<?php

/**
 * @file
 * Module to synchronize courses from LDAP to groups.
 */

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\field\FieldConfigInterface;
use Drupal\ldap_courses_sync\LdapCoursesSync;

/**
 * Implements hook_help().
 */
function ldap_courses_sync_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.ldap_courses_sync':
      return '<p>' . t('This module synchronizes courses from an LDAP server to groups through cron.') . '</p>';
  }
}

/**
 * Implements hook_cron().
 */
function ldap_courses_sync_cron() {
  // Check if module is properly configured
  $config = \Drupal::config('ldap_courses_sync.settings');
  $ldap_server_id = $config->get('ldap_server_id');
  $ldap_query_id = $config->get('ldap_query_id');

  // Validate LDAP server
  try {
    $entity_type_manager = \Drupal::entityTypeManager();
    $server_storage = $entity_type_manager->getStorage('ldap_server');
    $server = $server_storage->load($ldap_server_id);

    if (!$server || !$server->get('status')) {
      \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: LDAP server "@server_id" not found or inactive. Configure at /admin/config/local-modules/ldap-courses-sync', [
        '@server_id' => $ldap_server_id,
      ]);
      return;
    }
  }
  catch (\Exception $e) {
    \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: error checking LDAP server: @message', [
      '@message' => $e->getMessage(),
    ]);
    return;
  }

  // Validate LDAP query
  try {
    if ($entity_type_manager->hasDefinition('ldap_query_entity')) {
      $query_storage = $entity_type_manager->getStorage('ldap_query_entity');
      $query = $query_storage->load($ldap_query_id);

      if (!$query || !$query->get('status')) {
        \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: LDAP query "@query_id" not found or inactive. Configure at /admin/config/local-modules/ldap-courses-sync', [
          '@query_id' => $ldap_query_id,
        ]);
        return;
      }
    }
    else {
      \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: ldap_query module not available.');
      return;
    }
  }
  catch (\Exception $e) {
    \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: error checking LDAP query: @message', [
      '@message' => $e->getMessage(),
    ]);
    return;
  }

  // Validate group type
  try {
    $group_type_id = $config->get('group_type_id');
    $group_type_storage = $entity_type_manager->getStorage('group_type');
    $group_type = $group_type_storage->load($group_type_id);

    if (!$group_type) {
      \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: group type "@type_id" not found. Configure at /admin/config/local-modules/ldap-courses-sync', [
        '@type_id' => $group_type_id,
      ]);
      return;
    }
  }
  catch (\Exception $e) {
    \Drupal::logger('ldap_courses_sync')->warning('Synchronization cancelled: error checking group type: @message', [
      '@message' => $e->getMessage(),
    ]);
    return;
  }

  // Get LDAP synchronization service
  $ldap_sync = \Drupal::service('ldap_courses_sync.sync');

  // Execute courses synchronization
  try {
    $ldap_sync->syncCourses();
    \Drupal::logger('ldap_courses_sync')->info('Courses synchronization executed successfully.');
  }
  catch (\Exception $e) {
    \Drupal::logger('ldap_courses_sync')->error('Error in courses synchronization: @message', [
      '@message' => $e->getMessage(),
    ]);
  }
}

/**
 * Implements hook_entity_access().
 *
 * Evaluates access rules configured in the module settings for view, update
 * and delete operations on existing entities.
 */
function ldap_courses_sync_entity_access(EntityInterface $entity, $operation, AccountInterface $account) {
  // Skip group-related entities to avoid conflicts with the group module.
  $skip_types = ['group', 'group_content', 'group_relationship', 'group_role', 'group_type'];
  if (in_array($entity->getEntityTypeId(), $skip_types, TRUE)) {
    return AccessResult::neutral();
  }

  return \Drupal::service('ldap_courses_sync.access_rules')
    ->checkAccess($entity, $operation, $account);
}

/**
 * Implements hook_entity_create_access().
 *
 * Evaluates access rules configured in the module settings for create
 * operations on new entities.
 */
function ldap_courses_sync_entity_create_access(AccountInterface $account, array $context, $entity_bundle) {
  $entity_type_id = $context['entity_type_id'] ?? '';

  // Skip group-related entities.
  $skip_types = ['group', 'group_content', 'group_relationship', 'group_role', 'group_type'];
  if (in_array($entity_type_id, $skip_types, TRUE)) {
    return AccessResult::neutral();
  }

  return \Drupal::service('ldap_courses_sync.access_rules')
    ->checkCreateAccess($account, $entity_type_id, $entity_bundle ?? '');
}

/**
 * Implements hook_entity_field_access().
 *
 * Denies edit access to fields managed by the LDAP sync in forms and APIs
 * (REST, JSON:API). Programmatic saves are not affected.
 *
 * Protected user fields:
 *   - field_user_courses: multi-value reference to the courses the user belongs
 *     to, populated by our sync. Protecting this field prevents the validation
 *     error "This entity cannot be referenced" that occurs when the widget
 *     tries to validate the referenced group against the current user's access.
 */
function ldap_courses_sync_entity_field_access($operation, FieldDefinitionInterface $field_definition, AccountInterface $account, ?FieldItemListInterface $items = NULL) {
  $protected_user_fields = [
    'field_user_courses',
  ];

  if (
    $field_definition->getTargetEntityTypeId() === 'user' &&
    in_array($field_definition->getName(), $protected_user_fields, TRUE) &&
    $operation === 'edit'
  ) {
    // Sempre nega edição via UI/API, inclusive para o uid 1.
    // Saves programáticos (ldap_user, drush) não passam por este hook.
    return AccessResult::forbidden('This field is managed exclusively by LDAP synchronization.');
  }
  return AccessResult::neutral();
}

/**
 * Implements hook_user_presave().
 *
 * Protects fields managed by the LDAP sync from unauthorized programmatic
 * changes on existing users. Allows:
 *   - Saves during authorized LDAP sync (LdapCoursesSync::$syncing TRUE)
 *   - New user creation (initial provisioning via ldap_user)
 *   - Saves by users with the 'edit ldap managed user course fields' permission
 */
function ldap_courses_sync_user_presave(\Drupal\user\UserInterface $user) {
  // Permite durante qualquer sync LDAP autorizado.
  if (LdapCoursesSync::isSyncing()) {
    return;
  }

  // Permite na criação inicial do usuário (primeiro login LDAP).
  if ($user->isNew()) {
    return;
  }

  // Permite se o usuário atual tem a permissão de bypass.
  if (\Drupal::currentUser()->hasPermission('edit ldap managed user course fields')) {
    return;
  }

  $original = $user->original;
  if ($original === NULL) {
    return;
  }

  // Fields managed by LDAP that cannot be changed externally.
  $protected_fields = [
    'field_user_courses',
  ];

  foreach ($protected_fields as $field_name) {
    if (!$user->hasField($field_name)) {
      continue;
    }

    $original_value = $original->get($field_name)->getValue();
    $new_value = $user->get($field_name)->getValue();

    if ($original_value !== $new_value) {
      $user->set($field_name, $original_value);
      \Drupal::logger('ldap_courses_sync')->warning(
        'Unauthorized attempt to change @field on user @username was blocked. Use LDAP synchronization to update this field.',
        [
          '@field' => $field_name,
          '@username' => $user->getAccountName(),
        ]
      );
    }
  }
}