25-7-28-2

lib/controller/firebase/access_token.dart

@@ -0,0 +1,53 @@
+import 'dart:convert';
+import 'package:googleapis_auth/auth_io.dart';
+
+import '../../print.dart';
+
+class AccessTokenManager {
+  static final AccessTokenManager _instance = AccessTokenManager._internal();
+  late final String serviceAccountJsonKey;
+  AccessToken? _accessToken;
+  DateTime? _expiryDate;
+
+  AccessTokenManager._internal();
+
+  factory AccessTokenManager(String jsonKey) {
+    if (_instance._isServiceAccountKeyInitialized()) {
+      // Prevent re-initialization
+      return _instance;
+    }
+    _instance.serviceAccountJsonKey = jsonKey;
+    return _instance;
+  }
+
+  bool _isServiceAccountKeyInitialized() {
+    try {
+      serviceAccountJsonKey; // Access to check if initialized
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+
+  Future<String> getAccessToken() async {
+    if (_accessToken != null && DateTime.now().isBefore(_expiryDate!)) {
+      return _accessToken!.data;
+    }
+    try {
+      final serviceAccountCredentials = ServiceAccountCredentials.fromJson(
+          json.decode(serviceAccountJsonKey));
+      final client = await clientViaServiceAccount(
+        serviceAccountCredentials,
+        ['https://www.googleapis.com/auth/firebase.messaging'],
+      );
+
+      _accessToken = client.credentials.accessToken;
+      _expiryDate = client.credentials.accessToken.expiry;
+      client.close();
+      // Log.print('_accessToken!.data: ${_accessToken!.data}');
+      return _accessToken!.data;
+    } catch (e) {
+      throw Exception('Failed to obtain access token');
+    }
+  }
+}