<?php

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

/**
 * Determine possible actions for a transaction.
 *
 * @param $type
 *   Transaction type (sent or received).
 *
 * @param $status
 *   Current transaction status.
 *
 * @return
 *   Array of available action codes.
 */
function muamba_actions_available($type = 'sent', $status) {
  if ($type == 'sent') {
    switch ($status) {
    case MUAMBA_REQUESTED:
      $actions = array(
        MUAMBA_CANCELLED,
        );
      break;

    case MUAMBA_ACCEPTED:
      $actions = array(
        MUAMBA_RETURNED,
        );
      break;

    case MUAMBA_LOST:
      $actions = array(
        MUAMBA_RETURN,
        );
      break;

    default:
      $actions = array();
    }
  }
  else {
    switch ($status) {
    case MUAMBA_REQUESTED:
      $actions = array(
        MUAMBA_ACCEPTED,
        MUAMBA_REJECTED,
        );
      break;

    case MUAMBA_ACCEPTED:
      $actions = array(
        MUAMBA_RECOVERED,
        MUAMBA_LOST,
        );
      break;

    case MUAMBA_RETURNED:
      $actions = array(
        MUAMBA_RECOVERED,
        MUAMBA_LOST,
        );
      break;

    case MUAMBA_LOST:
      $actions = array(
        MUAMBA_RECOVERED,
        );
      break;

    default:
      $actions = array();
    }
  }

  return $actions;
}

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

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

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

  return $output;
}

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

  // Access check
  if (!muamba_has_request_access($node)) {
    drupal_not_found();
  }

  // Check if user is blocked by the item owner
  if (muamba_user_has_blocked($node, $user)) {
    return t('The item owner has blocked you from asking this item.');
  }

  // TODO: check if the item is available

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

  // Create transaction
  $transaction = array(
    'nid'    => $nid,
    'owner'  => $node->uid,
    'uid'    => $user->uid,
    'status' => MUAMBA_REQUESTED,
  );

  // Issue item request
  $transaction['mid'] = db_insert('muamba')
    ->fields($transaction)
    ->execute();

  // Notify item owner
  $subject   = t('Item request: @title', array('@title' => check_plain($node->title)));
  $message   = theme('muamba_request_message', array('transaction' => $transaction));
  $thread    = privatemsg_new_thread(array(user_load($node->uid)), $subject , $message);
  $thread_id = $thread['message']->thread_id;

  // Update request with thread id
  $update = db_update('muamba')
    ->fields(array(
      'thread_id' => $thread_id,
    ))
    ->condition('mid', $transaction['mid'], '=')
    ->execute();

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

/**
 * Accept a transaction request.
 *
 * @param $mid
 *   Transaction id.
 */
function muamba_accept($mid) {
  global $user;
  $mid         = (int) $mid;
  $transaction = muamba_get_transaction($mid);
  $node        = node_load($transaction->nid);

  // Access check
  if (!muamba_has_management_access($node)) {
    drupal_not_found();
  }

  // Status check
  if ($transaction->status != MUAMBA_REQUESTED) {
    drupal_not_found();
  }

  // Update database
  $update = db_update('muamba')
    ->fields(array(
      'status' => MUAMBA_ACCEPTED,
    ))
    ->condition('mid', $mid, '=')
    ->execute();

  // Notify item owner
  $message = theme('muamba_accept_message', array('transaction' => $transaction));
  $reply   = privatemsg_reply($transaction['thread_id'], $message);

  return t('Accepted item request.');
}

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

/**
 * Cancel a request.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_cancel($mid) {
}

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

/**
 * Recover an item.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_recover($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
  }
}

/**
 * Report a lost item.
 *
 * @param $mid
 *   Transaction id.
 *
 * @todo
 */
function muamba_lost($mid) {
}