add thread support

Fixes #129

lib/widgets/renderers/event.dart

@@ -44,6 +44,7 @@ import "package:nexus/widgets/renderers/power_levels_diff.dart";
 import "package:nexus/widgets/renderers/pinned_events_diff.dart";
 import "package:nexus/widgets/renderers/server_acl_diff.dart";
 import "package:nexus/widgets/swipe_to_reply.dart";
+import "package:nexus/widgets/thread_summary.dart";
 import "package:nexus/widgets/timestamp.dart";
 import "package:nexus/widgets/user_span.dart";
 
@@ -54,6 +55,7 @@ class const EventRenderer(
   final bool textOnly = false,
   final int? maxLines,
   final JumpToEvent? jumpToEvent,
+  final void Function(String threadRoot)? onOpenThread,
   final IList<PopupMenuEntry> Function(Event event)? getEventOptions,
 
   /// If set, events can be swiped, calling this
@@ -106,18 +108,18 @@ class const EventRenderer(
               (settings.hideMembershipEvents, settings.hideServerAclEvents),
         );
 
-    // Knocks and their outcomes stay visible, as moderators need to act on them
-    if (hideMembershipEvents &&
-        event.content is MembershipContent &&
-        ![event.content, event.previousContent].any(
-          (content) => content is MembershipContent && content.status == .knock,
-        )) {
-      return SizedBox.shrink();
-    }
+    final isHidden =
+        // Knocks and their outcomes stay visible, as moderators need to act
+        // on them
+        (hideMembershipEvents &&
+            event.content is MembershipContent &&
+            ![event.content, event.previousContent].any(
+              (content) =>
+                  content is MembershipContent && content.status == .knock,
+            )) ||
+        (hideServerAclEvents && event.content is ServerACLContent);
 
-    if (hideServerAclEvents && event.content is ServerACLContent) {
-      return SizedBox.shrink();
-    }
+    if (isHidden && !textOnly) return SizedBox.shrink();
 
     final isGrouped =
         (previousEvent?.isShownAsMessage ?? false) &&
@@ -170,15 +172,18 @@ class const EventRenderer(
             onTapReply: jumpToEvent == null
                 ? null
                 : () async {
-                    final replyEvent = await ref.read(
+                    final replyRowId = await ref.read(
                       EventController.provider(
                         .new(roomId: roomId, eventId: event.replyTo!),
                       ).future,
                     );
-                    if (replyEvent != null) {
-                      await jumpToEvent!(replyEvent.rowId);
+                    if (replyRowId != null) {
+                      await jumpToEvent!(replyRowId);
                     }
                   },
+            onTapThread: onOpenThread == null
+                ? null
+                : () => onOpenThread!(event.eventId),
             isGrouped: isGrouped,
             maxLines: maxLines,
             textOnly: textOnly,
@@ -236,11 +241,11 @@ class const EventRenderer(
                     ),
                   )
                   .value) {
-                final poll?
+                final pollRowId?
                     when ref
                             .watch(
                               PollVotesController.provider(
-                                .new(roomId: roomId, eventRowId: poll.rowId),
+                                .new(roomId: roomId, eventRowId: pollRowId),
                               ),
                             )
                             .value
@@ -430,6 +435,15 @@ class const EventRenderer(
             globalPosition: details.globalPosition,
           );
 
+    final threadSummary = switch (onOpenThread) {
+      final onOpenThread? when !textOnly && child is! MessageRenderer =>
+        ThreadSummary(event, onTap: () => onOpenThread(event.eventId)),
+      _ => null,
+    };
+    final belowIndent = child is MessageRenderer
+        ? 4.0
+        : 8 + GenericEventRenderer.textIndent(context);
+
     return Column(
       crossAxisAlignment: .start,
       children: [
@@ -492,6 +506,7 @@ class const EventRenderer(
 
             ...[
               if (child is! MessageRenderer) ReactionRow(event),
+              ?threadSummary,
 
               // Outside the message itself, so it doesn't move when swiped
               if (readReceiptsChat case final chat? when event.isShownAsMessage)
@@ -523,6 +538,7 @@ class const EventRenderer(
                               RoomChatController.provider((
                                 roomId: roomId,
                                 contextualEvent: null,
+                                threadRoot: null,
                               )).notifier,
                             )
                             .hideClientSticky(event.rowId),
@@ -530,13 +546,20 @@ class const EventRenderer(
                     ],
                   ),
                 ),
-            ].map((child) => Padding(padding: .only(left: 4), child: child)),
+            ].map(
+              (child) => Padding(
+                padding: .only(left: belowIndent),
+                child: child,
+              ),
+            ),
           ]
         else if (textOnly)
           Text(
             event.redactedBy == null ? "Unknown event type" : "Redacted event",
             style: errorStyle,
-          ),
+          )
+        else if (threadSummary != null)
+          Padding(padding: .only(left: 4), child: threadSummary),
       ],
     );
   }

