<?php
/**
 * @file
 * Provides infrequently used functions and hooks for menu_position.
 */

/**
 * Routes menu_position links to homepage; normally overridden.
 */
function menu_position_router() {
  drupal_goto('<front>');
}

/**
 * Form definition: global settings for Menu position rules.
 */
function menu_position_settings_form($form, &$form_state) {
  $form = array();
  $form['menu_position_active_link_display'] = array(
    '#type' => 'radios',
    '#title' => t('When a menu position rule matches:'),
    '#options' => array(
      'child' => t("Insert the current page's title into the menu tree."),
      'parent' => t('Mark the rule\'s parent menu item as being "active".'),
      'none' => t('Don\'t mark any menu item as being "active".'),
    ),
    '#default_value' => variable_get('menu_position_active_link_display', 'child'),
    '#description' => t("By default, a matching menu position rule will insert the current page's title into the menu tree just below the rule's parent menu item."),
  );
  return system_settings_form($form);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function _menu_position_form_menu_overview_form_alter(&$form, &$form_state) {
  // Retrieve all of the rules' mlids.
  $rules = db_query('SELECT rid, mlid FROM {menu_position_rules} WHERE enabled = :enabled ORDER BY weight, rid', array(':enabled' => 1));
  foreach ($rules as $rule) {
    $mlid = $rule->mlid;
    if (!empty($form['mlid:' . $mlid]['#item']['mlid']) && $mlid == $form['mlid:' . $mlid]['#item']['mlid']) {
      // Remove link and "disabled" text from the menu item's title.
      $form['mlid:' . $mlid]['title']['#markup'] = strip_tags(str_replace(' (' . t('disabled') . ')', '', $form['mlid:' . $mlid]['title']['#markup']));
      // Ensure that the menu item cannot be enabled.
      $form['mlid:' . $mlid]['hidden']['#default_value'] = TRUE;
      $form['mlid:' . $mlid]['hidden']['#disabled'] = TRUE;
      // Alter the edit link for this menu item.
      $form['mlid:' . $mlid]['operations']['edit']['#href'] = 'admin/structure/menu-position/edit/' . $rule->rid;
      $form['mlid:' . $mlid]['operations']['edit']['#options'] = array('query' => array('destination' => $_GET['q']));
    }
  }
}

/**
 * Implements hook_form_menu_edit_item_alter().
 *
 * This handles the edge case of another module accidentally exposing (or of a
 * user hacking the URL to) the standard "menu link edit" form for a menu
 * position rule's hidden menu link. We alter the form so that it is not posible
 * for the link to be edited.
 */
function _menu_position_form_menu_edit_item_alter(&$form, &$form_state) {
  if ($form['mlid']['#value'] == 0) {
    return;
  }
  // Retrieve all of the rules' mlids.
  $mlids = db_query('SELECT mlid FROM {menu_position_rules} WHERE mlid = :mlid ORDER BY weight, rid', array(':mlid' => (int) $form['mlid']['#value']))->fetchAll();
  if (!empty($mlids)) {
    // If the form hasn't been submitted, display a warning.
    if (empty($form_state['input'])) {
      drupal_set_message(t('This menu item cannot be edited.'), 'warning');
    }
    // Disable all the normal form elements.
    foreach (array('link_title', 'description', 'enabled', 'expanded', 'parent', 'weight') as $key) {
      $form[$key]['#disabled'] = TRUE;
    }
    // Remove the validator.
    $key = array_search('menu_edit_item_validate', $form['#validate']);
    if ($key !== FALSE) {
      unset($form['#validate'][$key]);
    }
    // Replace the standard submit handler with our own.
    $key = array_search('menu_edit_item_submit', $form['#submit']);
    if ($key !== FALSE) {
      $form['#submit'][$key] = 'menu_position_edit_item_submit';
    }
    // Replace the Save button with a Cancel button.
    unset($form['actions']['submit']);
    $form['actions']['cancel'] = array(
      '#type' => 'submit',
      '#value' => t('Cancel'),
    );
  }
}

