feat: Add global hotkey to summon BossTerm windows

[kshivang]

Summary

• Adds system-wide global hotkeys to summon specific BossTerm windows from anywhere (like iTerm2)
• Window-specific hotkeys: Modifiers+1 for window 1, Modifiers+2 for window 2, etc.
• Cross-platform: Windows (Win32 API), macOS (Carbon API), Linux (X11)
• Configurable modifiers in Settings → Global Hotkey
• Hotkey hint shown in title bar or as overlay

Test plan

• Enable global hotkey in Settings → Global Hotkey
• Open BossTerm, switch to another app
• Press Ctrl+1 (or configured hotkey) - BossTerm window 1 should appear
• Press hotkey again while focused - window should minimize
• Open second window, verify Ctrl+2 summons it
• Test on macOS/Windows/Linux

Closes #241

🤖 Generated with Claude Code

[claude]

Code Review: Global Hotkey Feature

I've completed a thorough review of this PR. Overall, this is a well-structured cross-platform implementation with good separation of concerns. However, there are several critical issues that need to be addressed before merging.

---

🔴 Critical Issues (Must Fix)

1. Linux Keycode Matching is Broken

Location: LinuxHotKeyApi.kt lines 553-569

The event loop invokes the callback for the first window in the map without checking if the keycode matches:

for ((windowNum, keycode) in linuxKeycodes) {
    invokeCallback(windowNum)  // Always triggers first window!
    break
}

Fix: Extract and compare the actual keycode from the XEvent:

val keyEvent = XKeyEvent()
event.pointer.read(0, keyEvent.pointer, XKeyEvent().size())
keyEvent.read()

for ((windowNum, keycode) in linuxKeycodes) {
    if (keyEvent.keycode == keycode) {
        invokeCallback(windowNum)
        break
    }
}

2. Race Condition in Thread Initialization

Location: GlobalHotKeyManager.kt lines 84-97

Windows can register before the handler thread completes initialization, leaving winThreadId/linuxDisplay uninitialized.

Fix: Use a CountDownLatch or CompletableDeferred to signal when initialization is complete.

3. Resource Leaks in Shutdown

Location: GlobalHotKeyManager.kt lines 157-166

If the thread doesn't stop within 1 second, it's interrupted but native resources (X11 display, Carbon event handlers) may not be cleaned up.

Fix: Ensure native cleanup happens in a finally block even if thread is interrupted. Consider longer timeout or more aggressive shutdown.

4. Status Not Updated on Errors

Location: Multiple locations (lines 240-241, 330-332, etc.)

Exceptions are caught and printed, but _registrationStatus isn't updated to FAILED. Users won't know hotkeys stopped working.

Fix: Update status on all error paths:

} catch (e: Exception) {
    println("GlobalHotKeyManager: Error: ${e.message}")
    _registrationStatus.value = HotKeyRegistrationStatus.FAILED
}

---

🟡 High Priority Issues (Should Fix)

5. Platform Detection Inconsistency

Location: Main.kt line 72

Uses raw System.getProperty("os.name") instead of ShellCustomizationUtils.isMacOS() as documented in CLAUDE.md.

Fix: Use ShellCustomizationUtils everywhere for consistency.

6. Linux Performance - Polling vs Event-Driven

Location: LinuxHotKeyApi.kt line 567

Polling with 50ms sleep adds ~25ms average latency to hotkey responses. This is noticeably sluggish.

Fix: Use XNextEvent() with timeout or select() on X11 connection FD for true event-driven behavior.

7. Windows Message Pump Thread Safety

Location: GlobalHotKeyManager.kt lines 264-273

winThreadId = 0 is set immediately, but thread may still be running. If stop() is called twice quickly, second call won't send WM_QUIT.

Fix: Set winThreadId = 0 only after thread has actually stopped (in finally block).

8. X11 Error Handling Missing

Location: GlobalHotKeyManager.kt lines 511-516

X11 errors from XGrabKey are silently ignored. If a hotkey conflicts with system bindings, it fails silently.

Fix: Set up X11 error handler to detect conflicts and update status to FAILED with descriptive message.

---

🟢 Medium Priority Issues (Nice to Have)

9. Reflection for HWND May Break on Modern JDKs

Location: WindowVisibilityController.kt lines 136-164

Deep reflection into JDK internals will break with strong encapsulation (JDK 17+).

Recommendation: Document required --add-opens flags or use JNA's Native.getComponentID().

10. macOS Event Loop Latency

Location: MacOSHotKeyApi.kt lines 404-408

Polling every 100ms adds latency. Consider longer timeout and interrupt via CFRunLoopStop() on shutdown.

11. XEvent.asKeyEvent() is Incomplete

Location: LinuxHotKeyApi.kt lines 254-263

This method doesn't copy data from XEvent union - it just creates an empty structure. It's never used in the code.

Fix: Either implement it properly or remove it entirely.

