HiBeacons/NTViewController.m - AlexSeverinov/HiBeacons - Gitiles

 //
 //  NTViewController.m
 //  HiBeacons
 //
 //  Created by Nick Toumpelis on 2013-10-06.
 //  Copyright (c) 2013 Nick Toumpelis.
 //
 //  Permission is hereby granted, free of charge, to any person obtaining a copy
 //  of this software and associated documentation files (the "Software"), to deal
 //  in the Software without restriction, including without limitation the rights
 //  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 //  copies of the Software, and to permit persons to whom the Software is
 //  furnished to do so, subject to the following conditions:
 //
 //  The above copyright notice and this permission notice shall be included in
 //  all copies or substantial portions of the Software.
 //
 //  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 //  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 //  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 //  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 //  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 //  THE SOFTWARE.
 //

 #import "NTViewController.h"

 static NSString * const kUUID = @"00000000-0000-0000-0000-000000000000";
 static NSString * const kIdentifier = @"SomeIdentifier";

 static NSString * const kOperationCellIdentifier = @"OperationCell";
 static NSString * const kBeaconCellIdentifier = @"BeaconCell";

 static NSString * const kAdvertisingOperationTitle = @"Advertising";
 static NSString * const kRangingOperationTitle = @"Ranging";
 static NSUInteger const kNumberOfSections = 2;
 static NSUInteger const kNumberOfAvailableOperations = 2;
 static CGFloat const kOperationCellHeight = 44;
 static CGFloat const kBeaconCellHeight = 52;
 static NSString * const kBeaconSectionTitle = @"Looking for beacons...";
 static CGPoint const kActivityIndicatorPosition = (CGPoint){205, 12};
 static NSString * const kBeaconsHeaderViewIdentifier = @"BeaconsHeader";

 typedef NS_ENUM(NSUInteger, NTSectionType) {
     NTOperationsSection,
     NTDetectedBeaconsSection
 };

 typedef NS_ENUM(NSUInteger, NTOperationsRow) {
     NTAdvertisingRow,
     NTRangingRow
 };

 @interface NTViewController ()

 @property (nonatomic, strong) CLLocationManager *locationManager;
 @property (nonatomic, strong) CLBeaconRegion *beaconRegion;
 @property (nonatomic, strong) CBPeripheralManager *peripheralManager;
 @property (nonatomic, strong) NSArray *detectedBeacons;
 @property (nonatomic, weak) UISwitch *advertisingSwitch;
 @property (nonatomic, weak) UISwitch *rangingSwitch;

 @end

 @implementation NTViewController

 #pragma mark - Beacon ranging
 - (void)createBeaconRegion
 {
     if (self.beaconRegion)
         return;

     NSUUID *proximityUUID = [[NSUUID alloc] initWithUUIDString:kUUID];
     self.beaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:proximityUUID identifier:kIdentifier];
 }

 - (void)turnOnRanging
 {
     NSLog(@"Turning on ranging...");

     if (![CLLocationManager isRangingAvailable]) {
         NSLog(@"Couldn't turn on ranging: Ranging is not available.");
         self.rangingSwitch.on = NO;
         return;
     }

     if (self.locationManager.rangedRegions.count > 0) {
         NSLog(@"Didn't turn on ranging: Ranging already on.");
         return;
     }

     [self createBeaconRegion];
     [self.locationManager startRangingBeaconsInRegion:self.beaconRegion];

     NSLog(@"Ranging turned on for region: %@.", self.beaconRegion);
 }

 - (void)changeRangingState:sender
 {
     UISwitch *theSwitch = (UISwitch *)sender;
     if (theSwitch.on) {
         [self startRangingForBeacons];
     } else {
         [self stopRangingForBeacons];
     }
 }

 - (void)startRangingForBeacons
 {
     self.locationManager = [[CLLocationManager alloc] init];
     self.locationManager.delegate = self;

     self.detectedBeacons = [NSArray array];