/**
 * Implements hook_menu_link_update().
 */
function _menu_position_menu_link_update($link) {
  $rules = db_query('SELECT rid, plid FROM {menu_position_rules} WHERE mlid = :mlid ORDER BY weight, rid', array(':mlid' => $link['mlid']));
  foreach ($rules as $rule) {
    // Check if the user has altered the parent menu item.
    if ($link['plid'] != $rule->plid) {
      // Update the rule with the new parent.
      db_update('menu_position_rules')
        ->fields(array(
          'menu_name' => $link['menu_name'],
          'plid' => $link['plid'],
          ))
        ->condition('rid', $rule->rid)
        ->execute();
    }
  }
}

/**
 * Process menu and menu item add/edit form submissions for menu_position links.
 */
function menu_position_edit_item_submit($form, &$form_state) {
  // Redirect to the menu edit form and display a message.
  list($menu_name, ) = explode(':', $form['parent']['#default_value']);
  $form_state['redirect'] = 'admin/structure/menu/manage/' . $menu_name;
  drupal_set_message(t('Your configuration was not saved.'), 'error');
}

/**
 * Fix rules after module has been re-enabled.
 *
 * During menu_position_enable(), existing rules are flagged with a zero-value
 * mlid. We fix that here.
 */
function menu_position_enable_helper() {
  // Find rules with zero-value menu links.
  $rules = db_query('SELECT rid, plid, admin_title FROM {menu_position_rules} WHERE enabled = :enabled AND mlid = :mlid', array(':enabled' => 1, ':mlid' => 0))->fetchAll();
  if (!empty($rules)) {
    drupal_set_message(t('Existing menu position rules were discovered and have now been re-configured so they will continue to work.'));
  }
  foreach ($rules as $rule) {
    $mlid = menu_position_add_menu_link($rule->rid, $rule->plid, $rule->admin_title);
    db_update('menu_position_rules')
      ->fields(array('mlid' => $mlid))
      ->condition('rid', $rule->rid)
      ->execute();
  }
}

/**
 * Menu callback: orders rules.
 */
function menu_position_rules_form_callback() {
  // This is a total hack. @see menu_position_enable(). You shouldn't be doing
  // non-Form API stuff in a form definition. So we've created this wrapper
  // callback to run the hack and then return the form definition.
  menu_position_enable_helper();

  return drupal_get_form('menu_position_rules_form');
}

/**
 * Form definition: orders rules.
 */
function menu_position_rules_form($form, &$form_state) {
  // We're re-using classes from the menu module.
  $form['#attached']['css'] = array(drupal_get_path('module', 'menu') . '/menu.css');

  $rules = db_query('SELECT rid, admin_title, plid, menu_name, enabled, weight FROM {menu_position_rules} ORDER BY weight, rid')->fetchAll();
  $delta = count($rules);

  $menus = menu_get_menus();

  // Default message if no rules.
  if ($delta == 0) {
    $form['rules'] = array(
      '#markup' => '<p>' . t('No rules have been created yet.') . '</p>',
    );
  }
  else {
    $form['rules'] = array(
      '#tree' => TRUE,
      '#theme' => 'menu_position_rules_order',
    );
    foreach ($rules as $rule) {
      $menu_link = menu_link_load($rule->plid);
      if ($menu_link === FALSE) {
        $menu_link = array('title' => '[' . t('deleted menu item') . ']');
      }
      $form['rules'][$rule->rid] = array(
        'title' => array(
          '#markup' => '<strong>' . check_plain($rule->admin_title) . '</strong> (' . t('Positioned under: %title', array('%title' => check_plain($menu_link['title']))) . ')',
        ),
        'menu_name' => array(
          '#markup' => check_plain($menus[$rule->menu_name]),
        ),
        'enabled' => array(
          '#type' => 'checkbox',
          '#default_value' => $rule->enabled,
        ),
        'weight' => array(
          '#type' => 'weight',
          '#default_value' => $rule->weight,
          '#delta' => max($delta, 5),
          '#id' => 'edit-rule-' . $rule->rid,
        ),
        'operations' => array(
          'edit-link' => array(
            '#type' => 'link',
            '#title' => t('edit'),
            '#href' => 'admin/structure/menu-position/edit/' . $rule->rid,
          ),
          'delete-link' => array(
            '#type' => 'link',
            '#title' => t('delete'),
            '#href' => 'admin/structure/menu-position/delete/' . $rule->rid,
          ),
        ),
      );
    }
    $form['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Save'),
    );
  }

