<?php
/**
 * The main module file for the Batch module.
 * 
 * Credit where credit is due:  This module is largely inspired by the excellent Batch processing functionality
 * baked into Drupal (like a lot of FlightPath).
 */




/**
 * Implementation of hook_menu
 * 
 */
function batch_menu() {
  
  $items = array();
  
  // Our test batch process, for testing...
  $items["batch-test-form"] = array(
    "title" => "Batch Test - Form",
    "page_callback" => "fp_render_form",
    "page_arguments" => array("batch_test_form"),
    "access_arguments" => array("batch_run_test"),
    "type" => MENU_TYPE_CALLBACK,
    "file" => menu_get_module_path("batch") . "/batch.test.inc",
  );
  
  
  $items["batch-processing/%"] = array(
    "page_callback" => "batch_processing_page",
    "page_arguments" => array(1),
    "access_callback" => TRUE,
    "type" => MENU_TYPE_CALLBACK,
  );

  
  $items["batch-finished/%"] = array(
    "page_callback" => "batch_finished_page",
    "page_arguments" => array(1),
    "access_callback" => TRUE,
    "type" => MENU_TYPE_CALLBACK,
  );
  
  
  $items["batch-ajax-callback/%"] = array(
    "page_callback" => "batch_ajax_callback",
    "page_arguments" => array(1),
    "access_callback" => TRUE,
    "type" => MENU_TYPE_CALLBACK,  
  );
  
  
  
  
  return $items;
  
}


/**
 * This function is called by ajax, and will trigger each run of the batch operation function, then
 * return appropriate results back to our javascript.
 *
 * @param unknown_type $batch_id
 */
function batch_ajax_callback($batch_id) {

  $rtn = array();  
  
  
  $batch = batch_get($batch_id);
  if ($batch["token"] != batch_get_token()) {
    //  Not allowed!  Bad token.
    header('Content-Type: application/json');
    print json_encode(array("error" => t("An error has occured-- you are now allowed to run this batch, or the batch does not exist.")));
    exit();
  }  
  
  
  ///////////////////////////////////
  // Run the batch operation.
  if (isset($batch["file"]) && $batch["file"] != "") {
    require_once($batch["file"]);    
  }
  $operation_callback = $batch["operation"][0];
  
  // If the operation callback doesn't exist, throw an error.
  if (!function_exists($operation_callback)) {
    header('Content-Type: application/json');
    print json_encode(array("error" => t("An error has occured: Cannot find operation callback function @function", array("@function" => addslashes($operation_callback)))));
    exit();    
  }
  
  $operation_args = $batch["operation"][1];
  // Add our $batch to the beginning of the $args array.
  //array_unshift($operation_args, $batch);
  $params = array(0 => &$batch);
  foreach ($operation_args as $val) {
    $params[] = $val;
  }
  
  call_user_func_array($operation_callback, $params);       

  
  
  // Coming out of this, $batch should be modified
  // Save it back to the database.
  db_query("UPDATE batch_queue 
            SET batch_data = '?'
            WHERE batch_id = '?' ", serialize($batch), $batch_id);
  
  
  // Output relavant results....
  $current = $batch["results"]["current"];
  $total = $batch["results"]["total"];
  $percent = "";
  if ($total > 0) {
    $percent = round(($current / $total) * 100, 1) * 1;
  }
  
  
  $rtn["progress_message"] = t($batch["progress_message"], array("@current" => $current, "@total" => $total, "@percent" => $percent));
  $rtn["percent"] = $percent;
  $rtn["display_percent"] = $batch["display_percent"];
  $rtn["finished"] = "";
  if ($batch["results"]["finished"] == TRUE) {
    $rtn["finished"] = "finished";
  }
  