     [self turnOnRanging];
 }

 - (void)stopRangingForBeacons
 {
     if (self.locationManager.rangedRegions.count == 0) {
         NSLog(@"Didn't turn off ranging: Ranging already off.");
         return;
     }

     [self.locationManager stopRangingBeaconsInRegion:self.beaconRegion];

     NSIndexSet *deletedSections = [self deletedSections];
     self.detectedBeacons = [NSArray array];

     [self.beaconTableView beginUpdates];
     if (deletedSections)
         [self.beaconTableView deleteSections:deletedSections withRowAnimation:UITableViewRowAnimationFade];
     [self.beaconTableView endUpdates];

     NSLog(@"Turned off ranging.");
 }

 #pragma mark - Index path management
 - (NSArray *)indexPathsOfRemovedBeacons:(NSArray *)beacons
 {
     NSMutableArray *indexPaths = nil;

     NSUInteger row = 0;
     for (CLBeacon *existingBeacon in self.detectedBeacons) {
         BOOL stillExists = NO;
         for (CLBeacon *beacon in beacons) {
             if ((existingBeacon.major.integerValue == beacon.major.integerValue) &&
                 (existingBeacon.minor.integerValue == beacon.minor.integerValue)) {
                 stillExists = YES;
                 break;
             }
         }
         if (!stillExists) {
             if (!indexPaths)
                 indexPaths = [NSMutableArray new];
             [indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
         }
         row++;
     }

     return indexPaths;
 }

 - (NSArray *)indexPathsOfInsertedBeacons:(NSArray *)beacons
 {
     NSMutableArray *indexPaths = nil;

     NSUInteger row = 0;
     for (CLBeacon *beacon in beacons) {
         BOOL isNewBeacon = YES;
         for (CLBeacon *existingBeacon in self.detectedBeacons) {
             if ((existingBeacon.major.integerValue == beacon.major.integerValue) &&
                 (existingBeacon.minor.integerValue == beacon.minor.integerValue)) {
                 isNewBeacon = NO;
                 break;
             }
         }
         if (isNewBeacon) {
             if (!indexPaths)
                 indexPaths = [NSMutableArray new];
             [indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
         }
         row++;
     }

     return indexPaths;
 }

 - (NSArray *)indexPathsForBeacons:(NSArray *)beacons
 {
     NSMutableArray *indexPaths = [NSMutableArray new];
     for (NSUInteger row = 0; row < beacons.count; row++) {
         [indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
     }

     return indexPaths;
 }

 - (NSIndexSet *)insertedSections
 {
     if (self.rangingSwitch.on && [self.beaconTableView numberOfSections] == kNumberOfSections - 1) {
         return [NSIndexSet indexSetWithIndex:1];
     } else {
         return nil;
     }
 }

 - (NSIndexSet *)deletedSections
 {
     if (!self.rangingSwitch.on && [self.beaconTableView numberOfSections] == kNumberOfSections) {
         return [NSIndexSet indexSetWithIndex:1];
     } else {
         return nil;
     }
 }

 - (NSArray *)filteredBeacons:(NSArray *)beacons
 {
     // Filters duplicate beacons out; this may happen temporarily if the originating device changes its Bluetooth id
     NSMutableArray *mutableBeacons = [beacons mutableCopy];

     NSMutableSet *lookup = [[NSMutableSet alloc] init];
     for (int index = 0; index < [beacons count]; index++) {
         CLBeacon *curr = [beacons objectAtIndex:index];
         NSString *identifier = [NSString stringWithFormat:@"%@/%@", curr.major, curr.minor];

