<?php

/**
 * @file
 * Contains multi_step.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_form_alter().
 */
function multi_step_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  switch ($form_id) {
    case 'user_login_form':
      $form['name']['#title'] = t('Username or Email');
      break;

    case 'user_register_form':
      $tempstore = \Drupal::service('user.private_tempstore')->get('multi_step');
      $data = $tempstore->get('combovalue');
      if (strpos($data, "@") == TRUE) {
        $form['account']['mail']['#default_value'] = $data;
      }
      else {
        $form['account']['name']['#default_value'] = $data;
      }
      break;
  }
}

/**
 * Implements hook_help().
 */
function multi_step_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the multi_step module.
    case 'help.page.multi_step':
      return check_markup(file_get_contents(dirname(__FILE__) . "/README.txt"));
  }
}

/**
 * Checking email is exist or not.
 */
function multi_step_check_for_existing_user_email($value) {
  $query = \Drupal::database()->select('users_field_data', 'u');
  $query->fields('u', ['mail']);
  $query->condition('u.mail', $value, '=');
  $results = $query->execute()->fetchAssoc();
  return $results;
}

/**
 * Fetching uid on basis of email and password.
 */
function multi_step_get_uid_from_email($email, $password) {
  $users = \Drupal::entityTypeManager()->getStorage('user')
    ->loadByProperties(['mail' => $email]);
  $user = reset($users);
  $username = $user->getDisplayName();
  if ($user) {
    $uid = \Drupal::service('user.auth')->authenticate($username, $password);
  }
  return $uid;
}

/**
 * Checking username is exist or not.
 */
function multi_step_check_for_existing_user_name($value) {
  $query = \Drupal::database()->select('users_field_data', 'u');
  $query->fields('u', ['name']);
  $query->condition('u.name', $value, '=');
  $results = $query->execute()->fetchAssoc();
  return $results;
}