added SPM

installer.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"fmt"
+	"path/filepath"
+	"spitfire-installer/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
+
+	// Paths
+	DownloadDir string
+	TempDir     string
+}
+
+// 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
+			inst.DoneDownload = (inst.LastError == nil)
+		}()
+
+		// Prepare download directory
+		spm.UpdateProgress(0, "Preparing to download...")
+		inst.DownloadDir = spm.GetTempDownloadDir()
+
+		// Download APPINDEX
+		appIndexPath := filepath.Join(inst.DownloadDir, "APPINDEX")
+		spm.UpdateProgress(0, "Downloading APPINDEX")
+		if err := spm.DownloadAppIndex(appIndexPath); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		// Download package
+		packageName := "spitfire-browser"
+		release := "nightly"
+		spm.UpdateProgress(0, "Downloading package...")
+		if err := spm.DownloadPackageFromAppIndex(appIndexPath, packageName, release, inst.DownloadDir); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		// Decompress
+		spm.UpdateProgress(0, "Decompressing...")
+		packagePath := filepath.Join(inst.DownloadDir, "browser-amd64-nightly-linux.tar.gz")
+		tempDir, err := spm.DecompressToTemp(packagePath)
+		if err != nil {
+			inst.LastError = err
+			return
+		}
+
+		inst.TempDir = tempDir
+	}()
+}
+
+// FinalInstall moves files to the final install directory in a background goroutine.
+func (inst *Installer) FinalInstall() {
+	if !inst.DoneDownload {
+		inst.LastError = fmt.Errorf("Cannot install: download and decompression are not complete")
+		return
+	}
+
+	inst.IsInstalling = true
+	go func() {
+		defer func() {
+			inst.IsInstalling = false
+			inst.DoneInstall = (inst.LastError == nil)
+		}()
+
+		// Generate default install directory
+		installDir, err := spm.GetDefaultInstallDir()
+		if err != nil {
+			inst.LastError = fmt.Errorf("failed to determine default install directory: %w", err)
+			return
+		}
+
+		if err := spm.MoveFilesToInstallDir(inst.TempDir, installDir); 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
+}

main.go

@@ -2,18 +2,23 @@ package main
 
 import (
 	"fmt"
-	"os"
 
 	rl "github.com/gen2brain/raylib-go/raylib"
 )
 
-var transition = NewTransitionManager()
-var currentStep = 0
-var targetStep = 0
-var useDefault = false
+// Keep your global variables for steps and transitions
+var (
+	transition  = NewTransitionManager()
+	currentStep = 0
+	targetStep  = 0
+	useDefault  = false
 
-var step1DefaultRect rl.Rectangle
-var step1CustomRect rl.Rectangle
+	step1DefaultRect rl.Rectangle
+	step1CustomRect  rl.Rectangle
+
+	// Our global Installer from installer.go
+	installer = NewInstaller()
+)
 
 func main() {
 	monitor := rl.GetCurrentMonitor()
@@ -32,6 +37,9 @@ func main() {
 
 	InitBackground(rl.GetScreenWidth(), rl.GetScreenHeight())
 
+	// Start the download+decompress in background immediately:
+	installer.StartDownloadDecompress()
+
 	targetStep = 0
 
 	for !rl.WindowShouldClose() {
@@ -46,12 +54,24 @@ func main() {
 		nextX := int32(screenW - 150)
 		nextY := prevY
 
+		// Update transition
 		oldAlpha, oldScale, oldOffsetX, newAlpha, newScale, newOffsetX := transition.Update()
 
 		if !transition.IsActive() && currentStep != targetStep {
 			currentStep = targetStep
 		}
 
