YTKNS Side By Side Editor

<?php
namespace YTKNS;

use Exception;

require_once __DIR__ . '/../startup.php';

if(!function_exists('base64uri_encode')) {
    function base64uri_encode(string $string): string {
        return rtrim(strtr(base64_encode($string), '+/', '-_'), '=');
    }
}

if(!function_exists('base64uri_decode')) {
    function base64uri_decode(string $string, bool $strict = false): string|false {
        return base64_decode(str_pad(strtr($string, '-_', '+/'), strlen($string) % 4, '=', STR_PAD_RIGHT));
    }
}

function page_url(string $path, array $params = []): string {
    if(isset($params['p']))
        unset($params['p']);

    $mainDomain = Config::get('domain.main');
    $url = '';

    if($_SERVER['HTTP_HOST'] !== $mainDomain)
        $url .= 'https://' . $mainDomain;

    $url .= $path;

    if(!empty($params))
        $url .= '?' . http_build_query($params);

    return $url;
}

function html_header(array $vars = []): string {
    $vars['title'] ??= 'You\'re the kid now, squid';
    $vars['head'] ??= '';

    if(!empty($vars['redirect'])) {
        $timeout = (int)($vars['redirect_timeout'] ?? 0);
        $vars['head'] .= '<meta http-equiv="refresh" content="' . $timeout . '; url=' . $vars['redirect'] . '">';
    }

    if(!empty($vars['styles']) && is_array($vars['styles'])) {
        foreach($vars['styles'] as $style)
            $vars['head'] .= sprintf('<link href="%s" type="text/css" rel="stylesheet"/>', $style);
    }

    $vars['menu_site'] = Template::renderSet('menu-site-item', [
        ['text' => 'Home', 'link' => page_url('/')],
        ['text' => 'Create a Zone', 'link' => page_url('/zones/create')],
        ['text' => 'Zones', 'link' => page_url('/zones')],
        ['text' => 'Random', 'link' => page_url('/zones/random')],
    ]);

    $userMenu = [];

    if(UserSession::hasInstance()) {
        $userName = UserSession::instance()->getUser()->getUsername();

        $userMenu = [
            ['text' => "@{$userName}", 'link' => page_url("/@{$userName}")],
            ['text' => 'My Zones', 'link' => page_url('/zones?f=my')],
            ['text' => 'Settings', 'link' => page_url('/settings')],
        ];

        $userMenu[] = ['text' => 'Log out', 'link' => page_url('/auth/logout', ['s' => UserSession::instance()->getSmallToken()])];
    } else {
        $userMenu = [
            ['text' => 'Log in', 'link' => page_url('/auth/login')],
        ];
    }

    $vars['menu_user'] = Template::renderSet('menu-user-item', $userMenu);

    $vars['maintenance'] = YTKNS_MAINTENANCE ? Template::renderRaw('maintenance') : '';

    return Template::renderRaw('header', $vars);
}

function html_footer(array $vars = []): string {
    $vars['footer_took'] = number_format(microtime(true) - YTKNS_STARTUP, 5);
    $vars['footer_year'] = date('Y');

    $scripts = $vars['scripts'] ?? null;
    $vars['scripts'] = '';

    if(!empty($scripts) && is_array($scripts)) {
        foreach($scripts as $script)
            $vars['scripts'] .= sprintf('<script type="text/javascript" charset="utf-8" src="%s"></script>', $script);
    }

    return Template::renderRaw('footer', $vars);
}

function html_information(string $message, string $title = 'Information', ?string $redirect = null, int $redirectTimeout = 2): string {
    $html = html_header([
        'title' => $title . ' - YTKNS',
        'redirect' => $redirect,
        'redirect_timeout' => $redirectTimeout,
    ]);

    if(!empty($redirect))
        $message .= Template::renderRaw('information-redirect', [
            'info_redirect' => $redirect,
        ]);

    $html .= Template::renderRaw('information', [
        'info_title' => $title,
        'info_content' => $message,
    ]);

