Add UI to record a voice message from the composer toolbar (#1892)

ElementX/Sources/Services/Audio/Recorder/AudioRecorder.swift

@@ -0,0 +1,115 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import AVFoundation
+import Combine
+import Foundation
+
+enum AudioRecorderError: Error {
+    case genericError
+}
+
+class AudioRecorder: NSObject, AudioRecorderProtocol, AVAudioRecorderDelegate {
+    private let silenceThreshold: Float = -50.0
+    
+    private var audioRecorder: AVAudioRecorder?
+    
+    private let actionsSubject: PassthroughSubject<AudioRecorderAction, Never> = .init()
+    var actions: AnyPublisher<AudioRecorderAction, Never> {
+        actionsSubject.eraseToAnyPublisher()
+    }
+    
+    var url: URL? {
+        audioRecorder?.url
+    }
+    
+    var currentTime: TimeInterval {
+        audioRecorder?.currentTime ?? 0
+    }
+    
+    var isRecording: Bool {
+        audioRecorder?.isRecording ?? false
+    }
+    
+    func recordWithOutputURL(_ url: URL) {
+        let settings = [AVFormatIDKey: Int(kAudioFormatMPEG4AAC),
+                        AVSampleRateKey: 48000,
+                        AVEncoderBitRateKey: 128_000,
+                        AVNumberOfChannelsKey: 1,
+                        AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue]
+        
+        do {
+            try AVAudioSession.sharedInstance().setCategory(.playAndRecord, mode: .default)
+            try AVAudioSession.sharedInstance().setActive(true)
+            audioRecorder = try AVAudioRecorder(url: url, settings: settings)
+            audioRecorder?.delegate = self
+            audioRecorder?.isMeteringEnabled = true
+            audioRecorder?.record()
+            actionsSubject.send(.didStartRecording)
+        } catch {
+            MXLog.error("audio recording failed: \(error)")
+            actionsSubject.send(.didFailWithError(error: error))
+        }
+    }
+
+    func stopRecording() {
+        audioRecorder?.stop()
+
+        do {
+            try AVAudioSession.sharedInstance().setActive(false)
+        } catch {
+            actionsSubject.send(.didFailWithError(error: error))
+        }
+    }
+    
+    func peakPowerForChannelNumber(_ channelNumber: Int) -> Float {
+        guard isRecording, let audioRecorder else {
+            return 0.0
+        }
+        
+        audioRecorder.updateMeters()
+
+        return normalizedPowerLevelFromDecibels(audioRecorder.peakPower(forChannel: channelNumber))
+    }
+    
+    func averagePowerForChannelNumber(_ channelNumber: Int) -> Float {
+        guard isRecording, let audioRecorder else {
+            return 0.0
+        }
+        
+        audioRecorder.updateMeters()
+        
+        return normalizedPowerLevelFromDecibels(audioRecorder.averagePower(forChannel: channelNumber))
+    }
+        
+    // MARK: - AVAudioRecorderDelegate
+    
+    func audioRecorderDidFinishRecording(_ recorder: AVAudioRecorder, successfully success: Bool) {
+        if success {
+            actionsSubject.send(.didStopRecording)
+        } else {
+            actionsSubject.send(.didFailWithError(error: AudioRecorderError.genericError))
+        }
+    }
+    
+    func audioRecorderEncodeErrorDidOccur(_ recorder: AVAudioRecorder, error: Error?) {
+        actionsSubject.send(.didFailWithError(error: error ?? AudioRecorderError.genericError))
+    }
+    
+    private func normalizedPowerLevelFromDecibels(_ decibels: Float) -> Float {
+        decibels / silenceThreshold
+    }
+}

ElementX/Sources/Services/Audio/Recorder/AudioRecorderProtocol.swift

@@ -0,0 +1,38 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Combine
+import Foundation
+
+enum AudioRecorderAction {
+    case didStartRecording
+    case didStopRecording
+    case didFailWithError(error: Error)
+}
+
+protocol AudioRecorderProtocol: AnyObject {
+    var actions: AnyPublisher<AudioRecorderAction, Never> { get }
+    var currentTime: TimeInterval { get }
+    var isRecording: Bool { get }
+    var url: URL? { get }
+    
+    func recordWithOutputURL(_ url: URL)
+    func stopRecording()
+    func averagePowerForChannelNumber(_ channelNumber: Int) -> Float
+}
+
+// sourcery: AutoMockable
+extension AudioRecorderProtocol { }

ElementX/Sources/Services/Audio/Recorder/AudioRecorderState.swift

@@ -0,0 +1,114 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Combine
+import Foundation
+import UIKit
+
+enum AudioRecorderRecordingState {
+    case recording
+    case stopped
+    case error
+}
+
+@MainActor
+class AudioRecorderState: ObservableObject, Identifiable {
+    let id = UUID()
+    
+    @Published private(set) var recordingState: AudioRecorderRecordingState = .stopped
+    @Published private(set) var duration = 0.0
+    @Published private(set) var waveform = Waveform(data: Array(repeating: 0, count: 100))
+    
+    private weak var audioRecorder: AudioRecorderProtocol?
+    private var cancellables: Set<AnyCancellable> = []
+    private var displayLink: CADisplayLink?
+    
+    func attachAudioRecorder(_ audioRecorder: AudioRecorderProtocol) {
+        if self.audioRecorder != nil {
+            detachAudioRecorder()
+        }
+        recordingState = .stopped
+        self.audioRecorder = audioRecorder
+        subscribeToAudioRecorder(audioRecorder)
+    }
+    
+    func detachAudioRecorder() {
+        guard audioRecorder != nil else { return }
+        audioRecorder?.stopRecording()
+        stopPublishUpdates()
+        cancellables = []
+        audioRecorder = nil
+        recordingState = .stopped
+    }
+    
+    func reportError(_ error: Error) {
+        recordingState = .error
+    }
+    
+    // MARK: - Private
+    
+    private func subscribeToAudioRecorder(_ audioRecorder: AudioRecorderProtocol) {
+        audioRecorder.actions
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] action in
+                guard let self else {
+                    return
+                }
+                self.handleAudioRecorderAction(action)
+            }
+            .store(in: &cancellables)
+    }
+    
+    private func handleAudioRecorderAction(_ action: AudioRecorderAction) {
+        switch action {
+        case .didStartRecording:
+            startPublishUpdates()
+            recordingState = .recording
+        case .didStopRecording:
+            stopPublishUpdates()
+            recordingState = .stopped
+        case .didFailWithError:
+            stopPublishUpdates()
+            recordingState = .stopped
+        }
+    }
+    
+    private func startPublishUpdates() {
+        if displayLink != nil {
+            stopPublishUpdates()
+        }
+        displayLink = CADisplayLink(target: self, selector: #selector(publishUpdate))
+        displayLink?.preferredFrameRateRange = .init(minimum: 10, maximum: 20)
+        displayLink?.add(to: .current, forMode: .common)
+    }
+    
+    @objc private func publishUpdate(displayLink: CADisplayLink) {
+        if let currentTime = audioRecorder?.currentTime {
+            duration = currentTime
+        }
+    }
+    
+    private func stopPublishUpdates() {
+        displayLink?.invalidate()
+        displayLink = nil
+    }
+}
+
+extension AudioRecorderState: Equatable {
+    nonisolated static func == (lhs: AudioRecorderState, rhs: AudioRecorderState) -> Bool {
+        lhs.id == rhs.id
+    }
+}