From 81e0925f6f112dc6515e5b58c0f80e09e9aab295 Mon Sep 17 00:00:00 2001
From: Jeremy Rand <jeremy@rand-family.com>
Date: Tue, 19 Oct 2021 00:55:58 -0400
Subject: [PATCH] Move application logic out of view code.

---
 ListenerGS/Info.plist            |   2 +-
 ListenerGS/SpeechForwarder.swift | 219 +++++++++++++++++++++++++++++++
 2 files changed, 220 insertions(+), 1 deletion(-)
 create mode 100644 ListenerGS/SpeechForwarder.swift

diff --git a/ListenerGS/Info.plist b/ListenerGS/Info.plist
index 2d15f66..32907fe 100644
--- a/ListenerGS/Info.plist
+++ b/ListenerGS/Info.plist
@@ -19,7 +19,7 @@
 	<key>CFBundleShortVersionString</key>
 	<string>1.0</string>
 	<key>CFBundleVersion</key>
-	<string>122</string>
+	<string>132</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.utilities</string>
 	<key>LSRequiresIPhoneOS</key>
diff --git a/ListenerGS/SpeechForwarder.swift b/ListenerGS/SpeechForwarder.swift
new file mode 100644
index 0000000..ec69ab3
--- /dev/null
+++ b/ListenerGS/SpeechForwarder.swift
@@ -0,0 +1,219 @@
+//
+//  SpeechForwarder.swift
+//  ListenerGS
+//
+//  Created by Jeremy Rand on 2021-10-18.
+//
+
+import Foundation
+
+import Speech
+
+class SpeechForwarder : ObservableObject {
+    @Published var listening = false
+    @Published var listenEnabled = false
+    @Published var log = ""
+    @Published var ipAddress = ""
+    private var textHeard = ""
+    @Published var isEditing = false
+    
+    let LISTEN_STATE_MSG = 1
+    let LISTEN_TEXT_MSG = 2
+    
+    let port = 19026
+    private var client: TCPClient?
+    
+    private let speechRecognizer = SFSpeechRecognizer(locale: Locale(identifier: "en-US"))!
+    
+    private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?
+    
+    private var recognitionTask: SFSpeechRecognitionTask?
+    
+    private let audioEngine = AVAudioEngine()
+    
+    func logError(message: String) {
+        log.append("ERROR: " + message + "\n")
+    }
+    
+    func logEvent(message: String) {
+        log.append("EVENT: " + message + "\n")
+    }
+    
+    func validate(destination : String) {
+        logEvent(message: "Attempting to connect to " + destination)
+        client = TCPClient(address: destination, port: Int32(port))
+        guard let client = client else { return }
+        switch client.connect(timeout: 10) {
+        case .success:
+            listenEnabled = true
+            logEvent(message: "Connected to " + destination)
+        case .failure(let error):
+            client.close()
+            self.client = nil
+            logError(message: String(describing: error))
+            break
+        }
+    }
+    
+    func listen() {
+        self.listening.toggle()
+        if (self.listening) {
+            SFSpeechRecognizer.requestAuthorization { authStatus in
+                // The authorization status results in changes to the
+                // app’s interface, so process the results on the app’s
+                // main queue.
+                OperationQueue.main.addOperation {
+                switch authStatus {
+                    case .authorized:
+                        break
+                        
+                    case .denied:
+                        self.listening = false
+                        break
+
+                    case .restricted:
+                        self.listening = false
+                        break
+
+                    case .notDetermined:
+                        self.listening = false
+                        break
+                        
+                    default:
+                        self.listening = false
+                        break
+                    }
+                }
+            }
+        }
+        
+        guard let client = client else { return }
+        if (self.listening) {
+            switch (client.send(data: isListening())) {
+                case .success:
+                    break
+                case .failure(let error):
+                    self.listening = false
+                    logError(message: String(describing: error))
+            }
+        }
+        
+        if (self.listening) {
+            do {
+                try startRecording()
+                logEvent(message: "Listening...")
