class RubyLsp::Requests::CodeActionResolve

def perform
  return Error::EmptySelection if @document.source.empty?
  source_range = @code_action.dig(:data, :range)
  return Error::EmptySelection if source_range[:start] == source_range[:end]
  scanner = @document.create_scanner
  start_index = scanner.find_char_position(source_range[:start])
  end_index = scanner.find_char_position(source_range[:end])
  extracted_source = T.must(@document.source[start_index...end_index])
  # Find the closest statements node, so that we place the refactor in a valid position
  closest_statements, parent_statements = @document
    .locate(@document.tree, start_index, node_types: [Prism::StatementsNode, Prism::BlockNode])
  return Error::InvalidTargetRange if closest_statements.nil? || closest_statements.child_nodes.compact.empty?
  # Find the node with the end line closest to the requested position, so that we can place the refactor
  # immediately after that closest node
  closest_node = T.must(closest_statements.child_nodes.compact.min_by do |node|
    distance = source_range.dig(:start, :line) - (node.location.end_line - 1)
    distance <= 0 ? Float::INFINITY : distance
  end)
  return Error::InvalidTargetRange if closest_node.is_a?(Prism::MissingNode)
  closest_node_loc = closest_node.location
  # If the parent expression is a single line block, then we have to extract it inside of the oneline block
  if parent_statements.is_a?(Prism::BlockNode) &&
      parent_statements.location.start_line == parent_statements.location.end_line
    variable_source = " #{NEW_VARIABLE_NAME} = #{extracted_source};"
    character = source_range.dig(:start, :character) - 1
    target_range = {
      start: { line: closest_node_loc.end_line - 1, character: character },
      end: { line: closest_node_loc.end_line - 1, character: character },
    }
  else
    # If the closest node covers the requested location, then we're extracting a statement nested inside of it. In
    # that case, we want to place the extraction at the start of the closest node (one line above). Otherwise, we
    # want to place the extract right below the closest node
    if closest_node_loc.start_line - 1 <= source_range.dig(
      :start,
      :line,
    ) && closest_node_loc.end_line - 1 >= source_range.dig(:end, :line)
      indentation_line_number = closest_node_loc.start_line - 1
      target_line = indentation_line_number
    else
      target_line = closest_node_loc.end_line
      indentation_line_number = closest_node_loc.end_line - 1
    end
    lines = @document.source.lines
    indentation_line = lines[indentation_line_number]
    return Error::InvalidTargetRange unless indentation_line
    indentation = T.must(indentation_line[/\A */]).size
    target_range = {
      start: { line: target_line, character: indentation },
      end: { line: target_line, character: indentation },
    }
    line = lines[target_line]
    return Error::InvalidTargetRange unless line
    variable_source = if line.strip.empty?
      "\n#{" " * indentation}#{NEW_VARIABLE_NAME} = #{extracted_source}"
    else
      "#{NEW_VARIABLE_NAME} = #{extracted_source}\n#{" " * indentation}"
    end
  end
  Interface::CodeAction.new(
    title: "Refactor: Extract Variable",
    edit: Interface::WorkspaceEdit.new(
      document_changes: [
        Interface::TextDocumentEdit.new(
          text_document: Interface::OptionalVersionedTextDocumentIdentifier.new(
            uri: @code_action.dig(:data, :uri),
            version: nil,
          ),
          edits: [
            create_text_edit(source_range, NEW_VARIABLE_NAME),
            create_text_edit(target_range, variable_source),
          ],
        ),
      ],
    ),
  )
end