         // this is very fast constant time lookup in a hash table
         if ([lookup containsObject:identifier]) {
             [mutableBeacons removeObjectAtIndex:index];
         } else {
             [lookup addObject:identifier];
         }
     }

     return [mutableBeacons copy];
 }

 #pragma mark - Beacon ranging delegate methods
 - (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
 {
     if (![CLLocationManager locationServicesEnabled]) {
         NSLog(@"Couldn't turn on ranging: Location services are not enabled.");
         self.rangingSwitch.on = NO;
         return;
     }

     if ([CLLocationManager authorizationStatus] != kCLAuthorizationStatusAuthorized) {
         NSLog(@"Couldn't turn on ranging: Location services not authorised.");
         self.rangingSwitch.on = NO;
         return;
     }

     self.rangingSwitch.on = YES;
 }

 - (void)locationManager:(CLLocationManager *)manager
         didRangeBeacons:(NSArray *)beacons
                inRegion:(CLBeaconRegion *)region {
     NSArray *filteredBeacons = [self filteredBeacons:beacons];

     if (filteredBeacons.count == 0) {
         NSLog(@"No beacons found nearby.");
     } else {
         NSLog(@"Found %lu %@.", (unsigned long)[filteredBeacons count],
                 [filteredBeacons count] > 1 ? @"beacons" : @"beacon");
     }

     NSIndexSet *insertedSections = [self insertedSections];
     NSIndexSet *deletedSections = [self deletedSections];
     NSArray *deletedRows = [self indexPathsOfRemovedBeacons:filteredBeacons];
     NSArray *insertedRows = [self indexPathsOfInsertedBeacons:filteredBeacons];
     NSArray *reloadedRows = nil;
     if (!deletedRows && !insertedRows)
         reloadedRows = [self indexPathsForBeacons:filteredBeacons];

     self.detectedBeacons = filteredBeacons;

     [self.beaconTableView beginUpdates];
     if (insertedSections)
         [self.beaconTableView insertSections:insertedSections withRowAnimation:UITableViewRowAnimationFade];
     if (deletedSections)
         [self.beaconTableView deleteSections:deletedSections withRowAnimation:UITableViewRowAnimationFade];
     if (insertedRows)
         [self.beaconTableView insertRowsAtIndexPaths:insertedRows withRowAnimation:UITableViewRowAnimationFade];
     if (deletedRows)
         [self.beaconTableView deleteRowsAtIndexPaths:deletedRows withRowAnimation:UITableViewRowAnimationFade];
     if (reloadedRows)
         [self.beaconTableView reloadRowsAtIndexPaths:reloadedRows withRowAnimation:UITableViewRowAnimationNone];
     [self.beaconTableView endUpdates];
 }

 #pragma mark - Beacon advertising
 - (void)turnOnAdvertising
 {
     if (self.peripheralManager.state != CBPeripheralManagerStatePoweredOn) {
         NSLog(@"Peripheral manager is off.");
         self.advertisingSwitch.on = NO;
         return;
     }

     time_t t;
     srand((unsigned) time(&t));
     CLBeaconRegion *region = [[CLBeaconRegion alloc] initWithProximityUUID:self.beaconRegion.proximityUUID
                                                                      major:rand()
                                                                      minor:rand()
                                                                 identifier:self.beaconRegion.identifier];
     NSDictionary *beaconPeripheralData = [region peripheralDataWithMeasuredPower:nil];
     [self.peripheralManager startAdvertising:beaconPeripheralData];

     NSLog(@"Turning on advertising for region: %@.", region);
 }

 - (void)changeAdvertisingState:sender
 {
     UISwitch *theSwitch = (UISwitch *)sender;
     if (theSwitch.on) {
         [self startAdvertisingBeacon];
     } else {
         [self stopAdvertisingBeacon];
     }
 }

 - (void)startAdvertisingBeacon
 {
     NSLog(@"Turning on advertising...");

     [self createBeaconRegion];

     if (!self.peripheralManager)
         self.peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil options:nil];

     [self turnOnAdvertising];
 }

 - (void)stopAdvertisingBeacon
 {
     [self.peripheralManager stopAdvertising];

     NSLog(@"Turned off advertising.");
 }

 #pragma mark - Beacon advertising delegate methods
 - (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheralManager error:(NSError *)error
 {
     if (error) {
         NSLog(@"Couldn't turn on advertising: %@", error);
         self.advertisingSwitch.on = NO;
         return;
     }

     if (peripheralManager.isAdvertising) {
         NSLog(@"Turned on advertising.");
         self.advertisingSwitch.on = YES;
     }
 }

