fix: smooth character-by-character deletion and echo suppression without backspace fighting

android/app/src/main/java/com/soniox/remotemic/MainActivity.kt

@@ -10,6 +10,8 @@ import android.content.Context
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
 import android.os.VibrationEffect
 import android.os.Vibrator
 import android.os.VibratorManager
@@ -49,10 +51,14 @@ class MainActivity : AppCompatActivity() {
     // Authoritative Permanent Gateway Server on Linux (116.16.16.19:8999)
     private val gatewayHost = "116.16.16.19:8999"
     
-    // Live Synchronized State (Google Docs / Figma style)
+    // Live Synchronized State (Collaborative Engine)
     private var currentRevision: Long = 0L
     private var isApplyingRemoteUpdate = false
     private var lastLocalText = ""
+    private var lastLocalUserEditTime = 0L
+    
+    private val debounceHandler = Handler(Looper.getMainLooper())
+    private var pendingSyncRunnable: Runnable? = null
     
     // Voice Insertion Anchor
     private var voiceInsertionCursorStart = 0
@@ -79,7 +85,7 @@ class MainActivity : AppCompatActivity() {
         setupUI()
         checkPermissions()
         
-        AppLogger.log("Main", "اپلیکیشن راه‌اندازی شد (همگام‌سازی بلادرنگ Google Docs/Figma Style با مک)")
+        AppLogger.log("Main", "اپلیکیشن راه‌اندازی شد (همگام‌سازی بلادرنگ بدون باگ پاک‌کردن)")
         
         // Initialize Collaborative WebSocket Client
         streamDictationClient = StreamDictationClient(
@@ -91,16 +97,23 @@ class MainActivity : AppCompatActivity() {
                 )
             },
             onSyncStateReceived = { state ->
-                // Apply update from Mac if source != android and revision is newer
+                // Drop echoes and do not interrupt active user editing on phone
                 if (state.source != "android") {
+                    val timeSinceLocalEdit = System.currentTimeMillis() - lastLocalUserEditTime
+                    
+                    // If user is actively typing or backspacing right now on phone, do not override with remote echo
+                    if (timeSinceLocalEdit < 1000L && binding.etTranscript.hasFocus()) {
+                        return@StreamDictationClient
+                    }
+                    
                     if (state.text != lastLocalText) {
                         isApplyingRemoteUpdate = true
                         lastLocalText = state.text
                         currentRevision = state.revision
                         
-                        // Preserve cursor safely
                         val currentCursor = binding.etTranscript.selectionStart
                         binding.etTranscript.setText(state.text)
+                        
                         val targetCursor = if (binding.etTranscript.hasFocus() && currentCursor >= 0) {
                             currentCursor.coerceIn(0, state.text.length)
                         } else {
@@ -143,20 +156,15 @@ class MainActivity : AppCompatActivity() {
         )
     }
 
-    /**
-     * Dynamically adjusts the layout when virtual keyboard opens or closes
-     */
     private fun setupKeyboardInsetHandling() {
         ViewCompat.setOnApplyWindowInsetsListener(binding.rootLayout) { _, insets ->
             val imeVisible = insets.isVisible(WindowInsetsCompat.Type.ime())
             
             if (imeVisible) {
-                // Keyboard OPEN: Hide huge bottom circle, expand editor box to full height directly above keyboard
                 binding.bottomVoiceSection.visibility = View.GONE
                 binding.tvSubtitle.visibility = View.GONE
                 binding.btnMiniMic.visibility = View.VISIBLE
             } else {
-                // Keyboard CLOSED: Restore spacious layout with large glowing mic button
                 binding.bottomVoiceSection.visibility = View.VISIBLE
                 binding.tvSubtitle.visibility = View.VISIBLE
                 binding.btnMiniMic.visibility = View.GONE
@@ -166,9 +174,6 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    /**
-     * Slices speech text right at the exact cursor/selection location
-     */
     private fun insertSpeechAtCursor(speechText: String) {
         val current = binding.etTranscript.text?.toString() ?: ""
         val start = voiceInsertionCursorStart.coerceIn(0, current.length)
@@ -188,18 +193,18 @@ class MainActivity : AppCompatActivity() {
         
         isApplyingRemoteUpdate = true
         lastLocalText = mergedText
+        lastLocalUserEditTime = System.currentTimeMillis()
         binding.etTranscript.setText(mergedText)
         binding.etTranscript.setSelection(newCursor)
         isApplyingRemoteUpdate = false
         
         AppLogger.log("Main", "تزریق گفتار در نشانگر: '$speechText' (موقعیت جدید: $newCursor)")
         
-        // Broadcast updated state to Mac immediately!
         streamDictationClient?.sendLocalSyncState(mergedText, newCursor)
     }
 
     private fun setupUI() {
-        // Real-time TextWatcher for local keyboard typing
+        // Real-time TextWatcher for local keyboard typing & backspacing
         binding.etTranscript.addTextChangedListener(object : TextWatcher {
             override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {}
             override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
@@ -207,11 +212,17 @@ class MainActivity : AppCompatActivity() {
                 val wordCount = if (text.trim().isEmpty()) 0 else text.trim().split("\\s+".toRegex()).size
                 binding.tvCharCount.text = "$wordCount کلمه"
                 
