is this too much voodoo?

installer_win.go

@@ -0,0 +1,130 @@
+//go:build windows
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+
+	spm "weforge.xyz/Spitfire/SPM"
+)
+
+// Installer manages the download, decompression, and installation processes.
+type Installer struct {
+	// Progress info from SPM
+	Progress int
+	Task     string
+
+	// Internal states
+	IsDownloading  bool
+	IsInstalling   bool
+	DoneDownload   bool
+	DoneInstall    bool
+	LastError      error
+	PendingInstall bool
+}
+
+// NewInstaller creates a new Installer with initial state.
+func NewInstaller() *Installer {
+	return &Installer{}
+}
+
+// StartDownloadDecompress starts the download and decompression in a background goroutine.
+func (inst *Installer) StartDownloadDecompress() {
+	inst.IsDownloading = true
+	go func() {
+		defer func() {
+			inst.IsDownloading = false
+			// Signal that download phase is complete.
+			inst.DoneDownload = (inst.LastError == nil)
+			// If a final install was requested, go ahead.
+			if inst.PendingInstall && inst.DoneDownload && !inst.IsInstalling && !inst.DoneInstall {
+				inst.doFinalInstall()
+			}
+		}()
+
+		spm.UpdateProgress(0, "Preparing to download...")
+
+		// Define the package specifications.
+		specs := []spm.AppIndexEntry{
+			{
+				Name:    "spitfire-luncher",
+				Release: "nightly",
+				OS:      "windows",
+				Arch:    runtime.GOARCH,
+				Type:    "luncher",
+			},
+			{
+				Name:    "spitfire-browser",
+				Release: "nightly",
+				OS:      "windows",
+				Arch:    runtime.GOARCH,
+				Type:    "browser",
+			},
+		}
+
+		spm.UpdateProgress(0, "Downloading specified packages...")
+		if err := spm.DownloadSpecified(specs); err != nil {
+			fmt.Println("DownloadSpecifiedPackages failed:", err)
+			inst.LastError = err
+			return
+		}
+
+		spm.UpdateProgress(0, "Download and decompression complete!")
+		// Here, update your installer state so FinalInstall() can proceed.
+		inst.DoneDownload = true
+	}()
+}
+
+// FinalInstall is called by the UI to request installation.
+// If download is done, it runs immediately, otherwise sets PendingInstall=true.
+func (inst *Installer) FinalInstall() {
+	// Already installed or installing => ignore repeated calls.
+	if inst.IsInstalling || inst.DoneInstall {
+		return
+	}
+
+	// If not done downloading, mark that we want to install once finished.
+	if !inst.DoneDownload {
+		fmt.Println("Cannot install now: download and decompression not complete -> pending install.")
+		inst.PendingInstall = true
+		return
+	}
+
+	// Otherwise, go ahead and install now.
+	inst.doFinalInstall()
+}
+
+// doFinalInstall does the actual installation by invoking InstallUpdates.
+func (inst *Installer) doFinalInstall() {
+	inst.IsInstalling = true
+	inst.PendingInstall = false // we are fulfilling the install now
+
+	go func() {
+		defer func() {
+			inst.IsInstalling = false
+			inst.DoneInstall = (inst.LastError == nil)
+		}()
+
+		spm.UpdateProgress(0, "Installing updates...")
+		if err := spm.InstallUpdates(); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		// Register the app in Windows (i.e. create registry entries)
+		spm.UpdateProgress(0, "Registering app...")
+		if err := spm.RegisterApp(); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		spm.UpdateProgress(100, "Installation complete!")
+	}()
+}
+
+// PollProgress fetches the latest progress and task from SPM.
+func (inst *Installer) PollProgress() {
+	p, t := spm.GetProgress()
+	inst.Progress, inst.Task = p, t
+}