Schedule Repeat events

You'll need to run a cron job periodically to handle the schedule tasks. You should check for the conflicts when the users enters the scheduled task. You definitely don't want to wait until the tasks are going to run to do this.

Hi
Thanks for the assistance your effort was appreciated.
The final code can be found below.
This bit of code insert events into a database with these functionalities:
1) Single or multiple time blocks
2) Repeat event booking
3) Checks for event time conflicts
Note: if single a event is being booked message is sent to user
else if multiple repeat booking conflicts are store in
table for user review and change event to another day or time.
I have only provided a quarter of the code so I hope I have not missed
anything related to this topic.

<?php 
 
 
   /**
    Note: form provide these parameters:
     $start_date
     $new_interval
     $new_frequency
     $end_date  //if no end_date use start date
     $time_block //each time block is 10 or 15 min, this indicates the number of blocks 1 to 10
 
    
    Note: determine settings manually or use database stored configuration  
     $double_book == "Y"; //event double booking
 $repeat == "no";//if no end_date use start date and repeat is no else repeat is yes
    **/
 /*******Note:
        - array repeatEvent(int $startTime, str $interval, int $frequency, int $endTime)
       returns array of UNIX times
    - $startTime and $endTime must be valid UNIX time integer values
    - $interval must be (case-insensitive): 'day', 'week', 'month', or 'year'
    - $frequency must be positive integer (1 = every, 2, = every other, 3 = every 3rd, 4 = every 4th. 5 = every 5th, 6 = every 6th)
 *********/
 function repeatEvent($startTime, $interval, $frequency, $endTime)
    {
     //make sure all paramters are valid
     $startTime = (int) $startTime;
     $endTime = (int) $endTime;
  if($startTime == 0)
      {
               user_error("repeatEvent(): invalid start time");
          return(FALSE);
       }
     
     if($endTime < $startTime)
       {
           user_error("repeatEvent(): invalid end time");
        }
            
     $interval = strtolower(trim($interval));
     if(!in_array($interval, array('day','week','month','year')))
       {
                 user_error("repeatEvent(): Invalid interval '$interval'");
                  return(FALSE);
           }
     $frequency = (int)$frequency;
    if($frequency < 1)
       {
                   user_error("repeatEvent(): Invalid frequency '$frequency'");
                   return(FALSE);
       }
     $schedule = array();
     for($time = $startTime; $time <= $endTime; $time = strtotime("+$frequency $interval", $time))
        {
              $schedule[] = $time;
        }
     return($schedule);
   }

     /**-----------------------insert appointment-----------------------**/
     $sched = repeatEvent(strtotime($start_date), $new_interval, $new_frequency, strtotime($end_date));
   
     //outer loop repeated inserts
     foreach($sched as $date)
         {
      
       //inner loop the number of time blocks
       for($i = 0, $eTime = strtotime($event_time); $i < $time_block; 
           $i++, $eTime = strtotime("+$event_length minutes", $eTime)) 
    { 
      $new_event_time = date('H:i', $eTime); //increment time for new single or multi block event 
   $new_event_date = date('Y-m-d', $date);//increment date for single or repeat event
     
   /**-----------------------check conflicts------------------------**/
      //determine the number of appointments for date and time to determine conflicts
   $event_count = "SELECT count(event_id) 
     FROM cal_appointment
     WHERE event_date = '$new_event_date'
     AND event_time = '$new_event_time '";
     $count = mysqli_query ($mysqli, $event_count);
     while($row = mysqli_fetch_array($count))
      {
       list($book_count) = $row;
      }       
    
    /**----------- tables for inserting information-----------**/
    /**Note: I have removed table fields to simplify example **/
    
    //insert if conflict insert in to cal_repeat_conflict
    $conflict_query = "INSERT INTO cal_repeat_conflict()
          VALUES()";
       
   //no conflicts insert into cal_appointment table 
   $cal_query = "INSERT INTO cal_appointment()
         VALUES();
    
   /**------------------------evaluate event time conflict---------------------**/
   //check to ensure that only allowed number of bookings for time slot is  entered
   if($double_book == "N" && $book_count == 1 && $repeat == "no")
          {
        event_conflict_message();//event time conflict assigned
           }
              elseif($double_book == "Y" && $book_count == 2 && $repeat == "no")
           {
          event_conflict_message();//event time conflict assigned
    }
    elseif($double_book == "N" && $book_count == 1 && $repeat == "yes")
          {
        //insert into table event if time conflict
     mysqli_query($mysqli, $conflict_query)or die(mysqli_error($mysqli));
          }
              elseif($double_book == "Y" && $book_count == 2 && $repeat == "yes")
            {
         //insert into table event if time conflict
        mysqli_query($mysqli, $conflict_query)or die(mysqli_error($mysqli));
     }       
     else
         {
            //no conflicts insert into cal_appointment table 
            mysqli_query($mysqli, $cal_query)or die(mysqli_error($mysqli));
               }
        }//end for loop
         }//end foreach loop
?>

I too am looking for this. In fact, I want to build a VERY flexible calendaring algorithm. The best (code available) one that i've seen is the REMIND program. It's in C, and I'm trying to digest it.

Google 'remind calendar', it's in the top 3 on my computer's preferences.

Schedule Repeat events
Hi

I am stuck in fact I don't know where to start, can you point
me in the right direction?

I have the form to capture the user input but don't
know how to proceed to use this information.

I need to allow the user to schedule repeated events for
the same time, for the same day between two time periods.
Ideally it would be great to check for conflicts.

Note: The info recorded by the form is listed below.

A) The start date and time is determine by the first event

B) The user selects a comdination of 1) interval 2) frequency and
3) week day to determine when the repeating event will occur:

1) interval:
Daily,
Weekly,
Monthly,
Annually
2) frequency:
Every
Every Other
Every 3rd
Every 4th
Every 5th
Every 6th

3) Week Day:
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday

C) The end date (YYYYMMDD) is then selected.

Note: I have the code to insert the results into the mysql database using PHP.