feat: enhance background folder watcher and improve UX/stability

.gitignore

@@ -11,3 +11,5 @@ frontend/dist
 # build package
 *.exe
 *.dmg
+ExifFrame
+

app.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"log"
 	"math"
 	"net/http"
 	"os"
@@ -50,6 +51,18 @@ func NewApp() *App {
 // so we can call the runtime methods
 func (a *App) startup(ctx context.Context) {
 	a.ctx = ctx
+	// Restart watcher if configured
+	settingsMu.RLock()
+	watchFolder := currentSettings.WatchFolder
+	settingsMu.RUnlock()
+	if watchFolder != "" {
+		a.updateWatcher(watchFolder)
+	}
+}
+
+// shutdown is called at application termination
+func (a *App) shutdown(ctx context.Context) {
+	a.updateWatcher("") // This properly closes the watcher and waits for its goroutine to exit
 }
 
 // getCurrentImagePath returns the path of the currently loaded image in a thread-safe manner.
@@ -90,6 +103,11 @@ func (a *App) OpenImage() ExifResult {
 		return ExifResult{Cancelled: true} // user cancelled
 	}
 
+	return a.processImageFile(filePath)
+}
+
+// processImageFile reads a file, validates it, and extracts EXIF
+func (a *App) processImageFile(filePath string) ExifResult {
 	const maxFileSize = 100 * 1024 * 1024 // 100 MB
 	fileInfo, err := os.Stat(filePath)
 	if err != nil {
@@ -109,6 +127,10 @@ func (a *App) OpenImage() ExifResult {
 		return ExifResult{Error: "Invalid file: selected file must be a JPG or PNG image."}
 	}
 
+	return a.doOpenImage(filePath, fileBytes, mimeType)
+}
+
+func (a *App) doOpenImage(filePath string, fileBytes []byte, mimeType string) ExifResult {
 	// Store the file path for the HTTP handler to serve later.
 	a.mu.Lock()
 	a.currentImagePath = filePath
@@ -303,6 +325,84 @@ func (a *App) SaveImage(isPng bool, defaultName string) SaveResult {
 	return SaveResult{SaveToken: token}
 }
 
+// SaveAutoImage bypasses the native dialog and prepares a save token for automated background saving.
+func (a *App) SaveAutoImage(isPng bool, savePath string) SaveResult {
+	// Validate path is within export folder
+	settingsMu.RLock()
+	exportFolder := currentSettings.ExportFolder
+	settingsMu.RUnlock()
+
+	if exportFolder == "" {
+		return SaveResult{Error: "Export folder is not configured"}
+	}
+
+	// Resolve symlinks to prevent path traversal attacks
+	realExport, err := filepath.EvalSymlinks(filepath.Clean(exportFolder))
+	if err != nil {
+		return SaveResult{Error: "Failed to resolve export folder path: " + err.Error()}
+	}
+
+	// Walk up from the save directory to find the nearest existing ancestor.
+	// This allows saving into not-yet-created subdirectories under ExportFolder
+	// (e.g. ExportFolder/2026-05/photo.jpg where 2026-05/ doesn't exist yet).
+	cleanSave := filepath.Clean(savePath)
+	ancestor := filepath.Dir(cleanSave)
+	for {
+		if _, statErr := os.Stat(ancestor); statErr == nil {
+			break
+		}
+		parent := filepath.Dir(ancestor)
+		if parent == ancestor {
+			// Reached filesystem root without finding an existing directory
+			break
+		}
+		ancestor = parent
+	}
+
+	realAncestor, err := filepath.EvalSymlinks(ancestor)
+	if err != nil {
+		return SaveResult{Error: "Failed to resolve save path: " + err.Error()}
+	}
+	rel, err := filepath.Rel(realExport, realAncestor)
+	if err != nil || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return SaveResult{Error: "Save path is outside of the allowed export folder"}
+	}
+
+	expectedMime := "image/jpeg"
+	if isPng {
+		expectedMime = "image/png"
+	}
+	if a.handler == nil {
+		return SaveResult{Error: "Internal error: image handler not initialized"}
+	}
+	token := a.handler.prepareSave(savePath, expectedMime)
+	return SaveResult{SaveToken: token}
+}
+
+// SelectWatchFolder opens a directory dialog to pick a watch folder
+func (a *App) SelectWatchFolder() string {
+	path, err := runtime.OpenDirectoryDialog(a.ctx, runtime.OpenDialogOptions{
+		Title: "Select Watch Folder",
+	})
+	if err != nil {
+		log.Println("Error opening directory dialog:", err)
+		return ""
+	}
+	return path
+}
+
+// SelectExportFolder opens a directory dialog to pick an export folder
+func (a *App) SelectExportFolder() string {
+	path, err := runtime.OpenDirectoryDialog(a.ctx, runtime.OpenDialogOptions{
+		Title: "Select Export Folder",
+	})
+	if err != nil {
+		log.Println("Error opening directory dialog:", err)
+		return ""
+	}
+	return path
+}
+
 func formatFocalLength(num, den int64) string {
 	if den == 0 {
 		return ""

frontend/src/App.css

@@ -370,3 +370,53 @@ body {
     opacity: 0.5;
     pointer-events: none;
 }
+
+/* Modal */
+.modal-overlay {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    background-color: rgba(0, 0, 0, 0.6);
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    z-index: 2000;
+}
+
+.modal-content {
+    background-color: var(--bg-panel);
+    border: 1px solid var(--border-color);
+    border-radius: 8px;
+    padding: 2rem;
+    width: 90%;
+    max-width: 400px;
+    max-height: 80vh;
+    overflow-y: auto;
+    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
+}
+
+.modal-content h2 {
+    margin-top: 0;
+    margin-bottom: 1.5rem;
+    font-size: 1.2rem;
+    color: var(--text-primary);
+}
+
+.modal-content .input-group {
+    margin-bottom: 1.2rem;
+}
+
+.modal-content small {
+    display: block;
+    margin-top: 0.4rem;
+    color: var(--text-secondary);
+    font-size: 0.75rem;
+}
+
+.modal-actions {
+    display: flex;
+    justify-content: flex-end;
+    margin-top: 2rem;
+}