---

✅ Positive Aspects

1. ✨ Clean platform abstraction - Excellent separation of concerns
2. 🎯 Proper JNA usage - Correct structure definitions and native mapping
3. 🔄 Good state management - Uses StateFlow for reactive updates
4. 🧵 Daemon threads - Prevents hanging JVM on exit
5. ⚙️ Well-integrated settings - Clean integration with existing settings system
6. 💬 Good UI feedback - Clear status indicators and hotkey hints
7. 🎨 Proper modifier handling - Correctly handles platform differences

---

🧪 Testing Recommendations

Before merging, please test:

1. Linux multi-window: Verify Ctrl+1, Ctrl+2, etc. summon the correct window (currently broken)
2. Race conditions: Start/stop manager rapidly and register windows immediately after start
3. Conflict detection: Register a system hotkey (e.g., Ctrl+1 in another app) and verify failure is detected
4. Memory leaks: Start/stop manager 1000+ times and monitor native handles
5. Platform-specific:
   • Linux: Test with CapsLock/NumLock on/off
   • macOS: Test with app unfocused to verify global registration
   • Windows: Test with elevated vs non-elevated process

---

📝 Summary

This is a solid foundation for global hotkey support, but the Linux keycode matching bug is critical - it makes the feature non-functional for Linux users with multiple windows. The resource leaks and race conditions could cause crashes or resource exhaustion in production.

Once the critical issues are addressed, this will be a great addition to BossTerm! 🚀

---

Review generated with attention to threading, resource management, platform-specific APIs, and security considerations.

[claude]

Code Review: Global Hotkey Support

Thanks for this feature! The overall architecture is solid with good platform abstraction. However, I found several critical issues that need to be addressed before merging.

Critical Issues (Must Fix)

1. Linux Event Handling is Broken (GlobalHotKeyManager.kt:556-564)

The Linux implementation does not parse the XKeyEvent to determine which key was pressed. This will always trigger window 1, regardless of which hotkey was pressed. Need to extract the actual keycode from the XEvent structure and match it.

2. Thread Safety Issues (GlobalHotKeyManager.kt)

Multiple problems: isRunning (line 40) accessed from multiple threads without @volatile; mutable collections accessed without synchronization. Can cause race conditions. Fix: Use @volatile for isRunning and ConcurrentHashMap for collections.

3. Resource Leak on macOS (GlobalHotKeyManager.kt:278-416)

If hotkey registration partially succeeds then fails, native event handlers are leaked. Need try-catch with proper cleanup.

High Priority Issues

4. Fragile Reflection (WindowVisibilityController.kt:137-163) - Can break with JDK updates. Document required --add-opens flags.

5. Windows Hotkey Strategy (GlobalHotKeyManager.kt:191-253) - Registers ALL hotkeys 1-9 upfront even if unused. Wastes resources and prevents other apps from using them.

6. Platform Detection (Main.kt:72) - Uses System.getProperty instead of ShellCustomizationUtils as documented in CLAUDE.md.

Medium Priority

7. Silent Native API Failures - No logging when JNA load fails. Users won't know why hotkeys don't work.

8. Missing Key Validation (GlobalHotKeyManager.kt:67-72) - Only validates modifiers, not the key field.

9. Linux Polling Performance - Uses 50ms polling instead of blocking XNextEvent(). Wastes CPU.

Strengths

• Clean platform abstraction
• Good use of ShellCustomizationUtils in GlobalHotKeyManager
• Proper Compose state patterns
• Good code comments

Testing Gap

No automated tests provided. Recommend adding unit tests for config validation and integration tests for manager lifecycle.

Summary

Production Ready: No - must fix critical issues 1-3 first

This is a valuable feature with solid architecture, but the Linux implementation is broken and there are thread safety issues that could cause crashes. Estimated 4-8 hours to fix critical issues.

[claude]

Pull Request #243 Review: Global Hotkey Functionality

Overview

This PR adds system-wide global hotkey functionality to summon BossTerm windows from anywhere, similar to iTerm2. The implementation spans 2,277 lines across 15 files with cross-platform support for Windows, macOS, and Linux.

✅ Excellent Adherence to BossTerm Conventions

Platform Detection - The PR correctly uses ShellCustomizationUtils throughout instead of raw System.getProperty("os.name"). Great job following CLAUDE.md guidelines!

🔴 Critical Issues

1. Race Condition in Initialization (Main.kt:62-63, 864-889)

The comment says "Windows only" but supports all platforms. More critically, startGlobalHotKeyManager() is called before the application {} block, meaning:

• WindowManager.windows is empty when hotkeys are registered
• The fallback logic to create window 1 (lines 874-880) races with normal initialization (lines 67-69)
• Could result in duplicate windows or timing issues

Recommendation: Move startGlobalHotKeyManager() inside the application {} block after initial window creation, or add synchronization.

2. Memory Leak: Callback References (GlobalHotKeyManager.kt:181)

The macOS event handler reference (macEventHandler at line 51) is not cleared in stop(), only in cleanupMacOS(). Add to stop() after line 182:

macEventHandler = null
macEventHandlerRef = null
macRunLoopMode = null

3. Thread Safety Issue (GlobalHotKeyManager.kt:42-43)

The isRunning flag is checked in platform loops but not @Volatile. Changes in stop() may not be visible to handler threads, causing delayed/failed shutdown.

Fix:

@Volatile private var isRunning = false

4. Hard-Coded X11 Structure Offset (LinuxHotKeyApi.kt:611)

val eventKeycode = event.pointer.getInt(84)

This offset is architecture-dependent and will break on 32-bit Linux, ARM, or non-standard X11. Use the properly defined XKeyEvent structure instead of bypassing JNA.

