Basic audio player with a buffer callback in Swift

AudioFilePlayer.swift

import AVFoundation
import CoreMedia
import CoreAudio

protocol AudioFilePlayerDelegate: AnyObject {
    func didReceiveAudioSample(_ buffer: AVAudioPCMBuffer, time: AVAudioTime)
}

class AudioFilePlayer: NSObject {
    private var audioFile: AVAudioFile?
    private var audioEngine: AVAudioEngine = AVAudioEngine()
    private var audioPlayerNode: AVAudioPlayerNode = AVAudioPlayerNode()
    private var format: AVAudioFormat?
    weak var delegate: (any AudioFilePlayerDelegate)?

    override init() {
        super.init()
        loadAudioFile()
        setupAudioEngine()
    }

    private func loadAudioFile() {
        guard let fileURL = Bundle.main.url(forResource: "audio", withExtension: "wav") else {
            print("Audio file not found in bundle")
            return
        }

        do {
            let file = try AVAudioFile(forReading: fileURL)
            self.audioFile = file
            self.format = file.processingFormat
        } catch {
            print("Error loading audio file: \(error)")
        }
    }

    private func setupAudioEngine() {
        guard let format = self.format else {
            print("Audio format is nil")
            return
        }

        audioEngine.attach(audioPlayerNode)
        audioEngine.connect(audioPlayerNode, to: audioEngine.mainMixerNode, format: format)

        audioPlayerNode.volume = 0

        do {
            try audioEngine.start()
        } catch {
            print("Error starting audio engine: \(error)")
        }
    }

    func play() {
        guard let audioFile = self.audioFile, let format = self.format else {
            print("Audio file or format is nil")
            return
        }

        audioPlayerNode.scheduleFile(audioFile, at: nil) {
            print("AudioFilePlayer finished")
        }

        audioPlayerNode.installTap(onBus: 0, bufferSize: 1024, format: format) { [weak self] (buffer, time) in
             self?.delegate?.didReceiveAudioSample(buffer, time: time)
        }

        audioPlayerNode.play()
    }
}