tab tree initial scroll

app/lib/features/geckoview/features/browser/presentation/dialogs/tab_tree.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:fast_equatable/fast_equatable.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
@@ -11,6 +12,55 @@ import 'package:weblibre/features/geckoview/domain/controllers/bottom_sheet.dart
 import 'package:weblibre/features/geckoview/domain/providers/selected_tab.dart';
 import 'package:weblibre/features/geckoview/features/browser/presentation/widgets/tab_preview.dart';
 import 'package:weblibre/features/geckoview/features/tabs/domain/providers.dart';
+import 'package:weblibre/utils/ui_helper.dart';
+
+class BuchheimWalkerAlgorithmWithFocus extends BuchheimWalkerAlgorithm {
+  bool _hasScrolled = false;
+
+  final Size childSize;
+  final TransformationController transforamtionController;
+  final dynamic initialNodeId;
+
+  BuchheimWalkerAlgorithmWithFocus(
+    super.configuration,
+    super.renderer, {
+    required this.childSize,
+    required this.transforamtionController,
+    this.initialNodeId,
+  });
+
+  @override
+  void setFocusedNode(Node node) {
+    final scale = transforamtionController.value.getMaxScaleOnAxis();
+    final newPosition =
+        (node.position - Offset(childSize.width / 2, childSize.height / 2)) *
+        scale;
+
+    transforamtionController.value = transforamtionController.value.clone()
+      ..setTranslation(Vector3(-newPosition.dx, -newPosition.dy, 0));
+  }
+
+  @override
+  Size run(Graph? graph, double shiftX, double shiftY) {
+    final size = super.run(graph, shiftX, shiftY);
+
+    if (initialNodeId != null && !_hasScrolled) {
+      final node = graph?.nodes.firstWhereOrNull(
+        (element) => element.key?.value == initialNodeId,
+      );
+
+      if (node != null && node.position != Offset.zero) {
+        WidgetsBinding.instance.addPostFrameCallback((_) {
+          setFocusedNode(node);
+        });
+
+        _hasScrolled = true;
+      }
+    }
+
+    return size;
+  }
+}
 
 class TabTreeDialog extends HookConsumerWidget {
   final String tabId;
@@ -26,22 +76,11 @@ class TabTreeDialog extends HookConsumerWidget {
   Widget build(BuildContext context, WidgetRef ref) {
     final transforamtionController = useTransformationController();
 
-    final builder = useMemoized(() {
-      final config = BuchheimWalkerConfiguration()
-        ..siblingSeparation = 100
-        ..levelSeparation = 150
-        ..subtreeSeparation = 150
-        ..orientation = BuchheimWalkerConfiguration.ORIENTATION_TOP_BOTTOM;
-
-      return BuchheimWalkerAlgorithm(config, TreeEdgeRenderer(config));
-    });
-
     final selectedTabId = ref.watch(selectedTabProvider);
     final tabs = ref.watch(tabDescendantsProvider(tabId));
 
     final graph = useMemoized(() {
-      final graph = Graph();
-      graph.isTree = true;
+      final graph = Graph()..isTree = true;
 
       if (tabs.hasValue) {
         for (final MapEntry(:key, :value) in tabs.valueOrNull!.entries) {
@@ -55,7 +94,23 @@ class TabTreeDialog extends HookConsumerWidget {
       }
 
       return graph;
-    }, [EquatableValue(tabs.valueOrNull)]);
+    }, [EquatableValue(tabs.valueOrNull), selectedTabId]);
+
+    final graphAlgo = useMemoized(() {
+      final config = BuchheimWalkerConfiguration()
+        ..siblingSeparation = 100
+        ..levelSeparation = 150
+        ..subtreeSeparation = 150
+        ..orientation = BuchheimWalkerConfiguration.ORIENTATION_TOP_BOTTOM;
+
+      return BuchheimWalkerAlgorithmWithFocus(
+        config,
+        TreeEdgeRenderer(config),
+        childSize: childSize,
+        transforamtionController: transforamtionController,
+        initialNodeId: selectedTabId,
+      );
+    }, [selectedTabId]);
 
     return Dialog.fullscreen(
       child: Scaffold(
@@ -72,17 +127,18 @@ class TabTreeDialog extends HookConsumerWidget {
         floatingActionButton: FloatingActionButton(
           child: const Icon(MdiIcons.target),
           onPressed: () {
-            final node = graph.getNodeUsingId(selectedTabId);
-            final scale = transforamtionController.value.getMaxScaleOnAxis();
-            final newPosition =
-                (node.position -
-                    Offset(childSize.width / 2, childSize.height / 2)) *
-                scale;
+            final node = graph.nodes.firstWhereOrNull(
+              (element) => element.key?.value == selectedTabId,
+            );
 
-            transforamtionController.value =
-                transforamtionController.value.clone()..setTranslation(
-                  Vector3(-newPosition.dx, -newPosition.dy, 0),
-                );
+            if (node != null) {
+              graphAlgo.setFocusedNode(node);
+            } else {
+              showErrorMessage(
+                context,
+                'The current tab is not part of this tree',
+              );
+            }
           },
         ),
         extendBodyBehindAppBar: true,
@@ -98,7 +154,7 @@ class TabTreeDialog extends HookConsumerWidget {
               replacement: const Bone.square(),
               child: GraphView(
                 graph: graph,
-                algorithm: builder,
+                algorithm: graphAlgo,
                 paint: Paint()
                   ..color = Theme.of(context).colorScheme.outline
                   ..strokeWidth = 1