5. Window Number Reuse Bug (WindowManager.kt:49-55)

When you close window 2 and create a new window, it gets number 2. But the global hotkey for window 2 is still registered and now points to the wrong window. There's no re-registration logic.

Solution: Either never reuse window numbers, OR add re-registration when numbers are reused.

🟡 High-Priority Issues

6. Missing Error Logging (WindowVisibilityController.kt:158-164)

Silent exception swallowing makes debugging impossible. Add:

} catch (e: Exception) {
    println("WindowVisibilityController: Failed to get HWND: ${e.javaClass.simpleName} - ${e.message}")
    null
}

7. Unsafe Latch Timeout (GlobalHotKeyManager.kt:117)

If initialization takes >5 seconds, registerWindow() proceeds anyway. Check the return value:

val initialized = initializationLatch?.await(5, TimeUnit.SECONDS) ?: false
if (!initialized) {
    println("GlobalHotKeyManager: Initialization timeout, cannot register window $windowNumber")
    return
}

8. Missing Null Check (GlobalHotKeyManager.kt:212)

api.GetCurrentThreadId() called without verifying api is non-null. Add:

winThreadId = api.GetCurrentThreadId() ?: 0
if (winThreadId == 0) {
    println("GlobalHotKeyManager: Failed to get thread ID")
    _registrationStatus.value = HotKeyRegistrationStatus.FAILED
    initializationLatch?.countDown()
    return
}

🟢 Medium-Priority Issues

9. Platform Availability Check Missing in UI (GlobalHotkeySection.kt)

Settings allow enabling hotkeys even if platform doesn't support them. Add:

val isAvailable = remember { GlobalHotKeyManager.isAvailable() }

SettingsToggle(
    // ...
    enabled = isAvailable
)

10. macOS Run Loop Mode String (GlobalHotKeyManager.kt:427)

Using literal string "kCFRunLoopDefaultMode" instead of the actual CoreFoundation constant. Verify this works correctly on macOS.

11. Weak Error Messages for Linux (GlobalHotKeyManager.kt:576-578)

X11's XGrabKey fails silently on conflicts. Check X11 error status explicitly:

api.XSync(display, 0)
// Check for X11 errors here

🔵 Low-Priority / Style Issues

12. Inconsistent Naming

• winThreadId vs macHotKeyRefs vs linuxDisplay
• Consider: windowsThreadId, macHotKeyRefs, linuxDisplay

13. Inaccurate Comment (Main.kt:62)

// Start global hotkey manager (Windows only)  // <- Should say "all platforms"

🎯 Security Considerations

14. Privacy Concern

Global hotkeys can summon BossTerm during screen sharing or presentations, potentially exposing sensitive terminal content. Consider:

• "Pause global hotkeys" toggle
• Require double-press confirmation
• Disable in fullscreen apps

💡 Performance Notes

15. Linux Polling Strategy (GlobalHotKeyManager.kt:621-630)

The 10ms sleep is a good compromise between CPU usage and responsiveness. Consider increasing to 20-50ms if acceptable.

📝 Documentation

16. Missing KDoc

GlobalHotKeyManager.start() needs comprehensive documentation about thread safety, callback invocation, and platform-specific behavior.

🌟 Positive Observations

1. ✅ Excellent platform abstraction with clean Windows/macOS/Linux separation
2. ✅ Proper resource cleanup with shutdown hooks and disposal effects
3. ✅ Good error handling for most edge cases
4. ✅ Well-integrated into existing settings UI with live status
5. ✅ Correct use of ShellCustomizationUtils (per CLAUDE.md requirements)
6. ✅ Defensive programming with null checks and timeouts

🎬 Summary

This is a well-implemented feature with solid cross-platform support. The main concerns are initialization race conditions, thread safety, and platform-specific edge cases.

Must Fix Before Merge:

1. Fix initialization race condition (move hotkey manager start)
2. Make isRunning volatile
3. Fix X11 hard-coded offset
4. Add timeout checking for initialization latch
5. Fix window number reuse issue

Should Fix:
6. Add null checks and error logging
7. Fix macOS run loop mode
8. Add platform availability check in UI

Overall Assessment:

• Code Quality: 8.5/10
• Platform Support: 9/10
• Thread Safety: 6.5/10 (needs fixes)
• Error Handling: 8/10

Recommendation: Approved with required fixes ✅ (after addressing critical issues #1-5)

[claude]

PR Review: Global Hotkey Feature

Overall Assessment

This is an impressive cross-platform implementation of global hotkeys for BossTerm. The code is well-structured, follows good practices, and demonstrates solid understanding of platform-specific APIs.

Strengths

1. Excellent Cross-Platform Architecture - Clean abstraction with platform-specific implementations isolated
2. Follows Project Conventions - Uses ShellCustomizationUtils for platform detection
3. Thread Safety - Proper use of @synchronized, @volatile, and CountDownLatch
4. UI/UX Polish - Status indicators, macOS-style symbols, iTerm2-inspired toggle behavior
5. Resource Management - Careful cleanup in finally blocks and onDispose
6. Good Documentation - Clear comments explaining API usage

Critical Issues

1. Thread Cleanup Race Condition (GlobalHotKeyManager.kt:282-283)

Problem: winThreadId is reset in the finally block, but stopWindows() relies on it != 0. Race condition could prevent graceful shutdown.
Fix: Move winThreadId = 0 to stop() method AFTER stopWindows() completes.