lib/widgets/renderers/generic_event.dart

@@ -13,6 +13,14 @@ class const GenericEventRenderer(
   final List<Widget> details = const [],
   super.key,
 }) extends StatelessWidget {
+  static const _iconPadding = 4.0;
+  static const _spacing = 8.0;
+
+  /// How far the text is from the start, past the icon, so what's shown under
+  /// the event can line up with it.
+  static double textIndent(BuildContext context) =>
+      (IconTheme.of(context).size ?? 24) + _iconPadding * 2 + _spacing;
+
   @override
   Widget build(BuildContext context) {
     // Only previewing the event, so it should stay short
@@ -22,12 +30,15 @@ class const GenericEventRenderer(
     return Padding(
       padding: .symmetric(vertical: 4),
       child: Row(
-        spacing: 8,
+        spacing: _spacing,
         mainAxisSize: .min,
         // At the top, by the text, rather than the middle of any details
         crossAxisAlignment: .start,
         children: [
-          Padding(padding: .symmetric(horizontal: 4), child: Icon(icon)),
+          Padding(
+            padding: .symmetric(horizontal: _iconPadding),
+            child: Icon(icon),
+          ),
           Flexible(
             child: Column(
               mainAxisSize: .min,

lib/widgets/renderers/message.dart

@@ -27,10 +27,15 @@ import "package:nexus/widgets/event_preview.dart";
 import "package:nexus/widgets/players/video.dart";
 import "package:nexus/widgets/players/audio.dart";
 import "package:nexus/widgets/renderers/poll.dart";
+import "package:nexus/widgets/thread_summary.dart";
 
 class const MessageRenderer(
   final Event event, {
   final VoidCallback? onTapReply,
+
+  /// If set, thread roots show a summary of their thread, calling this when
+  /// tapped.
+  final VoidCallback? onTapThread,
   final bool textOnly = false,
   final bool isGrouped = false,
   final int? maxLines,
@@ -255,9 +260,10 @@ class const MessageRenderer(
                                   ),
                                 )) {
                                   AsyncData(:final value?) ||
-                                  AsyncLoading(
-                                    :final value?,
-                                  ) => EventPreview(value),
+                                  AsyncLoading(:final value?) => EventPreview(
+                                    value,
+                                    roomId: event.roomId,
+                                  ),
                                   AsyncError _ => Text(
                                     "An error occurred while fetching the reply",
                                     style: errorStyle,
@@ -270,6 +276,8 @@ class const MessageRenderer(
                         ),
                       rendered,
                       if (!textOnly) ReactionRow(event),
+                      if (onTapThread case final onTapThread? when !textOnly)
+                        ThreadSummary(event, onTap: onTapThread),
                     ],
                   ),
                 ),

lib/widgets/renderers/pinned_events_diff.dart

@@ -2,6 +2,7 @@ import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:hooks_riverpod/hooks_riverpod.dart";
 import "package:material_ui/material_ui.dart";
 import "package:nexus/controllers/event.dart";
+import "package:nexus/controllers/rooms.dart";
 import "package:nexus/helpers/hooks/chat_scroll.dart";
 import "package:nexus/helpers/extensions/success_scheme.dart";
 import "package:nexus/models/content/message.dart";
@@ -54,17 +55,21 @@ class const PinnedEventsDiff(
               ),
             )) {
               // Keeps showing the event while it reloads
-              AsyncValue(value: final event?) => InkWell(
+              AsyncValue(value: final rowId?) => InkWell(
                 borderRadius: .circular(4),
                 hoverColor: color.withValues(alpha: 0.12),
-                onTap: jumpToEvent == null
-                    ? null
-                    : () => jumpToEvent!(event.rowId),
+                onTap: jumpToEvent == null ? null : () => jumpToEvent!(rowId),
                 child: Row(
                   mainAxisSize: .min,
                   children: [
                     // Other events already say who sent them
-                    if (event.content is MessageContent) ...[
+                    if (ref.watch(
+                          RoomsController.provider.select(
+                            (rooms) => rooms[roomId]?.events[rowId],
+                          ),
+                        )
+                        case final event?
+                        when event.content is MessageContent) ...[
                       MessageDisplayname(
                         event,
                         clickable: false,
@@ -81,8 +86,8 @@ class const PinnedEventsDiff(
                     Flexible(
                       child: IgnorePointer(
                         child: EventRenderer(
-                          event.rowId,
-                          roomId: event.roomId,
+                          rowId,
+                          roomId: roomId,
                           textOnly: true,
                           maxLines: 1,
                         ),

lib/widgets/renderers/poll.dart

@@ -66,6 +66,7 @@ class const PollRenderer(final Event event, final PollStart poll, {super.key})
     final notifier = RoomChatController.provider((
       roomId: event.roomId,
       contextualEvent: null,
+      threadRoot: null,
     )).notifier;
 
     Future<void> run(