpa/inet.h>
#import <ifaddrs.h>
#import <netdb.h>

#import <CoreFoundation/CoreFoundation.h>

#import "Reachability.h"

#define kShouldPrintReachabilityFlags 1

static void PrintReachabilityFlags(SCNetworkReachabilityFlags flags, const char *comment)
{
#if kShouldPrintReachabilityFlags

	NSLog(@"Reachability Flag Status: %c%c %c%c%c%c%c%c%c %s\n",
	      (flags & kSCNetworkReachabilityFlagsIsWWAN) ? 'W' : '-',
	      (flags & kSCNetworkReachabilityFlagsReachable) ? 'R' : '-',

	      (flags & kSCNetworkReachabilityFlagsTransientConnection) ? 't' : '-',
	      (flags & kSCNetworkReachabilityFlagsConnectionRequired) ? 'c' : '-',
	      (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) ? 'C' : '-',
	      (flags & kSCNetworkReachabilityFlagsInterventionRequired) ? 'i' : '-',
	      (flags & kSCNetworkReachabilityFlagsConnectionOnDemand) ? 'D' : '-',
	      (flags & kSCNetworkReachabilityFlagsIsLocalAddress) ? 'l' : '-',
	      (flags & kSCNetworkReachabilityFlagsIsDirect) ? 'd' : '-', comment);
#endif
}

@implementation Reachability
static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkReachabilityFlags flags,
                                 void *info)
{
#pragma unused(target, flags)
	NSCAssert(info != NULL, @"info was NULL in ReachabilityCallback");
	NSCAssert([(NSObject *)info isKindOfClass:[Reachability class]],
	          @"info was wrong class in ReachabilityCallback");

	// We're on the main RunLoop, so an NSAutoreleasePool is not necessary, but is added defensively
	// in case someone uses the Reachablity object in a different thread.
	NSAutoreleasePool *myPool = [[NSAutoreleasePool alloc] init];

	Reachability *noteObject = (Reachability *)info;
	// Post a notification to notify the client that the network reachability changed.
	[[NSNotificationCenter defaultCenter] postNotificationName:kReachabilityChangedNotification
	                                                    object:noteObject];

	[myPool release];
}

- (BOOL)startNotifier
{
	BOOL retVal = NO;
	SCNetworkReachabilityContext context = { 0, self, NULL, NULL, NULL };
	if (SCNetworkReachabilitySetCallback(reachabilityRef, ReachabilityCallback, &context))
	{
		if (SCNetworkReachabilityScheduleWithRunLoop(reachabilityRef, CFRunLoopGetCurrent(),
		                                             kCFRunLoopDefaultMode))
		{
			retVal = YES;
		}
	}
	return retVal;
}

- (void)stopNotifier
{
	if (reachabilityRef != NULL)
	{
		SCNetworkReachabilityUnscheduleFromRunLoop(reachabilityRef, CFRunLoopGetCurrent(),
		                                           kCFRunLoopDefaultMode);
	}
}

- (void)dealloc
{
	[self stopNotifier];
	if (reachabilityRef != NULL)
	{
		CFRelease(reachabilityRef);
	}
	[super dealloc];
}

+ (Reachability *)reachabilityWithHostName:(NSString *)hostName;
{
	Reachability *retVal = NULL;
	SCNetworkReachabilityRef reachability =
	    SCNetworkReachabilityCreateWithName(NULL, [hostName UTF8String]);
	if (reachability != NULL)
	{
		retVal = [[[self alloc] init] autorelease];
		if (retVal != NULL)
		{
			retVal->reachabilityRef = reachability;
			retVal->localWiFiRef = NO;
		}
	}
	return retVal;
}

+ (Reachability *)reachabilityWithAddress:(const struct sockaddr_in *)hostAddress;
{
	SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(
	    kCFAllocatorDefault, (const struct sockaddr *)hostAddress);
	Reachability *retVal = NULL;
	if (reachability != NULL)
	{
		retVal = [[[self alloc] init] autorelease];
		if (retVal != NULL)
		{
			retVal->reachabilityRef = reachability;
			retVal->localWiFiRef = NO;
		}
	}
	return retVal;
}

+ (Reachability *)reachabilityForInternetConnection;
{
	struct sockaddr_in zeroAddress;
	bzero(&zeroAddress, sizeof(zeroAddress));
	zeroAddress.sin_len = sizeof(zeroAddress);
	zeroAddress.sin_family = AF_INET;
	return [self reachabilityWithAddress:&zeroAddress];
}

+ (Reachability *)reachabilityForLocalWiFi;
{
	struct sockaddr_in localWifiAddress;
	bzero(&localWifiAddress, sizeof(localWifiAddress));
	localWifiAddress.sin_len = sizeof(localWifiAddress);
	localWifiAddress.sin_family = AF_INET;
	// IN_LINKLOCALNETNUM is defined in <netinet/in.h> as 169.254.0.0
	localWifiAddress.sin_addr.s_addr = htonl(IN_LINKLOCALNETNUM);
	Reachability *retVal = [self reachabilityWithAddress:&localWifiAddress];
	if (retVal != NULL)
	{
		retVal->localWiFiRef = YES;
	}
	return retVal;
}

#pragma mark Network Flag Handling

- (NetworkStatus)localWiFiStatusForFlags:(SCNetworkReachabilityFlags)flags
{
	PrintReachabilityFlags(flags, "localWiFiStatusForFlags");

	BOOL retVal = NotReachable;
	if ((flags & kSCNetworkReachabilityFlagsReachable) &&
	    (flags & kSCNetworkReachabilityFlagsIsDirect))
	{
		retVal = ReachableViaWiFi;
	}
	return retVal;
}

- (NetworkStatus)networkStatusForFlags:(SCNetworkReachabilityFlags)flags
{
	PrintReachabilityFlags(flags, "networkStatusForFlags");
	if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
	{
		// if target host is not reachable
		return NotReachable;
	}

	BOOL retVal = NotReachable;

	if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
	{
		// if target host is reachable and no connection is required
		//  then we'll assume (for now) that your on Wi-Fi
		retVal = ReachableViaWiFi;
	}

	if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand) != 0) ||
	     (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
	{
		// ... and the connection is on-demand (or on-traffic) if the
		//     calling application is using the CFSocketStream or higher APIs

		if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
		{
			// ... and no [user] intervention is needed
			retVal = ReachableViaWiFi;
		}
	}

	if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
	{
		// ... but WWAN connections are OK if the calling application
		//     is using the CFNetwork (CFSocketStream?) APIs.
		retVal = ReachableViaWWAN;
	}
	return retVal;
}

- (BOOL)connectionRequired;
{
	NSAssert(reachabilityRef != NULL, @"connectionRequired called with NULL reachabilityRef");
	SCNetworkReachabilityFlags flags;
	if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
	{
		return (flags & kSCNetworkReachabilityFlagsConnectionRequired);
	}
	return NO;
}

- (NetworkStatus)currentReachabilityStatus
{
	NSAssert(reachabilityRef != NULL, @"currentNetworkStatus called with NULL reachabilityRef");
	NetworkStatus retVal = NotReachable;
	SCNetworkReachabilityFlags flags;
	if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags))
	{
		if (localWiFiRef)
		{
			retVal = [self localWiFiStatusForFlags:flags];
		}
		else
		{
			retVal = [self networkStatusForFlags:flags];
		}
	}
	return retVal;
}
@end
