email reminders time driven google spread - email

Question

Can anyone help.
I have a simple google spreadsheet that enables me to book delegates onto a variety of courses at different venues and at different times and dates.
I used the same spreadsheet last year, kindly set up by Bob Rashkin! It worked perfectly and sent emails when delegates booked onto the course and also sent email reminders automatically when the course was 9 days or so from starting.
I have duplicated the spreadsheet for this term but the sheet refuses to send the reminder emails, I really could do with a little help on this?
A secondary matter is that when the script sends a booking confirmation email, it sometimes sends two of them which creates a lot of phone calls asking if they've booked on twice.
Help someone please
This is the reminder script that I'm using
function Reminder() {
var ss=SpreadsheetApp.getActiveSpreadsheet();
var s=ss.getActiveSheet();
var r1=s.getDataRange().getRow()+1;//Start past the header row!!! Doh!
var r2=s.getDataRange().getLastRow();
var mn,m,days,d=new Date(),coursedate=new Date(),dlen=8.64e7,i,course,r,year;//8.64e7
var subject="Just a gentle reminder that you or colleague(s) from your setting have a Paediatric First Aid course coming up in the next week or so. ";
var recipient, body, tail="Please be aware that Entrust (formerly Staffs Early Years) will make a charge for non attendance so";
tail+=" please make sure that you familiarise yourself with the times and dates of the course. ";
tail+="If you need help finding the venue then please follow the link below to find the venue and print off a map if required.";
tail+="\n\nhttp://www.blithfieldsafety.co.uk/venues/";
for (r=r1;r<=r2;r++) {
recipient=s.getRange(r,9).getValue();
course=s.getRange(r, 2).getValue();
body=subject+"\nCourse Details\n"+course+"\n\nDelegate Name: "+s.getRange(r,4).getValue()+"\n\n"+tail; //changed (r,2) to (r,4)
mn=course.match(/Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec/)[0];
m=["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"].indexOf(mn);
days=course.match(/(\d{1,2})(st|nd|rd|th)/g);
year=d.getFullYear();
for (i in days) {
coursedate.setMonth(m);
coursedate.setDate(days[i].slice(0,-2));
if ((coursedate-d)/dlen<14 && s.getRange(r,16).getValue()!="mail sent") {
GmailApp.sendEmail(recipient, subject, body);
s.getRange(r,16).setValue("mail sent");//arbitrarily picked col 15
}
}
}
};

Answer 1

It looks like the time remaining until the course begins is checked with this line:
if ((coursedate-d)/dlen<14 && s.getRange(r,16).getValue()!="mail sent") {
That line is making a date calculation, and checking if the value of a cell had the text "mail sent" in it. If the cell didn't have mail sent AND the date calculation is true, then an email gets sent. Notice that the divisor dlen is a value that was hard coded.
var mn,m,days,d=new Date(),coursedate=new Date(),dlen=8.64e7,i,course,r,year;//8.64e7
The value of the variable dlen is set to a constant value of 8.64e7. But I'm guessing that the math no longer works right for some reason.
The value of dlen is 86400000.
There are 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute.
24 * 60 * 60 = 86,400 seconds in a day. So, obviously, the 86,400,000 number is a multiple of the number of seconds in a day.
I'm guessing that there is a new course every month?
You can add a Logger.log() statement to your code, and run it so see what the variable values are:
Logger.log('coursedate: ' + coursedate);
If you put that line in your code:
for (i in days) {
coursedate.setMonth(m);
Logger.log('coursedate: ' + coursedate);
coursedate.setDate(days[i].slice(0,-2));
Logger.log('coursedate: ' + coursedate);
Logger.log('d: ' + d);
if ((coursedate-d)/dlen<14 && s.getRange(r,16).getValue()!="mail sent") {
That would tell you what the values of the variables coursedate and d are right when the calculation is being made.
Then you could hopefully figure out why the math is the way it is. To view the Logger.log() output, click on the View menu, and choose the Logs menu item. A list of logged values will be in the window.