controllerUserData.php

<?php 
session_start();
require "connection.php";
$email = "";
$name = "";
$errors = array();

//if user signup button
if(isset($_POST['signup'])){
    $name = mysqli_real_escape_string($con, $_POST['name']);
    $email = mysqli_real_escape_string($con, $_POST['email']);
  
    $email_check = "SELECT * FROM usertable WHERE email = '$email'";
    $res = mysqli_query($con, $email_check);
    if(mysqli_num_rows($res) > 0){
        $errors['email'] = "Email that you have entered is already exist!";
    }
    if(count($errors) === 0){
       
        $code = rand(999999, 111111);
        $status = "notverified";
        $insert_data = "INSERT INTO usertable (name, email, code, status)
                        values('$name', '$email', '$code', '$status')";
        $data_check = mysqli_query($con, $insert_data);
        if($data_check){
            $subject = "Email Verification Code";
            $message = "Your verification code is $code";
            $sender = "From: pradeeppal156@.com";
            if(mail($email, $subject, $message, $sender)){
                $info = "We've sent a verification code to your email - $email";
                $_SESSION['info'] = $info;
                $_SESSION['email'] = $email;
                
                header('location: user-otp.php');
                exit();
            }else{
                $errors['otp-error'] = "Failed while sending code!";
            }
        }else{
            $errors['db-error'] = "Failed while inserting data into database!";
        }
    }

}
    //if user click verification code submit button
    if(isset($_POST['check'])){
        $_SESSION['info'] = "";
        $otp_code = mysqli_real_escape_string($con, $_POST['otp']);
        $check_code = "SELECT * FROM usertable WHERE code = $otp_code";
        $code_res = mysqli_query($con, $check_code);
        if(mysqli_num_rows($code_res) > 0){
            $fetch_data = mysqli_fetch_assoc($code_res);
            $fetch_code = $fetch_data['code'];
            $email = $fetch_data['email'];
            $code = 0;
            $status = 'verified';
            $update_otp = "UPDATE usertable SET code = $code, status = '$status' WHERE code = $fetch_code";
            $update_res = mysqli_query($con, $update_otp);
            if($update_res){
                $_SESSION['name'] = $name;
                $_SESSION['email'] = $email;
                header('location: home.php');
                exit();
            }else{
                $errors['otp-error'] = "Failed while updating code!";
            }
        }else{
            $errors['otp-error'] = "You've entered incorrect code!";
        }
    }

    //if user click login button
    if(isset($_POST['login'])){
        $email = mysqli_real_escape_string($con, $_POST['email']);
        $check_email = "SELECT * FROM usertable WHERE email = '$email'";
        $res = mysqli_query($con, $check_email);
        $fetch = mysqli_fetch_assoc($res);
        if(mysqli_num_rows($res) > 0){
        
                $_SESSION['email'] = $email;
                $status = $fetch['status'];
                if($status == 'verified'){
                  $_SESSION['email'] = $email;
               
                    header('location: home.php');
                }else{
                    $info = "It's look like you haven't still verify your email - $email";
                    $_SESSION['info'] = $info;
                    header('location: user-otp.php');
                }
           }
        else{
            $errors['email'] = "It's look like you're not yet a member! Click on the bottom link to signup.";
        }
    }
    


    
   //if login now button click
    if(isset($_POST['login-now'])){
        header('Location: login-user.php');
    }
?>