Add user settings validation

backend/internal/api/handlers.go

@@ -73,6 +73,11 @@ func DeleteFile(fs *filesystem.FileSystem) http.HandlerFunc {
 	}
 }
 
+var defaultSettings = models.UserSettings{
+	Theme:    "light",
+	AutoSave: false,
+}
+
 func GetSettings(db *db.DB) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		userIDStr := r.URL.Query().Get("userId")
@@ -88,6 +93,8 @@ func GetSettings(db *db.DB) http.HandlerFunc {
 			return
 		}
 
+		settings.SetDefaults(defaultSettings)
+
 		json.NewEncoder(w).Encode(settings)
 	}
 }
@@ -100,6 +107,13 @@ func UpdateSettings(db *db.DB) http.HandlerFunc {
 			return
 		}
 
+		settings.SetDefaults(defaultSettings)
+
+		if err := settings.Validate(); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
 		err := db.SaveSettings(settings)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)

backend/internal/db/migrations.go

@@ -15,10 +15,9 @@ var migrations = []Migration{
 		Version: 1,
 		SQL: `CREATE TABLE IF NOT EXISTS settings (
 			user_id INTEGER PRIMARY KEY,
-			settings TEXT
+			settings JSON NOT NULL
 		)`,
 	},
-	// Add new migrations here as your schema evolves
 }
 
 func (db *DB) Migrate() error {

backend/internal/db/settings.go

@@ -9,17 +9,20 @@ import (
 
 func (db *DB) GetSettings(userID int) (models.Settings, error) {
 	var settings models.Settings
-	var settingsJSON string
+	var settingsJSON []byte
 
 	err := db.QueryRow("SELECT user_id, settings FROM settings WHERE user_id = ?", userID).Scan(&settings.UserID, &settingsJSON)
 	if err != nil {
 		if err == sql.ErrNoRows {
+			// If no settings found, return default settings
+			settings.UserID = userID
+			settings.Settings = models.UserSettings{} // This will be filled with defaults later
 			return settings, nil
 		}
 		return settings, err
 	}
 
-	err = json.Unmarshal([]byte(settingsJSON), &settings.Settings)
+	err = json.Unmarshal(settingsJSON, &settings.Settings)
 	if err != nil {
 		return settings, err
 	}
@@ -28,11 +31,15 @@ func (db *DB) GetSettings(userID int) (models.Settings, error) {
 }
 
 func (db *DB) SaveSettings(settings models.Settings) error {
+	if err := settings.Validate(); err != nil {
+		return err
+	}
+
 	settingsJSON, err := json.Marshal(settings.Settings)
 	if err != nil {
 		return err
 	}
 
-	_, err = db.Exec("INSERT OR REPLACE INTO settings (user_id, settings) VALUES (?, ?)", settings.UserID, string(settingsJSON))
+	_, err = db.Exec("INSERT OR REPLACE INTO settings (user_id, settings) VALUES (?, json(?))", settings.UserID, string(settingsJSON))
 	return err
 }

backend/internal/models/settings.go

@@ -1,6 +1,42 @@
 package models
 
-type Settings struct {
-	UserID   int                    `json:"userId"`
-	Settings map[string]interface{} `json:"settings"`
+import (
+	"encoding/json"
+
+	"github.com/go-playground/validator/v10"
+)
+
+type UserSettings struct {
+	Theme    string `json:"theme" validate:"oneof=light dark"`
+	AutoSave bool   `json:"autoSave"`
+}
+
+type Settings struct {
+	UserID   int          `json:"userId" validate:"required,min=1"`
+	Settings UserSettings `json:"settings" validate:"required,dive"`
+}
+
+var validate = validator.New()
+
+func (s *Settings) Validate() error {
+	return validate.Struct(s)
+}
+
+func (s *Settings) SetDefaults(defaults UserSettings) {
+	if s.Settings.Theme == "" {
+		s.Settings.Theme = defaults.Theme
+	}
+}
+
+func (s *Settings) UnmarshalJSON(data []byte) error {
+	type Alias Settings
+	aux := &struct {
+		*Alias
+	}{
+		Alias: (*Alias)(s),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	return s.Validate()
 }