    $html .= html_footer();

    return $html;
}

function html_pagination(int $pages, int $current, string $urlFormat): string {
    $html = '<div class="pagination">';

    for($i = 1; $i <= $pages; $i++)
        $html .= sprintf('<a href="%s" class="pagination-page%s">%d</a>', sprintf($urlFormat, $i), ($current === $i ? ' pagination-page-current' : ''), $i);

    return $html . '</div>';
}

if(!YTKNS_MAINTENANCE && !empty($_COOKIE['ytkns_login']) && is_string($_COOKIE['ytkns_login'])) {
    try {
        $session = UserSession::byToken($_COOKIE['ytkns_login']);
        $session->update();
        $session->setInstance();

        if($session->getBump())
            setcookie('ytkns_login', $session->getToken(), $session->getExpires(), '/', '.' . Config::get('domain.main'), false, true);

        unset($session);
    } catch(UserSessionNotFoundException $ex) {}
}

$zoneName = strtolower(substr($_SERVER['HTTP_HOST'], 0, -strlen(Config::get('domain.main')) - 1));

if(!empty($zoneName)) {
    $redirect = ZoneRedirect::find($zoneName);

    if($redirect !== null) {
        $redirect->execute();
        return;
    }

    try {
        $zoneInfo = Zone::byName($zoneName);
    } catch(ZoneNotFoundException $ex) {
        http_response_code(404);
        echo html_header(['title' => 'Zone not found!']);
        Template::render('zones/none', [
            'zone_create_url' => page_url('/zones/create', ['name' => $zoneName]),
        ]);
        echo html_footer();
        return;
    }

    if(!YTKNS_MAINTENANCE) {
        if(!empty($_GET['_refresh_screenshot'])) {
            header('Location: /');
            $zoneInfo->takeScreenshot();
            return;
        }

        ZoneView::increment($zoneInfo, $_SERVER['REMOTE_ADDR']);
    }

    echo (string)$zoneInfo->getPageBuilder(true);
    return;
}

$reqMethod = $_SERVER['REQUEST_METHOD'];
$reqPath = '/' . trim(parse_url($_SERVER['REQUEST_URI'] ?? '',  PHP_URL_PATH), '/');

if($reqPath === '/') {
    echo html_header();
    Template::render('home');
    echo html_footer();
    return;
}

if(substr($reqPath, 0, 4) === '/ss/') {
    header('Content-Type: image/jpeg');
    header('X-Accel-Redirect: /assets/no-screenshot.jpg');
    return;
}

if(preg_match('#^/@([A-Za-z0-9-_]+)$#', $reqPath, $matches)) {
    try {
        $profile = User::forProfile($matches[1]);
    } catch(Exception $ex) {
        http_response_code(404);
        echo html_header(['title' => 'User not found - YTKNS']);
        Template::render('profile/notfound');
        echo html_footer();
        return;
    }

    $zones = Zone::byUser($profile, 'zone_views', false);

    if(count($zones) < 1) {
        $profileZones = Template::renderRaw('profile/zone-none');
    } else {
        $profileZones = [];

        foreach($zones as $zone)
            $profileZones[] = [
                'zone_id' => $zone->getId(),
                'zone_name' => $zone->getName(),
                'zone_title' => $zone->getTitle(),
                'zone_views' => number_format($zone->getViews()),
                'zone_url' => $zone->getUrl(),
                'zone_screenshot' => $zone->getScreenshotUrl(),
            ];

        $profileZones = Template::renderRaw('profile/zone-list', [
            'zone_items' => Template::renderSet('profile/zone-item', $profileZones),
        ]);
    }

    echo html_header(['title' => $profile->username . ' @ YTKNS']);
    Template::render('profile/index', [
        'profile_username' => $profile->username,
        'profile_zones' => $profileZones,
    ]);
    echo html_footer();
    return;
}

if($reqPath === '/zones') {
    $zoneFilter = filter_input(INPUT_GET, 'f');

    if($zoneFilter === 'my' && !UserSession::hasInstance()) {
        echo html_information('You must be logged in to do this.');
        return;
    }