2. Unchecked Reflection Access (WindowVisibilityController.kt:140-164)

Problem: Reflection-based HWND access will break on Java 16+ without proper --add-opens flags.
Fix: Add required JVM flags to documentation and build config.

3. Memory Leak Risk (GlobalHotKeyManager.kt:341-370)

Problem: macEventHandler strong reference could leak if stop() fails to run.
Fix: Consider using WeakReference or ensure shutdown hooks clean up.

Important Issues

4. Linux Polling Performance (GlobalHotKeyManager.kt:636-638)

10ms polling adds CPU usage. Consider XConnectionNumber + select() for event-driven waiting, or document as tradeoff.

5. Missing Error Recovery (GlobalHotKeyManager.kt:589-591)

Failed hotkey registrations on Linux are silently ignored. Track failures and expose in registrationStatus.

6. X11 Structure Portability (LinuxHotKeyApi.kt:247)

188-byte padding assumes x64. May cause corruption on 32-bit/ARM. Use Native.POINTER_SIZE dynamically.

Code Quality

7. Duplicated configuration loading in Main.kt
8. Incomplete platform-specific validation in isValid()
9. Inconsistent error handling across platforms
10. Extract magic number constants

Security

11. No rate limiting - hotkey spam could cause DoS
12. Document that hotkeys can be triggered by any app

Testing Recommendations

• Test conflicting hotkeys
• Test rapid window creation/destruction
• Test Caps/Num Lock active
• Test ARM64 Linux
• Test Java 16+ restrictions
• Test graceful shutdown

Priority

Must Fix: Thread race, reflection docs
Should Fix: Memory leak, error tracking, X11 portability
Nice to Have: Polling, code quality, security

Overall: Production-ready with minor fixes. Great work!

[claude]

Code Review: PR #243 - Global Hotkey Functionality

Overall Assessment

This is a well-architected cross-platform implementation that adds iTerm2-style global hotkeys to BossTerm. The code demonstrates strong understanding of native APIs, proper JNA usage, and good separation of concerns. However, there are several critical issues that must be addressed before merging, particularly around thread safety, resource management, and error handling.

Lines Added: 2,370 across 16 files
Platforms: Windows (Win32 API), macOS (Carbon API), Linux (X11)
Quality Score: 7.5/10 (would be 8.5/10 after fixes)

---

🔴 Critical Issues (Blocking)

1. Thread Safety: registeredWindows Not Thread-Safe

File: GlobalHotKeyManager.kt:57

private val registeredWindows = mutableSetOf<Int>()

This set is accessed from:

• Main thread (registerWindow() line 110-133)
• Handler threads (Windows: line 239, macOS: line 421, Linux: line 589, 698)
• Cleanup code (lines 190, 283, 524)

Impact: Race conditions during concurrent window creation/deletion could cause crashes, duplicate registrations, or failed unregistrations.

Fix: Use thread-safe collection:

private val registeredWindows = Collections.synchronizedSet(mutableSetOf<Int>())

Similarly for macHotKeyRefs (line 49) and linuxKeycodes (line 54).

---

2. macOS Memory Leak: CFString Not Released on Error Paths

File: GlobalHotKeyManager.kt:441

macRunLoopMode = cfApi.CFStringCreateWithCString(null, "kCFRunLoopDefaultMode", 0x08000100)

If an exception occurs between line 441 and the cleanup at line 514, the CFString leaks native memory.

Impact: Memory leak accumulates on repeated start/stop cycles.

Fix: Move CFString creation to a try block with guaranteed release in finally:

var macRunLoopMode: Pointer? = null
try {
    macRunLoopMode = cfApi.CFStringCreateWithCString(...)
    // ... rest of code
} finally {
    macRunLoopMode?.let { cfApi.CFRelease(it) }
    macRunLoopMode = null
}

---

3. Reflection Error Messages

File: WindowVisibilityController.kt:145-169

On Java 16+ without --add-opens java.desktop/java.awt=ALL-UNNAMED, reflection throws InaccessibleObjectException, but the catch block only prints a generic message.

Impact: Users won't understand why hotkeys don't work properly.

Fix: Add specific error message:

} catch (e: InaccessibleObjectException) {
    println("WindowVisibilityController: Requires JVM flag: --add-opens java.desktop/java.awt=ALL-UNNAMED")
    null
} catch (e: Exception) {
    println("WindowVisibilityController: Failed to get HWND: ${e.javaClass.simpleName} - ${e.message}")
    null
}

---

🟡 High Priority Issues

4. Linux Partial Registration Status

File: GlobalHotKeyManager.kt:610-618

Status is REGISTERED even if only 1 out of 9 hotkeys worked. UI shows "Active" but most hotkeys are broken.

Fix: Consider a new status PARTIAL or change to FAILED if > 50% fail, with tooltip showing which work.

---

5. Inconsistent Status Updates on Failure

File: GlobalHotKeyManager.kt (multiple locations)

Windows and macOS update _registrationStatus on errors, but Linux doesn't consistently update during event loop failures.

Fix: Add _registrationStatus.value = HotKeyRegistrationStatus.FAILED to all exception handlers in event loops.

