add thread support

Fixes #129

lib/models/bot_command_draft.dart

@@ -2,6 +2,7 @@ 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/bot_command.dart";
+import "package:nexus/models/composer_params.dart";
 import "package:nexus/models/content/bot_command.dart";
 import "package:nexus/models/content/bot_command_description.dart";
 
@@ -10,7 +11,7 @@ part "bot_command_draft.freezed.dart";
 @Freezed(toJson: false, fromJson: false)
 class const BotCommandDraft({
   required final BotCommand command,
-  required final String roomId,
+  required final ComposerParams composer,
   final IMap<String, String> texts = const .empty(),
 
   // The servers to join rooms picked from suggestions through, by room ID
@@ -33,8 +34,9 @@ class const BotCommandDraft({
   BotParameter? get focusedParameter => command.description.parameters
       .firstWhereOrNull((parameter) => parameter.key == focused);
 
-  ({Object? value, String? error}) parse(BotParameter parameter) =>
-      parameter.schema.parseText(texts[parameter.key] ?? "", roomId: roomId);
+  ({Object? value, String? error}) parse(BotParameter parameter) => parameter
+      .schema
+      .parseText(texts[parameter.key] ?? "", roomId: composer.roomId);
 
   IMap<String, Object> get arguments => .fromEntries(
     shown

lib/models/composer_params.dart

@@ -0,0 +1 @@
+typedef ComposerParams = ({String roomId, String? threadRoot});

lib/models/event.dart

@@ -29,6 +29,8 @@ class const Event({
   final String? sendError,
   final IMap<String, int> reactions = const .empty(),
   @JsonKey(name: "last_edit_rowid") final int lastEditRowId = 0,
+  final int threadCount = 0,
+  @JsonKey(name: "thread_latest_rowid") final int threadLatestRowId = 0,
   final UnreadType? unreadType,
   final Profile? pmp,
   required final Content content,
@@ -36,6 +38,8 @@ class const Event({
 }) with _$Event {
   Map<String, Object?> toJson() => _$EventToJson(this);
 
+  String? get threadRoot => relationType == "m.thread" ? relatesTo : null;
+
   static String typeJsonFromJson(Map<dynamic, dynamic> json, _) =>
       json["decrypted_type"] ?? json["type"];
 
@@ -47,7 +51,15 @@ class const Event({
 
   static String? replyToFromJson(Map<dynamic, dynamic> json) {
     try {
-      return json["m.relates_to"]?["m.in_reply_to"]?["event_id"];
+      final relatesTo = json["m.relates_to"];
+
+      // Thread fallbacks are only for clients without thread support
+      if (relatesTo?["rel_type"] == "m.thread" &&
+          relatesTo?["is_falling_back"] == true) {
+        return null;
+      }
+
+      return relatesTo?["m.in_reply_to"]?["event_id"];
     } catch (_) {
       return null;
     }

lib/models/requests/get_threads.dart

@@ -0,0 +1,17 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+part "get_threads.freezed.dart";
+part "get_threads.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const GetThreadsRequest({
+  required final String roomId,
+  final String? since,
+  final int limit = 20,
+}) with _$GetThreadsRequest {
+  Map<String, Object?> toJson() => _$GetThreadsRequestToJson(this);
+
+  factory GetThreadsRequest.fromJson(Map<String, Object?> json) =>
+      _$GetThreadsRequestFromJson(json);
+}

lib/models/requests/send_event.dart

@@ -14,7 +14,7 @@ class const SendEventRequest({
   // Merged into the content by toJson, as gomuks doesn't take these
   @JsonKey(includeToJson: false) final String? relatesTo,
   @JsonKey(includeToJson: false) final String? relationType,
-  @JsonKey(includeToJson: false) final String? replyTo,
+  @JsonKey(includeToJson: false) final Relation? reply,
   @JsonKey(includeToJson: false) final Mentions? mentions,
   final bool synchronous = false,
   final bool disableEncryption = false,
@@ -27,14 +27,14 @@ class const SendEventRequest({
       "content": {
         ...content,
         "m.mentions": ?mentions?.toJson(),
-        if (relatesTo != null || replyTo != null)
+        if (relatesTo != null || reply != null)
           "m.relates_to": {
             ...((content["m.relates_to"] as Map<String, dynamic>?) ?? {}),
             if (relatesTo != null) ...{
               "event_id": relatesTo,
               "rel_type": relationType,
             },
-            if (replyTo != null) "m.in_reply_to": {"event_id": replyTo},
+            ...?reply?.toJson(),
           },
       },
     };

lib/models/requests/send_message.dart

@@ -38,11 +38,18 @@ class const Mentions({
 class const Relation({
   required final String eventId,
   required final RelationType relationType,
+  final String? threadRoot,
+  final bool isFallingBack = false,
 }) with _$Relation {
   Map<String, dynamic> toJson() {
     switch (relationType) {
       case RelationType.reply:
         return {
+          if (threadRoot != null) ...{
+            "rel_type": "m.thread",
+            "event_id": threadRoot,
+            "is_falling_back": isFallingBack,
+          },
           "m.in_reply_to": {"event_id": eventId},
         };