Quit if the application is already running

constants.py

@@ -6,6 +6,9 @@ from enum import Enum, auto
 from datetime import timedelta
 from typing import Any, Optional, Dict, Literal, Callable
 
+from version import __version__
+
+
 # Typing
 JsonType = Dict[str, Any]
 TopicProcess = Callable[[int, JsonType], Any]
@@ -32,8 +35,10 @@ PING_INTERVAL = timedelta(minutes=3)
 PING_TIMEOUT = timedelta(seconds=10)
 ONLINE_DELAY = timedelta(seconds=120)
 WATCH_INTERVAL = timedelta(seconds=58.8)
-# Tags
+# Strings
 DROPS_ENABLED_TAG = "c2542d6d-cd10-4532-919b-3d19f30a768b"
+WINDOW_TITLE = f"Twitch Drops Miner v{__version__} (by DevilXD)"
+# Logging
 FORMATTER = logging.Formatter(
     "{asctime}.{msecs:03.0f}:\t{levelname:>7}:\t{message}",
     style='{',

gui.py

@@ -18,8 +18,7 @@ try:
 except ModuleNotFoundError as exc:
     raise ImportError("You have to run 'pip install pystray' first") from exc
 
-from version import __version__
-from constants import FORMATTER, WS_TOPICS_LIMIT, MAX_WEBSOCKETS, State
+from constants import FORMATTER, WS_TOPICS_LIMIT, MAX_WEBSOCKETS, WINDOW_TITLE, State
 
 if TYPE_CHECKING:
     from twitch import Twitch
@@ -781,7 +780,7 @@ class GUIManager:
         self._root.withdraw()
         root.resizable(False, True)
         root.iconbitmap(resource_path("pickaxe.ico"))  # window icon
-        root.title(f"Twitch Drops Miner v{__version__} (by DevilXD)")  # window title
+        root.title(WINDOW_TITLE)  # window title
         root.protocol("WM_DELETE_WINDOW", self.close)
         root.bind_all("<KeyPress-Escape>", self.unfocus)
         self._style = ttk.Style(root)

main.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
+import ctypes
 import logging
 import argparse
 from typing import Optional
 
 from twitch import Twitch
 from version import __version__
-from constants import FORMATTER, LOG_PATH
+from constants import FORMATTER, LOG_PATH, WINDOW_TITLE
 
 
 class ParsedArgs(argparse.Namespace):
@@ -48,6 +49,15 @@ class ParsedArgs(argparse.Namespace):
         return logging.NOTSET
 
 
+# check if we're not already running
+try:
+    exists = ctypes.windll.user32.FindWindowW(None, WINDOW_TITLE)
+except AttributeError:
+    # we're not on Windows - continue
+    exists = False
+if exists:
+    # already running - exit
+    quit()
 # handle input parameters
 parser = argparse.ArgumentParser(
     "Twitch Drops Miner (by DevilXD).exe",