---

6. Missing Null Checks on API Instances

File: Multiple locations

Several places call API methods without verifying the instance is non-null (e.g., line 219, 332).

Fix: Add null checks:

winThreadId = api?.GetCurrentThreadId() ?: 0

---

🟢 Medium Priority Issues

7. Code Duplication in Main.kt

File: Main.kt:778-783, 846-851

Settings loading code is duplicated.

Fix: Extract to loadSettings() helper function.

---

8. Linux Polling Performance

File: GlobalHotKeyManager.kt:623-658

10ms polling is reasonable but could be optimized to 20-50ms or implement select() as documented in the comment.

---

9. Magic Numbers

Multiple locations use magic numbers without documentation:

• 0x424F5353 (line 39) - "BOSS" signature
• 0x08000100 (line 441) - kCFStringEncodingUTF8

Fix: Extract to named constants with documentation.

---

✅ Excellent Practices Observed

1. Platform Detection: Correctly uses ShellCustomizationUtils throughout (per CLAUDE.md) ✅
2. Resource Cleanup: Comprehensive cleanup in finally blocks and onDispose ✅
3. Error Handling: Graceful fallbacks (e.g., WindowVisibilityController falls back to toFront()) ✅
4. Threading: Proper use of daemon threads, CountDownLatch for initialization ✅
5. JNA Structure Definitions: Correct @Structure.FieldOrder annotations for Linux X11 ✅
6. Documentation: Good inline comments explaining native API usage and platform differences ✅
7. UI Integration: Live status updates using StateFlow, platform-specific symbols (⌃⌥⇧⌘) ✅
8. Cross-Platform Consistency: Same behavior across Windows/macOS/Linux where possible ✅

---

🔒 Security Considerations

10. Global Hotkey Privacy Risk

Global hotkeys can summon BossTerm during screen sharing/recording, potentially exposing sensitive terminal content.

Impact: Low-Medium

Fix: Consider adding a "Pause global hotkeys when screen sharing" option or visual indicator.

---

🧪 Testing Recommendations

Before merging, test:

1. Linux: Press Ctrl+1, Ctrl+2, Ctrl+3 with multiple windows - verify correct window appears
2. Thread Safety: Start/stop manager 100+ times rapidly
3. Memory: Run 1000+ start/stop cycles and check for native handle leaks
4. Conflicts: Register system hotkey elsewhere, verify BossTerm detects failure
5. CapsLock/NumLock: Test Linux with CapsLock and NumLock active
6. Java 16+: Test without --add-opens flags to verify fallback behavior
7. ARM64: Test on ARM64 Linux to verify X11 structure sizes

---

📊 Summary

Category	Score
Architecture	9/10
Code Quality	8/10
Thread Safety	6/10 ⚠️
Resource Management	7/10 ⚠️
Error Handling	8/10
Platform Support	9/10
Security	8/10

Overall: 7.5/10 → 8.5/10 after fixes

---

🎯 Recommendation

Approve with Required Changes

Must fix before merge:

1. Make registeredWindows, macHotKeyRefs, linuxKeycodes thread-safe (feat: Terminal rendering improvements + 4 high-priority features (#2, #3, #4, #5) #1)
2. Fix macOS CFString leak on error paths (🔍 Implement text search/find functionality (Ctrl+F) #2)
3. Add specific error message for reflection failures (🔗 Implement hyperlink detection and click handling #3)
4. Test Linux keycode extraction thoroughly

Should fix:
5. Improve partial registration status on Linux (#4)
6. Add null checks for API instances (#6)
7. Extract duplicated settings loading code (#7)

This is a valuable feature that enhances BossTerm's usability significantly! The implementation is solid, but the thread safety issues need to be addressed to prevent production crashes. Once these critical fixes are made, this will be an excellent addition! 🚀

[claude]

Pull Request Review: Global Hotkey Feature

I have completed a thorough review of PR #243. This is an impressive implementation of cross-platform global hotkeys!

Overall Assessment

Excellent work! This PR demonstrates strong engineering practices with clean architecture, comprehensive error handling, and good documentation.

Strengths

Architecture & Design

• Platform abstraction: GlobalHotKeyManager provides clean facade over Win32, Carbon, X11 APIs
• Thread safety: Proper synchronization with Collections.synchronizedMap/Set and @synchronized
• Resource management: Comprehensive cleanup in finally blocks and shutdown hooks

Platform-Specific Implementations

• Windows: Clean JNA interface with proper message pump pattern and MOD_NOREPEAT
• macOS: Uses GetEventDispatcherTarget() for truly global hotkeys (iTerm2-style)
• Linux: Handles Caps Lock/Num Lock variants, proper XEvent union structure handling

Error Handling

• Graceful fallbacks when native APIs unavailable
• CountDownLatch with 5s timeout prevents initialization deadlock
• Clear error messages guiding users to add JVM arguments

Critical Issues

1. Resource Leak: XKeyEvent allocation (LinuxHotKeyApi.kt:288)

• Structure.newInstance() allocates native memory on every KeyPress event
• Memory never freed, gradual leak
• Fix: Reuse single XKeyEvent instance

2. Security: Reflection without Permission Check (WindowVisibilityController.kt:146-149)

• Directly sets peerField.isAccessible without catching SecurityException
• Fix: Add SecurityException handling

