<?php
/**
 * Implements hook_form_FORM_ID_alter().
 */
function filter_perms_form_system_modules_alter(&$form, &$form_state, $form_id) {
  // Confirmation page for enabling dependencies will also fire this hook.
  if (isset($form['modules'])) {
    // Replace anchors in links with url paramaters so server side processing can happen.
    foreach ($form['modules'] as $group_key => $module_group) {
      if (is_array($module_group)) {
        $modules = element_children($module_group);
        foreach ($modules as $key => $module) {
          if(!empty($form['modules'][$group_key][$module]['links']['permissions']['#options']['fragment'])) {
            $form['modules'][$group_key][$module]['links']['permissions']['#href'] .= '/'. $form['modules'][$group_key][$module]['links']['permissions']['#options']['fragment'];
            unset($form['modules'][$group_key][$module]['links']['permissions']['#options']['fragment']);
          }
        }
      }
    }
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function filter_perms_form_user_admin_permissions_alter(&$form, $form_state, $form_id) {
  drupal_add_css(drupal_get_path('module', 'filter_perms') . '/filter_perms.css');

  if (isset($_SESSION['filter_perm_roles']) && count($_SESSION['filter_perm_roles'])) {
    $roles = $_SESSION['filter_perm_roles'];
    // If '--All Roles' is selected, get all roles.
    if (isset($roles['-1'])) {
      $user_roles = user_roles();
      foreach ($user_roles as $user_role_key => $user_role) {
        $roles[$user_role_key] = $user_role_key;
      }
    }
  }
  else {
    // Until the session variable is set, don't display any roles.
    $roles = array();
  }
  $cp_field_perms = array();
  if (isset($_SESSION['filter_perm_modules']) && count($_SESSION['filter_perm_modules'])) {
    $modules = $_SESSION['filter_perm_modules'];
    // if '--All Modules' is selected, get all modules.
    if (isset($modules['-1'])) {
      foreach (module_list(FALSE, FALSE, TRUE) as $module) {
        if (module_invoke($module, 'permission')) {
          $modules[$module] = $module;
        }
      }
    }
  }
  else {
    // Until the session variable is set, don't display any modules.
    $modules = array();
  }

  $perms = array();
  foreach ($form['permission'] as $perm_key => $perm) {
    if (is_numeric($perm_key)) {
      $perm_module = $perm['#id'];
      $perm_id = $perm_key;
    }
    else {
      if (in_array($perm_module, $modules)) {
        $perms[$perm_module][$perm_key] = $perm_id;
      }
    }
  }
  $old_perms = $form['permission'];
  $old_checkboxes = $form['checkboxes'];
  $old_roles = $form['role_names'];
  $form['permission'] = array();
  $form['checkboxes'] = array();
  $form['role_names'] = array();
  // If either a role or module is not selected, don't display checkboxes.
  if (count($roles) && count($modules)) {
    $new_roles = array();
    foreach ($old_roles as $rid => $role) {
      if (in_array($rid, $roles)) {
        $new_roles[$rid] = $role;
      }
    }
    $perm_index = 0;
    foreach ($perms as $perm_key => $perm) {

      foreach ($perms[$perm_key] as $perm_name => $perm_value) {
        $form['permission'][$perm_index] = $old_perms[$perm_value];
        $form['permission'][$perm_name] = $old_perms[$perm_name];
        foreach ($new_roles as $rid => $role) {
          $form['checkboxes'][$rid]['#type'] = 'checkboxes';
          $form['checkboxes'][$rid]['#options'][$perm_name] = '';
          $form['checkboxes'][$rid]['#default_value'] = $old_checkboxes[$rid]['#default_value'];
        }
      }
      $perm_index++;
    }
    $form['role_names'] = $new_roles;
    foreach ($new_roles as $new_rid => $new_role) {
      $form['role_names']['#value'][$new_rid] = $new_role['#markup'];
    }
    $form['role_names']['#type'] = 'value';
    //No longer need to add a custom submit handler as core appears to handle partial form submits.
  }
  else {
    // Put some basic info in if filters are not selected.
    $form['permission']['-1'] = array('#markup' => 'Filter Selection', '#id' => 'empty');
    $form['permission']['empty'] = array('#type' => 'item', '#markup' => 'Please select at least one value from both the Roles and Modules select boxes above and then click the "Filter Permissions" button');
    // Initialize an empty array to avoid warnings in theme function.
    $form['role_names']['#value'] = array();
    // Remove the Save permissions button when no permissions are present.
    unset($form['actions']['submit']);
  }
}

