auth.php

<?php
session_start();
include 'db_conn.php';

if (isset($_POST['email']) && isset($_POST['password']))
{
    $email = $_POST['email'];
    $password = $_POST['password'];

    if(empty($email))
    {
        header("Location: login.php?error=Email is required&email=$email");
    }else if(empty($password))
    {
        header("Location: login.php?error=Password is required!");
    }else
    {
        $stmt = $conn->prepare("select * from users where email=?");
        $stmt->execute([$email]);

        if ($stmt->rowCount() === 1) 
        {
            $user = $stmt->fetch();

            $user_id = $user['id'];
            $user_full_name = $user['full_name'];
            $user_email = $user['email'];
            $user_password = $user['password'];

            if ($email === $user_email) 
            {
                if (password_verify($password, $user_password)) 
                {
                    $_SESSION['user_id'] = $user_id;
                    $_SESSION['user_email'] = $user_email;
                    $_SESSION['user_full_name'] = $user_full_name;

                    header("Location: index.php");
                }else 
                {
                    header("Location: login.php?error=Incorrect Username or Password&email=$email");
                }
            }else 
            {
                header("Location: login.php?error=Incorrect Username or Password&email=$email");
            }
        }else
        {
            header("Location: login.php?error=Incorrect Username or Password&email=$email");
        }
    }
}