    $zoneTake = 20;
    $zonePage = max(filter_input(INPUT_GET, 'page', FILTER_SANITIZE_NUMBER_INT) - 1, 0);
    $zoneOffset = $zonePage * $zoneTake;
    $zoneSort = filter_input(INPUT_GET, 'sort');
    $zoneSortDesc = filter_input(INPUT_GET, 'asc', FILTER_SANITIZE_NUMBER_INT) < 1;
    $zoneOrderings = [
        'creation' => 'zone_created',
        'updated' => 'zone_updated',
        'views' => 'zone_views',
        'user' => 'user_id',
    ];

    if(!array_key_exists($zoneSort, $zoneOrderings)) {
        switch($zoneFilter) {
            case 'my':
                $zoneSort = 'creation';
                break;

            default:
                $zoneSort = 'views';
                $zoneSortDesc = false;
                break;
        }
    }

    switch($zoneFilter) {
        case 'my':
            $zones = Zone::byUser(UserSession::instance()->getUser(), $zoneOrderings[$zoneSort], $zoneSortDesc, $zoneTake, $zoneOffset);
            $zoneListTemplate = 'zones/my-item';
            $zoneListTitle = 'My Zones';
            break;

        default:
            $zones = Zone::all($zoneOrderings[$zoneSort], $zoneSortDesc, $zoneTake, $zoneOffset);
            $zoneListTemplate = 'zones/item';
            $zoneListTitle = 'Zones';
            $zoneFilter = '';
            break;
    }

    $zoneCount = Zone::count();
    $zonePages = ceil($zoneCount / $zoneTake);
    $zoneList = [];

    foreach($zones as $zone)
        $zoneList[] = [
            'zone_id'         => $zone->getId(),
            'zone_name'       => $zone->getName(),
            'zone_title'      => $zone->getTitle(),
            'zone_views'      => number_format($zone->getViews()),
            'zone_url'        => $zone->getUrl(),
            'zone_edit_url'   => page_url(sprintf('/zones/%d', $zone->getId())),
            'zone_delete_url' => page_url(sprintf('/zones/%d/delete', $zone->getId())),
            'zone_screenshot' => $zone->getScreenshotUrl(),
            'zone_user_url'   => page_url('/@' . $zone->getUser()->getUsername()),
            'zone_user_name'  => $zone->getUser()->getUsername(),
        ];

    $zoneSortings = '';

    foreach(array_keys($zoneOrderings) as $order) {
        $orderCurrent = $zoneSort === $order;
        $zoneSortings .= sprintf(
            '<a href="?f=%6$s&sort=%1$s&asc=%2$d" class="zones-sorts-sort%4$s">%3$s%5$s</a>',
            $order, $orderCurrent ? $zoneSortDesc : !$zoneSortDesc, ucfirst($order),
            $orderCurrent ? ' zones-sorts-current' : '',
            $orderCurrent ? sprintf(
                ' <img src="/assets/arrow_%s.png" alt="%s"/>',
                $zoneSortDesc ? 'down' : 'up',
                $zoneSortDesc ? 'Descending' : 'Ascending'
            ) : '', $zoneFilter
        );
    }

    echo html_header(['title' => $zoneListTitle . ' - YTKNS']);
    Template::render('zones/list', [
        'zone_list_title' => $zoneListTitle,
        'zone_list' => Template::renderSet($zoneListTemplate, $zoneList),
        'zone_sortings' => $zoneSortings,
    ]);
    echo html_pagination($zonePages, $zonePage + 1, sprintf('/zones?f=%s&sort=%s&asc=%d&page=%%s', $zoneFilter, $zoneSort, !$zoneSortDesc));
    echo html_footer();
    return;
}

if($reqPath === '/zones/random') {
    $zoneInfo = Zone::byRandom();
    header('Location: ' . $zoneInfo->getUrl());
    return;
}

if($reqPath === '/zones/create') {
    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo html_information('You must be logged in to do this.');
        return;
    }

    $createToken = UserSession::instance()->getSmallToken(4);

    if($reqMethod === 'POST') {
        $zoneToken = filter_input(INPUT_POST, 'zone_token');
        $zoneName  = filter_input(INPUT_POST, 'zone_subdomain');
        $zoneTitle = filter_input(INPUT_POST, 'zone_title');

        if($zoneToken !== $createToken) {
            $createError = 'Invalid request.';
        } else {
            if(empty($zoneName) || empty($zoneTitle)) {
                $createError = 'Please fill in all fields.';
            } else {
                if(!Zone::validName($zoneName)) {
                    $createError = 'Name contains invalid characters or is too long.';
                } elseif(ZoneRedirect::exists($zoneName) || Zone::exists($zoneName)) {
                    $createError = 'A Zone with this name already exists.';
                } elseif(!ctype_alpha($zoneName)
                    || mb_strlen($zoneTitle) > 255) {
                    $createError = 'Invalid data.';
                } else {
                    $createZone = Zone::create(UserSession::instance()->getUser(), $zoneName, $zoneTitle);
                    $createZone->addEffect(new \YTKNS\Effects\NewlyCreatedPageEffect);

