| 1 | import AVFoundation |
| 2 | import Foundation |
| 3 | |
| 4 | #if os(iOS) |
| 5 | import UIKit |
| 6 | #endif |
| 7 | |
| 8 | /// Where the system's microphone mode is read from, and how its picker is |
| 9 | /// opened. A protocol only so the tests can stand in for AVCaptureDevice, |
| 10 | /// whose mode is a class property that a test cannot set: Apple lets the |
| 11 | /// person choose the mode and lets an app do no more than look at it and |
| 12 | /// open the picker. |
| 13 | public protocol MicrophoneModeSource: AnyObject { |
| 14 | /// What the person chose in Control Center. |
| 15 | var preferred: AVCaptureDevice.MicrophoneMode { get } |
| 16 | /// What the microphone is actually doing, which can differ when the |
| 17 | /// route cannot honour the choice. |
| 18 | var active: AVCaptureDevice.MicrophoneMode { get } |
| 19 | /// Called whenever either may have changed, from any thread. |
| 20 | var changed: (@Sendable () -> Void)? { get set } |
| 21 | func showPicker() |
| 22 | } |
| 23 | |
| 24 | /// The iPhone's microphone mode — Standard, Voice Isolation or Wide |
| 25 | /// Spectrum — shown in words, with the way to Apple's picker beside it. |
| 26 | /// |
| 27 | /// Voice Isolation is the best noise suppression the phone has: wind, |
| 28 | /// typing and a room's echo, taken out before WebRTC ever sees the audio. |
| 29 | /// It is also not ours to switch on. There is no setter; the mode belongs |
| 30 | /// to the person and lives in Control Center, and the most an app can do |
| 31 | /// is say which one is in force and open the picker at the right page. |
| 32 | /// |
| 33 | /// It applies to Calls because the iOS WebRTC audio device runs on |
| 34 | /// Apple's voice-processing I/O unit, under a `.videoChat` session, and |
| 35 | /// the mic modes are voice-processing modes. The Mac app is deliberately |
| 36 | /// left out: WebRTC's macOS audio device does not use voice processing, |
| 37 | /// so the mode would not reach the call, and the Mac audio is the last |
| 38 | /// place a change nobody needed should be made. |
| 39 | @MainActor public final class MicrophoneModes: ObservableObject { |
| 40 | @Published public private(set) var preferred: AVCaptureDevice.MicrophoneMode |
| 41 | @Published public private(set) var active: AVCaptureDevice.MicrophoneMode |
| 42 | private let source: MicrophoneModeSource |
| 43 | |
| 44 | public init(source: MicrophoneModeSource) { |
| 45 | self.source = source |
| 46 | preferred = source.preferred |
| 47 | active = source.active |
| 48 | source.changed = { [weak self] in |
| 49 | Task { @MainActor in self?.refresh() } |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | #if os(iOS) |
| 54 | public convenience init() { self.init(source: SystemMicrophoneModes()) } |
| 55 | #endif |
| 56 | |
| 57 | public func refresh() { |
| 58 | preferred = source.preferred |
| 59 | active = source.active |
| 60 | } |
| 61 | |
| 62 | public func showPicker() { source.showPicker() } |
| 63 | |
| 64 | /// The mode in words. When the route has overridden the choice both are |
| 65 | /// named, because "Voice Isolation" on its own would be a claim about |
| 66 | /// audio the call is not getting. |
| 67 | public var summary: String { |
| 68 | MicrophoneModes.summary(preferred: preferred, active: active) |
| 69 | } |
| 70 | |
| 71 | public nonisolated static func summary( |
| 72 | preferred: AVCaptureDevice.MicrophoneMode, active: AVCaptureDevice.MicrophoneMode |
| 73 | ) -> String { |
| 74 | if preferred == active { return name(active) } |
| 75 | return "\(name(active)) — \(name(preferred)) is chosen, but this microphone cannot use it." |
| 76 | } |
| 77 | |
| 78 | /// Apple's own names for the modes, so the words here match the ones in |
| 79 | /// Control Center. |
| 80 | public nonisolated static func name(_ mode: AVCaptureDevice.MicrophoneMode) -> String { |
| 81 | switch mode { |
| 82 | case .standard: return "Standard" |
| 83 | case .voiceIsolation: return "Voice Isolation" |
| 84 | case .wideSpectrum: return "Wide Spectrum" |
| 85 | @unknown default: return "Unknown" |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | #if os(iOS) |
| 91 | /// The real thing: AVCaptureDevice's class properties, key-value observed. |
| 92 | /// |
| 93 | /// They are class properties, so the observation is registered on the |
| 94 | /// class object itself, which Swift's key-path `observe` cannot express. |
| 95 | /// Becoming active is watched as well: the picker is Control Center, so |
| 96 | /// the change happens while Calls is in the background, and returning is |
| 97 | /// the moment the panel most needs to be right. |
| 98 | final class SystemMicrophoneModes: NSObject, MicrophoneModeSource { |
| 99 | private static let keys = ["preferredMicrophoneMode", "activeMicrophoneMode"] |
| 100 | var changed: (@Sendable () -> Void)? |
| 101 | private var returning: NSObjectProtocol? |
| 102 | |
| 103 | override init() { |
| 104 | super.init() |
| 105 | for key in Self.keys { |
| 106 | (AVCaptureDevice.self as AnyObject).addObserver(self, forKeyPath: key, options: [.new], context: nil) |
| 107 | } |
| 108 | returning = NotificationCenter.default.addObserver( |
| 109 | forName: UIApplication.didBecomeActiveNotification, object: nil, queue: .main |
| 110 | ) { [weak self] _ in self?.changed?() } |
| 111 | } |
| 112 | |
| 113 | deinit { |
| 114 | for key in Self.keys { |
| 115 | (AVCaptureDevice.self as AnyObject).removeObserver(self, forKeyPath: key) |
| 116 | } |
| 117 | if let returning { NotificationCenter.default.removeObserver(returning) } |
| 118 | } |
| 119 | |
| 120 | var preferred: AVCaptureDevice.MicrophoneMode { AVCaptureDevice.preferredMicrophoneMode } |
| 121 | var active: AVCaptureDevice.MicrophoneMode { AVCaptureDevice.activeMicrophoneMode } |
| 122 | func showPicker() { AVCaptureDevice.showSystemUserInterface(.microphoneModes) } |
| 123 | |
| 124 | override func observeValue( |
| 125 | forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, |
| 126 | context: UnsafeMutableRawPointer? |
| 127 | ) { |
| 128 | changed?() |
| 129 | } |
| 130 | } |
| 131 | #endif |
| 132 | |
amadan