High Priority Issues

3. Race Condition: macRunLoopMode cleanup (GlobalHotKeyManager.kt:188-191)

• Comment acknowledges race but does not prevent it
• If stop() called during initialization, CFRelease() never called
• Fix: Use AtomicReference or ensure cleanup always runs

4. Hardcoded Success Threshold (GlobalHotKeyManager.kt:619)

• 50% threshold is arbitrary
• Poor UX if specific windows user needs fail registration
• Consider: Per-window registration status query

5. Settings Migration on Every Load (SettingsManager.kt:107-109)

• Re-saving on every load adds I/O overhead
• Better: Check version field and migrate only if needed

Medium Priority Issues

6. Missing windowNumber bounds validation in callback (Main.kt:873)

7. Incomplete platform detection logging (GlobalHotKeyManager.kt:94)

8. Thread interruption status lost (GlobalHotKeyManager.kt:179-180)

Testing Recommendations

1. Accessibility tests: Verify graceful degradation without JVM args
2. Concurrency tests: Rapid window creation/destruction while hotkeys firing
3. Resource tests: Monitor for handle leaks over long sessions
4. Edge cases: Hotkey conflicts, multiple instances, fast user switching
5. Platform coverage: Windows 10/11, macOS 12+, various Linux DEs

Documentation Suggestions

Add troubleshooting section to CLAUDE.md:

• Windows: Check for hotkey conflicts
• macOS: Grant Accessibility permissions
• Linux: Disable conflicting system shortcuts

Recommendation

Approve with minor fixes. Critical issues are addressable without major refactoring:

1. Fix XKeyEvent memory leak (highest priority)
2. Add SecurityException handling
3. Consider settings schema version for migration

The feature is production-ready with these fixes. Excellent work on this complex cross-platform feature!

---

Reviewed using BossTerm development guidelines from CLAUDE.md

[claude]

PR Review: Global Hotkey Feature

This is an impressive implementation of system-wide global hotkeys for BossTerm! The feature is well-engineered with proper cross-platform support and thorough attention to edge cases. Below is my detailed feedback:

---

✅ Strengths

1. Excellent Cross-Platform Support

• Clean abstraction across Windows (Win32), macOS (Carbon), and Linux (X11)
• Platform-specific APIs properly isolated in separate files
• Good use of JNA for native bindings

2. Robust Error Handling

• Multiple rounds of bug fixes show thorough testing
• Proper handling of reflection access issues (Java 16+ module system)
• Clear error messages with actionable guidance for users
• SecurityException and InaccessibleObjectException properly caught

3. Thread Safety

• Proper use of @Volatile for isRunning flag
• Thread-safe collections (Collections.synchronizedSet/Map)
• CountDownLatch for initialization synchronization
• Careful interrupt status preservation

4. Resource Management

• Proper cleanup in finally blocks
• Reference tracking for native resources (hotkey refs, event handlers)
• Graceful shutdown with timeouts

5. Documentation

• Well-documented JVM requirements in CLAUDE.md
• Clear inline comments explaining complex logic
• Good rationale for design decisions (e.g., Linux polling tradeoff)

---

🔍 Code Quality Observations

Architecture

• GlobalHotKeyManager.kt (755 lines): This is a large singleton. Consider splitting into:
  • GlobalHotKeyManager (core orchestration)
  • WindowsHotKeyHandler, MacOSHotKeyHandler, LinuxHotKeyHandler (platform implementations)
  • Would improve testability and maintainability

Memory & Performance

1. Linux XEvent Allocation (LinuxHotKeyApi.kt:281-295)

   • Current: Creates padding ByteArray on every XEvent instantiation
   • The getKeycode() optimization is good (reads directly from memory)
   • Consider: Reuse a single XEvent instance in the event loop instead of creating new ones

2. Linux Polling (GlobalHotKeyManager.kt:664-700)

   • 10ms polling is reasonable (~0.1% CPU)
   • Alternative: XConnectionNumber() + select() for true event-driven (as noted in comments)
   • Current tradeoff is acceptable for simplicity

3. Hotkey Registration (Windows/macOS)

   • Registers all 1-9 hotkeys upfront, even if only 1 window exists
   • Minor resource waste, but negligible impact
   • Simplifies lifecycle management

Thread Safety Edge Cases

1. GlobalHotKeyManager.kt:169-213 - stop() method:

   • Thread.interrupted() clears status, then tries to restore it
   • If another thread interrupts between check and restore, status could be lost
   • Unlikely in practice, but worth noting

2. GlobalHotKeyManager.kt:533-542 - macOS cleanup race:

   • Local capture of macRunLoopMode is good
   • Still a small window between null assignment and CFRelease
   • Consider: Use synchronized block or atomic reference

Platform-Specific Concerns

Linux (LinuxHotKeyApi.kt)

• Line 263-272: XEvent padding calculation assumes 192/96 bytes

  • Correct for x86_64/i386, but may differ on other architectures (RISC-V, PowerPC)
  • Consider: Runtime detection or structure size validation

• Line 584-619: X11 error handling

  • XGrabKey() failures are caught, but don't distinguish error types
  • Could improve UX by detecting specific conflicts (e.g., desktop environment shortcuts)

macOS (MacOSHotKeyApi.kt)

• Line 362: EventHandlerUPP callback
  • Kept as strong reference to prevent GC (good!)
  • Verify this works across different macOS versions and JVM implementations

Windows (Win32HotKeyApi.kt)

• Simple and clean implementation
• No concerns

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🐛 Potential Issues

Critical

None found. The multiple fix rounds have addressed critical issues.