 - (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheralManager
 {
     if (peripheralManager.state != CBPeripheralManagerStatePoweredOn) {
         NSLog(@"Peripheral manager is off.");
         self.advertisingSwitch.on = NO;
         return;
     }

     NSLog(@"Peripheral manager is on.");
     [self turnOnAdvertising];
 }

 #pragma mark - Table view functionality
 - (NSString *)detailsStringForBeacon:(CLBeacon *)beacon
 {
     NSString *proximity;
     switch (beacon.proximity) {
         case CLProximityNear:
             proximity = @"Near";
             break;
         case CLProximityImmediate:
             proximity = @"Immediate";
             break;
         case CLProximityFar:
             proximity = @"Far";
             break;
         case CLProximityUnknown:
         default:
             proximity = @"Unknown";
             break;
     }

     NSString *format = @"%@, %@ • %@ • %f • %li";
     return [NSString stringWithFormat:format, beacon.major, beacon.minor, proximity, beacon.accuracy, beacon.rssi];
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     UITableViewCell *cell = nil;
     switch (indexPath.section) {
         case NTOperationsSection: {
             cell = [tableView dequeueReusableCellWithIdentifier:kOperationCellIdentifier];
             switch (indexPath.row) {
                 case NTAdvertisingRow:
                     cell.textLabel.text = kAdvertisingOperationTitle;
                     self.advertisingSwitch = (UISwitch *)cell.accessoryView;
                     [self.advertisingSwitch addTarget:self
                                                action:@selector(changeAdvertisingState:)
                                      forControlEvents:UIControlEventValueChanged];
                     break;
                 case NTRangingRow:
                 default:
                     cell.textLabel.text = kRangingOperationTitle;
                     self.rangingSwitch = (UISwitch *)cell.accessoryView;
                     [self.rangingSwitch addTarget:self
                                            action:@selector(changeRangingState:)
                                  forControlEvents:UIControlEventValueChanged];
                     break;
             }
         }
             break;
         case NTDetectedBeaconsSection:
         default: {
             CLBeacon *beacon = self.detectedBeacons[indexPath.row];

             cell = [tableView dequeueReusableCellWithIdentifier:kBeaconCellIdentifier];

             if (!cell)
                 cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
                                               reuseIdentifier:kBeaconCellIdentifier];

             cell.textLabel.text = beacon.proximityUUID.UUIDString;
             cell.detailTextLabel.text = [self detailsStringForBeacon:beacon];
             cell.detailTextLabel.textColor = [UIColor grayColor];
         }
             break;
     }

     return cell;
 }

 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
 {
     if (self.rangingSwitch.on) {
         return kNumberOfSections;       // All sections visible
     } else {
         return kNumberOfSections - 1;   // Beacons section not visible
     }
 }

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
     switch (section) {
         case NTOperationsSection:
             return kNumberOfAvailableOperations;
         case NTDetectedBeaconsSection:
         default:
             return self.detectedBeacons.count;
     }
 }

 - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
 {
     switch (section) {
         case NTOperationsSection:
             return nil;
         case NTDetectedBeaconsSection:
         default:
             return kBeaconSectionTitle;
     }
 }

 - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     switch (indexPath.section) {
         case NTOperationsSection:
             return kOperationCellHeight;
         case NTDetectedBeaconsSection:
         default:
             return kBeaconCellHeight;
     }
 }

 - (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
 {
     UITableViewHeaderFooterView *headerView =
         [[UITableViewHeaderFooterView alloc] initWithReuseIdentifier:kBeaconsHeaderViewIdentifier];

     // Adds an activity indicator view to the section header
     UIActivityIndicatorView *indicatorView =
         [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
     [headerView addSubview:indicatorView];

     indicatorView.frame = (CGRect){kActivityIndicatorPosition, indicatorView.frame.size};