+		// Poll SPM progress for the GUI
+		installer.PollProgress()
+
+		// If an unrecoverable error occurred, you could handle it here:
+		// (For now, we just print it in the console.)
+		if installer.LastError != nil {
+			fmt.Println("SPM Error:", installer.LastError)
+			// You might choose to show a popup or do something else
+		}
+
+		// GUI input
 		if !transition.IsActive() && rl.IsMouseButtonPressed(rl.MouseLeftButton) {
 			handleInput(mousePos, screenW, screenH, buttonW, buttonH, prevX, prevY, nextX, nextY)
 		}
@@ -93,20 +113,27 @@ func main() {
 			}
 		}
 
+		// Draw the semi-transparent loading circle if user is downloading or installing
+		if installer.IsDownloading || installer.IsInstalling {
+			drawInstallProgress(screenW, installer.Progress, installer.Task)
+		}
+
 		rl.EndDrawing()
 	}
 }
 
-func startTransition(from, to int) {
-	targetStep = to
-	transition.Start(from, to)
-}
+// handleInput acts on mouse clicks in each step
+func handleInput(mousePos rl.Vector2, screenW, screenH, buttonW, buttonH int,
+	prevX, prevY, nextX, nextY int32) {
 
-func handleInput(mousePos rl.Vector2, screenW, screenH, buttonW, buttonH int, prevX, prevY, nextX, nextY int32) {
 	if currentStep == 0 {
 		if overRect(mousePos, step1DefaultRect) {
-			fmt.Println("Installation complete with default settings.")
-			os.Exit(0)
+			// user clicked "Default" => do final install if not already installing
+			useDefault = true
+			if !installer.IsInstalling && !installer.DoneInstall {
+				installer.FinalInstall()
+			}
+			fmt.Println("Installation started with default settings.")
 		}
 		if overRect(mousePos, step1CustomRect) {
 			useDefault = false
@@ -124,9 +151,12 @@ func handleInput(mousePos rl.Vector2, screenW, screenH, buttonW, buttonH int, pr
 		selectTheme(mousePos)
 	} else if currentStep == 2 {
 		if overButton(mousePos, nextX, nextY, int32(buttonW), int32(buttonH)) {
-			fmt.Printf("Installation complete:\nDefault: %v\nColor: %s\nTheme: %s\nLayout: %s\n",
+			// user clicked "Finish" => final install if not already installing
+			if !installer.IsInstalling && !installer.DoneInstall {
+				installer.FinalInstall()
+			}
+			fmt.Printf("Installation started:\nDefault: %v\nColor: %s\nTheme: %s\nLayout: %s\n",
 				useDefault, selectedColor, selectedTheme, selectedLayout)
-			os.Exit(0)
 		}
 		if overButton(mousePos, int32(prevX), int32(prevY), int32(buttonW), int32(buttonH)) {
 			startTransition(currentStep, 1)
@@ -135,6 +165,7 @@ func handleInput(mousePos rl.Vector2, screenW, screenH, buttonW, buttonH int, pr
 	}
 }
 
