Ember : if a value is set in controller , perform an Ajax command(written in template),

I have given a rough code to understand what I need to perform,

/app/route1/controller.js

export default Controller.extend({
    test: function(id) {
        $.ajax({
            .....
            .....
            .....
        }).then(() => {
           set('message','successfully added');
        });
    }
});

/app/route1/template.hbs

<div class="ui container">
  <div class="ui segment"
    <button class="ui button" >Submit</button>
  </div>
</div>
<div class="ui container">
  <div class="ui modal">
    <div class="header"
      Message
    </div>
    <div class="content"
      
    </div>
    <div class="actions">
      <div class="ui ok button">OK</button>
    </div>
  </div>
</div>
<script type="text/javascript">
  $.ajax({
    if(message) {
      $('.ui.modal').modal('show');   
    }
  })
</script>

If I set a message in controller then, I have to show this message in the MODAL. The Ajax command that I've written is not correct., Please help to solve this issue. Thanks in advance