Add support for jumping to event links (#103)

Fixes #78.

Reviewed-on: #103

lib/helpers/extensions/build_event_options.dart

@@ -202,7 +202,7 @@ extension BuildEventOptions on Event {
           await Clipboard.setData(
             ClipboardData(
               text:
-                  "matrix:roomid/${room.metadata?.id.substring(1)}/e/$eventId$vias",
+                  "matrix:roomid/${room.metadata?.id.substring(1)}/e/${eventId.substring(1)}$vias",
             ),
           );
         },

lib/helpers/extensions/focus_room.dart

@@ -1,27 +1,28 @@
 import "package:collection/collection.dart";
 import "package:flutter_riverpod/experimental/mutation.dart";
+import "package:nexus/controllers/contextual_event.dart";
 import "package:nexus/controllers/key.dart";
 import "package:nexus/controllers/spaces.dart";
 import "package:nexus/models/space.dart";
 
 extension FocusRoom on MutationTarget {
-  Future<bool> focusRoom(String id) async {
+  Future<bool> focusRoom(String roomId, [int? eventRowId]) async {
     final spaces = container.read(SpacesController.provider);
 
-    if (spaces.firstWhereOrNull((space) => space.id == id) case Space _?) {
+    if (spaces.firstWhereOrNull((space) => space.id == roomId) case Space _?) {
       await container
           .read(KeyController.provider(KeyController.spaceKey).notifier)
-          .set(id);
+          .set(roomId);
       return true;
     }
 
     final parent = spaces.firstWhereOrNull(
       (space) =>
-          space.children.any((room) => room.metadata?.id == id) ||
+          space.children.any((room) => room.metadata?.id == roomId) ||
           space.subSpaces.any(
             (sub) =>
-                sub.room.metadata?.id == id ||
-                sub.children.any((room) => room.metadata?.id == id),
+                sub.room.metadata?.id == roomId ||
+                sub.children.any((room) => room.metadata?.id == roomId),
           ),
     );
     if (parent == null) return false;
@@ -32,7 +33,13 @@ extension FocusRoom on MutationTarget {
 
     await container
         .read(KeyController.provider(KeyController.roomKey).notifier)
-        .set(id);
+        .set(roomId);
+
+    if (eventRowId != null) {
+      container
+          .read(ContextualEventController.provider(roomId).notifier)
+          .set(eventRowId);
+    }
 
     return true;
   }

lib/helpers/extensions/get_link_info.dart

@@ -0,0 +1,70 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+
+/// A parsed Matrix link.
+///
+/// [identifier] is the room ID, room alias or user ID (e.g. "#room:matrix.org"),
+/// [eventId] is set for event permalinks (e.g. "$abc123"), and [via] holds any
+/// `via` servers from the link.
+typedef LinkInfo = ({String identifier, String? eventId, IList<String> via});
+
+extension GetLinkInfo on String {
+  /// Parses this string as a Matrix link.
+  ///
+  /// Supports:
+  /// - https://matrix.to/#/{id}[/{eventId}][?via=...]
+  /// - matrix:roomid/{id}[/e/{eventId}][?via=...]
+  /// - matrix:r/{alias}[/e/{eventId}][?via=...]
+  /// - matrix:u/{userId}
+  ///
+  /// Returns null if this is not a Matrix link.
+  LinkInfo? get linkInfo {
+    final uri = Uri.tryParse(trim());
+    if (uri == null) return null;
+
+    if ((uri.scheme == "http" || uri.scheme == "https") &&
+        uri.host == "matrix.to") {
+      // matrix.to keeps everything, including the query, in the fragment,
+      // so parse the fragment as its own URI.
+      final inner = Uri.tryParse(uri.fragment);
+      final segments = inner?.pathSegments.where((s) => s.isNotEmpty).toList();
+      if (inner == null || segments == null || segments.isEmpty) return null;
+
+      return (
+        identifier: segments.first,
+        eventId: segments.length > 1 && segments[1].startsWith(r"$")
+            ? segments[1]
+            : null,
+        via: .new(inner.queryParametersAll["via"] ?? []),
+      );
+    }
+
+    if (uri.scheme == "matrix") {
+      final segments = uri.pathSegments;
+      if (segments.length < 2 || segments[1].isEmpty) return null;
+
+      final sigil = switch (segments[0].toLowerCase()) {
+        "r" => "#",
+        "roomid" => "!",
+        "u" => "@",
+        _ => null,
+      };
+      if (sigil == null) return null;
+
+      // Event segment is "e/{eventId}" (without the "$" sigil) and is
+      // only valid on room links.
+      final hasEvent =
+          sigil != "@" &&
+          segments.length >= 4 &&
+          segments[2].toLowerCase() == "e" &&
+          segments[3].isNotEmpty;
+
+      return (
+        identifier: "$sigil${segments[1]}",
+        eventId: hasEvent ? "\$${segments[3]}" : null,
+        via: .new(uri.queryParametersAll["via"] ?? []),
+      );
+    }
+
+    return null;
+  }
+}

lib/helpers/extensions/link_to_mention.dart

@@ -1,51 +0,0 @@
-import "package:fast_immutable_collections/fast_immutable_collections.dart";
-
-extension LinkToMention on String {
-  /// Extracts a Matrix identifier from this string.
-  ///
-  /// Supports:
-  /// - https://matrix.to/#/...
-  /// - matrix:roomid/...
-  /// - matrix:r/...
-  /// - matrix:u/...
-  ///
-  /// Returns the decoded identifier (e.g. "#room:matrix.org")
-  /// or null if this is not a Matrix link.
-  /// TODO: Needs to be reworked to handle event links. Might be worth just rewriting, I don't like this code.
-  String? get mention {
-    final trimmed = trim();
-
-    final matrixTo = RegExp(
-      r"^https?://matrix\.to/#/(.[^/?#]+)",
-      caseSensitive: false,
-    );
-
-    final matrixToMatch = matrixTo.firstMatch(trimmed);
-    if (matrixToMatch != null) {
-      return Uri.decodeComponent(matrixToMatch.group(1)!);
-    }
-
-    if (trimmed.toLowerCase().startsWith("matrix:")) {
-      try {
-        final uri = Uri.parse(trimmed);
-
-        if (uri.pathSegments.isNotEmpty) {
-          final identifier = uri.pathSegments.last;
-          if (identifier.isNotEmpty) {
-            return "${switch (uri.pathSegments.firstOrNull) {
-              "r" => "#",
-              "roomid" => "!",
-              "u" => "@",
-              _ => "",
-            }}${Uri.decodeComponent(identifier)}";
-          }
-        }
-      } catch (_) {}
-    }
-
-    return null;
-  }
-
-  IList<String> get via =>
-      .new(Uri.tryParse(replaceAll("/#", ""))?.queryParametersAll["via"] ?? []);
-}