                    echo html_information('Zone created!', 'Information - YTKNS', "/zones/{$createZone->getId()}");
                    return;
                }
            }
        }
    } elseif($reqMethod === 'GET') {
        $zoneName = filter_input(INPUT_GET, 'name');
    }

    if(isset($createError)) {
        $createError = Template::renderRaw('error', [
            'error_text' => $createError,
        ]);
    }

    echo html_header(['title' => 'Create a Zone - YTKNS']);

    Template::render('zones/create', [
        'create_action' => page_url('/zones/create'),
        'create_domain' => Config::get('domain.main'),
        'create_token' => $createToken,
        'create_error' => $createError ?? '',
        'create_subdomain' => $zoneName ?? '',
        'create_title' => $zoneTitle ?? '',
    ]);

    echo html_footer();
    return;
}

if($reqPath === '/zones/_effects') {
    header('Content-Type: application/json; charset=utf-8');

    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo json_encode([
            'err' => 'You must be logged in.',
        ]);
        return;
    }

    $effects = [];

    foreach(SITE_EFFECTS as $effectClass) {
        $instance = new $effectClass;
        $effects[] = [
            'type' => trim(substr($effectClass, 14, -6), '\\'),
            'name' => $instance->getEffectName(),
            'props' => $instance->getEffectProperties(),
        ];
    }

    echo json_encode($effects);
    return;
}

if($reqPath === '/zones/_preview') {
    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo html_information('You must be logged in to do this.');
        return;
    }

    if($reqMethod !== 'POST') {
        http_response_code(405);
        echo html_information('Must be a POST request.');
        return;
    }

    $zoneToken = filter_input(INPUT_POST, 'zone_token');

    if($zoneToken !== UserSession::instance()->getSmallToken(10)) {
        http_response_code(403);
        echo html_information('Invalid token.');
        return;
    }

    $zoneTitle = filter_input(INPUT_POST, 'zone_title');
    $zoneEffects = filter_input(INPUT_POST, 'zone_effect', FILTER_DEFAULT, FILTER_REQUIRE_ARRAY);

    try {
        $zoneInfo = new Zone;
        $zoneInfo->setTitle($zoneTitle);
        $zoneInfo->setPassiveMode();

        foreach($zoneEffects as $effectName => $effectValues) {
            $effectInfo = ZoneEffect::effectClass($effectName);
            $effectInfo->setEffectParams($effectValues);
            $zoneInfo->addEffect($effectInfo);
        }
    } catch(ZoneInvalidTitleException $ex) {
        http_response_code(400);
        echo html_information('Invalid title.');
        return;
    } catch(ZoneEffectClassNotFoundException $ex) {
        http_response_code(400);
        echo html_information(sprintf('Invalid effect name: %s.', $ex->getMessage()));
        return;
    } catch(PageEffectException $ex) {
        http_response_code(400);
        echo html_information(sprintf('%s: %s', $effectName ?? '', $ex->getMessage()));
        return;
    } catch(Exception $ex) {
        http_response_code(500);
        echo html_information(sprintf('Failed to generate preview.<br/>%s: %s', get_class($ex), $ex->getMessage()));
        return;
    }

    echo (string)$zoneInfo->getPageBuilder();
    return;
}

if(preg_match('#^/zones/([0-9]+)/delete$#', $reqPath, $matches)) {
    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo html_information('You must be logged in to do this.');
        return;
    }

    try {
        $zoneInfo = Zone::byId($matches[1]);
    } catch(ZoneNotFoundException $ex) {
        http_response_code(404);
        echo html_information('This zone doesn\'t exist.');
        return;
    }

    if($zoneInfo->getUserId() !== UserSession::instance()->getUserId()) {
        http_response_code(403);
        echo html_information('You aren\'t allowed to touch this zone.');
        return;
    }