     [indicatorView startAnimating];

     return headerView;
 }

 @end
	//
	// NTViewController.m
	// HiBeacons
	//
	// Created by Nick Toumpelis on 2013-10-06.
	// Copyright (c) 2013 Nick Toumpelis.
	//
	// Permission is hereby granted, free of charge, to any person obtaining a copy
	// of this software and associated documentation files (the "Software"), to deal
	// in the Software without restriction, including without limitation the rights
	// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	// copies of the Software, and to permit persons to whom the Software is
	// furnished to do so, subject to the following conditions:
	//
	// The above copyright notice and this permission notice shall be included in
	// all copies or substantial portions of the Software.
	//
	// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	// THE SOFTWARE.
	//

	#import "NTViewController.h"

	static NSString * const kUUID = @"00000000-0000-0000-0000-000000000000";
	static NSString * const kIdentifier = @"SomeIdentifier";

	static NSString * const kOperationCellIdentifier = @"OperationCell";
	static NSString * const kBeaconCellIdentifier = @"BeaconCell";

	static NSString * const kAdvertisingOperationTitle = @"Advertising";
	static NSString * const kRangingOperationTitle = @"Ranging";
	static NSUInteger const kNumberOfSections = 2;
	static NSUInteger const kNumberOfAvailableOperations = 2;
	static CGFloat const kOperationCellHeight = 44;
	static CGFloat const kBeaconCellHeight = 52;
	static NSString * const kBeaconSectionTitle = @"Looking for beacons...";
	static CGPoint const kActivityIndicatorPosition = (CGPoint){205, 12};
	static NSString * const kBeaconsHeaderViewIdentifier = @"BeaconsHeader";

	typedef NS_ENUM(NSUInteger, NTSectionType) {
	NTOperationsSection,
	NTDetectedBeaconsSection
	};

	typedef NS_ENUM(NSUInteger, NTOperationsRow) {
	NTAdvertisingRow,
	NTRangingRow
	};

	@interface NTViewController ()

	@property (nonatomic, strong) CLLocationManager *locationManager;
	@property (nonatomic, strong) CLBeaconRegion *beaconRegion;
	@property (nonatomic, strong) CBPeripheralManager *peripheralManager;
	@property (nonatomic, strong) NSArray *detectedBeacons;
	@property (nonatomic, weak) UISwitch *advertisingSwitch;
	@property (nonatomic, weak) UISwitch *rangingSwitch;

	@end

	@implementation NTViewController

	#pragma mark - Beacon ranging
	- (void)createBeaconRegion
	{
	if (self.beaconRegion)
	return;

	NSUUID *proximityUUID = [[NSUUID alloc] initWithUUIDString:kUUID];
	self.beaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:proximityUUID identifier:kIdentifier];
	}

	- (void)turnOnRanging
	{
	NSLog(@"Turning on ranging...");

	if (![CLLocationManager isRangingAvailable]) {
	NSLog(@"Couldn't turn on ranging: Ranging is not available.");
	self.rangingSwitch.on = NO;
	return;
	}

	if (self.locationManager.rangedRegions.count > 0) {
	NSLog(@"Didn't turn on ranging: Ranging already on.");
	return;
	}

	[self createBeaconRegion];
	[self.locationManager startRangingBeaconsInRegion:self.beaconRegion];

	NSLog(@"Ranging turned on for region: %@.", self.beaconRegion);
	}

	- (void)changeRangingState:sender
	{
	UISwitch theSwitch = (UISwitch )sender;
	if (theSwitch.on) {
	[self startRangingForBeacons];
	} else {
	[self stopRangingForBeacons];
	}
	}

	- (void)startRangingForBeacons
	{
	self.locationManager = [[CLLocationManager alloc] init];
	self.locationManager.delegate = self;

	self.detectedBeacons = [NSArray array];

	[self turnOnRanging];
	}

	- (void)stopRangingForBeacons
	{
	if (self.locationManager.rangedRegions.count == 0) {
	NSLog(@"Didn't turn off ranging: Ranging already off.");
	return;
	}

	[self.locationManager stopRangingBeaconsInRegion:self.beaconRegion];

