<?php

/**
 * @file
 * Business logic for Muamba.
 */

/**
 * Request an item.
 *
 * @param $nid
 *   Requested item.
 */
function muamba_request($nid) {
  global $user;
  $nid  = (int) $nid;
  $node = node_load($nid);

  // Access check
  if (!$node || $node->type != MUAMBA_NODE_TYPE || !node_access('view', $node)) {
    drupal_not_found();
  }

  // Check if user is blocked by the item owner
  if (module_exists('pm_block_user')) {
    $owner = user_load($node->uid);
    if (pm_block_user_has_blocked($user, $owner)) {
      return t('The item owner has blocked you from asking this item.');
    }
  }

  // Check if user already requested the item
  if (muamba_check_user_request($nid, $user->uid)) {
    return t('You already requested this item.');
  }

  // Notify item owner
  $thread = privatemsg_new_thread(array(user_load($node->uid)), t('Item request'), 'User has requested an item');
  $thread_id = $thread['message']->thread_id;

  // Issue item request
  $request = db_insert('muamba')
    ->fields(
      array(
        'nid'       => $nid,
        'owner'     => $node->uid,
        'uid'       => $user->uid,
        'status'    => MUAMBA_REQUESTED,
        'thread_id' => $thread_id,
      )
    )
    ->execute();

  // User output
  return t('You have requested an item');
}

/**
 * Check if user already requested an item.
 *
 * @param $nid
 *   Item nid.
 *
 * @param $uid
 *   Requester user nid.
 *
 * @return
 *   TRUE if user already requested an item, FALSE otherwise.
 */
function muamba_check_user_request($nid, $uid) {
  $nid = (int) $nid;
  $uid = (int) $uid;

  $query = db_select('muamba', 'm');

  $query
    ->condition('m.nid', $nid, '=')
    ->condition('m.uid', $uid, '=')
    ->condition('m.status', MUAMBA_REQUESTED, '=');

  $result = $query->countQuery()->execute()->fetchField();

  if ($result > 0) {
    return TRUE;
  }

  return FALSE;
}

/**
 * Get the requests sent or received.
 *
 * @param $uid
 *   Requester user uid.
 */
function muamba_get_transactions($uid, $type = 'sent', $status = MUAMBA_REQUESTED) {
  $uid   = (int) $uid;
  $query = db_select('muamba', 'm');

  if ($type == 'sent') {
    $query
      ->condition('m.uid', $uid, '=')
      ->condition('m.status', $status, '=')
      ->fields('m', array('mid', 'uid', 'owner', 'thread_id'));
  }
  else {
    $query
      ->condition('m.owner', $uid, '=')
      ->condition('m.status', $status, '=')
      ->fields('m', array('mid', 'uid', 'owner', 'thread_id'));
  }

  return $query->execute()->fetchAll();
}

/**
 * Transaction management page.
 */
function muamba() {
  global $user;

  $sent     = muamba_get_transactions($user->uid);
  $received = muamba_get_transactions($user->uid, 'received');

  $output  = theme('muamba_transactions', array('transactions' => $sent));
  $output .= theme('muamba_transactions', array('transactions' => $received));

  return $output;
}

/**
 * Accept a transaction request.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_accept($mid) {
}

/**
 * Reject a transaction request.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_reject($mid) {
}

/**
 * Release a transaction.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_release($mid) {
  global $user;

  // TODO: load nid from db
  $nid  = (int) $nid;
  $node = node_load($nid);

  if (!$node || $node->type != MUAMBA_NODE_TYPE) {
    drupal_not_found();
  }

  if ($node->uid != $user->uid) {
    // TODO: not node owner
  }
}


/**
 * Return an item.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_return($mid) {
}