Done login routine

lib/api/api_client.dart

@@ -0,0 +1,94 @@
+import 'dart:async';
+import 'dart:convert';
+import 'package:tuuli_app/api/model/access_token_model.dart';
+import 'package:http/browser_client.dart';
+import 'package:http/http.dart';
+
+class ErrorOrData<T> {
+  final T? data;
+  final Exception? error;
+
+  ErrorOrData(this.data, this.error);
+
+  void unfold(
+      void Function(T data) onData, void Function(Exception error) onError) {
+    if (data != null) {
+      onData(data as T);
+    } else {
+      onError(error!);
+    }
+  }
+}
+
+typedef FutureErrorOrData<T> = Future<ErrorOrData<T>>;
+
+class ApiClient {
+  final BrowserClient _client = BrowserClient();
+
+  final Uri baseUrl;
+
+  ApiClient(this.baseUrl);
+
+  ApiClient.fromString(String baseUrl) : this(Uri.parse(baseUrl));
+
+  FutureErrorOrData<AccessTokenModel> login(
+    String username,
+    String password,
+  ) async {
+    AccessTokenModel? data;
+    Exception? error;
+
+    final response = await post('/api/getAccessToken', body: {
+      'username': username,
+      'password': password,
+    }, headers: {
+      'Content-Type': 'application/json',
+    });
+    if (response.statusCode == 200) {
+      final body = json.decode(await response.stream.bytesToString());
+      if (body['error'] != null) {
+        error = Exception(body['error']);
+      } else if (body['access_token'] == null) {
+        error = Exception('No access token');
+      } else {
+        data = AccessTokenModel(accessToken: body['access_token']);
+      }
+    } else {
+      error = Exception('HTTP ${response.statusCode}');
+    }
+
+    return ErrorOrData(data, error);
+  }
+
+  Future<StreamedResponse> get(
+    String path, {
+    Map<String, String>? headers,
+  }) {
+    return _request(path, 'GET', headers: headers);
+  }
+
+  Future<StreamedResponse> post(
+    String path, {
+    Map<String, String>? headers,
+    dynamic body,
+  }) {
+    return _request(path, 'POST', headers: headers, body: body);
+  }
+
+  Future<StreamedResponse> _request(
+    String path,
+    String method, {
+    Map<String, String>? headers,
+    dynamic body,
+  }) async {
+    final uri = baseUrl.resolve(path);
+    final request = Request(method, uri);
+    if (headers != null) {
+      request.headers.addAll(headers);
+    }
+    if (body != null) {
+      request.body = json.encode(body);
+    }
+    return _client.send(request);
+  }
+}