Need to find, How many weeks in a month and how many days in same month as well [closed]

Question

I would like to send out an email to the customer automatically every month on the below dates. The day to send out the email will depend on whether it’s a 4- or 5-week month.

4 weeks in a month 17th 1st email and 24th 2nd email

5 weeks in a month 24th 1st email and 31st 2nd email

So, which means

1. If current month contains 4 weeks(Sunday) and If its contains 28 or 29 (February case)/30/31 days need to send on 17th and 24th

2. If current month contains 5 weeks(Sunday) and If its contains 31 days need to send on 24th and 31st, other wise 17th and 24th need to send email.

Can some one implement the logic and please help me in this.

Below is the my attempt which I tried:

      Integer mnth = Date.Today().month();
      Integer date_value = Date.Today().day();

      System.debug('*Date*******'+date_value);
      System.debug('*Month*******'+mnth);// 1=jan

      if(mnth == 2 || mnth == 4 || mnth == 6 || mnth == 9 || mnth == 11){

        if(date_value==17){
          System.debug('Send 17th date email');
        }
        if(date_value==24){
          System.debug('Send 24th date email');
        }
      }

      if(mnth == 1 || mnth == 3 || mnth == 5 || mnth == 7 || mnth == 8 || mnth == 10 || mnth == 12){

        if(date_value==24){
          System.debug('Send 24th date email');
        }
        if(date_value==31){
          System.debug('Send 31st date email');
        }
      }

Answer 1

Just use the method in Date class to retrieve the number of days in a month (it takes into consideration if it is a Leap Year):

daysInMonth(year, month)

To know how many weeks, just calculate daysInMonth / 7.

I coded a helper class for your case wrapping those functionalities:

public class DateUtils {
    public static integer getWeekCount(Date d) {
        Integer days = Date.daysInMonth(d.year(), d.month());
        return days/7;
    }

    public static integer getDayCount(Date d) {
        Integer days = Date.daysInMonth(d.year(), d.month());
        return days;
    }
}

Solution for your case:

        Date today = Date.today();
        Integer weeks = DateUtils.getWeekCount(today);
        Integer days = DateUtils.getDayCount(today);
        String firstEmailSubject = '';
        String secondEmailSubject = '';
        String firstEmailBody = '';
        String secondEmailBody = '';
        Boolean send = false;

        Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();
        message.toAddresses = new String[] { '[email protected]', '[email protected]' };
        message.optOutPolicy = 'FILTER';        

        // 4 weeks and 28 to 31 days...
        if(weeks == 4 && 28 <= days && days <= 31) {
            if(today.day() == 17) {
                // Send first email
                message.subject = firstEmailSubject;
                message.plainTextBody = firstEmailBody;
                send = true;
            } else if (today.day() == 24) {
                // Send second email
                message.subject = secondEmailSubject;
                message.plainTextBody = secondEmailBody;
                send = true;
            }

        // 5 weeks and 31 days...
        } if(weeks == 5 && days == 31) {
            if(today.day() == 24) {
                // Send first email
                message.subject = firstEmailSubject;
                message.plainTextBody = firstEmailBody;
                send = true;
            } else if (today.day() == 31) {
                // Send second email
                message.subject = secondEmailSubject;
                message.plainTextBody = secondEmailBody;
                send = true;
            }

        // 5 weeks but not 31 days...
        } else if(weeks == 5 && days != 31) {
            if(today.day() == 17) {
                // Send first email
                message.subject = firstEmailSubject;
                message.plainTextBody = firstEmailBody;
                send = true;
            } else if (today.day() == 24) {
                // Send second email
                message.subject = secondEmailSubject;
                message.plainTextBody = secondEmailBody;
                send = true;
            }
        }

        // Send if necessary.
        if(send) {
            Messaging.SingleEmailMessage[] messages = new List<Messaging.SingleEmailMessage> {message};
            Messaging.SendEmailResult[] results = Messaging.sendEmail(messages);    
        }

Reference: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_date.htm