High Priority

1. WindowVisibilityController.kt:143-183 - Reflection for HWND

   • Falls back gracefully, but users may not realize reduced functionality
   • Suggestion: Log a ONE-TIME warning to a file so users can check if needed
   • Consider: Startup check that validates JVM flags and shows UI warning if missing

2. GlobalHotKeyManager.kt:119-141 - Window registration

   • 5-second timeout for initialization (line 125)
   • If timeout occurs, window hotkey silently fails to register
   • Suggestion: Return boolean or throw exception so caller knows registration failed

Medium Priority

1. HotKeyConfig.kt:148-150 - Validation

   • isValid() only checks for non-empty key
   • Doesn't validate if key is in SUPPORTED_KEYS list
   • Could lead to invalid config being saved

2. GlobalHotkeySection.kt:44-120 - Settings UI

   • No validation preventing user from disabling ALL modifiers
   • Creates invalid hotkey (modifier-less number keys conflict with typing)
   • Suggestion: Disable save/apply if no modifiers selected

3. Main.kt:70-72 - Startup race

   • LaunchedEffect(Unit) runs after composition
   • Window could be interacted with before hotkey manager starts
   • Unlikely to cause issues, but not deterministic

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🔒 Security Considerations

Reflection Access

• Properly documented JVM flags required
• Falls back gracefully without flags
• ✅ No security concerns

Native Code Execution

• Uses JNA for native API calls (standard practice)
• No dynamic code generation or arbitrary native execution
• ✅ Acceptable risk

Input Handling

• Hotkeys filtered to numeric keys 1-9 only
• Modifiers validated before registration
• ✅ No injection risks

---

📊 Test Coverage

Missing Tests (understandable for JNA/native code, but worth noting):

1. Unit tests for:

   • HotKeyConfig.toDisplayString() formatting
   • HotKeyConfig.isValid() validation logic
   • Platform detection in GlobalHotKeyManager

2. Integration tests:

   • Simulating hotkey events (difficult with JNA)
   • Testing fallback behavior when native APIs fail
   • Verifying window number validation (1-9 bounds)

3. Edge cases:

   • Multiple rapid hotkey presses
   • Hotkey pressed during window creation/destruction
   • Changing settings while hotkeys are active

Recommendation: Focus on testing config validation and display string generation, as these are pure logic without native dependencies.

---

🎯 Suggestions for Future Work

Short Term

1. Add UI warning when JVM flags are missing (one-time on startup)
2. Validate hotkey config more strictly (prevent no-modifier configs)
3. Return registration status from registerWindow() for better error handling

Long Term

1. Refactor into platform-specific handler classes
2. Add telemetry to track which platforms/configs are used most
3. Consider supporting customizable hotkey patterns (not just 1-9)
4. Implement XConnectionNumber() + select() for Linux (eliminate polling)

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📝 Minor Nits

1. Inconsistent naming: macEventHandler vs macEventHandlerRef - consider clearer distinction
2. Magic numbers: HOTKEY_SIGNATURE = 0x424F5353 - good! But add comment: // 'BOSS' in ASCII
3. Code duplication: Key code mappings in 3 places (HotKeyConfig, LinuxHotKeyApi, MacOSHotKeyApi) - consider shared constant file
4. Line length: Some lines exceed 120 chars (e.g., LinuxHotKeyApi.kt:286-293) - minor style issue

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🎉 Conclusion

This is high-quality, production-ready code. The implementation is thorough, well-tested through multiple fix iterations, and handles edge cases gracefully. The cross-platform complexity is managed well, and the fallback behavior ensures the app remains usable even when native features aren't available.

Recommendation: ✅ Approve with minor suggestions

The suggestions above are nice-to-haves that can be addressed in follow-up PRs. The current implementation is solid and ready to merge.

Great work! 🚀

---

Reviewed by: Claude Sonnet 4.5
Review Date: 2026-01-30

[claude]

This is an excellent implementation of system-wide global hotkeys for BossTerm. The code is well-structured, thoroughly documented, and handles edge cases gracefully.

✅ Strengths

Excellent Architecture

• Clean separation with platform-specific APIs (Win32HotKeyApi, MacOSHotKeyApi, LinuxHotKeyApi)
• Window-specific hotkeys (Modifiers+1-9) is intuitive and scales well
• Proper lifecycle management with registration/unregistration callbacks

Cross-Platform Excellence

• All three major platforms fully supported
• Platform detection uses ShellCustomizationUtils consistently
• Graceful degradation when JNA fails
• Registration status tracking provides clear feedback

Robust Thread Safety

• @synchronized annotations on critical methods
• Collections.synchronizedMap/Set for thread-safe collections
• Proper @volatile for isRunning flag
• CountDownLatch for initialization sync
• Careful interrupt status handling

Excellent Error Handling

• Comprehensive try-catch blocks with informative logging
• Linux partial-success handling with 50% threshold is pragmatic
• Clear user-facing error messages with solutions
• Graceful fallback for reflection failures (Java 16+ modules)

Memory Safety

• macOS: Proper CFRelease() of CoreFoundation strings
• Event handler references kept to prevent GC
• Cleanup in finally blocks

User Experience

• iTerm2-style toggle behavior feels natural
• Hotkey hints in title bar and overlays
• Settings UI with real-time status indicators
• Comprehensive "How It Works" section
• Platform-specific keyboard symbols on macOS

[claude]

🔍 Issues Found

Critical: Race Condition Documentation in GlobalHotKeyManager.stop()

Location: GlobalHotKeyManager.kt:175-210

Issue: The macEventHandler, macEventHandlerRef, and macRunLoopMode references have a subtle lifecycle that could lead to bugs during refactoring.

