<?php

/**
 * @file
 * Module file for page_example_module.
 */

/**
 * @defgroup page_example Example: Page
 * @ingroup examples
 * @{
 * This example demonstrates how a module can display a page at a given URL.
 *
 * It's important to understand how the menu system works in order to
 * implement your own pages. See the Menu Example module for some insight.
 *
 * @see menu_example
 */

/**
 * Implements hook_help().
 *
 * Through hook_help(), a module can make documentation available to the user
 * for the module as a whole or for specific paths. Where the help appears
 * depends on the $path specified.
 *
 * In the first example below, the help text will appear on the simple page
 * defined in hook_menu below in the region designated for help text.
 *
 * In the second example, the text will be available through the module page as
 * a link beside the module or on the admin help page (admin/help) in the list
 * of help topics using the name of the module. To specify help in the admin
 * section use the module name in the path as in the second case below.
 *
 * @see hook_help()
 */
function page_example_help($path, $arg) {
  switch ($path) {
    case 'examples/page_example/simple':
      // Help text for the simple page registered for this path.
      return t('This is help text for the simple page.');

    case 'admin/help#page_example':
      // Help text for the admin section, using the module name in the path.
      return t("This is help text created in the page example's second case.");
  }
}

/**
 * Implements hook_permission().
 *
 * Since the access to our new custom pages will be granted based on
 * special permissions, we need to define what those permissions are here.
 * This ensures that they are available to enable on the user role
 * administration pages.
 */
function page_example_permission() {
  return array(
    'access simple page' => array(
      'title' => t('Access simple page'),
      'description' => t('Allow users to access simple page'),
    ),
    'access arguments page' => array(
      'title' => t('Access page with arguments'),
      'description' => t('Allow users to access page with arguments'),
    ),
  );
}

/**
 * Implements hook_menu().
 *
 * Because hook_menu() registers URL paths for items defined by the function, it
 * is necessary for modules that create pages. Each item can also specify a
 * callback function for a given URL. The menu items returned here provide this
 * information to the menu system.
 *
 * We will define some menus, and their paths will be interpreted as follows:
 *
 * If the user accesses http://example.com/?q=examples/page_example/simple,
 * the menu system will first look for a menu item with that path. In this case
 * it will find a match, and execute page_example_simple().
 *
 * If the user accesses http://example.com/?q=examples/page_example/arguments,
 * the menu system will find no explicit match, and will fall back to the
 * closest match, 'examples/page_example', executing page_example_description().
 *
 * If the user accesses
 * http://example.com/?q=examples/page_example/arguments/1/2, the menu
 * system will first look for examples/page_example/arguments/1/2. Not finding
 * a match, it will look for examples/page_example/arguments/1/%. Again not
 * finding a match, it will look for examples/page_example/arguments/%/2.
 * Yet again not finding a match, it will look for
 * examples/page_example/arguments/%/%. This time it finds a match, and so will
 * execute page_example_arguments(1, 2). Since the parameters are passed to
 * the function after the match, the function can do additional checking or
 * make use of them before executing the callback function.
 *
 * @see hook_menu()
 * @see menu_example
 */
function page_example_menu() {

  // This is the minimum information you can provide for a menu item. This menu
  // item will be created in the default menu, usually Navigation.
  $items['examples/page_example'] = array(
    'title' => 'Page Example',
    'page callback' => 'page_example_description',
    'access callback' => TRUE,
    'expanded' => TRUE,
  );

  $items['examples/page_example/simple'] = array(
    'title' => 'Simple - no arguments',
    'page callback' => 'page_example_simple',
    'access arguments' => array('access simple page'),
  );

  // By using the MENU_CALLBACK type, we can register the callback for this
  // path without the item appearing in the menu; the admin cannot enable the
  // item in the menu, either.
  //
  // Notice that 'page arguments' is an array of numbers. These will be
  // replaced with the corresponding parts of the menu path. In this case a 0
  // would be replaced by 'examples', a 1 by 'page_example', and a 2 by
  // 'arguments.' 3 and 4 will be replaced by whatever the user provides.
  // These will be passed as arguments to the page_example_arguments() function.
  $items['examples/page_example/arguments/%/%'] = array(
    'page callback' => 'page_example_arguments',
    'page arguments' => array(3, 4),
    'access arguments' => array('access arguments page'),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Constructs a descriptive page.
 *
 * Our menu maps this function to the path 'examples/page_example'.
 */
function page_example_description() {
  return array(
    '#markup' =>
    t('<p>The page_example provides two pages, "simple" and "arguments".</p><p>The <a href="@simple_link">simple page</a> just returns a renderable array for display.</p><p>The <a href="@arguments_link">arguments page</a> takes two arguments and displays them, as in @arguments_link</p>',
      array(
        '@simple_link' => url('examples/page_example/simple', array('absolute' => TRUE)),
        '@arguments_link' => url('examples/page_example/arguments/23/56', array('absolute' => TRUE)),
      )
    ),
  );
}

/**
 * Constructs a simple page.
 *
 * The simple page callback, mapped to the path 'examples/page_example/simple'.
 *
 * Page callbacks return a renderable array with the content area of the page.
 * The theme system will later render and surround the content in the
 * appropriate blocks, navigation, and styling.
 *
 * If you do not want to use the theme system (for example for outputting an
 * image or XML), you should print the content yourself and not return anything.
 */
function page_example_simple() {
  return array('#markup' => '<p>' . t('Simple page: The quick brown fox jumps over the lazy dog.') . '</p>');
}

/**
 * A more complex page callback that takes arguments.
 *
 * This callback is mapped to the path 'examples/page_example/arguments/%/%'.
 *
 * The % arguments are passed in from the page URL. In our hook_menu
 * implementation we instructed the menu system to extract the last two
 * parameters of the path and pass them to this function as arguments.
 *
 * This function also demonstrates a more complex render array in the returned
 * values. Instead of just rendering the HTML with a theme('item_list'), the
 * list is left unrendered, and a #theme attached to it so that it can be
 * rendered as late as possible, giving more parts of the system a chance to
 * change it if necessary.
 *
 * Consult @link http://drupal.org/node/930760 Render Arrays documentation
 * @endlink for details.
 */
function page_example_arguments($first, $second) {
  // Make sure you don't trust the URL to be safe! Always check for exploits.
  if (!is_numeric($first) || !is_numeric($second)) {
    // We will just show a standard "access denied" page in this case.
    drupal_access_denied();
    // We actually don't get here.
    return;
  }

  $list[] = t("First number was @number.", array('@number' => $first));
  $list[] = t("Second number was @number.", array('@number' => $second));
  $list[] = t('The total was @number.', array('@number' => $first + $second));

  $render_array['page_example_arguments'] = array(
    // The theme function to apply to the #items.
    '#theme' => 'item_list',
    // The list itself.
    '#items' => $list,
    '#title' => t('Argument Information'),
  );
  return $render_array;
}
/**
 * @} End of "defgroup page_example".
 */
