Make Gmail arrive on a schedule

scheduleinbox.gs

var LABEL_NAME = 'inbox-holding'

// Each time must have the format 'HOUR:MINUTE'
var schedule = [['13:00', '17:00'], // Sunday
                ['9:30', '13:00', '17:00'], // Monday
                ['9:30', '13:00', '17:00'], // Tuesday
                ['9:30', '13:00', '17:00'], // Wednesday
                ['9:30', '13:00', '17:00'], // Thursday
                ['9:30', '13:00', '17:00'], // Friday
                ['8:00', '13:00', '17:00']]; // Saturday

function setup() {
  // Create a label to put paused messages in
  // First go through all the labels and check that it doesn't already exist
  var label = null;
  allLabels = Gmail.Users.Labels.list('me');
  for (var i = 0; i < allLabels.labels.length; i++) {
    if(allLabels.labels[i].name == LABEL_NAME){
      label = allLabels.labels[i];
      break; // Found it, just quit now
    }
  }

  if(label == null){ // Didn't find it, so create it
    label = Gmail.Users.Labels.create({'name':LABEL_NAME,
                                       'labelListVisibility':'labelHide'},
                                      'me');
  }
  
  // TODO: check if filter already exists
  // Add a filter that automatically puts all incoming messages into this label
  // and archives them so they don't appear in the inbox
  var filter = Gmail.Users.Settings.Filters.create({'id':'schedule_inbox_filter',
                                                    'criteria':{
                                                      'from':'*',
                                                      'query':'label:inbox'
                                                    },
                                                    'action':{
                                                      'addLabelIds':[label.id],
                                                      'removeLabelIds':['INBOX']
                                                    }}, 
                                                   'me');
                                                   
  ScriptApp.newTrigger("check")
  .timeBased()
  .everyMinutes(10)
  .create();
}

function check() {
  var now = new Date();

  var schedToday = schedule[now.getDay()];
  for(var i = 0; i < schedToday.length; i++){ // For each of today's deliveries,
    hour = Number(schedToday[i].split(":")[0]); // parse the time
    minute = Number(schedToday[i].split(":")[1]);
    
    target = new Date(now);
    target.setHours(hour, minute);

    // Deliver if we're within 12 minutes of the desired time
    // This ensures we always get at least one delivery if we run every 10 minutes plus or minus a few seconds
    // TODO: we might also sometimes get 2; add logic to fix this
    if(target - now > -12*60*1000 && target - now < 0){
      deliver();
    }
  }
}

// Deliver mail stored in the special label to the inbox
// Scheduled for specific times of day, and will occur +/- 15 minutes of that time
function deliver() {
  // Find the label
  allLabels = Gmail.Users.Labels.list('me');
  var label = null;
  for (var i = 0; i < allLabels.labels.length; i++) {
    if(allLabels.labels[i].name == LABEL_NAME){
      label = allLabels.labels[i];
      break;
    }
  }
  if(label != null){
    // Get all the threads with the label
    allThreads = Gmail.Users.Threads.list('me', { 'labelIds':[label.id] } );
    
    // If there are no messages, we're done
    if(allThreads.resultSizeEstimate == 0){
      return;
    }
    
    Logger.log(new Date() + ": " + allThreads.threads.length + " messages delivered");
    
    // Now move each of these threads to the inbox and remove the label
    for (var i = 0; i < allThreads.threads.length; i++) {
      Gmail.Users.Threads.modify({'addLabelIds': ['INBOX'],
                                  'removeLabelIds': [label.id]},
                                 'me', allThreads.threads[i].id);
    }
  }
  else{
    Logger.log("Couldn't find scheduled inbox label!");
  }
}