add basic oauth methods

lib/business_logic/auth/oauth.dart

@@ -0,0 +1,53 @@
+import 'package:http/http.dart' as http;
+import 'package:url_launcher/url_launcher.dart';
+import '../../global.dart' as global;
+
+class App {
+  late String clientSecret;
+  late String clientId;
+  late String id;
+  late String name;
+  late String website;
+  late String redirectUri;
+  App(
+      {required this.clientSecret,
+      required this.clientId,
+      required this.id,
+      required this.name,
+      required this.website,
+      required this.redirectUri});
+  factory App.fromJson(Map<String, dynamic> json) {
+    return App(
+        id: json["id"].toString(),
+        name: json["name"].toString(),
+        website: json["website"].toString(),
+        redirectUri: json["redirect_uri"].toString(),
+        clientId: json["client_id"].toString(),
+        clientSecret: json["client_secret"].toString());
+  }
+}
+
+Future<http.Response> registerApp(String baseurl) async {
+  //String url = baseurl Uri."api/v1/apps";
+  Uri url = Uri.https(baseurl, "/api/v1/apps");
+  var response = await http.post(url, headers: global.defaultHeaders, body: {
+    'client_name': global.name,
+    'redirect_uris': "ietf:wg:oauth:2.0:oob",
+    'scopes': "read write",
+    'website': global.website
+  });
+  return response;
+}
+
+void openBrowserForAuthCode(String baseurl, App app) {
+  Uri url = Uri.https(
+      baseurl,
+      // ignore: prefer_interpolation_to_compose_strings
+      "/oauth/authorize" +
+          "?client_id=" +
+          app.clientId +
+          "&scope=read+write" +
+          "&redirect_uri=urn:ietf:wg:oauth:2.0:oob" +
+          "&response_type=code");
+  launchUrl(url);
+}