ProximityBluetoothMonitor.m

//
//  ProximityBluetoothMonitor.m
//  Proximity
//
//  Created by Dominik Pich on 8/1/12.
//
//

#import "ProximityBluetoothMonitor.h"

@implementation ProximityBluetoothMonitor {
	NSTimer *_timer;
}

- (id)init {
    self = [super init];
    if(self) {
        _priorStatus = _status = ProximityBluetoothStatusUndefined;
        _timeInterval = kDefaultPageTimeout;
        _requiredSignalStrength = NO;
    }
    return self;
}

- (void)start {
    [_timer invalidate];
    _timer = [NSTimer scheduledTimerWithTimeInterval:_timeInterval
                                             target:self
                                           selector:@selector(handleTimer:)
                                           userInfo:nil
                                            repeats:YES];
}

- (void)stop {
    [_timer invalidate];
    _timer = nil;
    
    _priorStatus = _status;
    _status = ProximityBluetoothStatusUndefined;
}

- (void)refresh {
    [self handleTimer:_timer];
}

- (void)setTimeInterval:(NSTimeInterval)timeInterval {
    if(_timeInterval < kDefaultPageTimeout)
        _timeInterval = kDefaultPageTimeout;
    
    _timeInterval = timeInterval;
    if(_timer) {
        [self start];
    }
}

#pragma mark

- (void)handleTimer:(NSTimer *)theTimer
{
    BOOL inRange = [self isInRange];
#ifdef DEBUG
    NSLog(@"BT device %@ inRange:%d",_device.name, inRange);
#endif
    
    _status = inRange ? ProximityBluetoothStatusInRange : ProximityBluetoothStatusOutOfRange;
	if( inRange ) {
		if( _priorStatus != ProximityBluetoothStatusInRange ) {
			_priorStatus = ProximityBluetoothStatusInRange;
            [_delegate proximityBluetoothMonitor:self foundDevice:_device];
#ifdef DEBUG
            NSLog(@"-- found");
#endif
		}
	}
	else {
		if( _priorStatus != ProximityBluetoothStatusOutOfRange ) {
			_priorStatus = ProximityBluetoothStatusOutOfRange;
            [_delegate proximityBluetoothMonitor:self lostDevice:_device];
#ifdef DEBUG
            NSLog(@"-- lost");
#endif
		}
	}
}

- (BOOL)isInRange
{
    if(!_device)
        return NO;
    
    IOReturn br = [_device openConnection:nil withPageTimeout:kDefaultPageTimeout authenticationRequired:NO];
    
    if(br == kIOReturnSuccess) {
//        BluetoothHCIRSSIValue rawRssi = [_device rawRSSI];
        BluetoothHCIRSSIValue rssi = [_device RSSI];
#ifdef DEBUG
//        if(rssi!=0)
            NSLog(@"RSSI of %@: %d/%d", _device.name, rssi, _requiredSignalStrength);
#endif
        BOOL inRange = rssi>=_requiredSignalStrength;
        
        [_device closeConnection];
        
        return inRange;
    }
    
    return NO;
}

@end