collapseOperation

gistfile1.txt

// get a collapsed operations array
private function collapseOperations($operations) {
  
  // setup a glossary of operations categorized by name
  $glossary = parseOperationsByName($operations);
  
  // serialize leftover operations
  $result = [];
  foreach ($glossary as $operation) {
    $result = array_merge($result, $operation);
  }
  return $result;
}

// get a glossary array in the following format:
// $glossary = [
//   '<operation name>' => [
//     <operation array 1>,
//     <operation array 2>,
//   ]
// ]
private function parseOperationsByName($operations) {
  $glossary = [];
  $matchingOperations = [
    'add'     => 'remove',
    'remove'  => 'add'
  ];

  foreach ($operations as $operation) {  
    // if operation name already exists, check details. else add operation with operation name as key
    if (array_key_exists($operation['name'], $glossary)) {
      foreach ($glossary[$operation['name']] as $key => $op) {
        // remove matching operations for this operation name, otherwise add the operation to array
        if (array_key_exists($operation['op'], $matchingOperations) &&
          $matchingOperations[$operation['op']] === $op['op']) {
          unset($glossary[$operation['name']][$key]);
        } else {
          // is not a matching operation, push into array
          array_push($glossary[$operation['name']], $op);
        }
        // remove names with empty operations
        if (empty($glossary[$operation['name']])) {
          unset($glossary[$operation['name']]);
        }
      }
    } else {
      $glossary[$operation['name']] = array($operation);
    }
  }
  return $glossary;
}