GSheets app script for pairing people's emails so that they can stay in touch

staying_in_touch_script.js

/** 
For a sheet which uses this script, go to

https://docs.google.com/spreadsheets/d/1v06lwTvqo-D1SBzAkRfNkGqxdI8KmcJkCZqbvVmKots/copy

For a blog post explaining this sheet, go to http://www.therobinlord.com/a-google-sheet-to-help-you-stay-in-touch/

*/



/** 
 * Shuffles list of people to email
 */
function shuffle(array) {
//  Getting current list
  var currentIndex = array.length, temporaryValue, randomIndex;

  // While there remain elements to shuffle...
  while (0 !== currentIndex) {

    // Pick a remaining element...
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;

    // And swap it with the current element.
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }

  return array;
}


/**
* Collects error messages
*/

function sendErrors(err_msg){
  
  try{
//    Get all the listed managers
        var managerRows = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Manager details').getDataRange().getValues(); 
    
//  Logging the rows so we can debug if this isn't working  
    console.log(managerRows)
    console.log("Manager emails:") 
    
    // Remove top row because those are our headings
    managerRows.shift(); 
    
    for (var i in managerRows){
//       Extract each recipient
       var recipientRow = managerRows.shift();
      var recipient = recipientRow[0]; //First column
         console.log(recipient)
          
//        Send an email with the failed email addresses
        MailApp.sendEmail(recipient, "Error", err_msg);}  
        }
      catch (err) {
//        Logging failures to help debugging
        console.log("Getting error message emails failed")
        console.log(err)
  
      }}


/**
 * Sends emails with data from the current spreadsheet.
 */
function sendEmails() {
  
  console.log("Starting")
  
//  Getting the date
  var currentTime = new Date();
  
//  Finding out day index  
  var day = currentTime.getDay();
  
  try {
  //Finding all the active rows in the sheeet
  var rows = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Email list').getDataRange().getValues(); 
  
  console.log(rows)
  
  // Remove top row because those are our headings
  rows.shift(); 
  
//  Some people don't want to be included every day, some
//  will only want wekends, weekdays, or intermittent.
//  This finds those people and removes them on certain days
    
  if ((day === 6) || (day === 0)){
//    Filtering all the rows to those that are weekend or
//    every day users
    var rows = rows.filter(function (row) {
    return (row[1] !== "Weekdays" && row[1]!== "Three working days");
    });   
  }
    else {
//    Filtering all the rows to those that are weekday or
//    every day users      
      var rows = rows.filter(function (row) {
    return row[1] !== "Weekends";
    });
      if ((day === 1) || (day === 3)){
            
//    Filtering all the rows to those that haven't set 
//    "only three days a week" as True
    var rows = rows.filter(function (row) {
    return row[1] !== "Three working days";
    }); 
  }
  }
    
      console.log("Done filtering");
      console.log(rows);
  

  
//  Shuffling remaining values to randomise pairings
  shuffle(rows);
  
//  Getting the half length of our list
  var half_length = Math.floor(rows.length / 2);    
    
//  Splitting our list into contacters and recipients
  var contacters = rows.slice(0, half_length);
  var recipients = rows.slice(half_length, rows.length);
  
//  Creating an array to populate with failed emails
  var failedEmails = []
  
//  For each of our contacter email addresses
  for (var i in contacters){
    
    // List is already randomly shuffled so take first elem
    var recipientRow = recipients.shift();
    var recipient = recipientRow[0]; //First column
    
//    Get email address
    var row = rows[i];
    var emailAddress = row[0]; // First column
    
//    Creating email text
    var message = 'Hey there! You should both get in touch';
    var subject = '[Automated reminder] Catch up';
    
//    If there is an issue with one of the emails just save and continue
    try {
      MailApp.sendEmail(emailAddress+", "+recipient, subject, message);
      console.log(emailAddress, recipient)
    }
    catch(err) {
      failedEmails.push(emailAddress+" ");
      failedEmails.push(recipient+" ");
      
    }
    
    
  }
  

  if(failedEmails.length>0){
//    If there were any issues, email sheet manager with details
    var errMsg = "The following emails failed:  \
".concat(failedEmails)

sendErrors(errMsg);}}
    catch (err) {
      console.log("Some kind of error, trying to alert sheet manager")

      console.log(err)
      sendErrors(err);
      

      }}