google forms send email with codes

gistfile1.txt

// This function will be called everytime the form is submitted.
function onFormSubmit(event) {
  sendAutomatedEmail()
}

function sendAutomatedEmail() {
  SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Form Responses 1").activate();
  var responsesheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();  // Get main Database Sheet
  var emailsheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Sheet2");  // Get Sheet with the Email Content
  var promocodesheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("PromoCodes");
  
  var lastResponseRow = responsesheet.getLastRow();   // User which last filled the form
  var promocodeTakenCol = getPromoCodesTakenCol()
  var availablePromoRow = getFirstEmptyRowByColumnArray(promocodeTakenCol)
    
  var name = responsesheet.getRange(lastResponseRow, 2).getValue(); 
  var email = responsesheet.getRange(lastResponseRow, 4).getValue();
  var subject = "Thank you!";
  
  var duplicateEmailRow = getRowMatchingText(email, promocodeTakenCol)
  var promoRow = availablePromoRow
  if (duplicateEmailRow >= 0) {
    promoRow = duplicateEmailRow
  }
  var availablepromocode = promocodesheet.getRange(promoRow, 1).getValue();

  var body = emailsheet.getRange(1, 1).getValue(); 
  body = body.replace("{name}", name);
  body = body.replace("{promo_code}", availablepromocode);

  try {
    MailApp.sendEmail(email, subject, body);
    promocodesheet.getRange(promoRow, 2).setValue(email)
  }
  catch(e) {
    Logger("Failed: Sending email to" + email)
  }
}

// returns column B (email addresses) values of PromoCodes
function getPromoCodesTakenCol() {
  var spr = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("PromoCodes");
  var column = spr.getRange('B:B');
  var values = column.getValues();
  return values
}

function getRowMatchingText(text, columnValues) {
  var values = columnValues; 
  for(var i = 0; i<values.length;i++){
    if((values[i][0]+"").toUpperCase() === text.toUpperCase()) {
      return i+1;
    }
  }

  return -1
}

// Don's array approach - checks first column only
// With added stopping condition & correct result.
// From answer https://stackoverflow.com/a/9102463/1677912
function getFirstEmptyRowByColumnArray(columnValues) {
  var values = columnValues;
  var ct = 0;
  while ( values[ct] && values[ct][0] != "" ) {
    ct++;
  }
  return (ct+1);
}