    $deleteToken = UserSession::instance()->getSmallToken(20);

    if($reqMethod === 'POST') {
        if(filter_input(INPUT_POST, 'zone_token') !== $deleteToken) {
            http_response_code(403);
            echo html_information('Invalid token.');
            return;
        }

        header('Location: /zones?f=my');
        $zoneInfo->delete();
        return;
    }

    echo html_header(['title' => sprintf('Deleting zone %s - YTKNS', $zoneInfo->getName())]);
    Template::render('zones/delete', [
        'delete_zone_id' => $zoneInfo->getId(),
        'delete_zone_name' => $zoneInfo->getName(),
        'delete_zone_token' => $deleteToken,
    ]);
    echo html_footer();
    return;
}

if(preg_match('#^/zones/([0-9]+)/sbs$#', $reqPath, $matches)) {
    echo '<!doctype html>';
    echo '<meta charset="utf-8"/><title>YTKNS Side By Side Editor</title>';
    echo '<iframe name="preview" style="position: absolute; top: 0; left: 0; bottom: 0; height: 100%; width: 70%; border-width: 0;"></iframe>';
    echo '<iframe name="editor" src="/zones/' . $matches[1] . '" style="position: absolute; top: 0; right: 0; bottom: 0; height: 100%; width: 30%; border-width: 0;"></iframe>';
    return;
}

if(preg_match('#^/zones/([0-9]+)$#', $reqPath, $matches)) {
    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo html_information('You must be logged in to do this.');
        return;
    }

    try {
        $zoneInfo = Zone::byId($matches[1]);
    } catch(ZoneNotFoundException $ex) {
        http_response_code(404);
        echo html_information('This zone doesn\'t exist.');
        return;
    }

    if(UserSession::instance()->getUserId() !== $zoneInfo->getUserId()
        && UserSession::instance()->getUserId() !== 1) {
        http_response_code(403);
        echo html_information('You aren\'t allowed to touch this zone.');
        return;
    }

    $isSBS = !empty($_GET['sbs']);
    $cssHash = hash_file('sha256', YTKNS_PUB . '/assets/editor.css');
    $jsHash = hash_file('sha256', YTKNS_PUB . '/assets/editor.js');

    if($isSBS) {
        echo '<!doctype html>';
        echo '<link href="/assets/style.css" type="text/css" rel="stylesheet"/>';
        echo '<link href="/assets/editor.css?v=' . $cssHash . '" type="text/css" rel="stylesheet"/>';
        echo '<style>.ye { height: 100%; width: 100%; } .ye-sidebar { min-width: 200px; }</style>';
    } else {
        echo html_header([
            'title' => 'Editing Zone - YTKNS',
            'styles' => [
                page_url('/assets/editor.css', ['v' => $cssHash]),
            ],
        ]);
    }

    Template::render('zones/edit', [
        'edit_id' => $zoneInfo->getId(),
        'edit_token' => UserSession::instance()->getSmallToken(10),
        'edit_css_ver' => substr($cssHash, 0, 16),
        'edit_js_ver' => substr($jsHash, 0, 16),
        'upload_token' => UserSession::instance()->getSmallToken(6),
    ]);

    if($isSBS) {
        echo '<script type="text/javascript" charset="utf-8" src="/assets/editor.js?v=' . $jsHash . '"></script>';
    } else {
        echo <<<HTML
    <script>
        window.addEventListener('DOMContentLoaded', function() {
            if(window.location !== window.parent.location)
                location.assign(location.toString() + '?sbs=1');
        });
    </script>
HTML;
        echo html_footer([
            'scripts' => [
                page_url('/assets/editor.js', ['v' => $jsHash]),
            ],
        ]);
    }
    return;
}

if(preg_match('#^/zones/([0-9]+).json$#', $reqPath, $matches)) {
    header('Content-Type: application/json; charset=utf-8');

    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo json_encode([
            'err' => 'You must be logged in to do this.',
        ]);
        return;
    }

    try {
        $zoneInfo = Zone::byId($matches[1]);
    } catch(ZoneNotFoundException $ex) {
        http_response_code(404);
        echo json_encode([
            'err' => 'This zone doesn\'t exist',
        ]);
        return;
    }

    if(UserSession::instance()->getUserId() !== $zoneInfo->getUserId()
        && UserSession::instance()->getUserId() !== 1) {
        http_response_code(403);
        echo json_encode([
            'err' => 'You aren\'t allowed to touch this zone.',
        ]);
        return;
    }

    if($reqMethod === 'GET') {
        echo $zoneInfo->toJson(true);
        return;
    }

    if($reqMethod !== 'POST') {
        http_response_code(405);
        echo json_encode([
            'err' => 'Invalid request method.',
        ]);
        return;
    }

