Initial commit: Eventify frontend

lib/core/storage/token_storage.dart

@@ -0,0 +1,62 @@
+// lib/core/storage/token_storage.dart
+
+import 'package:shared_preferences/shared_preferences.dart';
+
+class TokenStorage {
+  static const _tokenKey = "auth_token";
+  static const _authUsernameKey = "auth_username"; // new key used for backend identity
+  static const _oldUsernameKey = "username"; // old key (may have been used for UI or auth)
+  static const _displayNameKey = "display_name"; // UI display name
+
+  /// Save token and backend username.
+  /// Will save `auth_username` always. It will only overwrite the old `username` key
+  /// if that key is missing or already looks like an email (avoid overwriting user display names).
+  static Future<void> saveToken(String token, String username) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_tokenKey, token);
+    await prefs.setString(_authUsernameKey, username);
+
+    final oldVal = prefs.getString(_oldUsernameKey);
+    // If old key not present OR old value looks like an email (so it's probably the backend username),
+    // keep it in sync. Do not overwrite if it's a display name.
+    if (oldVal == null || oldVal.contains('@')) {
+      await prefs.setString(_oldUsernameKey, username);
+    }
+  }
+
+  static Future<String?> getToken() async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.getString(_tokenKey);
+  }
+
+  /// Return backend username (auth identity).
+  /// Tries new key first, falls back to old key for compatibility.
+  static Future<String?> getUsername() async {
+    final prefs = await SharedPreferences.getInstance();
+    final auth = prefs.getString(_authUsernameKey);
+    if (auth != null && auth.isNotEmpty) return auth;
+    // fallback (older apps used 'username' key)
+    final old = prefs.getString(_oldUsernameKey);
+    return old;
+  }
+
+  /// Helper to read display name (UI)
+  static Future<String?> getDisplayName() async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.getString(_displayNameKey);
+  }
+
+  /// Save display name for UI (do NOT use this key for backend authentication)
+  static Future<void> saveDisplayName(String displayName) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_displayNameKey, displayName);
+  }
+
+  static Future<void> clear() async {
+    final prefs = await SharedPreferences.getInstance();
+    // Intentionally clear only auth-related keys (keeps user display name if you want)
+    await prefs.remove(_tokenKey);
+    await prefs.remove(_authUsernameKey);
+    // do NOT remove _oldUsernameKey or _displayNameKey automatically to avoid losing UI settings
+  }
+}