	NSIndexSet *deletedSections = [self deletedSections];
	self.detectedBeacons = [NSArray array];

	[self.beaconTableView beginUpdates];
	if (deletedSections)
	[self.beaconTableView deleteSections:deletedSections withRowAnimation:UITableViewRowAnimationFade];
	[self.beaconTableView endUpdates];

	NSLog(@"Turned off ranging.");
	}

	#pragma mark - Index path management
	- (NSArray )indexPathsOfRemovedBeacons:(NSArray )beacons
	{
	NSMutableArray *indexPaths = nil;

	NSUInteger row = 0;
	for (CLBeacon *existingBeacon in self.detectedBeacons) {
	BOOL stillExists = NO;
	for (CLBeacon *beacon in beacons) {
	if ((existingBeacon.major.integerValue == beacon.major.integerValue) &&
	(existingBeacon.minor.integerValue == beacon.minor.integerValue)) {
	stillExists = YES;
	break;
	}
	}
	if (!stillExists) {
	if (!indexPaths)
	indexPaths = [NSMutableArray new];
	[indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
	}
	row++;
	}

	return indexPaths;
	}

	- (NSArray )indexPathsOfInsertedBeacons:(NSArray )beacons
	{
	NSMutableArray *indexPaths = nil;

	NSUInteger row = 0;
	for (CLBeacon *beacon in beacons) {
	BOOL isNewBeacon = YES;
	for (CLBeacon *existingBeacon in self.detectedBeacons) {
	if ((existingBeacon.major.integerValue == beacon.major.integerValue) &&
	(existingBeacon.minor.integerValue == beacon.minor.integerValue)) {
	isNewBeacon = NO;
	break;
	}
	}
	if (isNewBeacon) {
	if (!indexPaths)
	indexPaths = [NSMutableArray new];
	[indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
	}
	row++;
	}

	return indexPaths;
	}

	- (NSArray )indexPathsForBeacons:(NSArray )beacons
	{
	NSMutableArray *indexPaths = [NSMutableArray new];
	for (NSUInteger row = 0; row < beacons.count; row++) {
	[indexPaths addObject:[NSIndexPath indexPathForRow:row inSection:NTDetectedBeaconsSection]];
	}

	return indexPaths;
	}

	- (NSIndexSet *)insertedSections
	{
	if (self.rangingSwitch.on && [self.beaconTableView numberOfSections] == kNumberOfSections - 1) {
	return [NSIndexSet indexSetWithIndex:1];
	} else {
	return nil;
	}
	}

	- (NSIndexSet *)deletedSections
	{
	if (!self.rangingSwitch.on && [self.beaconTableView numberOfSections] == kNumberOfSections) {
	return [NSIndexSet indexSetWithIndex:1];
	} else {
	return nil;
	}
	}

	- (NSArray )filteredBeacons:(NSArray )beacons
	{
	// Filters duplicate beacons out; this may happen temporarily if the originating device changes its Bluetooth id
	NSMutableArray *mutableBeacons = [beacons mutableCopy];

	NSMutableSet *lookup = [[NSMutableSet alloc] init];
	for (int index = 0; index < [beacons count]; index++) {
	CLBeacon *curr = [beacons objectAtIndex:index];
	NSString *identifier = [NSString stringWithFormat:@"%@/%@", curr.major, curr.minor];

	// this is very fast constant time lookup in a hash table
	if ([lookup containsObject:identifier]) {
	[mutableBeacons removeObjectAtIndex:index];
	} else {
	[lookup addObject:identifier];
	}
	}

	return [mutableBeacons copy];
	}

	#pragma mark - Beacon ranging delegate methods
	- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
	{
	if (![CLLocationManager locationServicesEnabled]) {
	NSLog(@"Couldn't turn on ranging: Location services are not enabled.");
	self.rangingSwitch.on = NO;
	return;
	}

	if ([CLLocationManager authorizationStatus] != kCLAuthorizationStatusAuthorized) {
	NSLog(@"Couldn't turn on ranging: Location services not authorised.");
	self.rangingSwitch.on = NO;
	return;
	}

	self.rangingSwitch.on = YES;
	}

	- (void)locationManager:(CLLocationManager *)manager
	didRangeBeacons:(NSArray *)beacons
	inRegion:(CLBeaconRegion *)region {
	NSArray *filteredBeacons = [self filteredBeacons:beacons];

	if (filteredBeacons.count == 0) {
	NSLog(@"No beacons found nearby.");
	} else {
	NSLog(@"Found %lu %@.", (unsigned long)[filteredBeacons count],
	[filteredBeacons count] > 1 ? @"beacons" : @"beacon");
	}

