refactor(util): Centralize auth directory path resolution

Introduces a new utility function, `util.ResolveAuthDir`, to handle the normalization and resolution of the authentication directory path.

Previously, the logic for expanding the tilde (~) to the user's home directory was implemented inline in `main.go`. This refactoring extracts that logic into a reusable function within the `util` package.

The new `ResolveAuthDir` function is now used consistently across the application:
- During initial server startup in `main.go`.
- When counting authentication files in `util.CountAuthFiles`.
- When the configuration is reloaded by the watcher.

This change eliminates code duplication, improves consistency, and makes the path resolution logic more robust and maintainable.

cmd/server/main.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"strings"
 
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/cmd"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
@@ -123,22 +122,10 @@ func main() {
 	// Set the log level based on the configuration.
 	util.SetLogLevel(cfg)
 
-	// Expand the tilde (~) in the auth directory path to the user's home directory.
-	if strings.HasPrefix(cfg.AuthDir, "~") {
-		home, errUserHomeDir := os.UserHomeDir()
-		if errUserHomeDir != nil {
-			log.Fatalf("failed to get home directory: %v", errUserHomeDir)
-		}
-		// Reconstruct the path by replacing the tilde with the user's home directory.
-		remainder := strings.TrimPrefix(cfg.AuthDir, "~")
-		remainder = strings.TrimLeft(remainder, "/\\")
-		if remainder == "" {
-			cfg.AuthDir = home
-		} else {
-			// Normalize any slash style in the remainder so Windows paths keep nested directories.
-			normalized := strings.ReplaceAll(remainder, "\\", "/")
-			cfg.AuthDir = filepath.Join(home, filepath.FromSlash(normalized))
-		}
+	if resolvedAuthDir, errResolveAuthDir := util.ResolveAuthDir(cfg.AuthDir); errResolveAuthDir != nil {
+		log.Fatalf("failed to resolve auth directory: %v", errResolveAuthDir)
+	} else {
+		cfg.AuthDir = resolvedAuthDir
 	}
 
 	// Create login options to be used in authentication flows.

internal/util/util.go

@@ -4,6 +4,7 @@
 package util
 
 import (
+	"fmt"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -30,23 +31,42 @@ func SetLogLevel(cfg *config.Config) {
 	}
 }
 
-// CountAuthFiles returns the number of JSON auth files located under the provided directory.
-// The function resolves leading tildes to the user's home directory and performs a case-insensitive
-// match on the ".json" suffix so that files saved with uppercase extensions are also counted.
-func CountAuthFiles(authDir string) int {
+// ResolveAuthDir normalizes the auth directory path for consistent reuse throughout the app.
+// It expands a leading tilde (~) to the user's home directory and returns a cleaned path.
+func ResolveAuthDir(authDir string) (string, error) {
 	if authDir == "" {
-		return 0
+		return "", nil
 	}
 	if strings.HasPrefix(authDir, "~") {
 		home, err := os.UserHomeDir()
 		if err != nil {
-			log.Debugf("countAuthFiles: failed to resolve home directory: %v", err)
-			return 0
+			return "", fmt.Errorf("resolve auth dir: %w", err)
 		}
-		authDir = filepath.Join(home, authDir[1:])
+		remainder := strings.TrimPrefix(authDir, "~")
+		remainder = strings.TrimLeft(remainder, "/\\")
+		if remainder == "" {
+			return filepath.Clean(home), nil
+		}
+		normalized := strings.ReplaceAll(remainder, "\\", "/")
+		return filepath.Clean(filepath.Join(home, filepath.FromSlash(normalized))), nil
+	}
+	return filepath.Clean(authDir), nil
+}
+
+// CountAuthFiles returns the number of JSON auth files located under the provided directory.
+// The function resolves leading tildes to the user's home directory and performs a case-insensitive
+// match on the ".json" suffix so that files saved with uppercase extensions are also counted.
+func CountAuthFiles(authDir string) int {
+	dir, err := ResolveAuthDir(authDir)
+	if err != nil {
+		log.Debugf("countAuthFiles: failed to resolve auth directory: %v", err)
+		return 0
+	}
+	if dir == "" {
+		return 0
 	}
 	count := 0
-	walkErr := filepath.WalkDir(authDir, func(path string, d fs.DirEntry, err error) error {
+	walkErr := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			log.Debugf("countAuthFiles: error accessing %s: %v", path, err)
 			return nil

internal/watcher/watcher.go

@@ -463,6 +463,12 @@ func (w *Watcher) reloadConfig() bool {
 		return false
 	}
 
+	if resolvedAuthDir, errResolveAuthDir := util.ResolveAuthDir(newConfig.AuthDir); errResolveAuthDir != nil {
+		log.Errorf("failed to resolve auth directory from config: %v", errResolveAuthDir)
+	} else {
+		newConfig.AuthDir = resolvedAuthDir
+	}
+
 	w.clientsMutex.Lock()
 	oldConfig := w.config
 	w.config = newConfig
@@ -582,19 +588,22 @@ func (w *Watcher) reloadClients(rescanAuth bool) {
 
 		// Rebuild auth file hash cache for current clients
 		w.lastAuthHashes = make(map[string]string)
-		// Recompute hashes for current auth files
-		_ = filepath.Walk(cfg.AuthDir, func(path string, info fs.FileInfo, err error) error {
-			if err != nil {
-				return nil
-			}
-			if !info.IsDir() && strings.HasSuffix(strings.ToLower(info.Name()), ".json") {
-				if data, errReadFile := os.ReadFile(path); errReadFile == nil && len(data) > 0 {
-					sum := sha256.Sum256(data)
-					w.lastAuthHashes[path] = hex.EncodeToString(sum[:])
+		if resolvedAuthDir, errResolveAuthDir := util.ResolveAuthDir(cfg.AuthDir); errResolveAuthDir != nil {
+			log.Errorf("failed to resolve auth directory for hash cache: %v", errResolveAuthDir)
+		} else if resolvedAuthDir != "" {
+			_ = filepath.Walk(resolvedAuthDir, func(path string, info fs.FileInfo, err error) error {
+				if err != nil {
+					return nil
 				}
-			}
-			return nil
-		})
+				if !info.IsDir() && strings.HasSuffix(strings.ToLower(info.Name()), ".json") {
+					if data, errReadFile := os.ReadFile(path); errReadFile == nil && len(data) > 0 {
+						sum := sha256.Sum256(data)
+						w.lastAuthHashes[path] = hex.EncodeToString(sum[:])
+					}
+				}
+				return nil
+			})
+		}
 		w.clientsMutex.Unlock()
 	}
 
@@ -869,14 +878,13 @@ func (w *Watcher) loadFileClients(cfg *config.Config) int {
 	authFileCount := 0
 	successfulAuthCount := 0
 
-	authDir := cfg.AuthDir
-	if strings.HasPrefix(authDir, "~") {
-		home, err := os.UserHomeDir()
-		if err != nil {
-			log.Errorf("failed to get home directory: %v", err)
-			return 0
-		}
-		authDir = filepath.Join(home, authDir[1:])
+	authDir, errResolveAuthDir := util.ResolveAuthDir(cfg.AuthDir)
+	if errResolveAuthDir != nil {
+		log.Errorf("failed to resolve auth directory: %v", errResolveAuthDir)
+		return 0
+	}
+	if authDir == "" {
+		return 0
 	}
 
 	errWalk := filepath.Walk(authDir, func(path string, info fs.FileInfo, err error) error {