  
  
  
  header('Content-Type: application/json');
  $rtn["success"] = "SUCCESS";  // let javascript know we DID finish executing correctly.
  print json_encode($rtn);
  
  exit();
}





/**
 * We redirect to this page when we have finished a batch.
 *
 * @param unknown_type $batch_id
 */
function batch_finished_page($batch_id) {
  $batch = batch_get($batch_id);  
  if ($batch["token"] != batch_get_token()) {
    return "<p>" . t("Sorry, there is a token mismatch or this batch no longer exists.") . "</p>";
  }
  
  // Otherwise, we can just return whatever their callback function is.  If this is from a form submission, we will send them
  // to the form's original destination.
  
  if (isset($batch["file"]) && $batch["file"] != "") {
    require_once($batch["file"]);    
  }
  $finished_callback = $batch["finished_callback"][0];
  $finished_args = $batch["finished_callback"][1];
  if (!is_array($finished_args)) $finished_args = array();

  $params = array();

  // If we are NOT going to fp_goto, then add the $batch as the first argument.
  if ($finished_callback != "fp_goto") {
    // Add our $batch to the beginning of the $args array.
    //array_unshift($finished_args, $batch);
    $params = array (0 => &$batch);    
  }
  
  foreach ($finished_args as $val) {
    $params[] = $val;
  }
  
  if (isset($batch["success_message"])) {
    fp_add_message($batch["success_message"]);
  }
  
  // Okay, let's call our function:
  return call_user_func_array($finished_callback, $params);       
  
  
  
  
  
}





/**
 * This is the page the user sees while a batch is being processed.
 * 
 * It will contain all the AJAX and such necessary to begin the batch process.
 *
 * @param unknown_type $batch_id
 */
function batch_processing_page($batch_id) {
  $rtn = "";
  
  $batch = batch_get($batch_id);  
  if ($batch["token"] != batch_get_token()) {
    return "<p>" . t("Sorry, there is a token mismatch or this batch no longer exists.") . "</p>";
  }
  
  
  
  fp_set_title($batch["title"]);

  fp_add_css(fp_get_module_path("batch") . "/css/batch.css"); 
  
  // Set up our setting...
  fp_add_js(array("batch_id" => $batch_id), "setting");
  
  // Add our general js file...
  fp_add_js(fp_get_module_path("batch") . "/js/batch.js"); 

   
  
  
  
  $rtn .= "<div class='batch-progress-bar-wrapper'>
             <div class='batch-progress-bar' id='batch-progress-bar'></div>             
           </div>
           <div id='batch-progress-message'>" . t("Initializing... please wait...") . "</div>
           
           ";
  
  
  
  
  
  
  
  return $rtn;
}














/**
 * Implementation of hook_cron
 * 
 * Delete old batches from the batch_queue table.  These would be normal "old" batches we no longer need,
 * or ones that never finished for some reason and are just taking up space.
 *
 */
function batch_cron() {

  $older_than = strtotime("6 HOURS AGO");
  db_query("DELETE FROM batch_queue WHERE created < ? ", $older_than);
  
}




/**
 * Create a new batch process.
 * 
 * 
 *
 * @param $batch
 *   This is an array containing everything we need to know about the batch we are creating.
 *   The non-required fields will be substituted with default values if left out.
 * 
 *    - operation :[REQUIRED] an array containing the callback function to execute plus any arguments.  Ex:  "operation" => array('my_function_to_call', array($arg1, $arg2))
 *    - finished_callback  : an array containing the callback function and args to call once we are finished with the batch.  
 *          Ex:  "finished_callback" => array('my_finished_function', array($arg1, $arg2))
 *          Generally, this field is optional.  Since batches are usually set up in a form's submit handler, the default behavior is to go to whatever the form's destination
 *          was.  You can override that here, however.
 *    - title     : A title to display to the user while the batch is running.  Ex:  'title' => t('Processing Batch...')
 *    - progress_message : A message to be displayed while the batch runs.  It may use replacement patterns: @current, @total, @percent.
 *          Ex:  'progress_message' => 'Processed @current out of @total.'  // Do NOT run through t()!  It will be done at run time.
 *    - file      : An optional file system path to a file where the batch's operation and/or finished functions reside.  Ex: "file" => menu_get_module_path("my_example") . "/runme.inc"
 *    - success_message : An optional message which will display to the user when the batch is complete.  Ex:  "The process is now complete."
 *    - display_percent : boolean, default FALSE.  If set to TRUE, display percentage value in progress bar.
 * 
 * 
 * @return $batch_id - the id from batch_queue table for this batch.
 */
function batch_set($batch) {
  global $user;