Recommendation: Add explicit documentation in stop() explaining why macOS references are NOT cleared there (they are cleaned by handler thread finally block). Current comment acknowledges this but could be clearer to prevent future bugs.

---

Medium: Linux Event Loop Busy-Waiting

Location: GlobalHotKeyManager.kt:645-665

Issue: Uses 10ms polling with Thread.sleep() when no X11 events pending.

Analysis: Code comment acknowledges this tradeoff. While 0.1% CPU is acceptable, XConnectionNumber() + select() would provide true event-driven waiting with zero overhead.

Recommendation: Current approach is acceptable for v1. Consider optimizing in future PR.

---

Medium: Windows HWND Reflection Access

Location: WindowVisibilityController.kt:142-160

Issue: Reflection access to Component.peer requires JVM flag --add-opens on Java 16+, but no runtime warning if flag missing.

Recommendation: Log one-time warning on first reflection failure explaining missing JVM flag. Helps users understand why feature might not work optimally.

---

Low: Incomplete Keysym Mapping Comments

Location: LinuxHotKeyApi.kt:40-93

Issue: Comment says "subset - common keys" but does not indicate which keys are missing.

Recommendation: Add comment listing supported vs unsupported keys to clarify scope and ease future extension.

[claude]

🔒 Security Analysis - ✅ No Issues Found

1. No Command Injection: No shell commands with user input
2. No Privilege Escalation: Uses standard OS APIs without elevation
3. Resource Limits: Bounded to 9 windows, prevents resource exhaustion
4. Input Validation: Window numbers validated (1-9 range checks)
5. Thread Safety: Proper synchronization prevents race conditions
6. Memory Safety: Proper cleanup prevents leaks

The JVM flags required (--add-opens) only affect JVM modules, not system security.

---

⚡ Performance Analysis - ✅ Excellent

Minimal Overhead:

• Windows: Event-driven, zero overhead when idle
• macOS: Event-driven, zero overhead when idle
• Linux: 0.1% CPU from 10ms polling (acceptable)

Lock-Free Fast Path:

• Hotkey callback does not hold locks
• Window lookup is O(1)

Efficient Registration:

• All 9 hotkeys registered upfront (batch)
• No repeated registration overhead

Memory Efficient:

• Minimal memory footprint
• No allocations in hotkey callback path

---

🧪 Test Coverage - ❌ Missing Automated Tests

Impact: High-risk for regressions during refactoring

Recommendations:

Unit Tests (High Priority):

• HotKeyConfig.toWindowDisplayString() format validation
• HotKeyConfig.fromSettings() parsing
• Window number validation logic
• Modifier key combinations

Integration Tests (Medium Priority):

• Mock JNA to test registration flow
• Test lifecycle (start → register → unregister → stop)
• Test error handling

Manual Testing:

• ✅ Already present in PR description
• Consider adding: Caps Lock/Num Lock on Linux, multiple monitors, minimize/restore cycles

[claude]

📚 Documentation - ✅ Excellent

1. CLAUDE.md updated with JVM requirements - clear and actionable
2. Inline code comments explain complex logic
3. Settings UI has comprehensive "How It Works" section
4. Error messages are user-friendly and suggest solutions

Minor suggestion: Add troubleshooting section to CLAUDE.md:

• Windows: Check for hotkey conflicts with other apps
• macOS: Ensure Accessibility permissions granted
• Linux: Desktop environment hotkeys take precedence, try different modifiers

---

🎯 Code Quality - ✅ Excellent

Adherence to Project Guidelines:

• ✅ Uses ShellCustomizationUtils for platform detection
• ✅ Proper Compose patterns with remember {}
• ✅ No backwards-compatibility hacks
• ✅ No over-engineering
• ✅ Error handling at system boundaries

Code Smells: None significant

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🎬 Final Verdict

APPROVED ✅ with Minor Improvements Recommended

This is production-ready code. Issues identified are minor and do not block merging:

• Race condition docs: Already handled correctly, just needs better documentation
• Linux polling: Acceptable tradeoff, optimization optional
• Reflection warning: Nice-to-have for better UX
• Missing tests: Should be added in follow-up PR

Recommendation: Merge after addressing documentation issue (race condition comment in stop()). Other improvements can be done in follow-up PRs.

---

💡 Future Enhancements (Optional)

1. Custom hotkey combinations beyond 1-9
2. Hotkey recorder UI
3. Per-window custom hotkeys
4. macOS accessibility permission check
5. Linux XCB support

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Excellent work! This feature brings BossTerm to feature parity with iTerm2 for window summoning. The implementation is solid, well-tested (manually), and production-ready. 🚀