Linking-Tool/desktop/app.go

package main

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"os"
	"time"

	"github.com/wailsapp/wails/v2/pkg/runtime"
)

// App struct
type App struct {
	ctx   context.Context
	port  int
	debug bool
}

// NewApp creates a new App struct
func NewApp(debug bool) *App {
	return &App{
		debug: debug,
	}
}

func (a *App) logDebug(format string, args ...any) {
	if a != nil && a.debug {
		fmt.Printf("[debug] "+format+"\n", args...)
	}
}

// logHandler wraps HTTP handlers to log requests when debug is enabled.
func (a *App) logHandler(next http.Handler) http.Handler {
	if !a.debug {
		return next
	}
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		next.ServeHTTP(w, r)
		fmt.Printf("[debug] http %s %s %dms\n", r.Method, r.URL.Path, time.Since(start).Milliseconds())
	})
}

// startup is called when the app starts. The context is saved
// so we can call the runtime methods
func (a *App) startup(ctx context.Context) {
	a.ctx = ctx
	a.logDebug("startup begin")

	// Start local API server on a random port
	listener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		fmt.Printf("Error starting local server: %v\n", err)
		return
	}

	a.port = listener.Addr().(*net.TCPAddr).Port
	a.logDebug("local API listener bound on %s", listener.Addr().String())

	mux := http.NewServeMux()

	// CORS middleware for local desktop API
	cors := func(next http.HandlerFunc) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("Access-Control-Allow-Origin", "*")
			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
			w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
			if r.Method == "OPTIONS" {
				w.WriteHeader(http.StatusOK)
				return
			}
			next.ServeHTTP(w, r)
		}
	}

	mux.HandleFunc("/api/ping", cors(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprintf(w, `{"status":"ok"}`)
	}))

	server := &http.Server{
		Addr:         listener.Addr().String(),
		Handler:      a.logHandler(mux),
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	go func() {
		if err := server.Serve(listener); err != nil && err != http.ErrServerClosed {
			fmt.Printf("Error serving desktop API: %v\n", err)
		}
	}()
	fmt.Printf("Desktop API server started on port %d\n", a.port)
	a.logDebug("startup complete")
}

// GetAPIPort returns the port the local server is running on
func (a *App) GetAPIPort() int {
	a.logDebug("GetAPIPort -> %d", a.port)
	return a.port
}

// LogFrontend allows the frontend to log to the terminal
func (a *App) LogFrontend(message string) {
	fmt.Printf("[frontend] %s\n", message)
}

// SaveFile shows a save dialog and writes the content to the selected file
func (a *App) SaveFile(filename string, content string) error {
	a.logDebug("SaveFile filename=%s", filename)
	filePath, err := runtime.SaveFileDialog(a.ctx, runtime.SaveDialogOptions{
		DefaultFilename: filename,
		Title:           "Save Graph",
		Filters: []runtime.FileFilter{
			{
				DisplayName: "JSON Files (*.json)",
				Pattern:     "*.json",
			},
		},
	})
	if err != nil {
		return err
	}
	if filePath == "" {
		return nil // Cancelled
	}

	return os.WriteFile(filePath, []byte(content), 0644)
}

// LoadFile shows an open dialog and returns the content of the selected file
func (a *App) LoadFile() (string, error) {
	a.logDebug("LoadFile")
	filePath, err := runtime.OpenFileDialog(a.ctx, runtime.OpenDialogOptions{
		Title: "Open Graph",
		Filters: []runtime.FileFilter{
			{
				DisplayName: "JSON Files (*.json)",
				Pattern:     "*.json",
			},
		},
	})
	if err != nil {
		return "", err
	}
	if filePath == "" {
		return "", nil // Cancelled
	}

	content, err := os.ReadFile(filePath)
	if err != nil {
		return "", err
	}
	return string(content), nil
}