+// drawHeader is your original function
 func drawHeader(screenW int) {
 	title := "Spitfire Browser Installer"
 	titleFontSize := int32(30)
@@ -142,3 +173,170 @@ func drawHeader(screenW int) {
 	rl.DrawText(title, (int32(screenW)-titleWidth)/2, 20, titleFontSize, rl.RayWhite)
 	rl.DrawLine(50, 60, int32(screenW)-50, 60, rl.Fade(rl.White, 0.5))
 }
+
+// drawInstallProgress displays a simple white circle with partial alpha,
+// plus the current task text below it, in the top-right area.
+func drawInstallProgress(screenW int, progress int, task string) {
+	circleX := float32(screenW - 80)
+	circleY := float32(100)
+	radius := float32(30)
+
+	// Colors for the circle
+	bgColor := rl.Color{R: 255, G: 255, B: 255, A: 80}
+	fillColor := rl.Color{R: 255, G: 255, B: 255, A: 200}
+
+	// Draw background circle
+	rl.DrawCircle(int32(circleX), int32(circleY), radius, bgColor)
+
+	// Draw progress arc
+	angle := float32(progress) / 100.0 * 360.0
+	rl.DrawCircleSector(
+		rl.Vector2{X: circleX, Y: circleY},
+		radius,
+		0,
+		angle,
+		40,
+		fillColor,
+	)
+
+	// Print numeric progress
+	txt := fmt.Sprintf("%3d%%", progress)
+	rl.DrawText(txt, int32(circleX)-rl.MeasureText(txt, 18)/2, int32(circleY)-10, 18, rl.White)
+
+	// Draw wrapped task text below the circle
+	drawTextWrapped(task, int32(circleX)-100, int32(circleY)+40, 200, 18, rl.White)
+}
+
+// Custom function to draw text with wrapping
+func drawTextWrapped(text string, x, y int32, maxWidth, fontSize int32, color rl.Color) {
+	words := splitIntoWords(text)
+	line := ""
+	offsetY := int32(0)
+
+	for _, word := range words {
+		testLine := line + word + " "
+		if rl.MeasureText(testLine, fontSize) > int32(maxWidth) {
+			rl.DrawText(line, x, y+offsetY, fontSize, color)
+			line = word + " "
+			offsetY += fontSize + 2
+		} else {
+			line = testLine
+		}
+	}
+
+	// Draw the last line
+	if line != "" {
+		rl.DrawText(line, x, y+offsetY, fontSize, color)
+	}
+}
+
+// Helper function to split text into words
+func splitIntoWords(text string) []string {
+	words := []string{}
+	word := ""
+	for _, char := range text {
+		if char == ' ' || char == '\n' {
+			if word != "" {
+				words = append(words, word)
+				word = ""
+			}
+			if char == '\n' {
+				words = append(words, "\n")
+			}
+		} else {
+			word += string(char)
+		}
+	}
+	if word != "" {
+		words = append(words, word)
+	}
+	return words
+}
+
+// startTransition is your existing function
+func startTransition(from, to int) {
+	targetStep = to
+	transition.Start(from, to)
+}
+
+// SPM example
+
+// package main
+
+// import (
+// 	"fmt"
+// 	"os"
+// 	"path/filepath"
+// 	"spitfire-installer/spm"
+// 	"time"
+// )
+
+// func main() {
+// 	// Start a goroutine to display progress updates
+// 	done := make(chan bool)
+// 	go func() {
+// 		for {
+// 			select {
+// 			case <-done:
+// 				return
+// 			default:
+// 				percentage, task := spm.GetProgress()
+// 				fmt.Printf("\r[%3d%%] %s", percentage, task)
+// 				time.Sleep(500 * time.Millisecond)
+// 			}
+// 		}
+// 	}()
+
+// 	// Set up the download directory
+// 	downloadDir := spm.GetTempDownloadDir()
+// 	fmt.Println("\nTemporary download directory:", downloadDir)
+
+// 	// Download the APPINDEX
+// 	appIndexPath := filepath.Join(downloadDir, "APPINDEX")
+// 	spm.UpdateProgress(0, "Starting APPINDEX download")
+// 	if err := spm.DownloadAppIndex(appIndexPath); err != nil {
+// 		fmt.Println("\nError downloading APPINDEX:", err)
+// 		done <- true
+// 		os.Exit(1)
+// 	}
+
+// 	// Download the desired package version (e.g., nightly)
+// 	packageName := "spitfire-browser"
+// 	release := "nightly"
+
+// 	spm.UpdateProgress(0, "Starting package download")
+// 	if err := spm.DownloadPackageFromAppIndex(appIndexPath, packageName, release, downloadDir); err != nil {
+// 		fmt.Println("\nError downloading package:", err)
+// 		done <- true
+// 		os.Exit(1)
+// 	}
+
+// 	// Decompress and install
+// 	packagePath := filepath.Join(downloadDir, "browser-amd64-nightly-linux.tar.gz")
+// 	spm.UpdateProgress(0, "Starting decompression")
+// 	tempDir, err := spm.DecompressToTemp(packagePath)
+// 	if err != nil {
+// 		fmt.Println("\nError decompressing package:", err)
+// 		done <- true
+// 		os.Exit(1)
+// 	}
+// 	fmt.Println("\nDecompressed package to:", tempDir)
+
+// 		// Generate default install directory
+// 		installDir, err := spm.GetDefaultInstallDir()
+// 		if err != nil {
+// 			inst.LastError = fmt.Errorf("failed to determine default install directory: %w", err)
+// 			return
+// 		}
+
+// 	spm.UpdateProgress(0, "Starting installation")
+// 	if err := spm.MoveFilesToInstallDir(tempDir, installDir); err != nil {
+// 		fmt.Println("\nError installing package:", err)
+// 		done <- true
+// 		os.Exit(1)
+// 	}
+
+// 	// Notify progress display to stop and finalize
+// 	done <- true
+// 	fmt.Printf("\nSuccessfully installed %s (%s) to %s\n", packageName, release, installDir)
+// }

