Kulexiu/KulexiuForStudent/KulexiuForStudent/Common/MediaMerge/MusicPlayer/AVPlayer+KSSeekSmoothly.m

//
//  AVPlayer+KSSeekSmoothly.m
//  KulexiuSchoolStudent
//
//  Created by 王智 on 2023/11/24.
//

#import "AVPlayer+KSSeekSmoothly.h"
#import <objc/runtime.h>

@interface AVPlayerSeeker : NSObject
{
    CMTime targetTime;
    BOOL isSeeking;
}

@property (weak, nonatomic) AVPlayer *player;

@property (nonatomic, strong) dispatch_queue_t queue;

@end

@implementation AVPlayerSeeker

- (instancetype)initWithPlayer:(AVPlayer *)player {
    self = [super init];
    if (self) {
        self.player = player;
        _queue = dispatch_queue_create("ks.seekTimeQueue", DISPATCH_QUEUE_SERIAL);
    }
    return self;
}

- (void)seekSmoothlyToTime:(CMTime)time toleranceBefore:(CMTime)toleranceBefore toleranceAfter:(CMTime)toleranceAfter completionHandler:(void (^)(BOOL))completionHandler {
    targetTime = time;
    if (!isSeeking) {
        [self trySeekToTargetTimeWithToleranceBefore:toleranceBefore toleranceAfter:toleranceAfter completionHandler:completionHandler];
    }
}

- (void)trySeekToTargetTimeWithToleranceBefore:(CMTime)toleranceBefore toleranceAfter:(CMTime)toleranceAfter completionHandler:(void (^)(BOOL))completionHandler {
    if (self.player.currentItem.status == AVPlayerItemStatusReadyToPlay) {
        [self seekToTargetTimeToleranceBefore:toleranceBefore toleranceAfter:toleranceAfter completionHandler:completionHandler];
    }
}

- (void)seekToTargetTimeToleranceBefore:(CMTime)toleranceBefore toleranceAfter:(CMTime)toleranceAfter completionHandler:(void (^)(BOOL))completionHandler {
    isSeeking = YES;
    CMTime seekingTime = targetTime;
    
    dispatch_async(_queue, ^{
        [self.player seekToTime:seekingTime toleranceBefore:toleranceBefore
                 toleranceAfter:toleranceAfter completionHandler:
         ^(BOOL isFinished) {
            if (CMTIME_COMPARE_INLINE(seekingTime, ==, self->targetTime)) {
                 // seek completed
                 self->isSeeking = NO;
                dispatch_main_async_safe(^{
                    if (completionHandler) {
                        completionHandler(isFinished);
                    }
                });
             } else {
                 // targetTime has changed, seek again
                 [self trySeekToTargetTimeWithToleranceBefore:toleranceBefore toleranceAfter:toleranceAfter completionHandler:completionHandler];
             }
         }];
    });
    
    
}

@end

static NSString *seekerKey = @"ss_seeker";

@implementation AVPlayer (KSSeekSmoothly)

- (void)ss_seekToTime:(CMTime)time {
    [self ss_seekToTime:time toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero completionHandler:nil];
}

- (void)ss_seekToTime:(CMTime)time toleranceBefore:(CMTime)toleranceBefore toleranceAfter:(CMTime)toleranceAfter completionHandler:(void (^)(BOOL))completionHandler {

    AVPlayerSeeker *seeker = objc_getAssociatedObject(self, &seekerKey);
    if (!seeker) {
        seeker = [[AVPlayerSeeker alloc] initWithPlayer:self];
        objc_setAssociatedObject(self, &seekerKey, seeker, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }

//    [self pause];
    [seeker seekSmoothlyToTime:time toleranceBefore:toleranceBefore toleranceAfter:toleranceAfter completionHandler:completionHandler];
}



@end