Move argsparse code to top & do rename enforce_single_instance() -> no_other_instance_running()

1. We need the args available at the top.
2. In `develop` we'd renamed `enforce_single_instance()` to
   `no_other_instance_running()` so that it's obvious it's a function
   returning a boolean, rather than the function that does the
   enforcement.

EDMarketConnector.py

@@ -20,6 +20,27 @@ from constants import applongname, appname, protocolhandler_redirect
 # config will now cause an appname logger to be set up, so we need the
 # console redirect before this
 if __name__ == '__main__':
+    # Command-line arguments
+    parser = argparse.ArgumentParser(
+        prog=appname,
+        description="Utilises Elite Dangerous Journal files and the Frontier "
+                    "Companion API (CAPI) service to gather data about a "
+                    "player's state and actions to upload to third-party sites "
+                    "such as EDSM, Inara.cz and EDDB."
+    )
+
+    parser.add_argument('--trace',
+                        help='Set the Debug logging loglevel to TRACE',
+                        action='store_true',
+                        )
+
+    parser.add_argument('--suppress-dupe-process-popup',
+                        help='Suppress the popup from when the application detects another instance already running',
+                        action='store_true'
+                        )
+
+    args = parser.parse_args()
+
     def no_other_instance_running() -> bool:  # noqa: CCR001
         """
         Ensure only one copy of the app is running under this user account.
@@ -1157,65 +1178,6 @@ class AppWindow(object):
             self.blank_menubar.grid(row=0, columnspan=2, sticky=tk.NSEW)
 
 
-def enforce_single_instance() -> None:
-    # Ensure only one copy of the app is running under this user account. OSX does this automatically. Linux TODO.
-    if platform == 'win32':
-        import ctypes
-        from ctypes.wintypes import BOOL, HWND, INT, LPARAM, LPCWSTR, LPWSTR
-
-        EnumWindows = ctypes.windll.user32.EnumWindows  # noqa: N806
-        GetClassName = ctypes.windll.user32.GetClassNameW  # noqa: N806
-        GetClassName.argtypes = [HWND, LPWSTR, ctypes.c_int]
-        GetWindowText = ctypes.windll.user32.GetWindowTextW  # noqa: N806
-        GetWindowText.argtypes = [HWND, LPWSTR, ctypes.c_int]
-        GetWindowTextLength = ctypes.windll.user32.GetWindowTextLengthW  # noqa: N806
-        GetProcessHandleFromHwnd = ctypes.windll.oleacc.GetProcessHandleFromHwnd  # noqa: N806
-
-        SW_RESTORE = 9  # noqa: N806
-        SetForegroundWindow = ctypes.windll.user32.SetForegroundWindow  # noqa: N806
-        ShowWindow = ctypes.windll.user32.ShowWindow  # noqa: N806
-        ShowWindowAsync = ctypes.windll.user32.ShowWindowAsync  # noqa: N806
-
-        COINIT_MULTITHREADED = 0  # noqa: N806,F841
-        COINIT_APARTMENTTHREADED = 0x2  # noqa: N806
-        COINIT_DISABLE_OLE1DDE = 0x4  # noqa: N806
-        CoInitializeEx = ctypes.windll.ole32.CoInitializeEx  # noqa: N806
-
-        ShellExecute = ctypes.windll.shell32.ShellExecuteW  # noqa: N806
-        ShellExecute.argtypes = [HWND, LPCWSTR, LPCWSTR, LPCWSTR, LPCWSTR, INT]
-
-        def window_title(h):
-            if h:
-                text_length = GetWindowTextLength(h) + 1
-                buf = ctypes.create_unicode_buffer(text_length)
-                if GetWindowText(h, buf, text_length):
-                    return buf.value
-            return None
-
-        @ctypes.WINFUNCTYPE(BOOL, HWND, LPARAM)
-        def enumwindowsproc(window_handle, l_param):
-            # class name limited to 256 - https://msdn.microsoft.com/en-us/library/windows/desktop/ms633576
-            cls = ctypes.create_unicode_buffer(257)
-            if GetClassName(window_handle, cls, 257) \
-                    and cls.value == 'TkTopLevel' \
-                    and window_title(window_handle) == applongname \
-                    and GetProcessHandleFromHwnd(window_handle):
-                # If GetProcessHandleFromHwnd succeeds then the app is already running as this user
-                if len(sys.argv) > 1 and sys.argv[1].startswith(protocolhandler.redirect):
-                    # Browser invoked us directly with auth response. Forward the response to the other app instance.
-                    CoInitializeEx(0, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE)
-                    # Wait for it to be responsive to avoid ShellExecute recursing
-                    ShowWindow(window_handle, SW_RESTORE)
-                    ShellExecute(0, None, sys.argv[1], None, None, SW_RESTORE)
-                else:
-                    ShowWindowAsync(window_handle, SW_RESTORE)
-                    SetForegroundWindow(window_handle)
-                sys.exit(0)
-            return True
-
-        EnumWindows(enumwindowsproc, 0)
-
-
 def test_logging():
     logger.debug('Test from EDMarketConnector.py top-level test_logging()')
 
@@ -1232,29 +1194,6 @@ Locale LC_TIME: {locale.getlocale(locale.LC_TIME)}'''
 
 # Run the app
 if __name__ == "__main__":
-    # Command-line arguments
-    parser = argparse.ArgumentParser(
-        prog=appname,
-        description="Utilises Elite Dangerous Journal files and the Frontier "
-                    "Companion API (CAPI) service to gather data about a "
-                    "player's state and actions to upload to third-party sites "
-                    "such as EDSM, Inara.cz and EDDB."
-    )
-
-    parser.add_argument('--trace',
-                        help='Set the Debug logging loglevel to TRACE',
-                        action='store_true',
-                        )
-
-    parser.add_argument('--suppress-dupe-process-popup',
-                        help='Suppress the popup from when the application detects another instance already running',
-                        action='store_true'
-                        )
-
-    args = parser.parse_args()
-
-    enforce_single_instance()
-
     if args.trace:
         logger.setLevel(logging.TRACE)
         edmclogger.set_channels_loglevel(logging.TRACE)