feat: loader logic

pkg/storage/fs/fs.go

@@ -163,10 +163,10 @@ func (s *fsStorage) SaveOrderAsync(id client.GameID, turn uint, o order.Order, c
 	}()
 }
 
-func (s *fsStorage) FileExists(path string) (bool, error) {
+func (s *fsStorage) FileExists(path string) (bool, string, error) {
 	absPath, err := s.resolvePath(path)
 	if err != nil {
-		return false, err
+		return false, "", err
 	}
 
 	var exists bool
@@ -175,7 +175,13 @@ func (s *fsStorage) FileExists(path string) (bool, error) {
 		exists, opErr = s.fileExistsUnlocked(absPath)
 		return opErr
 	})
-	return exists, err
+	if err != nil {
+		return false, "", err
+	}
+	if !exists {
+		return false, "", nil
+	}
+	return true, absPath, nil
 }
 
 func (s *fsStorage) ReadFile(path string) ([]byte, error) {
@@ -254,7 +260,8 @@ func (s *fsStorage) ListFiles() ([]string, error) {
 }
 
 func (s *fsStorage) StateExists() (bool, error) {
-	return s.FileExists(stateFileName)
+	exists, _, err := s.FileExists(stateFileName)
+	return exists, err
 }
 
 func (s *fsStorage) LoadState() (client.State, error) {

pkg/storage/fs/fs_test.go

@@ -172,13 +172,28 @@ func TestRawFileCRUDAndList(t *testing.T) {
 		t.Fatalf("write beta: %v", err)
 	}
 
-	alphaExists, err := s.FileExists("nested/alpha.txt")
+	alphaExists, alphaPath, err := s.FileExists("nested/alpha.txt")
 	if err != nil {
 		t.Fatalf("file exists: %v", err)
 	}
 	if !alphaExists {
 		t.Fatal("nested/alpha.txt should exist")
 	}
+	wantAlphaPath := filepath.Join(s.storageRoot, "nested", "alpha.txt")
+	if alphaPath != wantAlphaPath {
+		t.Fatalf("file path = %q, want %q", alphaPath, wantAlphaPath)
+	}
+
+	missingExists, missingPath, err := s.FileExists("missing.txt")
+	if err != nil {
+		t.Fatalf("missing file exists: %v", err)
+	}
+	if missingExists {
+		t.Fatal("missing.txt should not exist")
+	}
+	if missingPath != "" {
+		t.Fatalf("missing file path = %q, want empty string", missingPath)
+	}
 
 	alphaData, err := s.ReadFile("nested/alpha.txt")
 	if err != nil {

pkg/storage/storage.go

@@ -8,7 +8,7 @@ import (
 
 type Storage interface {
 	UIStorage
-	FileExists(string) (bool, error)
+	FileExists(string) (bool, string, error)
 	ReadFile(string) ([]byte, error)
 	WriteFile(string, []byte) error
 	DeleteFile(string) error