//this is a function that fires when the webapp receives a GET request
function doGet(e) {
  return HtmlService.createHtmlOutput("request received");
}

//this is a function that fires when the webapp receives a POST request
function doPost(e) {
  var myData = JSON.parse(e.postData.contents);
  
  var itemType = myData.itemType;
  var itemID = myData.itemId;
  var runID = myData.runId;

  // USERS MUST PROVIDE THE INFO BELOW

  let apiKey = 'XXXXXXXXXXXXXXXXXXXXX'; //insert your API key here
  let email = 'XXXXXXXXXXXXXXXXXXX'; //provide recipient emails here
  let subject = 'ObservePoint | Comparison Alert'; //provide a custom subject line here

 ///////////////////////////////////////////////////////////////////////////////////////
  
  let htmlBody; //this will be defined based on whether this alert is for an audit or web-journey

  //this flag will determine whether an email is sent or not
  let changes = false;

  if(itemType == 'audit') {

    //get audit comparisons data
    let endpoint = '/comparisons/audits/' + itemID + '/scores';
    let comparisonResults = apiRequestGET(endpoint, apiKey);
    let comparisonSummary = '';

    comparisonResults.forEach(cr => {

      if(cr.tagParityScore != 100 || cr.variableParityScore != 100 || cr.variableValueParityScore != 100) {
      changes = true;
      comparisonSummary += '<br><br><b>Tag Parity:</b> ' + cr.tagParityScore + '%<br><b>Variable Parity:</b> ' + cr.variableParityScore + '%<br><b>Value Parity:</b> ' + cr.variableValueParityScore + '%<br><br>';
    }

    });

    //update htmlBody if changes occurred
    if(changes) {
      htmlBody = '<b>Comparison Alert Summary</b><br><br>In a Web Audit that just completed scanning, changes were identified in your analytics implementation.' + comparisonSummary + 'To see details, click the following link to take you to the full report:';
      htmlBody += '<br><br><a href="https://app.observepoint.com/audit/' + itemID + '/run/' + runID +'/comparisons/results">https://app.observepoint.com/audit/' + itemID + '/run/' + runID +'/comparisons/results</a>';
    }
  } else if(itemType == 'web-journey') {

    //check for variable differences
    
    let endpoint = '/comparisons/web-journeys/' + itemID +'/runs/' + runID + '/variables'
    let response = apiRequestGET(endpoint, apiKey);
    
    if(response.length > 0) {
      changes = true;
    }

//check for tag differences
  let tagEndpoint = '/comparisons/web-journeys/' + itemID + '/runs/' + runID + '/tag-account-presence';
  let tagResponse = apiRequestGET(tagEndpoint, apiKey);

if(tagResponse != undefined) {
  tagResponse.forEach(res => {
        res.tagAccountPresenceDifferences.forEach(diff => {            
          if(diff.actualCount != diff.expectedCount) {
                changes = true;
          }
        });
    });
}
  
//update htmlBody if changes occurred
if(changes) {
  htmlBody = '<b>Comparison Alert Summary</b><br><br>In a Web Journey execution that just completed, changes were identified in your analytics implementation. To see details, click the following link to take you to the full report (<b>Note:</b> Use the "Only Show Changes toggle" to zoom in on changes):';
  htmlBody += '<br><br><a href="https://app.observepoint.com/web-journey/' + itemID +'/run/' + runID + '/results">https://app.observepoint.com/web-journey/' + itemID +'/run/' + runID + '/results</a>';
 }
}

//if differences exist, send alert
if(changes) {

//send email via Gmail API
  MailApp.sendEmail(
    email,
    subject,
    '',
    {
      htmlBody: htmlBody,
      noReply: true //all emails will be send from [email protected]
    }
  );
 }
  return HtmlService.createHtmlOutput("post request received");
}

function apiRequestGET(endpoint,apiKey) {
  var url = 'https://api.observepoint.com/v3' + endpoint;
  var options = {
    'method': 'GET',
    'headers': {
      Authorization: 'api_key ' + apiKey
    },
    'contentType': 'application/json',
    'muteHttpExceptions': true
  }
  var ret = UrlFetchApp.fetch(url, options);
  return JSON.parse(ret);
                    
}