  return $form;
}

/**
 * Handles form submission for menu_position_rules_form().
 */
function menu_position_rules_form_submit($form, &$form_state) {
  foreach ($form_state['values']['rules'] as $rid => $rule) {
    $fields = array(
      'enabled' => $rule['enabled'],
      'weight' => $rule['weight'],
    );
    $db_rule = db_query('SELECT * FROM {menu_position_rules} WHERE rid = :rid', array(':rid' => $rid))->fetchObject();
    if (!$rule['enabled']) {
      // If the rule has been disabled, remove the menu link.
      menu_link_delete($db_rule->mlid);
    }
    elseif (!$db_rule->enabled) {
      // If the rule has been enabled, add a menu link.
      $fields['mlid'] = menu_position_add_menu_link($rid, $db_rule->plid, $db_rule->admin_title);
    }
    db_update('menu_position_rules')
      ->fields($fields)
      ->condition('rid', $rid)
      ->execute();
  }
  drupal_set_message(t('The new rules ordering has been applied.'));
}

/**
 * Returns HTML for the menu position rules form.
 */
function theme_menu_position_rules_order($variables) {
  $element = $variables['element'];
  drupal_add_tabledrag('menu-position-rules', 'order', 'sibling', 'rule-weight');

  $variables = array(
    'header' => array(
      t('Rule'),
      t('Affected menu'),
      array(
        'data' => t('Enabled'),
        'class' => array('checkbox'),
      ),
      t('Weight'),
      array(
        'data' => t('Operations'),
        'colspan' => '2',
      ),
    ),
    'rows' => array(),
    'attributes' => array('id' => 'menu-position-rules'),
  );

  // Generate table of draggable menu names.
  foreach (element_children($element) as $rule) {
    // Add special classes to be used for tabledrag.js.
    $element[$rule]['weight']['#attributes']['class'] = array('rule-weight');
    // Render the title, enabled, and weight columns.
    $data = array(
      drupal_render($element[$rule]['title']),
      drupal_render($element[$rule]['menu_name']),
      array(
        'data' => drupal_render($element[$rule]['enabled']),
        'class' => array('checkbox', 'menu-enabled'),
      ),
      drupal_render($element[$rule]['weight']),
    );
    // Render the operations links.
    foreach (element_children($element[$rule]['operations']) as $op) {
      $data[] = array(
        'data' => drupal_render($element[$rule]['operations'][$op]),
        'class' => array('menu-operations'),
      );
    }
    $variables['rows'][] = array(
      'data' => $data,
      'class' => array('draggable'),
    );
  }

  return theme('table', $variables);
}

/**
 * Menu callback; Adds rules.
 */
function menu_position_add_rule_form($form, &$form_state) {
  return menu_position_rule_form($form, $form_state);
}

/**
 * Menu callback; Edits rules.
 */
function menu_position_edit_rule_form($form, &$form_state, $rid = 0) {
  // Make sure rid is set.
  if ($rid == 0) {
    drupal_goto('admin/structure/menu-position');
    return;
  }
  // Grab the rule from the database.
  $form_state['#menu-position-rule'] = menu_position_read_rule($rid);
  return menu_position_rule_form($form, $form_state);
}

/**
 * Returns form to add or edit a menu position rule.
 */
function menu_position_rule_form($form, &$form_state) {
  // Set the default values.
  $rid          = !empty($form_state['#menu-position-rule']['rid'])         ? $form_state['#menu-position-rule']['rid'] : '';
  $admin_title  = !empty($form_state['#menu-position-rule']['admin_title']) ? $form_state['#menu-position-rule']['admin_title'] : '';
  $machine_name = !empty($form_state['#menu-position-rule']['machine_name'])   ? $form_state['#menu-position-rule']['machine_name'] : '';
  $menu_name    = !empty($form_state['#menu-position-rule']['menu_name'])   ? $form_state['#menu-position-rule']['menu_name'] : '';
  $plid         = !empty($form_state['#menu-position-rule']['plid'])        ? $form_state['#menu-position-rule']['plid'] : NULL;
  $mlid         = !empty($form_state['#menu-position-rule']['mlid'])        ? $form_state['#menu-position-rule']['mlid'] : NULL;