spm/appindex.go

@@ -0,0 +1,108 @@
+package spm
+
+import (
+	"bufio"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+)
+
+const appIndexURL = "https://downloads.sourceforge.net/project/spitfire-browser/APPINDEX"
+
+func DownloadAppIndex(dest string) error {
+	UpdateProgress(0, "Downloading APPINDEX")
+	resp, err := http.Get(appIndexURL)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	out, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	totalSize := resp.ContentLength
+	var downloaded int64
+
+	// Track progress as bytes are downloaded
+	buf := make([]byte, 1024)
+	for {
+		n, err := resp.Body.Read(buf)
+		if n > 0 {
+			downloaded += int64(n)
+			percentage := int(float64(downloaded) / float64(totalSize) * 100)
+			UpdateProgress(percentage, "Downloading APPINDEX")
+			if _, err := out.Write(buf[:n]); err != nil {
+				return err
+			}
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	UpdateProgress(100, "APPINDEX downloaded")
+	return nil
+}
+
+type AppIndexEntry struct {
+	Name        string
+	Version     string
+	Release     string
+	Arch        string
+	OS          string
+	DownloadURL string
+}
+
+func ParseAppIndex(filePath string) ([]AppIndexEntry, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var entries []AppIndexEntry
+	scanner := bufio.NewScanner(file)
+	entry := AppIndexEntry{}
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "C:") {
+			if entry.Name != "" {
+				entries = append(entries, entry)
+				entry = AppIndexEntry{}
+			}
+		}
+		parts := strings.SplitN(line, ":", 2)
+		if len(parts) < 2 {
+			continue
+		}
+
+		switch parts[0] {
+		case "P":
+			entry.Name = parts[1]
+		case "R":
+			entry.Release = parts[1]
+		case "V":
+			entry.Version = parts[1]
+		case "A":
+			entry.Arch = parts[1]
+		case "p":
+			entry.OS = parts[1]
+		case "d":
+			entry.DownloadURL = parts[1]
+		}
+	}
+
+	if entry.Name != "" {
+		entries = append(entries, entry)
+	}
+
+	return entries, scanner.Err()
+}

