Gmail Snooze

gmailsnooze.js

var
  MARK_UNREAD = true,
  UNSNOOZED_LABEL = null,
  LABEL_NAME_TEMPLATE = "Snooze/{{days}} days",
  DEBUG_LEVEL = 0
;

var LABEL_REGEX = RegExp(LABEL_NAME_TEMPLATE.replace('{{days}}','(\\d+)'));

function debugLog(message, minDebugLevel) {
  if (DEBUG_LEVEL > 0 && (!minDebugLevel || DEBUG_LEVEL >= minDebugLevel)) {
    return Logger.log(message);
  }
}

function getLabelName(days) {
  days = ('00' + days);
  days = days.substr(days.length - 3);
  return LABEL_NAME_TEMPLATE.replace('{{days}}', days);
}

function getLabelDays(label) {
  if (label.days) {
    return +label.days;
  } else {
    if (label.name)    label = label.name;
    if (label.getName) label = label.getName();
    
    if (typeof label == 'string') return +label.match(LABEL_REGEX)[1];
  }
  return null;
}

function sumLabelDays(labels) {
  if (typeof labels == 'string') return getLabelDays(labels);

  var ret = 0;

  debugLog('Summing days for ' + labels.map(function(l){ return '"' + l.name + '"' }).join(','), 2);

  labels.forEach(function(label) {
    debugLog('Adding ' + getLabelDays(label) + ' days for ' + label.name, 3);
    ret += (getLabelDays(label) || 0);
  });
  return ret;
}

function labelList() {
  var ret = [], days, name, label;
  for (var i = 0; i <= 7; ++i) {
    days = Math.pow(2,i);
    name = getLabelName(days);
    label = GmailApp.getUserLabelByName(name);
    ret.push({sys: label, name: name, days: days});
  }
  return ret;
}

function getSnoozeLabelsOn(thread) {
  var ret = [], match;

  thread.getLabels().sort().forEach(function(label) {
    if (match = label.getName().match(LABEL_REGEX)) {
      ret.push({sys: label, name: match[0], days: getLabelDays(match[0])});
    }
  });
  
  return ret.sort(function(a, b){
    return a.name > b.name ? 1 : -1 
  });
}

function setup() {
  // Create the labels we’ll need for snoozing
  GmailApp.createLabel("Snooze");
  labelList().forEach(function(label) {
    GmailApp.createLabel(label.name);
  });
  if (UNSNOOZED_LABEL) GmailApp.createLabel(UNSNOOZED_LABEL);
}

function moveSnoozes() {
  var labelsOnThread, labelToRemove, daysToAdd;

  labelList().forEach(function(label) {
    debugLog('Processing label: ' + label.name);
    label.sys.getThreads().forEach(function(thread) {

      labelsOnThread = getSnoozeLabelsOn(thread);
      if (2 * label.days > sumLabelDays(labelsOnThread)) { // Process a thread only when we get to its biggest label
        debugLog('Processing thread: ' + thread.getFirstMessageSubject() + ' (' + sumLabelDays(labelsOnThread) + ' days to go)');
        // Decrement the number of days
        if (labelToRemove = labelsOnThread[0]) { // Remove the smallest label
          debugLog('Removing label: ' + labelToRemove.name);
          if ((daysToAdd = labelToRemove.days) > 1) {
            while ((daysToAdd /= 2) >= 1) { // Add every label that's smaller than the former smallest label
              debugLog('Adding label: ' + getLabelName(daysToAdd));
              thread.addLabel(GmailApp.getUserLabelByName(getLabelName(daysToAdd)));
            }
          } else if (labelsOnThread.length == 1) {
            // time to unsnooze it
            debugLog('Unsnoozing thread');
            thread.moveToInbox();
            if (MARK_UNREAD) thread.markUnread();
            if (UNSNOOZED_LABEL) {
              thread.addLabel(GmailApp.getUserLabelByName(UNSNOOZED_LABEL));
            }
          }
          
          labelToRemove.sys.removeFromThread(thread);      
        }
      }

    });
  });
}