yujinakayama/transpec

# coding: utf-8

require 'active_support/concern'
require 'transpec/syntax/mixin/send'
require 'transpec/util'

module Transpec
  class Syntax
    module Mixin
      module UselessAndReturn
        extend ActiveSupport::Concern
        include Send

        def remove_useless_and_return!
          return unless useless_and_return?
          remove(and_return_range)
          true
        end

        def useless_and_return?
          return false unless and_return?
          arg_node = and_return_node.children[2]
          arg_node.nil?
        end

        def and_return_with_block?
          block_node = Util.block_node_taken_by_method(and_return_node)
          block_node
        end

        def and_return?
          and_return_node
        end

        def and_return_node
          return @and_return_node if instance_variable_defined?(:@and_return_node)

          @and_return_node = Util.each_backward_chained_node(node) do |chained_node|
            method_name = chained_node.children[1]
            break chained_node if method_name == :and_return
          end
        end

        private

        def and_return_range
          receiver_node = and_return_node.children.first
          receiver_node.loc.expression.end.join(and_return_node.loc.expression.end)
        end

        class RecordBuilder < Transpec::RecordBuilder
          param_names :host

          def old_syntax
            syntax = base_syntax
            syntax << '.and_return'
            syntax << ' { value }' if host.and_return_with_block?
            syntax
          end

          def new_syntax
            syntax = base_syntax
            syntax << ' { value }' if host.and_return_with_block?
            syntax
          end

          def base_syntax
            fail NotImplementedError
          end
        end

        class MonkeyPatchRecordBuilder < UselessAndReturn::RecordBuilder
          def base_syntax
            "obj.#{host.method_name}(:message)"
          end
        end
      end
    end
  end
end