Fix issues with Windows installer

Don't reuse the old installation dir since it might not be compatible
with the new layout.
Ensure previous legacy install is cleaned up to avoid plugin being
installed twice.

Author: WarmUpTill

.github/scripts/Package-Windows.ps1

@@ -119,6 +119,7 @@ function Package {
         Log-Information 'Creating InnoSetup installer...'
         Push-Location -Stack BuildTemp
         Ensure-Location -Path "${ProjectRoot}/release"
+        Remove-Item -Path Package -Recurse -Force -ErrorAction SilentlyContinue
         Copy-Item -Path ${Configuration} -Destination Package -Recurse
         Invoke-External iscc ${IsccFile} /O"${ProjectRoot}/release" /F"${OutputName}-Installer"
         Remove-Item -Path Package -Recurse

cmake/windows/resources/installer-Windows.iss.in

@@ -2,12 +2,13 @@
 #define MyAppVersion "@CMAKE_PROJECT_VERSION@"
 #define MyAppPublisher "@PLUGIN_AUTHOR@"
 #define MyAppURL "@PLUGIN_WEBSITE@"
+#define MyAppId "@UUID_APP@"
 
 [Setup]
 ; NOTE: The value of AppId uniquely identifies this application.
 ; Do not use the same AppId value in installers for other applications.
 ; (To generate a new GUID, click Tools | Generate GUID inside the IDE.)
-AppId={{@UUID_APP@}
+AppId={{{#MyAppId}}
 AppName={#MyAppName}
 AppVersion={#MyAppVersion}
 AppPublisher={#MyAppPublisher}
@@ -20,6 +21,7 @@ OutputBaseFilename={#MyAppName}-{#MyAppVersion}-Windows-Installer
 Compression=lzma
 SolidCompression=yes
 DirExistsWarning=no
+UsePreviousAppDir=no
 SetupIconFile=installer.ico
 UninstallDisplayIcon={app}\advanced-scene-switcher\data\res\images\logo.ico
 DisableDirPage=no
@@ -51,10 +53,34 @@ begin
   );
 end;
 
-// credit where it's due :
-// following function come from https://github.com/Xaymar/obs-studio_amf-encoder-plugin/blob/master/%23Resources/Installer.in.iss#L45
 function GetDirName(Value: string): string;
 begin
   Result := ExpandConstant('{commonappdata}\obs-studio\plugins');
 end;
 
+// Remove files placed by the legacy installer (obs-plugins/64bit and
+// data/obs-plugins layout) so the plugin is not loaded twice by OBS.
+// We read InstallLocation from our own previous uninstall entry, which is
+// the exact directory the old installer used regardless of OBS install path.
+procedure RemoveLegacyFiles();
+var
+  OldInstallPath: string;
+  UninstallKey: string;
+begin
+  UninstallKey := 'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\' + '{' + '{#MyAppId}' + '}_is1';
+  if not RegQueryStringValue(HKLM, UninstallKey, 'InstallLocation', OldInstallPath) then
+    Exit;
+  DeleteFile(OldInstallPath + '\obs-plugins\64bit\advanced-scene-switcher.dll');
+  DeleteFile(OldInstallPath + '\obs-plugins\64bit\advanced-scene-switcher.pdb');
+  DeleteFile(OldInstallPath + '\obs-plugins\64bit\advanced-scene-switcher-lib.dll');
+  DeleteFile(OldInstallPath + '\obs-plugins\64bit\advanced-scene-switcher-lib.pdb');
+  DelTree(OldInstallPath + '\obs-plugins\64bit\advanced-scene-switcher-plugins', True, True, True);
+  DelTree(OldInstallPath + '\data\obs-plugins\advanced-scene-switcher', True, True, True);
+end;
+
+procedure CurStepChanged(CurStep: TSetupStep);
+begin
+  if CurStep = ssInstall then
+    RemoveLegacyFiles();
+end;
+