+            }
+            catch {
+                self.listening = false
+            }
+        }
+        
+        if (!self.listening) {
+            logEvent(message: "Listening stopped")
+            audioEngine.stop()
+            recognitionRequest?.endAudio()
+            switch (client.send(data: isListening())) {
+                case .success:
+                    break
+                case .failure(let error):
+                    self.listening = false
+                    logError(message: String(describing: error))
+            }
+        }
+    }
+    
+    private func isListening() -> Data {
+        return pack("<hh", [LISTEN_STATE_MSG, listening ? 1 : 0])
+    }
+
+    private func send(latestText : String) {
+        guard let client = client else { return }
+        var commonChars = self.textHeard.count
+        while (commonChars > 0) {
+            if (latestText.prefix(commonChars) ==  self.textHeard.prefix(commonChars)) {
+                break
+            }
+            commonChars -= 1
+        }
+        var stringToSend = ""
+        if (commonChars < self.textHeard.count) {
+            stringToSend = String(repeating: "\u{7f}", count: self.textHeard.count - commonChars)
+        }
+        stringToSend.append(contentsOf: latestText.suffix(latestText.count - commonChars).replacingOccurrences(of: "\n", with: "\r"))
+        
+        if (stringToSend.count > 0) {
+            // TODO - Handle strings to send that are longer than 64K (doubt that would happen though)
+            // TODO - Try to convert encoding from utf8 to something the GS can understand.
+            switch (client.send(data: pack("<hh\(stringToSend.count)s", [LISTEN_TEXT_MSG, stringToSend.count, stringToSend]))) {
+                case .success:
+                    self.textHeard = latestText
+                    logEvent(message: "Sent \"" + stringToSend + "\"")
+                    break
+                case .failure(let error):
+                    self.listening = false
+                    logError(message: String(describing: error))
+            }
+        }
+    }
+    
+    private func startRecording() throws {
+        
+        // Cancel the previous task if it's running.
+        recognitionTask?.cancel()
+        self.recognitionTask = nil
+        
+        // Configure the audio session for the app.
+        let audioSession = AVAudioSession.sharedInstance()
+        try audioSession.setCategory(.record, mode: .measurement, options: .duckOthers)
+        try audioSession.setActive(true, options: .notifyOthersOnDeactivation)
+        let inputNode = audioEngine.inputNode
+
+        // Create and configure the speech recognition request.
+        recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
+        guard let recognitionRequest = recognitionRequest else { fatalError("Unable to create a SFSpeechAudioBufferRecognitionRequest object") }
+        recognitionRequest.shouldReportPartialResults = true
+        
+        // Keep speech recognition data on device
+        if #available(iOS 13, *) {
+            recognitionRequest.requiresOnDeviceRecognition = false
+        }
+        
+        self.textHeard = ""
+        
+        // Create a recognition task for the speech recognition session.
+        // Keep a reference to the task so that it can be canceled.
+        recognitionTask = speechRecognizer.recognitionTask(with: recognitionRequest) { result, error in
+            var isFinal = false
+            
+            if let result = result {
+                // Update the text view with the results.
+                self.send(latestText: result.bestTranscription.formattedString)
+                isFinal = result.isFinal
+                print("Text \(result.bestTranscription.formattedString)")
+            }
+            
+            if error != nil || isFinal {
+                // Stop recognizing speech if there is a problem.
+                self.audioEngine.stop()
+                inputNode.removeTap(onBus: 0)
+
+                self.recognitionRequest = nil
+                self.recognitionTask = nil
+                self.listening = false
+                self.logEvent(message: "Listening stopped")
+                guard let client = self.client else { return }
+                client.send(data: self.isListening())
+            }
+        }
+
+        // Configure the microphone input.
+        let recordingFormat = inputNode.outputFormat(forBus: 0)
+        inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer: AVAudioPCMBuffer, when: AVAudioTime) in
+            self.recognitionRequest?.append(buffer)
+        }
+        
+        audioEngine.prepare()
+        try audioEngine.start()
+    }
+}
+