<?php

/**
 * @file
 * Allow ubercart products to have stock levels associated with their SKU
 *
 * uc_stock enables ubercart to manage stock for products. Store admins can set
 * the stock levels on a product edit page and a threshold for each SKU value
 * When that threshold is reached admins can be optionally notified about the
 * current stock level. Store admins can view all stock levels in the reports
 * section of Ubercart.
 */

/**
 * Implements hook_help().
 */
function uc_stock_help($path, $arg) {
  switch ($path) {
    case 'node/%/edit/stock':
      return '<p>' . t('To keep track of stock for a particular product SKU, make sure it is marked as active and enter a stock value. When the stock level drops below the threshold value, you can be notified based on your stock settings.') . '</p>';

    case 'admin/store/reports/stock':
    case 'admin/store/reports/stock/threshold':
      return '<p>' . t('This is the list of product SKUs that are currently active. Stock levels below their threshold have highlighted rows. Toggle the checkbox below to alter which stock levels are shown.') . '</p>';
  }
}

/**
 * Implements hook_menu().
 */
function uc_stock_menu() {
  $items = array();

  $items['admin/store/settings/stock'] = array(
    'title' => 'Stock notifications',
    'description' => 'Enable or disable stock level notifications.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('uc_stock_settings_form'),
    'access arguments' => array('administer product stock'),
    'file' => 'uc_stock.admin.inc',
  );
  if (module_exists('uc_reports')) {
    $items['admin/store/reports/stock'] = array(
      'title' => 'Stock reports',
      'description' => 'View reports for product stock.',
      'page callback' => 'uc_stock_report',
      'access arguments' => array('view reports'),
      'file' => 'uc_stock.admin.inc',
    );
  }
  $items['node/%node/edit/stock'] = array(
    'title' => 'Stock',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('uc_stock_edit_form', 1),
    'access callback' => 'uc_stock_product_access',
    'access arguments' => array(1),
    'weight' => 10,
    'type' => MENU_LOCAL_TASK,
    'file' => 'uc_stock.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_admin_paths().
 */
function uc_stock_admin_paths() {
  $paths = array(
    'node/*/edit/stock' => TRUE,
  );

  return $paths;
}

/**
 * Access callback for node/%node/edit/stock.
 */
function uc_stock_product_access($node) {
  if ($node->type == 'product_kit') {
    return FALSE;
  }

  return uc_product_is_product($node) && node_access('update', $node) && user_access('administer product stock');
}

/**
 * Implements hook_permission().
 */
function uc_stock_permission() {
  return array(
    'administer product stock' => array(
      'title' => t('Administer product stock'),
    ),
  );
}

/**
 * Implements hook_theme().
 */
function uc_stock_theme() {
  return array(
    'uc_stock_edit_form' => array(
      'render element' => 'form',
      'file' => 'uc_stock.admin.inc',
    ),
  );
}

/**
 * Implements hook_mail().
 */
function uc_stock_mail($key, &$message, $params) {
  switch ($key) {
    case 'threshold':
      $message['subject'] = $params['subject'];
      $message['body'][] = $params['body'];
      break;
  }
}

/**
 * Implements hook_uc_message().
 */
function uc_stock_uc_message() {
  $messages['uc_stock_threshold_notification_subject'] = t('[store:name]: Stock threshold limit reached');
  $messages['uc_stock_threshold_notification_message'] = t('This message has been sent to let you know that the stock level for "[node:title]" with SKU [uc_stock:model] has reached [uc_stock:level]. There may not be enough units in stock to fulfill order #[uc_order:link].');
  return $messages;
}

/**
 * Adjusts the product stock level by a set amount.
 *
 * @param $sku
 *   The product SKU of the stock level to adjust.
 * @param $qty
 *   The amount to add to or subtract from the stock level.
 * @param $check_active
 *   If FALSE, don't check if stock tracking is active for this SKU.
 */
function uc_stock_adjust($sku, $qty, $check_active = TRUE) {
  $stock = db_query("SELECT active, stock FROM {uc_product_stock} WHERE sku = :sku", array(':sku' => $sku))->fetchObject();

  if ($check_active) {
    if (!$stock || !$stock->active) {
      return;
    }
  }

  db_update('uc_product_stock')
    ->expression('stock', 'stock + :qty', array(':qty' => $qty))
    ->condition('sku', $sku)
    ->execute();

  module_invoke_all('uc_stock_adjusted', $sku, $stock->stock, $qty);
}

/**
 * Sets the product stock level.
 *
 * @param $sku
 *   The product SKU of the stock level to set.
 * @param $qty
 *   The number of items in stock.
 */
function uc_stock_set($sku, $qty) {
  db_update('uc_product_stock')
    ->fields(array('stock' => $qty))
    ->condition('sku', $sku)
    ->execute();
}

