add poll support

Fixes #130

lib/models/configs/event.dart

@@ -0,0 +1,16 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+part "event.freezed.dart";
+part "event.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const EventConfig({
+  required final String roomId,
+  required final int eventRowId,
+}) with _$EventConfig {
+  Map<String, Object?> toJson() => _$EventConfigToJson(this);
+
+  factory EventConfig.fromJson(Map<String, Object?> json) =>
+      _$EventConfigFromJson(json);
+}

lib/models/configs/reactions.dart

@@ -1,16 +0,0 @@
-import "package:freezed_annotation/freezed_annotation.dart";
-
-part "reactions.freezed.dart";
-part "reactions.g.dart";
-
-@Freezed(toJson: false, fromJson: false)
-@JsonSerializable()
-class const ReactionsConfig({
-  required final String roomId,
-  required final int eventRowId,
-}) with _$ReactionsConfig {
-  Map<String, Object?> toJson() => _$ReactionsConfigToJson(this);
-
-  factory ReactionsConfig.fromJson(Map<String, Object?> json) =>
-      _$ReactionsConfigFromJson(json);
-}

lib/models/content/content.dart

@@ -17,6 +17,9 @@ import "package:nexus/models/content/topic.dart";
 import "package:nexus/models/content/sticker.dart";
 import "package:nexus/models/content/history_visibility.dart";
 import "package:nexus/models/content/image_pack.dart";
+import "package:nexus/models/content/poll_end.dart";
+import "package:nexus/models/content/poll_response.dart";
+import "package:nexus/models/content/poll_start.dart";
 
 class const Content({final String? parseError, final StackTrace? stackTrace}) {
   factory Content.fromJson(Map<String, dynamic> json) => const Content();
@@ -64,5 +67,11 @@ enum EventType(
   pinnedEvents("m.room.pinned_events", PinnedEventsContent.fromJson),
   imagePack("m.room.image_pack", ImagePackContent.fromJson),
   legacyImagePack("im.ponies.room_emotes", ImagePackContent.fromJson),
+  pollStart("org.matrix.msc3381.poll.start", PollStartContent.fromJson),
+  pollResponse(
+    "org.matrix.msc3381.poll.response",
+    PollResponseContent.fromJson,
+  ),
+  pollEnd("org.matrix.msc3381.poll.end", PollEndContent.fromJson),
   message("m.room.message", MessageContent.fromJson),
 }

lib/models/content/poll_end.dart

@@ -0,0 +1,12 @@
+import "package:nexus/models/content/content.dart";
+
+class const PollEndContent() extends Content {
+  factory PollEndContent.fromJson(Map<String, dynamic> json) =>
+      const PollEndContent();
+
+  @override
+  Map<String, dynamic> toJson() => {
+    "org.matrix.msc3381.poll.end": {},
+    "org.matrix.msc1767.text": "Ended the poll",
+  };
+}

lib/models/content/poll_response.dart

@@ -0,0 +1,23 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/content/content.dart";
+part "poll_response.freezed.dart";
+part "poll_response.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const PollResponseContent({
+  @JsonKey(readValue: PollResponseContent.answersFromJson)
+  final IList<String> answers = const .empty(),
+}) extends Content with _$PollResponseContent {
+  static List<dynamic>? answersFromJson(Map<dynamic, dynamic> json, _) =>
+      json["org.matrix.msc3381.poll.response"]?["answers"];
+
+  @override
+  Map<String, Object?> toJson() => {
+    "org.matrix.msc3381.poll.response": {"answers": answers.toList()},
+  };
+
+  factory PollResponseContent.fromJson(Map<String, Object?> json) =>
+      _$PollResponseContentFromJson(json);
+}