	NSIndexSet *insertedSections = [self insertedSections];
	NSIndexSet *deletedSections = [self deletedSections];
	NSArray *deletedRows = [self indexPathsOfRemovedBeacons:filteredBeacons];
	NSArray *insertedRows = [self indexPathsOfInsertedBeacons:filteredBeacons];
	NSArray *reloadedRows = nil;
	if (!deletedRows && !insertedRows)
	reloadedRows = [self indexPathsForBeacons:filteredBeacons];

	self.detectedBeacons = filteredBeacons;

	[self.beaconTableView beginUpdates];
	if (insertedSections)
	[self.beaconTableView insertSections:insertedSections withRowAnimation:UITableViewRowAnimationFade];
	if (deletedSections)
	[self.beaconTableView deleteSections:deletedSections withRowAnimation:UITableViewRowAnimationFade];
	if (insertedRows)
	[self.beaconTableView insertRowsAtIndexPaths:insertedRows withRowAnimation:UITableViewRowAnimationFade];
	if (deletedRows)
	[self.beaconTableView deleteRowsAtIndexPaths:deletedRows withRowAnimation:UITableViewRowAnimationFade];
	if (reloadedRows)
	[self.beaconTableView reloadRowsAtIndexPaths:reloadedRows withRowAnimation:UITableViewRowAnimationNone];
	[self.beaconTableView endUpdates];
	}

	#pragma mark - Beacon advertising
	- (void)turnOnAdvertising
	{
	if (self.peripheralManager.state != CBPeripheralManagerStatePoweredOn) {
	NSLog(@"Peripheral manager is off.");
	self.advertisingSwitch.on = NO;
	return;
	}

	time_t t;
	srand((unsigned) time(&t));
	CLBeaconRegion *region = [[CLBeaconRegion alloc] initWithProximityUUID:self.beaconRegion.proximityUUID
	major:rand()
	minor:rand()
	identifier:self.beaconRegion.identifier];
	NSDictionary *beaconPeripheralData = [region peripheralDataWithMeasuredPower:nil];
	[self.peripheralManager startAdvertising:beaconPeripheralData];

	NSLog(@"Turning on advertising for region: %@.", region);
	}

	- (void)changeAdvertisingState:sender
	{
	UISwitch theSwitch = (UISwitch )sender;
	if (theSwitch.on) {
	[self startAdvertisingBeacon];
	} else {
	[self stopAdvertisingBeacon];
	}
	}

	- (void)startAdvertisingBeacon
	{
	NSLog(@"Turning on advertising...");

	[self createBeaconRegion];

	if (!self.peripheralManager)
	self.peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil options:nil];

	[self turnOnAdvertising];
	}

	- (void)stopAdvertisingBeacon
	{
	[self.peripheralManager stopAdvertising];

	NSLog(@"Turned off advertising.");
	}

	#pragma mark - Beacon advertising delegate methods
	- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager )peripheralManager error:(NSError )error
	{
	if (error) {
	NSLog(@"Couldn't turn on advertising: %@", error);
	self.advertisingSwitch.on = NO;
	return;
	}

	if (peripheralManager.isAdvertising) {
	NSLog(@"Turned on advertising.");
	self.advertisingSwitch.on = YES;
	}
	}

	- (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheralManager
	{
	if (peripheralManager.state != CBPeripheralManagerStatePoweredOn) {
	NSLog(@"Peripheral manager is off.");
	self.advertisingSwitch.on = NO;
	return;
	}

