feat(todo): a location's search goes through the instance (ADR 0033, D32)

The picker now searches with the server's `search`, and says search
isn't available where the instance has no Photon rather than that it
failed. A debug build may still ask for komoot's public one, for an
instance without. A point on the map stays unnamed through the instance,
which searches by name alone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/todo/halkyon_todo_flutter/lib/src/app/todo_dependencies.dart

@@ -193,9 +193,9 @@ class TodoDependencies({
   /// that a report can name the release; none in tests that don't say.
   final ({String version, int? build}) appVersion = (version: '', build: null),
 
-  /// Finds places for a task's location (ADR 0033, D32). The seam for the
-  /// instance's own search: [create] names it. Where there is none, the
-  /// picker says search isn't available and pins are placed by hand.
+  /// Finds places for a task's location (ADR 0033, D32), through the
+  /// instance. Where it has no search, the picker says so and pins are
+  /// placed by hand.
   final PlaceSearchGateway? places,
 
   /// The tile layer of the location picker's map; none in widget tests,
@@ -298,7 +298,9 @@ class TodoDependencies({
       ),
       speech: DeviceSpeechInput(),
       appVersion: (version: device.appVersion, build: device.appBuild),
-      places: _publicPhoton ? PublicPhotonGateway() : null,
+      places: _publicPhoton
+          ? PublicPhotonGateway()
+          : InstancePlaceSearch.of(client),
       mapTiles: vectorTiles,
       sourceCodeUrl: () async =>
           (await client.modules.base.instance.basics()).sourceCodeUrl,
@@ -496,8 +498,9 @@ class TodoDevice({
   }
 }
 
-/// Whether this build searches on komoot's public Photon (ADR 0033, D32):
-/// a debug build asked to alone, until the instance searches.
+/// Whether this build searches on komoot's public Photon (ADR 0033, D32),
+/// not the instance's: a debug build asked to alone, for an instance without
+/// one.
 const _publicPhoton = kDebugMode && bool.fromEnvironment('TODO_PUBLIC_PHOTON');
 
 /// The system's notifications, or none where they don't start (a desktop

apps/todo/halkyon_todo_flutter/lib/src/feature/location/data/place_search_gateway.dart

@@ -1,12 +1,17 @@
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:halkyon_todo_client/halkyon_todo_client.dart' as protocol;
 import 'package:halkyon_todo_flutter/src/feature/location/data/location_reminder_gateway.dart';
 import 'package:halkyon_todo_flutter/src/feature/location/model/task_location.dart';
 
 /// Finds places (ADR 0033, D32): by what people know, a city or district and
 /// a name (`Lindau EDEKA`), not an address.
 abstract interface class PlaceSearchGateway() {
+  /// Whether it searches at all; false where the instance has no Photon or
+  /// can't be asked, so that the picker says so.
+  Future<bool> offered();
+
   /// The places [query] finds, those [near] first, named in [language].
   Future<List<TaskLocation>> search(
     String query, {
@@ -18,6 +23,64 @@ abstract interface class PlaceSearchGateway() {
   Future<TaskLocation?> at(LatLon point, {String? language});
 }
 
+/// The instance's search (D32), on Todo's server (`search`), which leaves
+/// out what is no place to go itself. It names no point on the map: a pin
+/// placed by hand stays unnamed.
+class InstancePlaceSearch({
+  required final Future<bool> Function() asked,
+  required final Future<List<protocol.Place>> Function(
+    String query,
+    protocol.PlacePoint? near,
+    String? language,
+  )
+  find,
+}) implements PlaceSearchGateway {
+  factory of(protocol.Client client) => InstancePlaceSearch(
+    asked: client.search.offered,
+    find: (query, near, language) =>
+        client.search.places(query, near: near, language: language),
+  );
+
+  @override
+  Future<bool> offered() async {
+    try {
+      return await asked();
+    } on Object {
+      return false;
+    }
+  }
+
+  @override
+  Future<List<TaskLocation>> search(
+    String query, {
+    LatLon? near,
+    String? language,
+  }) async {
+    final places = await find(
+      query,
+      switch (near) {
+        final at? => protocol.PlacePoint(lat: at.lat, lon: at.lon),
+        null => null,
+      },
+      language,
+    );
+    return [
+      for (final place in places)
+        TaskLocation(
+          name: place.name,
+          lat: place.lat,
+          lon: place.lon,
+          address: place.detail ?? '',
+          osmType: place.osmType,
+          osmId: place.osmId,
+        ),
+    ];
+  }
+
+  @override
+  Future<TaskLocation?> at(LatLon point, {String? language}) async => null;
+}
+
 /// What a search leaves out: places of that kind beside the place itself
 /// (`EDEKA` the car park, the charging station at `Lidl Lindau`).
 const _beside = {'parking', 'parking_space', 'charging_station'};
@@ -63,6 +126,9 @@ TaskLocation? _place(Map<String, Object?> at, double lat, double lon) {
 class PublicPhotonGateway() implements PlaceSearchGateway {
   final _client = HttpClient();
 
+  @override
+  Future<bool> offered() async => true;
+
   Future<List<TaskLocation>> _get(Uri uri) async {
     final request = await _client.getUrl(uri);
     request.headers.set(HttpHeaders.userAgentHeader, 'halkyon-todo-debug/1.0');

apps/todo/halkyon_todo_flutter/lib/src/feature/location/widget/location_picker.dart