lib/models/content/poll_start.dart

@@ -0,0 +1,90 @@
+import "dart:math";
+
+import "package:collection/collection.dart";
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/content/content.dart";
+part "poll_start.freezed.dart";
+part "poll_start.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const PollStartContent({
+  @JsonKey(name: "org.matrix.msc3381.poll.start") required final PollStart poll,
+}) extends Content with _$PollStartContent {
+  @override
+  Map<String, Object?> toJson() => {
+    "org.matrix.msc3381.poll.start": poll.toJson(),
+    // Shown by clients without poll support
+    "org.matrix.msc1767.text": [
+      poll.question,
+      ...poll.answers.mapIndexed(
+        (index, answer) => "${index + 1}. ${answer.text}",
+      ),
+    ].join("\n"),
+  };
+
+  factory PollStartContent.fromJson(Map<String, Object?> json) =>
+      _$PollStartContentFromJson(json);
+}
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const PollStart({
+  @JsonKey(readValue: PollStart.questionFromJson) final String question = "",
+  final int? maxSelections,
+  @JsonKey(readValue: PollStart.answersFromJson)
+  final IList<PollAnswer> answers = const .empty(),
+}) with _$PollStart {
+  static const maxAnswers = 20;
+
+  static String? extensibleTextFromJson(Object? json) => switch (json) {
+    {"org.matrix.msc1767.text": final String text} => text,
+    {"body": final String body} => body,
+    {"org.matrix.msc1767.message": final List message} =>
+      message
+          .whereType<Map>()
+          .map((part) => part["body"])
+          .whereType<String>()
+          .firstOrNull,
+    _ => null,
+  };
+
+  static String? questionFromJson(Map<dynamic, dynamic> json, String key) =>
+      PollStart.extensibleTextFromJson(json[key]);
+
+  static List<dynamic>? answersFromJson(
+    Map<dynamic, dynamic> json,
+    String key,
+  ) => (json[key] as List?)?.take(maxAnswers).toList();
+
+  /// [maxSelections], defaulting to 1, and at most the number of answers
+  int get selectionLimit =>
+      (maxSelections ?? 1).clamp(1, max(answers.length, 1));
+
+  Map<String, Object?> toJson() => {
+    ..._$PollStartToJson(this),
+    // We don't allow undisclosed polls as they make no sense
+    "kind": "org.matrix.msc3381.poll.disclosed",
+    "question": {"org.matrix.msc1767.text": question},
+    "answers": answers.map((answer) => answer.toJson()).toList(),
+  };
+
+  factory PollStart.fromJson(Map<String, Object?> json) =>
+      _$PollStartFromJson(json);
+}
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const PollAnswer({
+  required final String id,
+  @JsonKey(readValue: PollAnswer.textFromJson) final String text = "",
+}) with _$PollAnswer {
+  static String? textFromJson(Map<dynamic, dynamic> json, _) =>
+      PollStart.extensibleTextFromJson(json);
+
+  Map<String, Object?> toJson() => {"id": id, "org.matrix.msc1767.text": text};
+
+  factory PollAnswer.fromJson(Map<String, Object?> json) =>
+      _$PollAnswerFromJson(json);
+}

lib/models/poll_votes.dart

@@ -0,0 +1,25 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+
+class const PollVotes({
+  /// Each user's answers, by user ID
+  final IMap<String, IList<String>> votes = const .empty(),
+  final String? endEventId,
+  final int undecryptable = 0,
+}) {
+  bool get hasEnded => endEventId != null;
+
+  IMap<String, IList<String>> get votersByAnswer => votes.entries.fold(
+    const .empty(),
+    (acc, entry) => entry.value.fold(
+      acc,
+      (acc, answer) => acc.update(
+        answer,
+        (voters) => voters.add(entry.key),
+        ifAbsent: () => .new([entry.key]),
+      ),
+    ),
+  );
+
+  int get voterCount =>
+      votes.values.where((answers) => answers.isNotEmpty).length;
+}

lib/models/room.dart

@@ -24,6 +24,14 @@ class const Room({
   @JsonKey(fromJson: Room.eventsJsonToIMap)
   final IMap<int, Event> events = const .empty(),
 
+  /// [relations] is an IMap of event ID to the eventRowIds relating to it
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  final IMap<String, ISet<int>> relations = const .empty(),
+
+  /// [eventIds] is an IMap of event ID to eventRowId
+  @JsonKey(includeFromJson: false, includeToJson: false)
+  final IMap<String, int> eventIds = const .empty(),
+
   final bool reset = false,
   @JsonKey(includeFromJson: false, includeToJson: false)
   final bool resetClientSticky = false,

lib/models/room_power_levels.dart

@@ -8,4 +8,7 @@ class const RoomPowerLevels({
   double levelOf(String userId) => creators.contains(userId)
       ? double.infinity
       : (content.users[userId] ?? content.usersDefault).toDouble();
+
+  bool canEndPoll(String userId, {required String pollSender}) =>
+      userId == pollSender || levelOf(userId) >= content.redact;
 }