build method

Implementation

@override
Widget build(BuildContext context, WidgetRef ref) {
  final editorState = ref.watch(editorStateProvider);
  final settings = ref.watch(settingsProvider);

  return Column(
    mainAxisSize: MainAxisSize.min,
    children: [
      if (statements.isEmpty && !settings.canChange)
        Text(
          "No statements.",
          style: Theme.of(
            context,
          ).textTheme.bodySmall?.apply(fontStyle: FontStyle.italic),
        ),
      ReorderableListView(
        physics: const NeverScrollableScrollPhysics(),
        buildDefaultDragHandles: false,
        shrinkWrap: true,
        children: statements
            .mapIndexed(
              (
                index,
                bodyStatement,
              ) => CustomReorderableDelayedDragStartListener(
                delay: const Duration(milliseconds: 500),

                /// Important to disable dragging when only 1 statement is there:
                /// Otherwise, Flutter throws rendering errors when the single statement is moved outside this widget.
                enabled: canReorder && statements.length > 1,
                index: index,
                key: ValueKey(bodyStatement.hashCode),
                // IMPORTANT: on the use of UncontrolledProviderScope here:
                // When a drag operation is started, e.g., using Draggable or ReorderableListView,
                // The dragged widget is moved to an Overlay. Consequently, the original widget is
                // no longer part of the main widget tree, i.e., it uses a different BuildContext.
                // This can cause issues with InheritedWidgets and Providers (including riverpod),
                // as they rely on the BuildContext to retrieve the correct dependencies.
                // For example, if the main ProviderScope wraps the main app widget (DartBlockEditor),
                // and it defines a provider such as programProvider, the dragged widget cannot rely
                // on a ConsumerWidget to access programProvider anymore, because its BuildContext is now
                // different and does not have access to the original ProviderScope.
                // Illustration of the problem:
                // MaterialApp
                // - ProviderScope
                //     - ...
                // - Overlay (DIFFERENT BUILDCONTEXT)

                // SOLUTION: By wrapping the widget which can be dragged with UncontrolledProviderScope,
                // we expose our original ProviderScope to the dragged widget, ensuring it can still access
                // all providers once a drag operation has started.
                child: UncontrolledProviderScope(
                  container: ProviderScope.containerOf(context),
                  child: StatementWidget(
                    statement: bodyStatement,
                    includeBottomPadding:
                        true, // statements.length > 1 &&   (index < statements.length - 1)
                    onChanged: (value) {
                      statements[index] = value;
                      onChanged(statements);
                    },
                    canReorder: canReorder,
                    canDelete: canDelete,
                    onDelete: () {
                      statements.removeAt(index);
                      onChanged(statements);
                    },
                    onDuplicate: (statementToDuplicate) {
                      onDuplicate(index);
                    },
                    onAppendNewStatement: (newStatement) {
                      if (index + 1 < statements.length) {
                        statements.insert(index + 1, newStatement);
                      } else {
                        statements.add(newStatement);
                      }
                      onChanged(statements);
                    },
                    onCopyStatement: (statementToCopy, cut) {
                      if (cut) {
                        statements.removeAt(index);
                        onChanged(statements);
                      }
                      onCopiedStatement(statementToCopy, cut);
                    },
                    onCopiedStatement: onCopiedStatement,
                    onPastedStatement: onPastedStatement,
                    onPasteStatement: (statementToPaste) {
                      // If the current statement is not the last one, paste the copied statement after it.
                      if (index + 1 < statements.length) {
                        statements.insert(index + 1, statementToPaste.copy());
                      } else {
                        // Otherwise, append the copied statement at the end.
                        statements.add(statementToPaste.copy());
                      }
                      onPastedStatement();
                      onChanged(statements);
                    },
                  ),
                ),
              ),
            )
            .toList(),
        onReorderStart: (index) {
          DartBlockInteraction.create(
            dartBlockInteractionType:
                DartBlockInteractionType.startedDraggingStatementToReorder,
          ).dispatch(context);
        },
        onReorder: (oldIndex, newIndex) {
          if (oldIndex < newIndex) {
            newIndex -= 1;
          }
          DartBlockInteraction.create(
            dartBlockInteractionType:
                DartBlockInteractionType.reorderedStatement,
          ).dispatch(context);
          final targetStatement = statements.removeAt(oldIndex);
          statements.insert(newIndex, targetStatement);
          onChanged(statements);
        },
      ),
      if (settings.canChange) //  && statements.isEmpty
        ToolboxDragTarget(
          isEnabled: settings.canChange,
          nodeKey: neoTechCoreNodeKey,
          onSaved: (savedStatement) {
            //Navigator.of(context).pop();
            statements.add(savedStatement);
            ScaffoldMessenger.of(context).showSnackBar(
              createDartBlockInfoSnackBar(
                context,
                iconData: Icons.add,
                message:
                    "Created '${savedStatement.statementType.toString()}' statement.",
              ),
            );
            onChanged(statements);
          },
          onPasteStatement:
              // Only show "Paste" option if there is a copied statement
              editorState.copiedStatement != null
              ? () {
                  // Retrieve copied statement and make a copy of it.
                  final statementToPaste = editorState.copiedStatement
                      ?.copy();
                  if (statementToPaste != null) {
                    statements.add(statementToPaste);
                    onPastedStatement();
                    onChanged(statements);
                  }
                }
              : null,
        ),
    ],
  );
}