#import "ViewController.h"

@interface ViewController ()
{
    NSString *_LRC;
    NSTimer *_timer;
}
@property (nonatomic, strong)NSDateFormatter *dateFormatter;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //根据文件名和类型找到文件的路径
    NSString *LRCPath = [[NSBundle mainBundle] pathForResource:@"小幸运" ofType:@"lrc"];
    _LRC = [NSString stringWithContentsOfFile:LRCPath encoding:NSUTF8StringEncoding error:nil];
    
    _timer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(didTime:) userInfo:nil repeats:YES];
}

- (void) didTime: (NSTimer *)timer {
    static double time = 0;
    //计时器每次都会加载，所以要进行懒加载
    NSDateFormatter *dateFormatter = self.dateFormatter;
    //设置时间格式
    dateFormatter.dateFormat = @"mm:ss.SS";
    //将double型转换成NSDate类型
    NSDate *date = [NSDate dateWithTimeIntervalSince1970:time];
    //将把date转换成自己定义的格式
    NSString *timeStr = [dateFormatter stringFromDate:date];
    
    NSString *resultLrc = [self parseLRC:_LRC andTimeStamp:timeStr];
    if (resultLrc.length) {
        NSLog(@"%@", resultLrc);
    }
    //加上计时器的变化时间
    time = time + timer.timeInterval;
}

- (NSString *)parseLRC: (NSString *)LRC andTimeStamp:(NSString *)timeStamp {
    NSArray *LRCArray = [LRC componentsSeparatedByString:@"\n"];
    __block NSString *targetStr;
    [LRCArray enumerateObjectsUsingBlock:^(NSString *obj, NSUInteger idx, BOOL * _Nonnull stop) {
        if ([obj containsString:timeStamp]) {
            targetStr = obj;
            *stop = YES;
        }
    }];
    NSArray *lrcArray = [targetStr componentsSeparatedByString:@"]"];
    NSString *lrc = [lrcArray.lastObject stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    return lrc;
}

- (NSDateFormatter *)dateFormatter {
    //懒加载，dateFormatter是实例变量
    if (!_dateFormatter) {
        _dateFormatter = [NSDateFormatter new];
    }
    return _dateFormatter;
}
@end