spm/download.go

@@ -0,0 +1,91 @@
+package spm
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+type Package struct {
+	Name        string
+	Arch        string
+	OS          string
+	DownloadURL string
+}
+
+func DownloadPackage(pkg Package, destDir string) error {
+	UpdateProgress(0, fmt.Sprintf("Downloading %s", pkg.Name))
+	resp, err := http.Get(pkg.DownloadURL)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	filePath := filepath.Join(destDir, filepath.Base(pkg.DownloadURL))
+	out, err := os.Create(filePath)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	totalSize := resp.ContentLength
+	var downloaded int64
+
+	// Track progress as bytes are downloaded
+	buf := make([]byte, 1024)
+	for {
+		n, err := resp.Body.Read(buf)
+		if n > 0 {
+			downloaded += int64(n)
+			percentage := int(float64(downloaded) / float64(totalSize) * 100)
+			UpdateProgress(percentage, fmt.Sprintf("Downloading %s", pkg.Name))
+			if _, err := out.Write(buf[:n]); err != nil {
+				return err
+			}
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	UpdateProgress(100, fmt.Sprintf("%s downloaded", pkg.Name))
+	return nil
+}
+
+func FindPackage(entries []AppIndexEntry, name, release, arch, os string) (*AppIndexEntry, error) {
+	for _, entry := range entries {
+		if entry.Name == name && entry.Release == release && entry.Arch == arch && entry.OS == os {
+			return &entry, nil
+		}
+	}
+	return nil, errors.New("package not found")
+}
+
+func DownloadPackageFromAppIndex(appIndexPath, packageName, release, destDir string) error {
+	arch := runtime.GOARCH
+	osName := runtime.GOOS
+
+	entries, err := ParseAppIndex(appIndexPath)
+	if err != nil {
+		return err
+	}
+
+	entry, err := FindPackage(entries, packageName, release, arch, osName)
+	if err != nil {
+		return err
+	}
+
+	return DownloadPackage(Package{
+		Name:        entry.Name,
+		Arch:        entry.Arch,
+		OS:          entry.OS,
+		DownloadURL: entry.DownloadURL,
+	}, destDir)
+}

spm/install.go

@@ -0,0 +1,161 @@
+package spm
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+func DecompressToTemp(filePath string) (string, error) {
+	UpdateProgress(0, "Decompressing package")
+	tempDir, err := os.MkdirTemp("", "spm_decompress")
+	if err != nil {
+		return "", err
+	}
+
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	gzr, err := gzip.NewReader(file)
+	if err != nil {
+		return "", err
+	}
+	defer gzr.Close()
+
+	tarReader := tar.NewReader(gzr)
+	var totalFiles, processedFiles int
+	// Count total files
+	for {
+		_, err := tarReader.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+		totalFiles++
+	}
+
+	file.Seek(0, io.SeekStart)
+	gzr.Reset(file)
+	tarReader = tar.NewReader(gzr)
+
+	for {
+		header, err := tarReader.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+
+		targetPath := filepath.Join(tempDir, header.Name)
+		switch header.Typeflag {
+		case tar.TypeDir:
+			if err := os.MkdirAll(targetPath, os.FileMode(header.Mode)); err != nil {
+				return "", err
+			}
+		case tar.TypeReg:
+			outFile, err := os.Create(targetPath)
+			if err != nil {
+				return "", err
+			}
+			if _, err := io.Copy(outFile, tarReader); err != nil {
+				return "", err
+			}
+			outFile.Close()
+		}
+
+		processedFiles++
+		UpdateProgress(int(float64(processedFiles)/float64(totalFiles)*100), "Decompressing package")
+	}
+
+	UpdateProgress(100, "Package decompressed")
+	return tempDir, nil
+}
+
+func MoveFilesToInstallDir(tempDir, installDir string) error {
+	// Count total files to copy
+	var totalFiles, copiedFiles int
+	err := filepath.Walk(tempDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !info.IsDir() {
+			totalFiles++
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// Copy files and track progress
+	err = filepath.Walk(tempDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		relPath, err := filepath.Rel(tempDir, path)
+		if err != nil {
+			return err
+		}
+
+		targetPath := filepath.Join(installDir, relPath)
+		if info.IsDir() {
+			// Create directories in the install directory
+			if err := os.MkdirAll(targetPath, os.ModePerm); err != nil {
+				return err
+			}
+		} else {
+			// Copy files to the install directory
+			if err := copyFile(path, targetPath); err != nil {
+				return err
+			}
+			copiedFiles++
+			UpdateProgress(int(float64(copiedFiles)/float64(totalFiles)*100), "Copying files to install directory")
+		}
+		return nil
+	})
+
+	if err != nil {
+		return err
+	}
+
+	// Clean up temporary directory
+	UpdateProgress(100, "Cleaning up temporary files")
+	return os.RemoveAll(tempDir)
+}
+
+// copyFile copies the contents of the source file to the destination file.
+func copyFile(src, dst string) error {
+	sourceFile, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer sourceFile.Close()
+
+	// Create the destination file
+	destinationFile, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer destinationFile.Close()
+
+	// Copy the file content
+	if _, err := io.Copy(destinationFile, sourceFile); err != nil {
+		return err
+	}
+
+	// Preserve file permissions
+	info, err := sourceFile.Stat()
+	if err != nil {
+		return err
+	}
+	return os.Chmod(dst, info.Mode())
+}

