check_availability.php

<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require 'vendor/autoload.php'; // Ensure you have installed PHPMailer via Composer
require_once("includes/config.php");

session_start();

// Email availability check and OTP sending
if (!empty($_POST["emailid"])) {
    $email = $_POST["emailid"];
    if (filter_var($email, FILTER_VALIDATE_EMAIL) === false) {
        echo "error : You did not enter a valid email.";
    } else {
        $sql = "SELECT EmailId FROM tblusers WHERE EmailId=:email";
        $query = $dbh->prepare($sql);
        $query->bindParam(':email', $email, PDO::PARAM_STR);
        $query->execute();
        if ($query->rowCount() > 0) {
            echo "<span style='color:red'> Email already exists.</span>";
            echo "<script>$('#submit').prop('disabled',true);</script>";
        } else {
            // Generate OTP
            $otp = rand(100000, 999999);
            $_SESSION['otp'] = $otp;
            $_SESSION['email'] = $email;

            // Store OTP in database
            $sql = "INSERT INTO otp_verification (EmailId, OTP, Expiry) VALUES (:email, :otp, DATE_ADD(NOW(), INTERVAL 10 MINUTE))";
            $query = $dbh->prepare($sql);
            $query->bindParam(':email', $email, PDO::PARAM_STR);
            $query->bindParam(':otp', $otp, PDO::PARAM_INT);
            $query->execute();

            // Send OTP via email
            $mail = new PHPMailer(true);
            try {
                $mail->isSMTP();
                $mail->Host = 'smtp.gmail.com'; // Set your SMTP host
                $mail->SMTPAuth = true;
                $mail->Username = 'hostelatib@gmail.com'; // SMTP username
                $mail->Password = 'kwpc qhay eydk bqse'; // SMTP password
                $mail->SMTPSecure = 'tls'; // Use TLS
                $mail->Port = 587; // SMTP port

                $mail->setFrom('hostelatib@gmail.com', 'DriveMate');
                $mail->addAddress($email);
                
                $mail->isHTML(true);
                $mail->Subject = 'Your OTP Code';
                $mail->Body    = "Your OTP for email verification is: <b>$otp</b>";

                $mail->send();
				echo "<span style='color:green'> Email available OTP sent, Please verify.</span>";
				echo "<script>$('#submit').prop('disabled',false);</script>";
            } catch (Exception $e) {
                echo "<script>alert('Mailer Error: {$mail->ErrorInfo}');</script>";
            }
        }
    }
}
?>