  $form['rid'] = array(
    '#type' => 'hidden',
    '#value' => $rid,
  );
  $form['admin_title'] = array(
    '#type' => 'textfield',
    '#default_value' => $admin_title,
    '#title' => t('Administrative title'),
    '#description' => t('This title will be used administratively to identify this rule.'),
    '#required' => TRUE,
  );
  $form['machine_name'] = array(
    '#type' => 'machine_name',
    '#default_value' => $machine_name,
    '#title' => t('Machine name'),
    '#required' => TRUE,
    '#size' => 15,
    '#maxlength' => 255,
    '#machine_name' => array(
      'exists' => 'menu_position_machine_name_exists',
      'source' => array('admin_title'),
    ),
  );
  // Parent menu item.
  if ($mlid) {
    $options = menu_parent_options(menu_get_menus(), menu_link_load($mlid));
    $default = $menu_name . ':' . $plid;
  }
  else {
    $options = menu_parent_options(menu_get_menus(), array('mlid' => 0));
    $default = 'main-menu:0';
  }
  $form['plid'] = array(
    '#type' => 'select',
    '#title' => t('Parent menu item'),
    '#required' => TRUE,
    '#options' => $options,
    '#default_value' => $default,
    '#description' => t('Select the place in the menu where the rule should position its menu links.'),
  );

  // Place holder for all condition plug-ins.
  // Visibility settings.
  $form['conditions_title'] = array(
    '#type' => 'item',
    '#title' => t('Conditions'),
    '#description' => t('All the conditions must be met before a rule is applied.'),
  );
  $form['conditions'] = array(
    '#type' => 'vertical_tabs',
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
  );
  if ($rid) {
    $form['delete'] = array(
      '#type' => 'submit',
      '#value' => t('Delete'),
    );
  }

  // Add conditions.
  foreach (menu_position_get_plugins() as $plugin) {
    // Load the required include file.
    if (!empty($plugin['file'])) {
      $file = pathinfo($plugin['file']);
      // Allow plugins to be in a sub-directory.
      if ($file['dirname']) {
        $file['filename'] = $file['dirname'] . '/' . $file['filename'];
      }
      module_load_include($file['extension'], $plugin['module'], $file['filename']);
    }
    // Call form callback to add additional form elements.
    $function = $plugin['form_callback'];
    if (function_exists($function)) {
      $function($form, $form_state);
    }
  }

  // Form validation and submission.
  $form['#validate'][] = 'menu_position_rule_form_validate';
  $form['#submit'][] = 'menu_position_rule_form_submit';

  return $form;
}

/**
 * Helper function to check if a given machine name already exists.
 */
function menu_position_machine_name_exists($machine_name) {
  $result = db_select('menu_position_rules', 'menu_position_rules')
    ->fields('menu_position_rules')
    ->condition('machine_name', $machine_name)
    ->execute();
  $num_of_results = $result->rowCount();
  return ($num_of_results == 1) ? TRUE : FALSE;
}

/**
 * Validates the form for menu_position_rule_form().
 */
function menu_position_rule_form_validate($form, &$form_state) {
  // Check if the user deleted the rule.
  if (!empty($form['delete']) && $form_state['values']['op'] == $form['delete']['#value']) {
    drupal_goto('admin/structure/menu-position/delete/' . $form_state['values']['rid']);
    return;
  }
  // Don't allow the user to select a menu name instead of a menu item.
  list($menu_name, $plid) = explode(':', $form_state['values']['plid']);
  if ($plid == 0) {
    form_set_error('plid', t('Please select a menu item. You have selected the name of a menu.'));
  }
}