spm/progress.go

@@ -0,0 +1,30 @@
+package spm
+
+import (
+	"fmt"
+	"sync"
+)
+
+type Progress struct {
+	mu         sync.Mutex
+	percentage int
+	task       string
+}
+
+var progress = Progress{}
+
+// UpdateProgress sets the current percentage and task.
+func UpdateProgress(percentage int, task string) {
+	progress.mu.Lock()
+	defer progress.mu.Unlock()
+	progress.percentage = percentage
+	progress.task = task
+	fmt.Printf("\r[%3d%%] %s", percentage, task) // Print progress to the terminal
+}
+
+// GetProgress returns the current progress state.
+func GetProgress() (int, string) {
+	progress.mu.Lock()
+	defer progress.mu.Unlock()
+	return progress.percentage, progress.task
+}

spm/utils.go

@@ -0,0 +1,64 @@
+package spm
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+func GetTempDownloadDir() string {
+	dir, err := os.MkdirTemp("", "spm_downloads")
+	if err != nil {
+		panic(err)
+	}
+	return dir
+}
+
+func SetDownloadFolder(customDir string) (string, error) {
+	if err := os.MkdirAll(customDir, os.ModePerm); err != nil {
+		return "", err
+	}
+	return customDir, nil
+}
+
+// GetDefaultInstallDir generates the default installation directory based on the OS and environment.
+func GetDefaultInstallDir() (string, error) {
+	var installDir string
+
+	switch runtime.GOOS {
+	case "windows":
+		// Use %APPDATA% or Program Files on Windows
+		appData := os.Getenv("APPDATA")
+		if appData != "" {
+			installDir = filepath.Join(appData, "Spitfire")
+		} else {
+			programFiles := os.Getenv("ProgramFiles")
+			if programFiles == "" {
+				return "", fmt.Errorf("unable to determine default install directory on Windows")
+			}
+			installDir = filepath.Join(programFiles, "Spitfire")
+		}
+
+	case "darwin":
+		// Use ~/Library/Application Support on macOS
+		homeDir, err := os.UserHomeDir()
+		if err != nil {
+			return "", fmt.Errorf("unable to determine home directory on macOS: %w", err)
+		}
+		installDir = filepath.Join(homeDir, "Library", "Application Support", "Spitfire")
+
+	case "linux":
+		// Use ~/.local/share or /opt on Linux
+		homeDir, err := os.UserHomeDir()
+		if err != nil {
+			return "", fmt.Errorf("unable to determine home directory on Linux: %w", err)
+		}
+		installDir = filepath.Join(homeDir, ".local", "share", "Spitfire")
+
+	default:
+		return "", fmt.Errorf("unsupported operating system: %s", runtime.GOOS)
+	}
+
+	return installDir, nil
+}

transition.go

@@ -122,9 +122,9 @@ func (t *TransitionManager) Update() (
 	oldAlpha, oldScale, oldOffsetX = 1, 1, 0
 	newAlpha, newScale, newOffsetX = 1, 1, 0
 
-	slideDir := float32(-1)
+	slideDir := float32(1)
 	if t.direction == DirectionBackward {
-		slideDir = 1
+		slideDir = -1
 	}
 
 	p := t.accumSec / t.totalSec