function cashstarExtract() {
  var threads = GmailApp.search('label:cashstar-extract');
  var columns = ['code', 'pin', 'to'];
  var data = {};
  var tags = []
  var requests = [];
  var responses = [];

  // Scrap emails

  Logger.log('Collecting emails...');

  for (var i = 0; i < threads.length; i++) {
    var messages = threads[i].getMessages();

    for (var j = 0; j < messages.length; j++) {
      var to = messages[j].getTo();
      var body = messages[j].getPlainBody();
      var exec = /https:\/\/bestbuy\.cashstar\.com\/gift-card\/view\/(\w+)\//.exec(body);

      data[exec[1]] = {to: to, url: exec[0], tag: exec[1]};
      tags.push(exec[1]);
    }
  }

  // Requests 1: csrfmiddlewaretoken

  Logger.log('Fetching tokens...');

  requests = tags.map(function(tag) {
    return {
      url: data[tag].url,
      method: 'get',
    };
  });

  responses = UrlFetchApp.fetchAll(requests);

  for (var i = 0; i < tags.length; i++) {
    var body = responses[i].getContentText();
    var token = /<input type='hidden' name='csrfmiddlewaretoken' value='(\w+)' \/>/.exec(body)[1];

    data[tags[i]].token = token;
  }

  // Request 2: Key

  Logger.log('Fetching keys...');

  requests = tags.map(function(tag) {
    return {
      url: data[tag].url,
      method: 'post',
      followRedirects: false,
      payload: {
        csrfmiddlewaretoken: data[tag].token,
        value: data[tag].to,
      },
    };
  });

  responses = UrlFetchApp.fetchAll(requests);

  for (var i = 0; i < tags.length; i++) {
    var header = responses[i].getHeaders()['Location'];
    var key = /\/recipient-experience\/redemption\/\w+\/(\w+)\//.exec(header)[1];

    data[tags[i]].key = key;
  }

  // Request 3: GC codes

  Logger.log('Fetching codes...');

  requests = [];

  requests = tags.map(function(tag) {
    return {
      url: Utilities.formatString('https://bestbuy.cashstar.com/recipient-experience/redemption/%s/%s/?continue=true', tag, data[tag].key),
      method: 'get',
    };
  });

  responses = UrlFetchApp.fetchAll(requests);

  for (var i = 0; i < tags.length; i++) {
    var body = responses[i].getContentText();
    var code = /https:\/\/bc-s.cashstar.com\/v1\/barcode\/(\d{16})\/format\/CODE128/.exec(body)[1];
    var pin = /<p>PIN: (\d{4})<\/p>/i.exec(body)[1];

    data[tags[i]].code = code;
    data[tags[i]].pin = pin;
  }

  // Send to sheet

  Logger.log('Writing to sheet...');

  var sheetName = 'Cashstar - ' + new Date().toString();
  var sheet = SpreadsheetApp.create(sheetName).getSheets()[0];
  sheet.appendRow(columns);

  var range = sheet.getRange(2, 1, tags.length, columns.length);
  range.setNumberFormat('@STRING@');

  var values = tags.map(function(tag) {
    return columns.map(function(column) {
      return data[tag][column];
    });
  });

  range.setValues(values);

  // Finish

  Logger.log('%s rows written to %s.', tags.length, sheetName);
}