    $zoneToken = filter_input(INPUT_POST, 'zone_token');

    if($zoneToken !== UserSession::instance()->getSmallToken(10)) {
        http_response_code(403);
        echo json_encode([
            'err' => 'Invalid token.',
        ]);
        return;
    }

    $zoneId = filter_input(INPUT_POST, 'zone_id', FILTER_VALIDATE_INT);

    if($zoneId !== $zoneInfo->getId()) {
        http_response_code(400);
        echo json_encode([
            'err' => 'Zone ID in POST data does not match the target zone ID.',
        ]);
        return;
    }

    $zoneTitle = filter_input(INPUT_POST, 'zone_title');
    $zoneEffects = filter_input(INPUT_POST, 'zone_effect', FILTER_DEFAULT, FILTER_REQUIRE_ARRAY);

    try {
        $zoneInfo->setTitle($zoneTitle);
        $zoneInfo->setPassiveMode();

        if(is_array($zoneEffects)) {
            foreach($zoneEffects as $effectName => $effectValues) {
                $effectInfo = ZoneEffect::effectClass($effectName);
                $effectInfo->setEffectParams($effectValues);
                $zoneInfo->addEffect($effectInfo);
            }
        }

        $zoneInfo->update(['zone_title']);

        // Schedule a screenshot to be taken
        $zoneInfo->queueTask('screenshot');
    } catch(ZoneInvalidTitleException $ex) {
        http_response_code(400);
        echo json_encode([
            'err' => 'Invalid title.',
        ]);
        return;
    } catch(ZoneEffectClassNotFoundException $ex) {
        http_response_code(400);
        echo json_encode([
            'err' => sprintf('Invalid effect name: %s.', $ex->getMessage()),
        ]);
        return;
    } catch(PageEffectException $ex) {
        http_response_code(400);
        echo json_encode([
            'err' => sprintf('%s: %s', $effectName ?? '', $ex->getMessage()),
        ]);
        return;
    } catch(Exception $ex) {
        http_response_code(500);
        echo json_encode([
            'err' => sprintf("An unexpected error occurred.\r\n%s: %s", get_class($ex), $ex->getMessage()),
        ]);
        return;
    }

    echo json_encode([
        'msg' => 'Saved!',
    ]);
    return;
}

if($reqPath === '/uploads') {
    header('Content-Type: application/json; charset=utf-8');

    if($reqMethod !== 'POST') {
        http_response_code(405);
        echo json_encode([
            'err' => 'Unsupported request method.',
        ]);
        return;
    }

    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo json_encode([
            'err' => 'You must be logged in to upload files.',
        ]);
        return;
    }

    if(filter_input(INPUT_POST, 'upload_token') !== UserSession::instance()->getSmallToken(6)) {
        http_response_code(403);
        echo json_encode([
            'err' => 'Invalid upload token.',
        ]);
        return;
    }

    if(empty($_FILES['upload_file']['tmp_name'])) {
        http_response_code(400);
        echo json_encode([
            'err' => 'Missing file.',
        ]);
        return;
    }

    $hash = hash_file('sha256', $_FILES['upload_file']['tmp_name']);
    $existing = Upload::byHash($hash);

    if($existing !== null) {
        if($existing->getDMCA() > 0) {
            http_response_code(451);
            echo json_encode([
                'err' => 'This file has been removed in response to a DMCA takedown request. It may not be used.',
            ]);
            return;
        }

        if($existing->getDeleted() > 0) {
            http_response_code(404);
            echo json_encode([
                'err' => 'This file has been flagged for deletion, it cannot be reuploaded at this time.',
            ]);
            return;
        }

        http_response_code(200);
        echo json_encode([
            'err' => 'File has been uploaded already.',
            'file' => $existing->getId(),
        ]);
        return;
    }

    if($_FILES['upload_file']['size'] > 5242880) {
        http_response_code(413);
        echo json_encode([
            'err' => 'Upload is too large.',
        ]);
        return;
    }