/**
 * Handles form submission for menu_position_rule_form().
 */
function menu_position_rule_form_submit($form, &$form_state) {
  list($menu_name, $plid) = explode(':', $form_state['values']['plid']);
  $rule = array(
    'admin_title' => $form_state['values']['admin_title'],
    'conditions'  => isset($form_state['values']['conditions']) ? $form_state['values']['conditions'] : array(),
    'menu_name'   => $menu_name,
    'plid'        => $plid,
    'machine_name' => $form_state['values']['machine_name'],
  );
  // Add the rule to the database.
  if ($form_state['values']['rid'] == '') {
    menu_position_add_rule($rule);
    drupal_set_message(t('Rule has been added.'));
  }
  // Update an exisiting rule.
  else {
    $rule['rid'] = $form_state['values']['rid'];
    menu_position_edit_rule($rule);
    drupal_set_message(t('Rule has been modified.'));
  }

  $form_state['redirect'] = 'admin/structure/menu-position';
}

/**
 * Adds a menu position rule.
 *
 * @param $rule
 *   An associate array defining the new rule to be created. Must contain the
 *   following keys:
 *   - admin_title: The administrative title of the rule.
 *   - conditions: An associative array whose keys are the machine names of the
 *     plugins actively configured in the rule. The value of each array element
 *     is array containing the necessary variables for that plugin.
 *   - menu_name: The machine name of the menu where this rule is positioned.
 *   - plid: The mlid of the parent menu link specified in the rule.
 */
function menu_position_add_rule($rule) {
  $fields = array(
    'admin_title' => $rule['admin_title'],
    'conditions'  => serialize($rule['conditions']),
    'menu_name'   => $rule['menu_name'],
    'plid'        => $rule['plid'],
    'machine_name' => $rule['machine_name'],
  );
  $rid = db_insert('menu_position_rules')
    ->fields($fields)
    ->execute();

  $mlid = menu_position_add_menu_link($rid, $rule['plid'], $rule['admin_title']);

  // Now add the mlid back to the rule.
  db_update('menu_position_rules')
    ->fields(array('mlid' => $mlid))
    ->condition('rid', $rid)
    ->execute();
}

/**
 * Adds a menu position rule.
 *
 * @param $rid
 *   ID of the rule needing a menu link.
 * @param $plid
 *   The mlid of the parent menu link specified in the rule.
 * @param $admin_title
 *   The administrative title of the rule.
 * @return
 *   The mlid of the rule's new menu link.
 */
function menu_position_add_menu_link($rid, $plid, $admin_title) {
  // Add a menu link to handle matching pages. Passing NULL as the mlid will
  // cause menu_link_save() to add a new menu link.
  return menu_position_edit_menu_link($rid, NULL, $plid, $admin_title);
}

/**
 * Retrieves a menu position rule from the database.
 *
 * @param $rid
 *   The ID of the requested rule.
 * @return
 *   An associative array for the requested rule.
 */
function menu_position_read_rule($rid) {
  $rule = db_query('SELECT * FROM {menu_position_rules} WHERE rid = :rid', array(':rid' => $rid))->fetchAssoc();
  $rule['conditions'] = unserialize($rule['conditions']);
  return $rule;
}

/**
 * Retrieves a menu position rule from the database.
 *
 * @return
 *   An associative array for all rules with keys equal to the rid of each rule.
 */
function menu_position_read_rules() {
  $query = db_query('SELECT * FROM {menu_position_rules} ORDER BY weight, rid');
  $rules = array();
  foreach ($query as $rule) {
    $rule->conditions = unserialize($rule->conditions);
    $rules[$rule->rid] = $rule;
  }
  return $rules;
}

