cardSortingAlg

<?php
function cardDance() {
  $cards = array(
    'rpid00001' => array(
      'delta' => 1,
      'status' => 'A',
    ),
    'rpid00002' => array(
      'delta' => 2,
      'status' => 'B',
    ),
    'rpid00003' => array(
      'delta' => 3,
      'status' => 'B',
    ),
    'rpid00004' => array(
      'delta' => 4,
      'status' => 'A',
    ),
    'rpid00005' => array(
      'delta' => 5,
      'status' => 'B',
    ),
  );
  moveCards($cards);
  print_r($cards);
}

function moveCards(&$rpid_cards) {
  $cards = array();
  $max_delta = count($rpid_cards);
  // reorganize cards by delta
  foreach ($rpid_cards as $rpid => $card) {
    $delta = $card['delta'];
    $cards[$delta] = $card;
    $cards[$delta]['rpid'] = $rpid;
  }

  // Sort by delta
  sortRecursive($cards);

  // update array
  foreach ($cards as $delta => $card) {
    $rpid_cards[$card['rpid']]['delta'] = $delta;
  }
}

function sortRecursive(&$cards) {
  foreach ($cards as $delta => $card) {
    if (isset($cards[$delta + 1])) {
      $below = $cards[$delta + 1];
      if ($below['status'] == 'B' && $card['status'] != 'B') {
        $cards[$delta + 1] = $card;
        $cards[$delta] = $below;
        return sortRecursive($cards);
      }
    }
  }
  return $cards;
}

cardDance();