    $contentType = mime_content_type($_FILES['upload_file']['tmp_name']);

    if(!in_array($contentType, ALLOWED_UPLOADS)) {
        http_response_code(400);
        echo json_encode([
            'err' => sprintf('File type not allowed. (Must be %s)', implode(', ', ALLOWED_UPLOADS)),
        ]);
        return;
    }

    try {
        $upload = Upload::create(UserSession::instance()->getUser(), $_FILES['upload_file']['name'], $contentType, $hash);
    } catch(UploadCreationFailedException $ex) {
        http_response_code(500);
        echo json_encode([
            'err' => 'Failed to create upload record.',
        ]);
        return;
    }

    if(!move_uploaded_file($_FILES['upload_file']['tmp_name'], $upload->getPath())) {
        http_response_code(500);
        echo json_encode([
            'err' => 'Upload failed.',
        ]);
        return;
    }

    http_response_code(201);
    echo json_encode([
        'file' => $upload->getId(),
    ]);
    return;
}

if(preg_match('#^/uploads/([a-zA-Z0-9-_]{16})$#', $reqPath, $matches)) {
    try {
        $uploadInfo = Upload::byId($matches[1]);
    } catch(UploadNotFoundException $ex) {
        http_response_code(404);
        return;
    }

    if(!empty($_SERVER['HTTP_ORIGIN'])) {
        $zoneDomain = sprintf(Config::get('domain.zone'), '');
        $originPart = substr($_SERVER['HTTP_ORIGIN'], strlen($_SERVER['HTTP_ORIGIN']) - strlen($zoneDomain));

        if($originPart === $zoneDomain) {
            header('Access-Control-Allow-Origin: ' . $_SERVER['HTTP_ORIGIN']);
        }
    }

    if($_SERVER['REQUEST_METHOD'] !== 'HEAD' && $_SERVER['REQUEST_METHOD'] !== 'OPTIONS')
        header('X-Accel-Redirect: /raw-uploads/' . $uploadInfo->getId());

    header('Content-Type: ' . $uploadInfo->getType());
    header('Content-Disposition: inline; filename="' . $uploadInfo->getName() . '"');
    return;
}

if(preg_match('#^/uploads/([a-zA-Z0-9-_]{16}).json$#', $reqPath, $matches)) {
    header('Content-Type: application/json; charset=utf-8');

    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo json_encode([
            'err' => 'You must be logged in to do this.',
        ]);
        return;
    }

    try {
        $uploadInfo = Upload::byId($matches[1]);
    } catch(UploadNotFoundException $ex) {
        http_response_code(404);
        echo json_encode([
            'err' => 'Upload not found.',
        ]);
        return;
    }

    echo $uploadInfo->toJson(true);
    return;
}

if($reqPath === '/settings') {
    if(!UserSession::hasInstance()) {
        http_response_code(403);
        echo html_information('You must be logged in to access this page.');
        return;
    }

    echo html_header(['title' => 'Settings - YTKNS']);
    Template::render('settings/index');
    echo html_footer();
    return;
}

if($reqPath === '/auth/login') {
    if(YTKNS_MAINTENANCE) {
        http_response_code(503);
        echo html_information('You cannot log in during maintenance.');
        return;
    }

    if(UserSession::hasInstance()) {
        http_response_code(404);
        echo html_information('You are logged in already.');
        return;
    }

    if(filter_has_var(INPUT_GET, 'state')) {
        $state = base64uri_decode((string)filter_input(INPUT_GET, 'state'));
        if($state === false || strlen($state) !== 60) {
            http_response_code(400);
            echo html_information('Provided state is invalid.');
            return;
        }

        $signature = hash_hmac('sha256', substr($state, 32), YTKNS_OA2_STATE_SECRET, true);
        if(!hash_equals($signature, substr($state, 0, 32))) {
            http_response_code(403);
            echo html_information('Request verification failed.');
            return;
        }

        $state = unpack('a32hash/Jtime/a20verifier', $state);
        if($state === false) {
            http_response_code(500);
            echo html_information('State unpack failed.');
            return;
        }

        if($state['time'] < strtotime('-15 minutes') || $state['time'] > strtotime('+15 minutes')) {
            http_response_code(403);
            echo html_information('Authorisation request timestamp is no longer valid.');
            return;
        }

