image querying from within the frontend

frontend/lib/utils/fetch_trip.dart

@@ -1,5 +1,6 @@
 import "dart:convert";
 import "dart:developer";
+import "package:anyway/utils/load_landmark_image.dart";
 import 'package:dio/dio.dart';
 
 import 'package:anyway/constants.dart';
@@ -85,6 +86,15 @@ fetchTrip(
 }
 
 
+patchLandmarkImage(Landmark landmark) async {
+  // patch the landmark to include an image from an external source
+  if (landmark.imageURL == null) {
+    String? newUrl = await getImageUrlFromName(landmark.name);
+    if (newUrl != null) {
+      landmark.imageURL = newUrl;
+    }
+  }
+}
 
 Future<(Landmark, String?)> fetchLandmark(String uuid) async {
   final response = await dio.get(
@@ -101,5 +111,7 @@ Future<(Landmark, String?)> fetchLandmark(String uuid) async {
   log(response.data.toString());
   Map<String, dynamic> json = response.data;
   String? nextUUID = json["next_uuid"];
-  return (Landmark.fromJson(json), nextUUID);
+  Landmark landmark = Landmark.fromJson(json);
+  patchLandmarkImage(landmark);
+  return (landmark, nextUUID);
 }

frontend/lib/utils/load_landmark_image.dart

@@ -0,0 +1,60 @@
+import 'dart:developer';
+
+import 'package:dio/dio.dart';
+import 'package:fuzzywuzzy/fuzzywuzzy.dart';
+import 'dart:convert';
+
+import 'package:fuzzywuzzy/model/extracted_result.dart';
+
+const String baseUrl = "https://en.wikipedia.org/w/api.php";
+final Dio dio = Dio();
+
+Future<int?> bestPageMatch(String title) async {
+    final response = await dio.get(baseUrl, queryParameters: {
+        "action": "query",
+        "format": "json",
+        "list": "prefixsearch",
+        "pssearch": title,
+    });
+
+    final data = jsonDecode(response.toString());
+    log(data.toString());
+    final List<dynamic> results = data["query"]["prefixsearch"] ?? {};
+    final Map<String, int> titlesAndIds = {
+        for (var d in results) d["title"]: d["pageid"]
+    };
+    if (titlesAndIds.isEmpty) {
+        log("No pages found for $title");
+        return null;
+    }
+
+    // after the empty check, we can safely assume that there is a best match
+    final ExtractedResult<String> bestMatch = extractOne(
+      query: title,
+      choices: titlesAndIds.keys.toList(),
+      cutoff: 70,
+    );
+    return titlesAndIds[bestMatch.choice];
+}
+
+Future<String?> getImageUrl(int pageId) async {
+    final response = await dio.get(baseUrl, queryParameters: {
+        "action": "query",
+        "format": "json",
+        "prop": "pageimages",
+        "pageids": pageId,
+        "pithumbsize": 500,
+    });
+
+    final data = jsonDecode(response.toString());
+    final pageData = data["query"]["pages"][pageId.toString()];
+    return pageData["thumbnail"]?["source"];
+}
+
+Future<String?> getImageUrlFromName(String title) async {
+    int? pageId = await bestPageMatch(title);
+    if (pageId == null) {
+        return null;
+    }
+    return await getImageUrl(pageId);
+}