/**
 * Implements hook_menu_alter().
 */
function filter_perms_menu_alter(&$callbacks) {
    $callbacks['admin/people/permissions']['page callback'] = 'filter_perms_admin_perm';
}

/**
 * Page callback which appends a filter form to the standard user_admin_permissions form.
 */
function filter_perms_admin_perm() {
  $output = array();
  $output['filter_perms_admin_perm_filter'] = drupal_get_form('filter_perms_admin_perm_filter');
  $output['user_admin_permissions'] = drupal_get_form('user_admin_permissions');
  return $output;
}

/**
 * Form providing a multiple select for roles and modules for filtering permissions.
 */
function filter_perms_admin_perm_filter() {
  // @todo: Move this handling to a more appropriate place prior to drupal_goto().
  $url_parts = explode('/', request_uri());
  $url_last = $url_parts[count($url_parts) - 1];
  if (is_numeric($url_last)) {
    // Role Ids will come from role page referral.
    $_SESSION['filter_perm_roles'] = array($url_last => $url_last);
    // Show selected role for all modules.
    foreach (module_list(FALSE, FALSE, TRUE) as $module) {
      if (module_invoke($module, 'permission')) {
        $_SESSION['filter_perm_modules'][$module] = $module;
      }
    }
  }
  elseif (strstr($url_last, 'module-')) {
    // module- prefix indicates module page referral.
    $single_module = str_replace('module-', '', $url_last);
    $_SESSION['filter_perm_modules'] = array($single_module => $single_module);
    // Show all roles for selected module.
    $user_roles = user_roles();
    foreach ($user_roles as $user_role_key => $user_role) {
      $_SESSION['filter_perm_roles'][$user_role_key] = $user_role_key;
    }
  }
  if ($url_last != 'permissions' && (strpos($url_last, 'permissions?') === FALSE)) {
    drupal_goto('admin/people/permissions');
  }
  $form['filters'] = array(
    '#type' => 'fieldset',
    '#title' => t('Permission Filters'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $role_options = user_roles();
  // Displays all user roles.
  $form['filters']['roles'] = array(
    '#title' => t('Roles to display'),
    '#type' => 'select',
    '#options' => array('-1' => '--All Roles') + $role_options,
    '#default_value' => isset($_SESSION['filter_perm_roles']) ? $_SESSION['filter_perm_roles'] : '',
    '#size' => 8,
    '#multiple' => TRUE,
  );
  $module_options = array();
  // TRUE for the 3rd parameter forces name sorting instead of by module weight.
  foreach (module_list(FALSE, FALSE, TRUE) as $module) {
    if (module_invoke($module, 'permission')) {
      $module_options[$module] = $module;
    }
  }
  // Displays all modules which implement hook_permission().
  $form['filters']['modules'] = array(
    '#title' => t('Modules to display'),
    '#type' => 'select',
    '#options' => array('-1' => '--All Modules') + $module_options,
    '#default_value' => isset($_SESSION['filter_perm_modules']) ? $_SESSION['filter_perm_modules'] : '',
    '#size' => 8,
    '#multiple' => TRUE,
  );

  $form['filters']['submit'] = array('#type' => 'submit', '#value' => t('Filter Permissions'));
  return $form;
}

/**
 * Submit handler for filter_perms_admin_perm_filter form.
 */
function filter_perms_admin_perm_filter_submit($form, &$form_state) {
  $_SESSION['filter_perm_roles'] = $form_state['values']['roles'];
  $_SESSION['filter_perm_modules'] = $form_state['values']['modules'];
}