[packaging] Add Windows installer build doc

packaging/README.md

@@ -0,0 +1,101 @@
+# Generate Windows installer
+
+## Prerequisites
+
+Earthly release prep step must be executed and the output `dist` folder should be present in the root directory of the repository. (Probably needs to be done on separate machine running linux or downloaded from the CI)
+```
+  earthly +release-prep
+```
+
+## Building the installers
+
+In the root directory of the repository, run the PowerShell script to generate the installers:
+```
+./packaging\windows\generate_windows_installers.ps1
+```
+
+This will output both .exe (NSIS) and .msi (WIX) installers inside the dist folder:
+```
+...\Portmaster\dist\windows_amd64\Portmaster_0.1.0_x64-setup.exe
+...\Portmaster\dist\windows_amd64\Portmaster_0.1.0_x64_en-US.msi
+```
+
+## Manual build
+
+### Prerequisites
+
+Ensure you have Rust and Cargo installed.
+Install Tauri CLI by running:
+```
+cargo install tauri-cli --version "^2.0.0" --locked
+```
+
+### Folder structure
+
+Create binary and intel folder inside the tauri project folder and place all the necessary files inside.
+The folder structure should look like this:
+```
+...\Portmaster\desktop\tauri\src-tauri\binary
+    assets.zip
+    index.json
+    portmaster-core.dll
+    portmaster-core.exe
+    portmaster-kext.dll
+    portmaster-kext.sys
+    portmaster.zip
+    WebView2Loader.dll
+
+...\Portmaster\desktop\tauri\src-tauri\intel
+    base.dsdl
+    geoipv4.mmdb
+    geoipv6.mmdb
+    index.dsd
+    index.json
+    intermediate.dsdl
+    main-intel.yaml
+    news.yaml
+    notifications.yaml
+    urgent.dsdl
+```
+
+### Building the Installer
+
+Navigate to the `src-tauri` directory:
+```
+cd desktop/tauri/src-tauri
+```
+
+Run the following commands to build the installers:
+
+For both NSIS and WIX installers:
+```
+cargo tauri bundle
+```
+
+For NSIS installer only:
+```
+cargo tauri bundle --bundles nsis
+```
+
+For WIX installer only:
+```
+cargo tauri bundle --bundles wix
+```
+
+The produced files will be in:
+```
+target\release\bundle\msi\
+target\release\bundle\nsis\
+```
+
+## Debug MSI Installer
+
+To see error messages during the build of the installer, run the bundler with the verbose flag:
+```
+cargo tauri bundle --bundles msi --verbose
+```
+
+To examine the logs during installation, run the installer with the following command:
+```
+msiexec /i "target\release\bundle\msi\Portmaster_0.1.0_x64_en-US.msi" /lv install.log
+```