[CMSR] Add LSP command 'Move selected formal parameter(s) left'.

Change-Id: Ia30e9bad9643d80c183d8b17a0d3aae065c30dc7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/310969
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Samuel Rawlins <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/services/refactoring/agnostic/change_method_signature.dart

@@ -72,6 +72,8 @@ sealed class Available extends Availability {
   });
 
   bool get hasSelectedFormalParametersToConvertToNamed => false;
+
+  bool get hasSelectedFormalParametersToMoveLeft => false;
 }
 
 /// The supertype return types from [computeSourceChange].
@@ -439,6 +441,36 @@ final class _AvailableWithDeclaration extends Available {
 
     return true;
   }
+
+  @override
+  bool get hasSelectedFormalParametersToMoveLeft {
+    final selected = declaration.selected;
+    final firstSelected = selected.firstOrNull;
+    if (firstSelected == null) {
+      return false;
+    }
+
+    final formalParameterList = declaration.node.formalParameterList;
+    if (formalParameterList == null) {
+      return false;
+    }
+
+    final all = formalParameterList.parameters.toList();
+    final firstSelectedIndex = all.indexOf(firstSelected);
+    if (firstSelectedIndex < 1) {
+      return false;
+    }
+
+    final previous = all[firstSelectedIndex - 1];
+    if (firstSelected.isOptionalPositional && !previous.isOptionalPositional) {
+      return false;
+    }
+    if (firstSelected.isNamed && !previous.isNamed) {
+      return false;
+    }
+
+    return true;
+  }
 }
 
 final class _AvailableWithExecutableElement extends Available {

pkg/analysis_server/lib/src/services/refactoring/framework/refactoring_processor.dart

@@ -8,6 +8,7 @@ import 'package:analysis_server/src/services/refactoring/convert_all_formal_para
 import 'package:analysis_server/src/services/refactoring/convert_selected_formal_parameters_to_named.dart';
 import 'package:analysis_server/src/services/refactoring/framework/refactoring_context.dart';
 import 'package:analysis_server/src/services/refactoring/framework/refactoring_producer.dart';
+import 'package:analysis_server/src/services/refactoring/move_selected_formal_parameters_left.dart';
 import 'package:analysis_server/src/services/refactoring/move_top_level_to_file.dart';
 
 /// A function that can be executed to create a refactoring producer.
@@ -20,6 +21,8 @@ class RefactoringProcessor {
         ConvertAllFormalParametersToNamed.new,
     ConvertSelectedFormalParametersToNamed.commandName:
         ConvertSelectedFormalParametersToNamed.new,
+    MoveSelectedFormalParametersLeft.commandName:
+        MoveSelectedFormalParametersLeft.new,
     MoveTopLevelToFile.commandName: MoveTopLevelToFile.new,
   };
 

pkg/analysis_server/lib/src/services/refactoring/move_selected_formal_parameters_left.dart

@@ -0,0 +1,105 @@
+// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
+import 'package:analysis_server/src/services/refactoring/agnostic/change_method_signature.dart';
+import 'package:analysis_server/src/services/refactoring/framework/refactoring_producer.dart';
+import 'package:analysis_server/src/services/refactoring/framework/write_invocation_arguments.dart'
+    show ArgumentsTrailingComma;
+import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
+import 'package:collection/collection.dart';
+
+/// The refactoring that move selected formal parameters one position left
+/// in the list of formal parameters.
+class MoveSelectedFormalParametersLeft extends RefactoringProducer {
+  static const String commandName =
+      'dart.refactor.move_selected_formal_parameters_left';
+
+  static const String constTitle = 'Move selected formal parameter(s) left';
+
+  MoveSelectedFormalParametersLeft(super.context);
+
+  @override
+  bool get isExperimental => true;
+
+  @override
+  List<CommandParameter> get parameters => const <CommandParameter>[];
+
+  @override
+  String get title => constTitle;
+
+  @override
+  Future<void> compute(
+    List<Object?> commandArguments,
+    ChangeBuilder builder,
+  ) async {
+    final availability = analyzeAvailability(
+      refactoringContext: refactoringContext,
+    );
+    if (availability is! Available) {
+      return;
+    }
+
+    final selection = await analyzeSelection(
+      available: availability,
+    );
+
+    if (selection is! ValidSelectionState) {
+      return;
+    }
+
+    final all = selection.formalParameters.toList();
+    final selected = all.where((e) => e.isSelected).toList();
+
+    final firstSelected = selected.firstOrNull;
+    if (firstSelected == null) {
+      return;
+    }
+
+    final firstSelectedIndex = all.indexOf(firstSelected);
+    if (firstSelectedIndex < 1) {
+      return;
+    }
+
+    final beforePrevious = all.take(firstSelectedIndex - 1);
+    final afterPrevious = all.skip(firstSelectedIndex - 1);
+    final reordered = [
+      ...beforePrevious,
+      ...selected,
+      ...afterPrevious.whereNot(selected.contains),
+    ];
+
+    final formalParameterUpdates = reordered.map(
+      (formalParameter) {
+        return FormalParameterUpdate(
+          id: formalParameter.id,
+          kind: formalParameter.kind,
+        );
+      },
+    ).toList();
+
+    final signatureUpdate = MethodSignatureUpdate(
+      formalParameters: formalParameterUpdates,
+      formalParametersTrailingComma: TrailingComma.ifPresent,
+      argumentsTrailingComma: ArgumentsTrailingComma.ifPresent,
+    );
+
+    await computeSourceChange(
+      selectionState: selection,
+      signatureUpdate: signatureUpdate,
+      builder: builder,
+    );
+  }
+
+  @override
+  bool isAvailable() {
+    final availability = analyzeAvailability(
+      refactoringContext: refactoringContext,
+    );
+    if (availability is! Available) {
+      return false;
+    }
+    return availability.hasSelectedFormalParametersToMoveLeft;
+  }
+}