@@ -84,6 +84,7 @@ class _LocationPickerState() extends State<LocationPicker> {
   var _asked = 0;
   var _searching = false;
   var _failed = false;
+  var _offered = true;
   List<TaskLocation>? _results;
   LatLon? _position;
   TaskLocation? _picked;
@@ -93,6 +94,7 @@ class _LocationPickerState() extends State<LocationPicker> {
   @override
   void initState() {
     super.initState();
+    unawaited(_askOffered());
     _searchFocus.addListener(() => setState(() {}));
     unawaited(_locate());
     if (widget.query?.trim().isNotEmpty ?? false) {
@@ -161,6 +163,14 @@ class _LocationPickerState() extends State<LocationPicker> {
     return _position;
   }
 
+  /// Asks once whether there is a search, as the instance may have none.
+  Future<void> _askOffered() async {
+    final offered = await widget.places?.offered() ?? false;
+    if (mounted && !offered) {
+      setState(() => _offered = false);
+    }
+  }
+
   Future<void> _find(String text) async {
     final places = widget.places;
     if (places == null) {
@@ -297,7 +307,7 @@ class _LocationPickerState() extends State<LocationPicker> {
   Widget build(BuildContext context) {
     final l10n = AppLocalizations.of(context);
     final scheme = Theme.of(context).colorScheme;
-    final search = widget.places != null;
+    final search = widget.places != null && _offered;
     return Scaffold(
       appBar: AppBar(title: Text(l10n.locationAdd)),
       body: SafeArea(

apps/todo/halkyon_todo_flutter/test/feature/location/location_picker_test.dart

@@ -8,7 +8,8 @@ import 'package:halkyon_todo_flutter/src/feature/location/model/task_location.da
 import 'package:halkyon_todo_flutter/src/feature/location/widget/location_picker.dart';
 import 'package:material_ui/material_ui.dart';
 
-class _Places(final List<TaskLocation> found) implements PlaceSearchGateway {
+class _Places(final List<TaskLocation> found, {final bool isOffered = true})
+    implements PlaceSearchGateway {
   final asked = <String>[];
   LatLon? near;
 
@@ -25,6 +26,9 @@ class _Places(final List<TaskLocation> found) implements PlaceSearchGateway {
 
   @override
   Future<TaskLocation?> at(LatLon point, {String? language}) async => null;
+
+  @override
+  Future<bool> offered() async => isOffered;
 }
 
 /// The location picker (ADR 0033, D32), without tiles.
@@ -132,6 +136,21 @@ void main() {
     expect(find.byKey(locationMapKey), findsOneWidget);
   });
 
+  testWidgets('an instance without a search says so, the map stays', (
+    tester,
+  ) async {
+    await open(tester, places: _Places(const [], isOffered: false));
+    await tester.pump();
+    expect(find.byKey(locationSearchKey), findsNothing);
+    expect(
+      find.text(
+        "Search isn't available here. Move the map and tap to place a pin.",
+      ),
+      findsOneWidget,
+    );
+    expect(find.byKey(locationMapKey), findsOneWidget);
+  });
+
   testWidgets('recent places show before a search', (tester) async {
     await open(tester, places: _Places(const []), recents: const [aeschach]);
     expect(find.text('Recent'), findsOneWidget);

apps/todo/halkyon_todo_flutter/test/feature/location/place_search_test.dart

@@ -1,8 +1,72 @@
+import 'package:halkyon_todo_client/halkyon_todo_client.dart';
 import 'package:halkyon_todo_flutter/src/feature/location/data/place_search_gateway.dart';
 import 'package:test/test.dart';
 
 /// Replies as Photon's (ADR 0033, D32).
 void main() {
+  test("the instance's places keep their address and object", () async {
+    final gateway = InstancePlaceSearch(
+      asked: () async => true,
+      find: (query, near, language) async {
+        expect((query, near?.lat, language), ('Lindau EDEKA', 47.5, 'de'));
+        return [
+          Place(
+            name: 'EDEKA',
+            detail: 'Ludwig-Kick-Straße 1, Lindau',
+            kind: 'house',
+            osmType: 'N',
+            osmId: 7,
+            lat: 47.55,
+            lon: 9.7,
+          ),
+        ];
+      },
+    );
+    final [place] = await gateway.search(
+      'Lindau EDEKA',
+      near: (lat: 47.5, lon: 9.7),
+      language: 'de',
+    );
+    expect(place.address, 'Ludwig-Kick-Straße 1, Lindau');
+    expect((place.lat, place.lon), (47.55, 9.7));
+    expect((place.osmType, place.osmId), ('N', 7));
+  });
+
+  test('a place without a detail has no address', () async {
+    final gateway = InstancePlaceSearch(
+      asked: () async => true,
+      find: (_, _, _) async => [
+        Place(name: 'Lindau', kind: 'city', lat: 47.55, lon: 9.7),
+      ],
+    );
+    final [place] = await gateway.search('Lindau');
+    expect(place.address, '');
+  });
+
+  test("an instance that can't be asked offers no search", () async {
+    final gateway = InstancePlaceSearch(
+      asked: () async => throw Exception('offline'),
+      find: (_, _, _) async => const [],
+    );
+    expect(await gateway.offered(), isFalse);
+  });
+
+  test('a refusal reaches the picker, which says the search failed', () {
+    final gateway = InstancePlaceSearch(
+      asked: () async => true,
+      find: (_, _, _) async => throw SearchRefused(reason: 'unreachable'),
+    );
+    expect(gateway.search('Lindau'), throwsA(isA<SearchRefused>()));
+  });
+
+  test('a point on the map has no name from the instance', () async {
+    final gateway = InstancePlaceSearch(
+      asked: () async => true,
+      find: (_, _, _) async => const [],
+    );
+    expect(await gateway.at((lat: 47.5, lon: 9.7)), isNull);
+  });
+
   Map<String, Object?> feature(
     Map<String, Object?> properties, {
     List<num> at = const [9.70, 47.55],