/*

     File: BatStatViewController.m

 Abstract: Receives battery status change notifications. Queries the battery status and presents it in a UITableView. Enables and disables battery status updates.

  Version: 1.2

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 */

#import "BatStatViewController.h"

@interface BatStatViewController ()

- (IBAction)switchAction:(id)sender;

@end

@implementation BatStatViewController

#pragma mark - Battery notifications

- (void)updateBatteryLevel

{

    float batteryLevel = [UIDevice currentDevice].batteryLevel;

    if (batteryLevel < 0.0) {

        // -1.0 means battery state is UIDeviceBatteryStateUnknown

        self.levelLabel.text = NSLocalizedString(@"Unknown", @"");

    }

    else {

        static NSNumberFormatter *numberFormatter = nil;

        if (numberFormatter == nil) {

            numberFormatter = [[NSNumberFormatter alloc] init];

            [numberFormatter setNumberStyle:NSNumberFormatterPercentStyle];

            [numberFormatter setMaximumFractionDigits:1];

        }

        NSNumber *levelObj = [NSNumber numberWithFloat:batteryLevel];

        self.levelLabel.text = [numberFormatter stringFromNumber:levelObj];

    }

}

- (void)updateBatteryState

{

    NSArray *batteryStateCells = @[self.unknownCell, self.unpluggedCell, self.chargingCell, self.fullCell];

    UIDeviceBatteryState currentState = [UIDevice currentDevice].batteryState;

    for (int i = 0; i < [batteryStateCells count]; i++) {

        UITableViewCell *cell = (UITableViewCell *) batteryStateCells[i];

        if (i + UIDeviceBatteryStateUnknown == currentState) {

            cell.accessoryType = UITableViewCellAccessoryCheckmark;

        }

        else {

            cell.accessoryType = UITableViewCellAccessoryNone;

        }

    }

}

- (void)batteryLevelChanged:(NSNotification *)notification

{

    [self updateBatteryLevel];

}

- (void)batteryStateChanged:(NSNotification *)notification

{

    [self updateBatteryLevel];

    [self updateBatteryState];

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Register for battery level and state change notifications.

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(batteryLevelChanged:)

                                                 name:UIDeviceBatteryLevelDidChangeNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(batteryStateChanged:)

                                                 name:UIDeviceBatteryStateDidChangeNotification object:nil];

    [self switchAction:self.monitorSwitch];

}

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

#pragma mark - Switch action handler

- (IBAction)switchAction:(id)sender

{

    if ([sender isOn]) {

        [UIDevice currentDevice].batteryMonitoringEnabled = YES;

        // The UI will be updated as a result of the first UIDeviceBatteryStateDidChangeNotification notification.

        // Note that enabling monitoring only triggers a UIDeviceBatteryStateDidChangeNotification;

        // a UIDeviceBatteryLevelDidChangeNotification is not sent.

    }

    else {

        [UIDevice currentDevice].batteryMonitoringEnabled = NO;

        [self batteryStateChanged:nil];

    }

}

@end