/**
 * Gets the stock level of a particular product SKU.
 *
 * @param $sku
 *   The Ubercart product SKU of the stock level to return.
 *
 * @return
 *   The SKU's stock level, or FALSE if not active.
 */
function uc_stock_level($sku) {
  $stock = db_query("SELECT active, stock FROM {uc_product_stock} WHERE sku = :sku", array(':sku' => $sku))->fetchObject();

  if ($stock && $stock->active) {
    return $stock->stock;
  }

  return FALSE;
}

/**
 * Checks if a SKU has an active stock record.
 *
 * @param $sku
 *   The Ubercart product SKU to check
 *
 * @return
 *   Boolean indicating whether or not the sku has an active stock record.
 */
function uc_stock_is_active($sku) {
  return (bool) db_query("SELECT active FROM {uc_product_stock} WHERE sku = :sku", array(':sku' => $sku))->fetchField();
}

/**
 * Emails administrator regarding any stock level thresholds hit.
 *
 * @param $order
 *   The order object that tripped the threshold limit.
 * @param $node
 *   The node object that is associated with the SKU/model.
 * @param $stock
 *   The stock level object that contains the stock level and SKU.
 *
 * @return
 *   The result of drupal_mail().
 */
function _uc_stock_send_mail($order, $node, $stock) {
  $account = user_load($order->uid);
  $token_filters = array('uc_order' => $order, 'user' => $account, 'uc_stock' => $stock, 'node' => $node);

  $to = variable_get('uc_stock_threshold_notification_recipients', uc_store_email());
  $to = explode(',', $to);

  $from = uc_store_email_from();

  $subject = variable_get('uc_stock_threshold_notification_subject', uc_get_message('uc_stock_threshold_notification_subject'));
  $subject = token_replace($subject, $token_filters);

  $body = variable_get('uc_stock_threshold_notification_message', uc_get_message('uc_stock_threshold_notification_message'));
  $body = token_replace($body, $token_filters);

  // Send to each recipient.
  foreach ($to as $email) {
    $sent = drupal_mail('uc_stock', 'threshold', $email, uc_store_mail_recipient_language($email), array('body' => $body, 'subject' => $subject, 'order' => $order, 'stock' => $stock), $from);

    if (!$sent['result']) {
      watchdog('uc_stock', 'Attempt to e-mail @email concerning stock level on sku @sku failed.', array('@email' => $email, '@sku' => $stock->sku), WATCHDOG_ERROR);
    }
  }
}

/**
 * Implements hook_views_api().
 */
function uc_stock_views_api() {
  return array(
    'api' => '2.0',
    'path' => drupal_get_path('module', 'uc_stock') . '/views',
  );
}

/**
 * Decrement a product's stock.
 *
 * @param $product
 *   The product whose stock is being adjusted.
 * @param $key
 *   Internal, so this function can be used as a callback of array_walk().
 * @param $order
 *   Order object.
 */
function uc_stock_adjust_product_stock($product, $key, $order) {
  // Product has an active stock?
  if (!uc_stock_is_active($product->model)) {
    return;
  }

  // Do nothing if decrement quantity is 0.
  if ($product->qty == 0) {
    return;
  }

  // Adjust the product's stock.
  uc_stock_adjust($product->model, -$product->qty);

  // Load the new stock record.
  $stock = db_query("SELECT * FROM {uc_product_stock} WHERE sku = :sku", array(':sku' => $product->model))->fetchObject();

  // Should we notify?
  if (variable_get('uc_stock_threshold_notification', FALSE) && $stock->stock <= $stock->threshold) {
    $node = node_load($product->nid);
    _uc_stock_send_mail($order, $node, $stock);
  }

  // Save a comment about the stock level.
  uc_order_comment_save($order->order_id, 0, t('The stock level for %model_name has been !action to !qty.', array('%model_name' => $product->model, '!qty' => $stock->stock, '!action' => (-$product->qty <= 0) ? t('decreased') : t('increased') )));
}

/**
 * Increment a product's stock.
 */
function uc_stock_increment_product_stock($product, $key, $order) {
  $product->qty = -$product->qty;
  return uc_stock_adjust_product_stock($product, $key, $order);
}