/**
 * Edits a menu position rule.
 *
 * @param $rule
 *   An associate array defining the rule to be edited. Must contain the
 *   following keys:
 *   - rid: The rule ID.
 *   - admin_title: The administrative title of the rule.
 *   - conditions: An associative array whose keys are the machine names of the
 *     plugins actively configured in the rule. The value of each array element
 *     is array containing the necessary variables for that plugin.
 *   - menu_name: The machine name of the menu where this rule is positioned.
 *   - plid: The mlid of the parent menu link specified in the rule.
 */
function menu_position_edit_rule($rule) {
  $fields = array(
    'admin_title' => $rule['admin_title'],
    'conditions'  => serialize($rule['conditions']),
    'menu_name'   => $rule['menu_name'],
    'plid'        => $rule['plid'],
    'machine_name' => $rule['machine_name'],
  );
  // Update the rule.
  db_update('menu_position_rules')
    ->condition('rid', $rule['rid'])
    ->fields($fields)
    ->execute();
  // Update the link.
  $mlid = db_query('SELECT mlid FROM {menu_position_rules} WHERE rid = :rid', array(':rid' => $rule['rid']))->fetchField();
  menu_position_edit_menu_link($rule['rid'], $mlid, $rule['plid'], $rule['admin_title']);
}

/**
 * Adds a menu position rule.
 *
 * @param $rid
 *   ID of the rule needing a menu link.
 * @param $mlid
 *   The mlid of the menu link used in the rule.
 * @param $plid
 *   The mlid of the parent menu link specified in the rule.
 * @param $admin_title
 *   The administrative title of the rule.
 * @return
 *   The mlid of the rule's new menu link.
 */
function menu_position_edit_menu_link($rid, $mlid, $plid, $admin_title) {
  // Add a menu link to handle matching pages.
  $item = array(
    'link_path' => 'menu-position/' . $rid,
    'link_title' => $admin_title . ' (menu position rule)',
    'mlid' => $mlid,
    'plid' => $plid,
    'hidden' => 1,
    'module' => 'menu_position',
    'options' => array(
      'alter' => TRUE,
      'attributes' => array('class' => array('menu-position-link')),
    ),
  );
  // If this is an existing menu link, get the existing weight.
  if ($item['mlid']) {
    $existing_item = db_query("SELECT plid, weight FROM {menu_links} WHERE mlid = :mlid", array(':mlid' => $item['mlid']))->fetchAssoc();
    $item['weight'] = ($existing_item['plid'] == $plid) ? $existing_item['weight'] : 0;
    // If the rule has a new parent, update the old parent.
    if ($existing_item['plid'] != $item['plid']) {
      $old_parent = menu_link_load($existing_item['plid']);
      if ($old_parent !== FALSE) {
        $old_parent['options']['alter'] = FALSE;
        menu_link_save($old_parent);
      }
    }
  }
  // Update the new parent.
  $parent = menu_link_load($item['plid']);
  $parent['options']['alter'] = TRUE;
  menu_link_save($parent);
  return menu_link_save($item);
}

/**
 * Menu callback: confirms deletion of rule.
 */
function menu_position_delete_rule_form($form, &$form_state, $rid = 0) {
  // Make sure rid is set.
  if ($rid == 0) {
    drupal_goto('admin/structure/menu-position');
    return;
  }
  $form['rid'] = array('#type' => 'hidden', '#value' => $rid);

  $title = db_query('SELECT admin_title FROM {menu_position_rules} WHERE rid = :rid', array(':rid' => $rid))->fetchField();

  return confirm_form($form, t('Are you sure you want to delete the %title rule?', array('%title' => $title)), 'admin/structure/menu-position/edit/' . $rid, NULL, t('Delete'), t('Cancel'));
}

/**
 * Handles form submission for menu_position_delete_rule_form().
 */
function menu_position_delete_rule_form_submit($form, &$form_state) {
  $title = db_query('SELECT admin_title FROM {menu_position_rules} WHERE rid = :rid', array(':rid' => $form_state['values']['rid']))->fetchField();

  menu_position_delete_rule($form_state['values']['rid']);

  drupal_set_message(t('The %title rule has been deleted.', array('%title' => $title)));
  $form_state['redirect'] = 'admin/structure/menu-position';
}

/**
 * Deletes a menu position rule.
 */
function menu_position_delete_rule($rid) {
  db_delete('menu_position_rules')
    ->condition('rid', $rid)
    ->execute();
  menu_link_delete(NULL, 'menu-position/' . $rid);
}