Feature: Add user idle and screen lock detection for macOS

macos/main.mm

@@ -141,9 +141,113 @@ static std::string getTimeString()
     return std::string([dateString UTF8String]);
 }
 
-// Get active application name
+// Get user idle time in seconds (time since last keyboard/mouse input)
+static double getUserIdleTime()
+{
+    // CGEventSourceSecondsSinceLastEventType returns seconds since last event
+    // kCGEventSourceStateCombinedSessionState includes all input sources
+    CFTimeInterval idleTime = CGEventSourceSecondsSinceLastEventType(
+        kCGEventSourceStateCombinedSessionState,
+        kCGAnyInputEventType
+    );
+    // Defensive: ensure non-negative (edge case protection)
+    return idleTime > 0 ? idleTime : 0;
+}
+
+// Check if screen is locked
+static bool isScreenLocked()
+{
+    // Method 1: Check CGSession dictionary for screen lock status
+    CFDictionaryRef sessionDict = CGSessionCopyCurrentDictionary();
+    if (sessionDict) {
+        // Check for "CGSSessionScreenIsLocked" key
+        CFBooleanRef screenLocked = (CFBooleanRef)CFDictionaryGetValue(
+            sessionDict, CFSTR("CGSSessionScreenIsLocked"));
+        if (screenLocked && CFBooleanGetValue(screenLocked)) {
+            CFRelease(sessionDict);
+            return true;
+        }
+        CFRelease(sessionDict);
+    }
+
+    // Method 2: Check if loginwindow is frontmost (screen saver / lock screen)
+    NSRunningApplication* frontApp = [[NSWorkspace sharedWorkspace] frontmostApplication];
+    if (frontApp) {
+        NSString* bundleId = [frontApp bundleIdentifier];
+        if ([bundleId isEqualToString:@"com.apple.loginwindow"] ||
+            [bundleId isEqualToString:@"com.apple.ScreenSaver.Engine"]) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+// Format time as HH:MM:SS with prefix
+static std::string formatStatusTime(const char* prefix, double seconds)
+{
+    int totalSecs = (int)seconds;
+    int hours = totalSecs / 3600;
+    int mins = (totalSecs % 3600) / 60;
+    int secs = totalSecs % 60;
+
+    char buffer[64];
+    snprintf(buffer, sizeof(buffer), "%s: %02d:%02d:%02d", prefix, hours, mins, secs);
+    return std::string(buffer);
+}
+
+// Get active application name or idle/locked status (works for background processes)
 static std::string getActiveApp()
 {
+    double idleTime = getUserIdleTime();
+
+    // Check if screen is locked first
+    if (isScreenLocked()) {
+        return formatStatusTime("Locked", idleTime);
+    }
+
+    // Check user idle time (matches Windows/Linux: 6 seconds threshold)
+    // If idle for more than 6 seconds, report inactive status
+    if (idleTime >= 6.0) {
+        return formatStatusTime("Inactive", idleTime);
+    }
+
+    // Use CGWindowListCopyWindowInfo to get the frontmost window
+    // This works reliably even when running as a background/nohup process
+    CFArrayRef windowList = CGWindowListCopyWindowInfo(
+        kCGWindowListOptionOnScreenOnly | kCGWindowListExcludeDesktopElements,
+        kCGNullWindowID
+    );
+
+    if (windowList) {
+        CFIndex count = CFArrayGetCount(windowList);
+        for (CFIndex i = 0; i < count; i++) {
+            CFDictionaryRef window = (CFDictionaryRef)CFArrayGetValueAtIndex(windowList, i);
+
+            // Get window layer - layer 0 is normal windows
+            CFNumberRef layerRef = (CFNumberRef)CFDictionaryGetValue(window, kCGWindowLayer);
+            int layer = 0;
+            if (layerRef) {
+                CFNumberGetValue(layerRef, kCFNumberIntType, &layer);
+            }
+
+            // Skip non-normal windows (menu bar, dock, etc.)
+            if (layer != 0) continue;
+
+            // Get owner name (application name)
+            CFStringRef ownerName = (CFStringRef)CFDictionaryGetValue(window, kCGWindowOwnerName);
+            if (ownerName) {
+                char buffer[256] = {};
+                if (CFStringGetCString(ownerName, buffer, sizeof(buffer), kCFStringEncodingUTF8)) {
+                    CFRelease(windowList);
+                    return std::string(buffer);
+                }
+            }
+        }
+        CFRelease(windowList);
+    }
+
+    // Fallback to NSWorkspace (may not work for background processes)
     NSRunningApplication* app = [[NSWorkspace sharedWorkspace] frontmostApplication];
     if (app) {
         NSString* name = [app localizedName];