location image search and population for new session

lib/services/apis/google_places_service.dart

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+import 'dart:async';
+import 'dart:convert';
+
+import 'package:http/http.dart';
+import 'package:uuid/uuid.dart';
+
+class GooglePlacesService {
+  final sessionToken = Uuid().v4();
+  final apiKey = "AIzaSyBCjMCEAyyNVpsnVYvZj6VL1mmB98Vd6AE";
+  final client = Client();
+
+  void finish() {
+    client.close();
+  }
+
+  Future<List<Suggestion>?> fetchSuggestions(String input, String lang) async {
+    var headers = {
+      'Content-Type': 'application/json',
+      'X-Goog-Api-Key': apiKey,
+      "Access-Control-Allow-Origin": "*",
+      'X-Goog-FieldMask':
+          'places.displayName,places.id,places.formattedAddress,places.photos'
+    };
+    var request = Request('POST',
+        Uri.parse('https://places.googleapis.com/v1/places:searchText'));
+    request.body = json.encode({"textQuery": input});
+    request.headers.addAll(headers);
+
+    StreamedResponse response = await request.send();
+
+    if (response.statusCode == 200) {
+      final result = json.decode(await response.stream.bytesToString());
+
+      if (result.isNotEmpty) {
+        return result['places']
+            .map<Suggestion>((p) => Suggestion(
+                placeId: p['id'],
+                description: p['displayName']['text'],
+                address: p['formattedAddress'],
+                imageReferences: p['photos']))
+            .toList();
+      } else {
+        return null;
+      }
+    } else {
+      throw Exception(response.reasonPhrase);
+    }
+  }
+
+  Future fetchPhoto(String name) async {
+    var headers = {
+      "Access-Control-Allow-Origin": "*",
+    };
+
+    var request = Request('GET',
+      Uri.parse('https://places.googleapis.com/v1/$name/media?key=$apiKey&maxWidthPx=800&skipHttpRedirect=true')
+    );
+    request.headers.addAll(headers);
+
+    StreamedResponse response = await request.send();
+
+    if (response.statusCode == 200) {
+      final result = json.decode(await response.stream.bytesToString());
+
+      if (result.isNotEmpty) {
+        return result;
+      } else {
+        return null;
+      }
+    } else {
+      throw Exception(response.reasonPhrase);
+    }
+  }
+}
+
+class Suggestion {
+  final String placeId;
+  final String description;
+  final String address;
+  final List<dynamic>? imageReferences;
+
+  Suggestion(
+      {required this.placeId,
+      required this.description,
+      required this.address,
+      this.imageReferences});
+
+  @override
+  String toString() {
+    return 'Suggestion(description: $description, placeId: $placeId)';
+  }
+
+  Map toJson() => {
+        'placeId': placeId,
+        'name': description,
+        'address': address,
+        'imageReferences': imageReferences
+      };
+}

lib/services/functional/debouncer.dart

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+import 'dart:async';
+
+typedef _Debounceable<S, T> = Future<S?> Function(T parameter);
+
+class Debouncer {
+  Debouncer(this._duration, this._callback);
+
+  final Duration _duration;
+  final dynamic _callback;
+  late final _Debounceable<dynamic, String> _debouncedSearch = _debounce<dynamic, String>(_callback);
+
+  /// Returns a new function that is a debounced version of the given function.
+  ///
+  /// This means that the original function will be called only after no calls
+  /// have been made for the given Duration.
+  _Debounceable<S, T> _debounce<S, T>(_Debounceable<S?, T> function) {
+    _DebounceTimer? debounceTimer;
+
+    return (T parameter) async {
+      if (debounceTimer != null && !debounceTimer!.isCompleted) {
+        debounceTimer!.cancel();
+      }
+      debounceTimer = _DebounceTimer(_duration);
+      try {
+        await debounceTimer!.future;
+      } on _CancelException {
+        return null;
+      }
+      return function(parameter);
+    };
+  }
+
+  process(data) {
+    return _debouncedSearch(data);
+  }
+}
+
+// A wrapper around Timer used for debouncing.
+class _DebounceTimer {
+  final Duration debounceDuration;
+
+  _DebounceTimer(
+    this.debounceDuration
+  ) {
+    _timer = Timer(debounceDuration, _onComplete);
+  }
+
+  late final Timer _timer;
+  final Completer<void> _completer = Completer<void>();
+
+  void _onComplete() {
+    _completer.complete();
+  }
+
+  Future<void> get future => _completer.future;
+
+  bool get isCompleted => _completer.isCompleted;
+
+  void cancel() {
+    _timer.cancel();
+    _completer.completeError(const _CancelException());
+  }
+}
+
+// An exception indicating that the timer was canceled.
+class _CancelException implements Exception {
+  const _CancelException();
+}