Demonstrates how to show a custom summary value for a Participants Database Participant Log

pdb-custom_summary.php

<?php
/**
 * Plugin Name: PDB Custom Summary
 * Description: provides a customized sum value for the "Work Log" log
 * Version: 1.0
 * 
 */

class pdb_work_log_summary {
  
  /**
   * @var string name of the log
   */
  private $log_name = 'work_log';
  
  /**
   * @var string name of the project we want to get the total hours for
   */
  private $project_name = 'Mailer Assembly';
  
  /**
   * sets up the filter handler
   */
  public function __construct()
  {
    add_filter( 'pdblog-' . $this->log_name . '_sum', array( $this, 'sum_value' ), 10, 2 );
  }
  
  /**
   * provides the custom sum value
   * 
   * @param int $sum
   * @param array $log_data
   * @return int sum
   */
  public function sum_value( $sum, $log_data )
  {
    return $this->calc_sum( $log_data );
  }
  
  /**
   * calculates the sum
   * 
   * @param array $log_data
   * @return int sum value
   */
  private function calc_sum( $log_data )
  {
    /*
     * the $log_data argument will come in as an array of std objects, 
     * each object is a log entry
     * 
     * for your application, you would calculate your sum based on the values in 
     * this array
     * 
     * In this example, we will iterate through the array to build our sum, which 
     * is all the hours logged while working on the "Mailer Assembly" project
     */
    $sum = 0;
    
    // check each entry, if they logged time on the mailer project, add the hours
    foreach ( $log_data as $entry )
    {
      if ( $entry->project === $this->project_name ) {
        $sum += $entry->hours;
      }
    }
    
    return $sum;
  }
}

new pdb_work_log_summary();