Synvert::Rewriter.new "convert_rspec_one_liner_expectation" do
  description <<-EOF
It convers rspec one liner expectation.

    it { should matcher } => it { is_expected.to matcher }
    it { should_not matcher } => it { is_expected.not_to matcher }

    it { should have(3).items }
    =>
    it 'has 3 items' do
      expect(subject.size).to eq(3)
    end

    it { should have_at_least(3).players }
    =>
    it 'has at least 3 players' do
      expect(subject.players.size).to be >= 3
    end
  EOF

  if_gem 'rspec', {gte: '2.99.0'}

  matcher_converters = {have: 'eq', have_exactly: 'eq', have_at_least: 'be >=', have_at_most: 'be <='}
  within_files 'spec/**/*.rb' do
    {should: 'to', should_not: 'not_to'}.each do |old_message, new_message|
      # it { should matcher } => it { is_expected.to matcher }
      # it { should_not matcher } => it { is_expected.not_to matcher }
      with_node type: 'block', caller: {message: 'it'} do
        if_only_exist_node type: 'send', receiver: nil, message: old_message do
          receiver = node.body.first.arguments.first.receiver
          unless receiver && matcher_converters.include?(receiver.message)
            matcher = node.body.first.arguments.first.source(self)
            replace_with "it { is_expected.#{new_message} #{matcher} }"
          end
        end
      end

      # it { should have(3).items }
      # =>
      # it 'has 3 items' do
      #   expect(subject.size).to eq(3)
      # end
      #
      # it { should have_at_least(3).players }
      # =>
      # it 'has at least 3 players' do
      #   expect(subject.players.size).to be >= 3
      # end
      matcher_converters.each do |old_matcher, new_matcher|
        with_node type: 'block', caller: {message: 'it'} do
          if_only_exist_node type: 'send', receiver: nil, message: old_message, arguments: {first: {type: 'send', receiver: {type: 'send', message: old_matcher}}} do
            times = node.body.first.arguments.first.receiver.arguments.first.source(self)
            items_name = node.body.first.arguments.first.message
            new_code = ""
            if :items == items_name
              new_code << "it 'has #{times} items' do\n"
              new_code << "  expect(subject.size).#{new_message} #{new_matcher}(#{times})\n"
              new_code << "end"
            else
              it_message = "#{old_matcher.to_s.sub('have', 'has').gsub('_', ' ')} #{times} #{items_name}"
              new_code << "it '#{it_message}' do\n"
              new_code << "  expect(subject.#{items_name}.size).#{new_message} #{new_matcher} #{times}\n"
              new_code << "end"
            end
            replace_with new_code
          end
        end
      end
    end
  end
end