	NSLog(@"Peripheral manager is on.");
	[self turnOnAdvertising];
	}

	#pragma mark - Table view functionality
	- (NSString )detailsStringForBeacon:(CLBeacon )beacon
	{
	NSString *proximity;
	switch (beacon.proximity) {
	case CLProximityNear:
	proximity = @"Near";
	break;
	case CLProximityImmediate:
	proximity = @"Immediate";
	break;
	case CLProximityFar:
	proximity = @"Far";
	break;
	case CLProximityUnknown:
	default:
	proximity = @"Unknown";
	break;
	}

	NSString *format = @"%@, %@ • %@ • %f • %li";
	return [NSString stringWithFormat:format, beacon.major, beacon.minor, proximity, beacon.accuracy, beacon.rssi];
	}

	- (UITableViewCell )tableView:(UITableView )tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
	{
	UITableViewCell *cell = nil;
	switch (indexPath.section) {
	case NTOperationsSection: {
	cell = [tableView dequeueReusableCellWithIdentifier:kOperationCellIdentifier];
	switch (indexPath.row) {
	case NTAdvertisingRow:
	cell.textLabel.text = kAdvertisingOperationTitle;
	self.advertisingSwitch = (UISwitch *)cell.accessoryView;
	[self.advertisingSwitch addTarget:self
	action:@selector(changeAdvertisingState:)
	forControlEvents:UIControlEventValueChanged];
	break;
	case NTRangingRow:
	default:
	cell.textLabel.text = kRangingOperationTitle;
	self.rangingSwitch = (UISwitch *)cell.accessoryView;
	[self.rangingSwitch addTarget:self
	action:@selector(changeRangingState:)
	forControlEvents:UIControlEventValueChanged];
	break;
	}
	}
	break;
	case NTDetectedBeaconsSection:
	default: {
	CLBeacon *beacon = self.detectedBeacons[indexPath.row];

	cell = [tableView dequeueReusableCellWithIdentifier:kBeaconCellIdentifier];

	if (!cell)
	cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
	reuseIdentifier:kBeaconCellIdentifier];

	cell.textLabel.text = beacon.proximityUUID.UUIDString;
	cell.detailTextLabel.text = [self detailsStringForBeacon:beacon];
	cell.detailTextLabel.textColor = [UIColor grayColor];
	}
	break;
	}

	return cell;
	}

	- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
	{
	if (self.rangingSwitch.on) {
	return kNumberOfSections; // All sections visible
	} else {
	return kNumberOfSections - 1; // Beacons section not visible
	}
	}

	- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
	{
	switch (section) {
	case NTOperationsSection:
	return kNumberOfAvailableOperations;
	case NTDetectedBeaconsSection:
	default:
	return self.detectedBeacons.count;
	}
	}

	- (NSString )tableView:(UITableView )tableView titleForHeaderInSection:(NSInteger)section
	{
	switch (section) {
	case NTOperationsSection:
	return nil;
	case NTDetectedBeaconsSection:
	default:
	return kBeaconSectionTitle;
	}
	}

	- (CGFloat)tableView:(UITableView )tableView heightForRowAtIndexPath:(NSIndexPath )indexPath
	{
	switch (indexPath.section) {
	case NTOperationsSection:
	return kOperationCellHeight;
	case NTDetectedBeaconsSection:
	default:
	return kBeaconCellHeight;
	}
	}

	- (UIView )tableView:(UITableView )tableView viewForHeaderInSection:(NSInteger)section
	{
	UITableViewHeaderFooterView *headerView =
	[[UITableViewHeaderFooterView alloc] initWithReuseIdentifier:kBeaconsHeaderViewIdentifier];

	// Adds an activity indicator view to the section header
	UIActivityIndicatorView *indicatorView =
	[[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
	[headerView addSubview:indicatorView];

	indicatorView.frame = (CGRect){kActivityIndicatorPosition, indicatorView.frame.size};

	[indicatorView startAnimating];

	return headerView;
	}

	@end