feat: make analysis tree view more "tree like"

lib/src/model/analysis/analysis_controller.dart

@@ -265,16 +265,24 @@ class AnalysisController extends _$AnalysisController {
     _setPath(path);
   }
 
-  void showAllVariations(UciPath path) {
-    final parent = _root.parentAt(path);
-    for (final node in parent.children) {
-      node.isHidden = false;
+  void expandVariations(UciPath path) {
+    final node = _root.nodeAt(path);
+    for (final child in node.children) {
+      child.isHidden = false;
+      for (final grandChild in child.children) {
+        grandChild.isHidden = false;
+      }
     }
     state = state.copyWith(root: _root.view);
   }
 
-  void hideVariation(UciPath path) {
-    _root.hideVariationAt(path);
+  void collapseVariations(UciPath path) {
+    final node = _root.parentAt(path);
+
+    for (final child in node.children) {
+      child.isHidden = true;
+    }
+
     state = state.copyWith(root: _root.view);
   }
 

lib/src/model/common/node.dart

@@ -234,22 +234,6 @@ abstract class Node {
     parentAt(path).children.removeWhere((child) => child.id == path.last);
   }
 
-  /// Hides the variation from the node at the given path.
-  void hideVariationAt(UciPath path) {
-    final nodes = nodesOn(path).toList();
-    for (int i = nodes.length - 2; i >= 0; i--) {
-      final node = nodes[i + 1];
-      final parent = nodes[i];
-      if (node is Branch && parent.children.length > 1) {
-        for (final child in parent.children) {
-          if (child.id == node.id) {
-            child.isHidden = true;
-          }
-        }
-      }
-    }
-  }
-
   /// Promotes the node at the given path.
   void promoteAt(UciPath path, {required bool toMainline}) {
     final nodes = nodesOn(path).toList();
@@ -484,8 +468,8 @@ class Root extends Node {
       position: PgnGame.startingPosition(game.headers),
     );
 
-    final List<({PgnNode<PgnNodeData> from, Node to})> stack = [
-      (from: game.moves, to: root),
+    final List<({PgnNode<PgnNodeData> from, Node to, int nesting})> stack = [
+      (from: game.moves, to: root, nesting: 1),
     ];
 
     while (stack.isNotEmpty) {
@@ -503,7 +487,7 @@ class Root extends Node {
           final branch = Branch(
             sanMove: SanMove(childFrom.data.san, move),
             position: newPos,
-            isHidden: hideVariations && childIdx > 0,
+            isHidden: frame.nesting > 2 || hideVariations && childIdx > 0,
             lichessAnalysisComments:
                 isLichessAnalysis ? comments?.toList() : null,
             startingComments: isLichessAnalysis
@@ -516,7 +500,17 @@ class Root extends Node {
           );
 
           frame.to.addChild(branch);
-          stack.add((from: childFrom, to: branch));
+          stack.add(
+            (
+              from: childFrom,
+              to: branch,
+              nesting: frame.from.children.length == 1 ||
+                      // mainline continuation
+                      (childIdx == 0 && frame.nesting == 1)
+                  ? frame.nesting
+                  : frame.nesting + 1,
+            ),
+          );
 
           onVisitNode?.call(root, branch, isMainline);
         }

lib/src/model/common/uci.dart

@@ -90,6 +90,8 @@ class UciPath with _$UciPath {
     return UciPath(path.toString());
   }
 
+  factory UciPath.join(UciPath a, UciPath b) => UciPath(a.value + b.value);
+
   /// Creates a UciPath from a list of UCI moves.
   ///
   /// Throws an [ArgumentError] if any of the moves is invalid.