/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

*/

#import "ViewController.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIButton *button;

@property (weak, nonatomic) IBOutlet UITextField *barTextField;

@property (weak, nonatomic) IBOutlet UITextField *beatTextField;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    NSLog(@"Hello, Metronome!\n");

    NSError *error = nil;

    AVAudioSession *audioSession = [AVAudioSession sharedInstance];

    [audioSession setCategory:AVAudioSessionCategoryAmbient error:&error];

    if (error) {

        NSLog(@"AVAudioSession error %ld, %@", error.code, error.localizedDescription);

    }

    [audioSession setActive:YES error:&error];

    if (error) {

        NSLog(@"AVAudioSession error %ld, %@", error.code, error.localizedDescription);

    }

    // if media services are reset, we need to rebuild our audio chain

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(handleMediaServicesWereReset:)

                                                 name:AVAudioSessionMediaServicesWereResetNotification

                                               object:audioSession];

    metronome = [[Metronome alloc] init];

    metronome.delegate = self;

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

#pragma mark- Actions

- (IBAction)buttonPressed:(UIButton*)sender {

    // change the selected state thereby the button color and title

    // toggle between Start & Stop

    sender.selected = !sender.selected;

    if (metronome.isPlaying) {

        [metronome stop];

    } else {

        [metronome start];

    }

}

#pragma mark- Delegate

- (void)metronomeTicking:(Metronome * _Nonnull)metronome bar:(int32_t)bar beat:(int32_t)beat {

    dispatch_async(dispatch_get_main_queue(), ^{

        self.barTextField.text = [NSString stringWithFormat:@"%d", bar];

        self.beatTextField.text = [NSString stringWithFormat:@"%d", beat];

    });

}

#pragma mark- AVAudioSession Notifications

// see https://developer.apple.com/library/content/qa/qa1749/_index.html

- (void)handleMediaServicesWereReset:(NSNotification *)notification

{

    NSLog(@"Media services have reset...");

    // tear down

    metronome.delegate = nil;

    metronome = nil;

    self.button.selected = NO;

    // re-create

    metronome = [[Metronome alloc] init];

    metronome.delegate = self;

    NSError *error = nil;

    [[AVAudioSession sharedInstance] setActive:YES error:&error];

    if (error) {

        NSLog(@"AVAudioSession error %ld, %@", error.code, error.localizedDescription);

    }

}

@end