How can I add wrappers to a file based on a pattern?

For instance I have the following:

  ...
  find(css_policy_form_stage3).click
  with_ajax_wait
    expect(css_coverage_type_everquote).to be_visible
  end
  with_ajax_wait
    expect(css_coverage_type_everquote).to be_visible
  end
end
it "Stage 3" do
  select(coverage_type, from: css_coverage_type_everquote)
  find(css_has_auto_insurance).click
  ...

And I want to 'wrap' those "with_ajax_wait" blocks with it "waits" do ... end around them.

i.e. I want to get:

  ...
  find(css_policy_form_stage3).click
  it "waits" do
    with_ajax_wait
      expect(css_coverage_type_everquote).to be_visible
    end
  end
  it "waits" do
    with_ajax_wait
      expect(css_coverage_type_everquote).to be_visible
    end
  do
end
it "Stage 3" do
  select(coverage_type, from: css_coverage_type_everquote)
  find(css_has_auto_insurance).click
  ...

Notes and Assumptions:

• block to indent code is always 3 lines long (with... expect... and end). It would be nice to allow for more than i inner code line but not required for the simplest case.
• the block itself should have an extra 2 space indent.
• there are other end's that are not related (example shown just before "Stage 3"
• it would be nice to be able to specify an inner pattern also, e.g. only these blocks that have expect starting the code line being indented. I think awk is probably the tool due to the ability to read consecutive lines but I am struggling to know how to write this.

I'm imagining this is a generally useful q&a as adding wrapper within files is not uncommon.

Somewhat similar to my previous question: How to use awk to indent a source file based on simple rules?
However in this case I am adding the wrapper plus the indent.