<?php

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

  $items['admin/config/development/myhook'] = array(
    'title' => 'MyHook Administration',
    'page callback' => 'myhookadmin_admin',
    'access arguments' => array('define custom hooks'),
    'file' => 'myhookadmin.inc',
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function myhookadmin_permission() {
  return array(
    'define custom hooks' => array(
      'title' => 'Define custom hooks',
      'restrict access' => TRUE,
    ),
  );
}

/**
 * Gets a myhook variable
 */
function myhookadmin_var_get($name, $default = NULL, $reset = FALSE) {
  static $vars = array();
  if ($reset || !array_key_exists($name, $vars)) {
    $vars[$name] = db_query('SELECT value FROM {myhookadmin} WHERE name = :name', array(':name' => $name))->fetchField();
  }
  return isset($vars[$name]) ? $vars[$name] : $default;
}

/**
 * Sets a myhook variable
 */
function myhookadmin_var_set($name, $value = NULL) {
  db_delete('myhookadmin')->condition('name', $name)->execute();
  isset($value) && db_insert('myhookadmin')->fields(array('name' => $name, 'value' => $value))->execute();
  myhookadmin_var_get($name, NULL, TRUE);
}

/**
 * Includes/evaluates custom code/hooks.
 */
function myhookadmin_myhook() {
  if (isset($_GET['myhook']) && !$_GET['myhook']) {
    module_load_include('module', 'user');
    if (user_access('define custom hooks')) {
      return;
    }
  }

  // Include file
  if (variable_get('myhookadmin_is_inc', 0)) {
    $inc_path = variable_get('myhookadmin_inc_path', '');
    if ($inc_path && @is_readable($inc_path)) {
      $included = include_once $inc_path;
      if ($included) {
        return;
      }
    }
  }

  // Include failed. Eval code.
  $code = myhookadmin_var_get('myhook_code');
  if (!empty($code)) {
    eval($code);
  }
}

// Include/execute custom code/myhooks.
module_exists('myhook') && myhookadmin_myhook();