web/functions/account_functions.php

<?php
require 'db_functions.php';

function user_id_exists($user_id)
{
    $query = 'SELECT user_id FROM user WHERE user_id = ' . $user_id . ';';
    $result = query_one_result($query);

    if ($result == null)
        return false;
    return true;
}

function auth_level($user_id)
{
    $query = 'SELECT role_id FROM user WHERE user_id = ' . $user_id . ';';
    $result = query_one_result($query);
    $role = $result['role_id'];
    return $role;
}

function modify_self()
{
    return -1;
}

function delete_self()
{
    return -1;
}

function create_account($username, $email, $password, $verify_password, $role_id, $profile_picture)
{
    if ($password != $verify_password) {
        $error_msg = '
            <div class="error">
                Passwords do not match!
            </div>
        ';

        return $error_msg;
    }

    $password_hash = hash('sha256', $password);

    $id = rand(1000, 999999999);
    while (user_id_exists($id))
        $id = rand(1000, 999999999);

    if (!empty($profile_picture)) {
        $filetype = explode('.', $profile_picture);
        $pic_path = $id . $filetype[count($filetype) - 1];
    }

    $stmt = 'INSERT INTO user (user_id, username, email, password_hash, role_id' . (!empty($profile_picture) ? ', profile_picture' : '') . ') VALUES (' . $id . ', "' . $username . '", "' . $email . '", "' . $password_hash . '", ' . $role_id . (!empty($profile_picture) ? '", "' . $pic_path . '"' : '') . ');';
    exec_statement($stmt, 0);

    login($username, $password, false);

    return true;
}

function login($username, $password, $stay_logged_in)
{
    $password_hash = hash('sha256', $password);
    $query = 'SELECT user_id, username, email, role_id, profile_picture FROM user WHERE username ="' . $username . '" AND password_hash = "' . $password_hash . '";';
    $user = query_one_result($query);

    if ($user == null) {
        $error_msg = '
            <div class="error">
                Username and/or Password are invalid!
            </div>
        ';

        return $error_msg;
    }

    if ($stay_logged_in)
        $time = time() + 60 * 60 * 24 * 365;
    else
        $time = time() + 60 * 60 * 24 * 1;

    cookies($user, $time);

    return true;
}

function cookies($user, $time)
{
    setcookie('user_id', $user['user_id'], $time);
    setcookie('username', $user['username'], $time);
    setcookie('email', $user['email'], $time);
    setcookie('role_id', $user['role_id'], $time);
    setcookie('profile_picture', $user['profile_picture'], $time);
}

function logout()
{
    foreach ($_COOKIE as $key => $value) {
        echo 'unsetting ' . $key . ' now.';
        setcookie($key, '', time() - 3600, '/');
        unset($_COOKIE[$key]);
    }

    header('Location: articles.php');
}

function login_form($error_msg = '')
{
    $form = '
        <div class="form_card">
            <h3>Log In</h3>
            <form method="post">
                <label for="username">Username / Email</label>
                <input id="username" name="username" required>

                <label for="password">Password</label>
                <input id="password" name="password" type="password" required>

                <label class="form_checkbox_container">Stay Logged In?
                    <input name="stay_logged_in" type="checkbox" value="true">
                    <span class="checkmark"></span>
                </label>

                <a href="user.php?action=signup">Sign Up</a>
                <input class="button" type="submit" value="Log In">
                ' . $error_msg . '
            </form>
        </div>
    ';

    return $form;
}

function signup_form($error_msg = '')
{
    $form = '
        <div class="form_card">
            <h3>Sign Up</h3>
            <form method="post">
                <label for="username">Username</label>
                <input id="username" name="username" required>

                <label for="email">Email Address</label>
                <input id="email" name="email" required>

                <label for="password">Password</label>
                <input id="password" name="password" type="password" required>

                <label for="verify_password">Verify Password</label>
                <input id="verify_password" name="verify_password" type="password" required>

                <label for="profile_picture_upload" class="upload_button">Upload a Profile Picture</label>
                <input id="profile_picture_upload" name="profile_picture_upload" type="file" accept="image/png, image/jpeg">

                <label class="form_checkbox_container">Stay Logged In?
                    <input name="stay_logged_in" type="checkbox" value="true">
                    <span class="checkmark"></span>
                </label>

                <a href="user.php?action=login">Log In</a>
                <input class="button" type="submit" value="Sign Up">
                ' . $error_msg . '
            </form>
        </div>
    ';

    return $form;
}