  if (!isset($batch["title"])) {
    $batch["title"] = t("Processing Batch...");    
  }
  if (!isset($batch["progress_message"])) {
    $batch["progress_message"] = t("Processed @current out of @total.");
  }
  if (!isset($batch["display_percent"])) {
    $batch["display_percent"] = FALSE;
  }
  
  // Add to the database
  $ser_batch = serialize($batch);
  
  $token = batch_get_token();
  db_query("INSERT INTO batch_queue (token, created, batch_data)
            VALUES ('?', '?', '?') ", $token, time(), $ser_batch);  
  $batch_id = db_insert_id();
  
  // Set a session variable so we are aware of this batch process's existence, so we can call it from system's handle_form_submit if necessary.
  $_SESSION["fp_batch_id"] = $batch_id;
  
  
  // Return back the $bid for the next function to work with.
  return $batch_id;
  
}


/**
 * Return the batch_data array for this batch_id, or FALSE if it doesn't exist or can't be unserialized.
 *
 * @param unknown_type $batch_id
 */
function batch_get($batch_id) {
  $res = db_query("SELECT * FROM batch_queue 
                   WHERE batch_id = ? ", $batch_id);
  $cur = db_fetch_array($res);
  
  if ($batch = unserialize($cur["batch_data"])) {
    $batch["batch_id"] = $batch_id;
    $batch["token"] = $cur["token"];
    $batch["created"] = $cur["created"];
    
    return $batch;
  }
  
  return FALSE;
  
}




/**
 * Return a token for this user.
 *
 */
function batch_get_token() {
  global $user;
  
  $uid = 0;
  if (isset($user->user_id)) {
    $uid = $user->user_id;  
  }
  
  // Return back md5 of user_id + session_id.
  return md5($uid . session_id());
  
}


/**
 * Implementation of hook_perm
 *
 */
function batch_perm() {
  
  $perms = array (
    "batch_run_test" => array(
      "title" => t("Run test batch function"),
      "description" => t("This is only useful for developers.  It allows a user to execute a test batch process by visiting example.com/batch-test-form in their browser."),
    ),
  );

  return $perms;
}


/**
 * A batch process is being initiated from a form submission.
 *
 * @param unknown_type $batch_id
 */
function batch_start_batch_from_form_submit($batch_id, $redirect_path = "", $redirect_query = "") {
    
  // We need to confirm that this user is allowed to access THIS batch.
  $current_user_token = batch_get_token();
  
  
  $batch = batch_get($batch_id);
    
  
  if ($batch["token"] == $current_user_token) {  
    // Yes, we can proceed!
    
    // If there isn't a finished_callback set, we will set it using fp_goto() to return to the original form's redirect path and query.
    if (!isset($batch["finished_callback"])) {
      $batch["finished_callback"] = array("fp_goto", array($redirect_path, $redirect_query));
      // Update the database...
      db_query("UPDATE batch_queue
                SET batch_data = '?'
                WHERE batch_id = '?'", serialize($batch), $batch_id);
    }
    
    
    
    
    // Let's fp_goto to our batch-processing page...
    fp_goto("batch-processing/$batch_id");
    
  }
  else {
    // No... some problem.
    fp_add_message(t("Sorry, this batch process could not be initialized.  Bad token, or batch does not exist?"), "error");
    return;
  }
  
  
  
  
}