context.getLogger().info("publishDisambiguateMessage");
                        
let messageModel = context.getMessageModel();
            
//define a list of values to select from
var postbacks = [];
            
//iterate the values in the disambiguation list and create a list item for each
for(let i=0; i< event.disambiguationValues.length; i++){                              
              
//add a character like "a", "b", "c" and the label itself as a keyword
let chr = String.fromCharCode(97 + i);              
let keywords = [event.disambiguationValues[i],chr];
              
// set label as e.g. a. <label>, b. <label>
let label = chr+". "+event.disambiguationValues[i];

//define a JSON message that will be sent to the bot when a user selects a list item.
//The message invokes the setPizzaTopping custom event
let postbackPayload = {"event" : {"name":"setPizzaTopping","properties":{"PizzaTopping": event.disambiguationValues[i]}}};
              
//add postback action object to list of values
postbacks.push(messageModel.postbackActionObject(label, null, postbackPayload,keywords));
}            
//Define the disambiguation dialog prompt
let prompt = "You selected "+event.disambiguationValues.length+ " toppings. Unfortunately You can only have one. Please choose from the list.";
            
let textMessage = messageModel.textConversationMessage(prompt, postbacks);
context.addMessage(textMessage);