feat: implement custom attachment download feature with folder selection and automatic opening of Explorer

backend/utils/ini-reader.go

@@ -22,6 +22,9 @@ type EMLyConfig struct {
 	UpdateCheckEnabled       string `ini:"UPDATE_CHECK_ENABLED"`
 	UpdatePath               string `ini:"UPDATE_PATH"`
 	UpdateAutoCheck          string `ini:"UPDATE_AUTO_CHECK"`
+	WebView2UserDataPath     string `ini:"WEBVIEW2_USERDATA_PATH"`
+	WebView2DownloadPath     string `ini:"WEBVIEW2_DOWNLOAD_PATH"`
+	ExportAttachmentFolder   string `ini:"EXPORT_ATTACHMENT_FOLDER"`
 }
 
 // LoadConfig reads the config.ini file at the given path and returns a Config struct

backend/utils/mail/file_dialog.go

@@ -2,6 +2,13 @@ package internal
 
 import (
 	"context"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
 
 	"github.com/wailsapp/wails/v2/pkg/runtime"
 )
@@ -16,6 +23,14 @@ var EmailDialogOptions = runtime.OpenDialogOptions{
 	ShowHiddenFiles: false,
 }
 
+var FolderDialogOptions = runtime.OpenDialogOptions{
+	Title: "Select Folder",
+	Filters: []runtime.FileFilter{
+		{DisplayName: "Folders", Pattern: "*"},
+	},
+	ShowHiddenFiles: false,
+}
+
 func ShowFileDialog(ctx context.Context) (string, error) {
 	filePath, err := runtime.OpenFileDialog(ctx, EmailDialogOptions)
 	if err != nil {
@@ -23,3 +38,86 @@ func ShowFileDialog(ctx context.Context) (string, error) {
 	}
 	return filePath, nil
 }
+
+func ShowFolderDialog(ctx context.Context) (string, error) {
+	folderPath, err := runtime.OpenDirectoryDialog(ctx, FolderDialogOptions)
+	if err != nil {
+		return "", err
+	}
+	return folderPath, nil
+}
+
+// SaveAttachmentToFolder saves a base64-encoded attachment to the specified folder.
+// If folderPath is empty, uses the user's Downloads folder as default.
+// Expands environment variables in the format %%VAR%% or %VAR%.
+//
+// Parameters:
+//   - filename: The name to save the file as
+//   - base64Data: The base64-encoded file content
+//   - folderPath: Optional custom folder path (uses Downloads if empty)
+//
+// Returns:
+//   - string: The full path where the file was saved
+//   - error: Any file system or decoding errors
+func SaveAttachmentToFolder(filename string, base64Data string, folderPath string) (string, error) {
+	// Decode base64 data
+	data, err := base64.StdEncoding.DecodeString(base64Data)
+	if err != nil {
+		return "", fmt.Errorf("failed to decode attachment data: %w", err)
+	}
+
+	// Use configured folder or default to Downloads
+	targetFolder := folderPath
+	if targetFolder == "" {
+		targetFolder = filepath.Join(os.Getenv("USERPROFILE"), "Downloads")
+	} else {
+		// Expand environment variables (%%VAR%% or %VAR% format)
+		re := regexp.MustCompile(`%%([^%]+)%%|%([^%]+)%`)
+		targetFolder = re.ReplaceAllStringFunc(targetFolder, func(match string) string {
+			varName := strings.Trim(match, "%")
+			return os.Getenv(varName)
+		})
+	}
+
+	// Ensure the target folder exists
+	if err := os.MkdirAll(targetFolder, 0755); err != nil {
+		return "", fmt.Errorf("failed to create target folder: %w", err)
+	}
+
+	// Create full path
+	fullPath := filepath.Join(targetFolder, filename)
+
+	// Save the file
+	if err := os.WriteFile(fullPath, data, 0644); err != nil {
+		return "", fmt.Errorf("failed to save attachment: %w", err)
+	}
+
+	return fullPath, nil
+}
+
+// OpenFileExplorer opens Windows Explorer and selects the specified file.
+// Uses the /select parameter to highlight the file in Explorer.
+// If the path is a directory, opens the directory without selecting anything.
+//
+// Parameters:
+//   - filePath: The full path to the file or directory to open in Explorer
+//
+// Returns:
+//   - error: Any execution errors
+func OpenFileExplorer(filePath string) error {
+	// Check if path is a directory or file
+	info, err := os.Stat(filePath)
+	if err != nil {
+		return fmt.Errorf("failed to stat path: %w", err)
+	}
+
+	if info.IsDir() {
+		// Open directory
+		cmd := exec.Command("explorer.exe", filePath)
+		return cmd.Start()
+	}
+
+	// Open and select file
+	cmd := exec.Command("explorer.exe", "/select,", filePath)
+	return cmd.Start()
+}