syncwarden/internal/tray/panel.go

package tray

import (
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"sync"
)

var (
	panelMu   sync.Mutex
	panelProc *os.Process
)

// launchPanel opens the Syncthing admin UI.
// Tries the embedded panel binary first, falls back to the default browser.
func launchPanel(baseURL string) {
	panelMu.Lock()
	defer panelMu.Unlock()

	// Check if panel subprocess is already running
	if panelProc != nil {
		if err := panelProc.Signal(os.Signal(nil)); err == nil {
			log.Println("panel already running")
			return
		}
		panelProc = nil
	}

	// Try embedded panel binary
	panelBin := panelBinaryPath()
	if panelBin != "" {
		cmd := exec.Command(panelBin, "-addr", baseURL)
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		if err := cmd.Start(); err == nil {
			panelProc = cmd.Process
			log.Printf("panel started (pid %d)", cmd.Process.Pid)
			go func() {
				_ = cmd.Wait()
				panelMu.Lock()
				panelProc = nil
				panelMu.Unlock()
				log.Println("panel exited")
			}()
			return
		}
		log.Printf("failed to start panel binary: %v", panelBin)
	}

	// Fallback: open in default browser
	log.Printf("opening %s in browser", baseURL)
	openBrowser(baseURL)
}

func panelBinaryPath() string {
	exe, err := os.Executable()
	if err != nil {
		return ""
	}
	dir := filepath.Dir(exe)

	name := "syncwarden-panel"
	if runtime.GOOS == "windows" {
		name = "syncwarden-panel.exe"
	}

	p := filepath.Join(dir, name)
	if _, err := os.Stat(p); err == nil {
		return p
	}
	return ""
}

func openBrowser(url string) {
	var cmd *exec.Cmd
	switch runtime.GOOS {
	case "windows":
		cmd = exec.Command("rundll32", "url.dll,FileProtocolHandler", url)
	case "darwin":
		cmd = exec.Command("open", url)
	default:
		cmd = exec.Command("xdg-open", url)
	}
	if err := cmd.Start(); err != nil {
		log.Printf("failed to open browser: %v", err)
	}
}