From 02698251796ef93f39e1fde90dcee4e865a8dfb2 Mon Sep 17 00:00:00 2001
From: edde746 <86283021+edde746@users.noreply.github.com>
Date: Thu, 5 Mar 2026 14:59:40 +0100
Subject: [PATCH] fix: windows single instance mutex

---
 windows/runner/main.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/windows/runner/main.cpp b/windows/runner/main.cpp
index 4c305dd0..43a8489b 100644
--- a/windows/runner/main.cpp
+++ b/windows/runner/main.cpp
@@ -7,6 +7,18 @@
 
 int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
                       _In_ wchar_t *command_line, _In_ int show_command) {
+  // Single instance enforcement
+  HANDLE mutex = CreateMutex(nullptr, TRUE, L"com.edde746.Plezy.SingleInstance");
+  if (GetLastError() == ERROR_ALREADY_EXISTS) {
+    HWND existing = FindWindow(L"FLUTTER_RUNNER_WIN32_WINDOW", L"Plezy");
+    if (existing) {
+      ShowWindow(existing, SW_RESTORE);
+      SetForegroundWindow(existing);
+    }
+    CloseHandle(mutex);
+    return EXIT_SUCCESS;
+  }
+
   // Attach to console when present (e.g., 'flutter run') or create a
   // new console when running with a debugger.
   if (!::AttachConsole(ATTACH_PARENT_PROCESS) && ::IsDebuggerPresent()) {