var LABEL = 'STARRED';
var TOTAL = 10;

function Install() {
  ScriptApp.newTrigger('readStarredMessages').timeBased().everyDays(1).create();
}

function readStarredMessages() {
  var thread,
    subject,
    link,
    body,
    from,
    date,
    html,
    emails,
    color,
    index = [],
    i;

  var mySheet = SpreadsheetApp.getActiveSpreadsheet();

  emails = GmailApp.search('label:' + LABEL);
  var count = emails.length;

  if (count == 0) return;

  if (count > TOTAL) index = getIndex(TOTAL, 0, count);
  else {
    for (i = 0; i < count; i++) index.push(i);
  }

  for (i = 0; i < TOTAL; i++) {
    var n = index[i];

    if (emails[n]) {
      thread = emails[n].getMessages()[0];

      subject = thread.getSubject();
      body = processHTML(thread.getBody(), 250);
      link = thread.getId(); // can also use GetPermalink()
      from = thread.getFrom();
      date = Utilities.formatDate(thread.getDate(), Session.getTimeZone(), 'MMM dd, yyyy');

      if (i % 2 == 0) color = '#f0f0f0';
      else color = '#f9f9f9';

      html += '<p>On ' + date + ', <i>' + from + '</i> wrote: ';
      html += '<strong>' + subject + '</strong><br /><br />';
      html += body + " <a href='https://mail.google.com/mail/#all/";
      html += link + "'>Click to read &raquo;</a></p>";
    }
  }

  html += "<p><a href='" + SpreadsheetApp.getActiveSpreadsheet().getUrl();
  html += "'>click here</a> and choose Gmail &gt; unsubscribe.</p> ";

  GmailApp.sendEmail(Session.getActiveUser(), emails.length + ' pending messages in Gmail', '', {
    htmlBody: html,
  });
}

// Pick random messages from the Gmail label

function getIndex(count, min, max) {
  var results = [],
    index;
  while (count > 0) {
    randNumber = Math.round(min + Math.random() * (max - min));
    if (results.indexOf(randNumber) == -1) {
      results.push(randNumber);
      count--;
    }
  }
  return results;
}

// Remove HTML tags from the Gmail messages

function processHTML(html, count) {
  html = html.replace(/<(?:.|\n)*?>/gm, '');
  html = html.replace(/^\s+|\s+$/g, '');
  return html.substring(0, count);
}