-                // If typed locally by user, broadcast to Mac immediately!
                 if (!isApplyingRemoteUpdate && !isCurrentlyRecording) {
                     lastLocalText = text
+                    lastLocalUserEditTime = System.currentTimeMillis()
                     val cur = binding.etTranscript.selectionStart.coerceIn(0, text.length)
-                    streamDictationClient?.sendLocalSyncState(text, cur)
+                    
+                    // Debounce sending to Mac by 60ms to allow 120Hz lag-free backspacing and typing
+                    pendingSyncRunnable?.let { debounceHandler.removeCallbacks(it) }
+                    pendingSyncRunnable = Runnable {
+                        streamDictationClient?.sendLocalSyncState(text, cur)
+                    }
+                    debounceHandler.postDelayed(pendingSyncRunnable!!, 60)
                 }
             }
             override fun afterTextChanged(s: Editable?) {}
@@ -222,6 +233,7 @@ class MainActivity : AppCompatActivity() {
             isApplyingRemoteUpdate = true
             binding.etTranscript.setText("")
             lastLocalText = ""
+            lastLocalUserEditTime = System.currentTimeMillis()
             isApplyingRemoteUpdate = false
             streamDictationClient?.sendLocalSyncState("", 0)
             binding.tvInstruction.text = getString(R.string.hold_to_speak)

mac/src/FocusedInputSync.swift

@@ -26,8 +26,11 @@ public final class FocusedInputSync {
     
     private let systemWideElement: AXUIElement
     private var isApplyingRemoteChange: Bool = false
-    private var lastObservedHash: Int = 0
+    private var lastObservedText: String = ""
+    private var lastObservedCursor: Int = -1
+    private var lastObservedApp: String = ""
     private var localRevision: Int64 = 0
+    private var remoteChangeExpiryTime: Double = 0
     
     private init() {
         self.systemWideElement = AXUIElementCreateSystemWide()
@@ -113,7 +116,11 @@ public final class FocusedInputSync {
     
     /// Inspects the current focused element and returns a state snapshot if changed
     public func inspectCurrentState() -> MacInputState? {
-        guard !isApplyingRemoteChange else { return nil }
+        let now = Date().timeIntervalSince1970
+        if isApplyingRemoteChange || now < remoteChangeExpiryTime {
+            return nil
+        }
+        
         guard let (elem, appName) = getFocusedElement() else { return nil }
         
         // Extract text
@@ -156,10 +163,14 @@ public final class FocusedInputSync {
             }
         }
         
-        // Check hash to prevent echo loops
-        let currentHash = "\(appName)_\(text)_\(cursor)_\(selLen)".hashValue
-        guard currentHash != lastObservedHash else { return nil }
-        lastObservedHash = currentHash
+        // Check if text or cursor actually changed on Mac
+        if text == lastObservedText && cursor == lastObservedCursor && appName == lastObservedApp {
+            return nil
+        }
+        
+        lastObservedText = text
+        lastObservedCursor = cursor
+        lastObservedApp = appName
         localRevision += 1
         
         return MacInputState(app: appName, text: text, cursor: cursor, selection: selLen, revision: localRevision)
@@ -169,22 +180,30 @@ public final class FocusedInputSync {
     @discardableResult
     public func applyRemoteUpdate(text: String, cursor: Int? = nil, isFullReplace: Bool = true) -> Bool {
         isApplyingRemoteChange = true
+        remoteChangeExpiryTime = Date().timeIntervalSince1970 + 0.45 // 450ms quiet window
+        
         defer {
-            DispatchQueue.main.asyncAfter(deadline: .now() + 0.12) {
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.45) {
                 self.isApplyingRemoteChange = false
             }
         }
         
-        // 1. Flatten all newlines and carriage returns
+        // 1. Clean and normalize text
         var cleanText = text.components(separatedBy: .newlines).joined(separator: " ")
         cleanText = cleanText.replacingOccurrences(of: "\t", with: " ")
         cleanText = cleanText.replacingOccurrences(of: "\\s+", with: " ", options: .regularExpression)
         cleanText = cleanText.trimmingCharacters(in: .whitespacesAndNewlines)
         
+        let targetCursor = cursor ?? cleanText.count
+        lastObservedText = cleanText
+        lastObservedCursor = targetCursor
+        
         guard let (elem, appName) = getFocusedElement() else {
             // Fallback: clipboard paste
+            lastObservedApp = NSWorkspace.shared.frontmostApplication?.localizedName ?? "App"
             return pasteViaKeystroke(cleanText, isFullReplace: isFullReplace)
         }
+        lastObservedApp = appName
         
         if isFullReplace {
             // Try setting AXValue directly
@@ -196,7 +215,6 @@ public final class FocusedInputSync {
                         AXUIElementSetAttributeValue(elem, kAXSelectedTextRangeAttribute as CFString, axRange)
                     }
                 }
-                lastObservedHash = "\(appName)_\(cleanText)_\(cursor ?? cleanText.count)_0".hashValue
                 print("FocusedInputSync: ✅ Updated AXValue for \(appName)")
                 return true
             }
@@ -204,7 +222,6 @@ public final class FocusedInputSync {
             // Try setting selected text
             let setSelErr = AXUIElementSetAttributeValue(elem, kAXSelectedTextAttribute as CFString, cleanText as CFTypeRef)
             if setSelErr == .success {
-                lastObservedHash = "\(appName)_\(cleanText)_\(cursor ?? cleanText.count)_0".hashValue
                 print("FocusedInputSync: ✅ Inserted text via AXSelectedText for \(appName)")
                 return true
             }
@@ -228,7 +245,7 @@ public final class FocusedInputSync {
             aDown?.post(tap: .cghidEventTap)
             aUp?.post(tap: .cghidEventTap)
             
-            usleep(25000)
+            usleep(20000)
         }
         
         // Paste: Cmd + V