        if(filter_has_var(INPUT_GET, 'error')) {
            $error = (string)filter_input(INPUT_GET, 'error');
            $text = (string)filter_input(INPUT_GET, 'error_description');
            if($text === '')
                $text = match($error) {
                    'access_denied' => 'You rejected the authorisation request.',
                    'invalid_request' => 'YTKNS sent an invalid request to the authorisation server, please report this!',
                    'invalid_scope' => 'YTKNS sent an invalid request to the authorisation server, please report this!',
                    'server_error' => 'Something went wrong on the authorisation server, please try again later.',
                    default => sprintf('An unexpected error occurred: %s', $error),
                };

            http_response_code(400);
            echo html_information(htmlspecialchars($text));
            return;
        }

        if(filter_has_var(INPUT_GET, 'code')) {
            try {
                $postData = sprintf(
                    'grant_type=authorization_code&code=%s&code_verifier=%s',
                    rawurlencode((string)filter_input(INPUT_GET, 'code')),
                    rawurldecode($state['verifier'])
                );
                $authz = sprintf('Basic %s', base64_encode(sprintf('%s:%s', YTKNS_OA2_CLIENT_ID, YTKNS_OA2_CLIENT_SECRET)));

                $tokenInfo = json_decode(file_get_contents('https://api.flashii.net/oauth2/token', false, stream_context_create([
                    'http' => [
                        'method' => 'POST',
                        'header' => implode("\r\n", [
                            sprintf('Authorization: %s', $authz),
                            'Content-Type: application/x-www-form-urlencoded',
                            sprintf('Content-Length: %d', strlen($postData)),
                            'User-Agent: YTKNS',
                        ]),
                        'content' => $postData,
                    ],
                ])));

                if(isset($tokenInfo->access_token)) {
                    $fUserInfo = json_decode(file_get_contents('https://api.flashii.net/v1/me', false, stream_context_create([
                        'http' => [
                            'method' => 'GET',
                            'header' => implode("\r\n", [
                                sprintf('Authorization: Bearer %s', $tokenInfo->access_token),
                                'User-Agent: YTKNS',
                            ]),
                        ],
                    ])));

                    if(empty($fUserInfo->id)) {
                        http_response_code(500);
                        echo html_information('Authentication failed.');
                        return;
                    }

                    try {
                        $userInfo = User::byRemoteId($fUserInfo->id);
                        $loginMessage = 'You are now logged in!';
                    } catch(UserNotFoundException) {
                        try {
                            $userInfo = User::create($fUserInfo->id, $fUserInfo->name);
                        } catch(\PDOException) {
                            $userInfo = User::create($fUserInfo->id, sprintf('%s_%04d', $fUserInfo->name, random_int(0, 9999)));
                        }

                        $loginMessage = 'Your account been created!';
                    }

                    // leaving session bumping off for now, the implementation needs to be better for that
                    $session = UserSession::create($userInfo, false);
                    $session->setInstance();
                    setcookie('ytkns_login', $session->getToken(), $session->getExpires(), '/', '.' . Config::get('domain.main'), false, true);
                    echo html_information($loginMessage, 'Welcome', '/');
                    return;
                }
            } catch(\Exception $ex) {
                http_response_code(500);
                echo html_information('Authorisation request failed, please try again.');
            }
            return;
        }
    }

    $verifier = random_bytes(20);
    $time = pack('J', time());
    $signature = hash_hmac('sha256', $time . $verifier, YTKNS_OA2_STATE_SECRET, true);
    $state = base64uri_encode($signature . $time . $verifier);

    header(sprintf(
        'Location: https://id.flashii.net/oauth2/authorise?response_type=code&scope=identify&code_challenge_method=S256&client_id=%s&state=%s&code_challenge=%s&redirect_uri=%s',
        rawurlencode(YTKNS_OA2_CLIENT_ID),
        rawurlencode($state),
        rawurlencode(base64uri_encode(hash('sha256', $verifier, true))),
        rawurlencode('https://ytkns.com/auth/login'),
    ));
    return;
}

if($reqPath === '/auth/logout') {
    if(!UserSession::hasInstance()) {
        http_response_code(404);
        echo html_information('You are not logged in.');
        return;
    }

    if(filter_input(INPUT_GET, 's') !== UserSession::instance()->getSmallToken()) {
        http_response_code(403);
        echo html_information('Log out verification failed, please try again.');
        return;
    }

    UserSession::instance()->destroy();
    UserSession::unsetInstance();
    echo html_information('You have been logged out.', 'Log out', '/');
    return;
}

http_response_code(404);
echo html_information('The requested page does not exist.', 'Page not found');