MTMR/MTMR/Widgets/VolumeViewController.swift

import AppKit
import AVFoundation
import Cocoa
import CoreAudio

class VolumeViewController: CustomTouchBarItem {
    private(set) var sliderItem: CustomSlider!
    
    override class var typeIdentifier: String {
        return "volume"
    }
    
    private enum CodingKeys: String, CodingKey {
        case image
    }

    init(identifier: NSTouchBarItem.Identifier, image: NSImage? = nil) {
        super.init(identifier: identifier)

        self.setup(image: image)
    }
    
    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        let image = try container.decodeIfPresent(Source.self, forKey: .image)?.image
        
        try super.init(from: decoder)

        self.setup(image: image)
    }
    
    func setup(image: NSImage?) {
        var forPropertyAddress = AudioObjectPropertyAddress(
            mSelector: kAudioHardwareServiceDeviceProperty_VirtualMasterVolume,
            mScope: kAudioDevicePropertyScopeOutput,
            mElement: kAudioObjectPropertyElementMaster
        )

        AudioObjectAddPropertyListenerBlock(defaultDeviceID, &forPropertyAddress, nil, audioObjectPropertyListenerBlock)

        if image == nil {
            sliderItem = CustomSlider()
        } else {
            sliderItem = CustomSlider(knob: image!)
        }
        sliderItem.target = self
        sliderItem.action = #selector(VolumeViewController.sliderValueChanged(_:))
        sliderItem.minValue = 0.0
        sliderItem.maxValue = 100.0
        sliderItem.floatValue = getInputGain() * 100

        view = sliderItem
    }

    func audioObjectPropertyListenerBlock(numberAddresses _: UInt32, addresses _: UnsafePointer<AudioObjectPropertyAddress>) {
        DispatchQueue.main.async {
            self.sliderItem.floatValue = self.getInputGain() * 100
        }
    }
    

    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    deinit {
        sliderItem.unbind(NSBindingName.value)
    }

    @objc func sliderValueChanged(_ sender: Any) {
        if let sliderItem = sender as? NSSlider {
            _ = setInputGain(Float32(sliderItem.intValue) / 100.0)
        }
    }

    private var defaultDeviceID: AudioObjectID {
        var deviceID: AudioObjectID = AudioObjectID(0)
        var size: UInt32 = UInt32(MemoryLayout<AudioObjectID>.size)
        var address: AudioObjectPropertyAddress = AudioObjectPropertyAddress()
        address.mSelector = AudioObjectPropertySelector(kAudioHardwarePropertyDefaultOutputDevice)
        address.mScope = AudioObjectPropertyScope(kAudioObjectPropertyScopeGlobal)
        address.mElement = AudioObjectPropertyElement(kAudioObjectPropertyElementMaster)
        AudioObjectGetPropertyData(AudioObjectID(kAudioObjectSystemObject), &address, 0, nil, &size, &deviceID)
        return deviceID
    }

    private func getInputGain() -> Float32 {
        var volume: Float32 = 0.5
        var size: UInt32 = UInt32(MemoryLayout.size(ofValue: volume))
        var address: AudioObjectPropertyAddress = AudioObjectPropertyAddress()
        address.mSelector = AudioObjectPropertySelector(kAudioHardwareServiceDeviceProperty_VirtualMasterVolume)
        address.mScope = AudioObjectPropertyScope(kAudioDevicePropertyScopeOutput)
        address.mElement = AudioObjectPropertyElement(kAudioObjectPropertyElementMaster)
        AudioObjectGetPropertyData(defaultDeviceID, &address, 0, nil, &size, &volume)
        return volume
    }

    private func setInputGain(_ volume: Float32) -> OSStatus {
        var inputVolume: Float32 = volume

        if inputVolume == 0.0 {
            _ = setMute(mute: 1)
        } else {
            _ = setMute(mute: 0)
        }

        let size: UInt32 = UInt32(MemoryLayout.size(ofValue: inputVolume))
        var address: AudioObjectPropertyAddress = AudioObjectPropertyAddress()
        address.mScope = AudioObjectPropertyScope(kAudioDevicePropertyScopeOutput)
        address.mElement = AudioObjectPropertyElement(kAudioObjectPropertyElementMaster)
        address.mSelector = AudioObjectPropertySelector(kAudioHardwareServiceDeviceProperty_VirtualMasterVolume)
        return AudioObjectSetPropertyData(defaultDeviceID, &address, 0, nil, size, &inputVolume)
    }

    private func setMute(mute: Int) -> OSStatus {
        var muteVal: Int = mute
        var address: AudioObjectPropertyAddress = AudioObjectPropertyAddress()
        address.mSelector = AudioObjectPropertySelector(kAudioDevicePropertyMute)
        let size: UInt32 = UInt32(MemoryLayout.size(ofValue: muteVal))
        address.mScope = AudioObjectPropertyScope(kAudioDevicePropertyScopeOutput)
        address.mElement = AudioObjectPropertyElement(kAudioObjectPropertyElementMaster)
        return AudioObjectSetPropertyData(defaultDeviceID, &address, 0, nil, size, &muteVal)
    }
}