<?php

/**
 * Small response cache for the public app_games list pages.
 * Login state is loaded by the existing AJAX endpoint after this HTML is shown.
 */
function xxiaw_list_cache_page_number($server)
{
    if (!isset($server['REQUEST_METHOD']) || strtoupper($server['REQUEST_METHOD']) !== 'GET') {
        return false;
    }
    $requestUri = isset($server['REQUEST_URI']) ? $server['REQUEST_URI'] : '';
    // Nginx adds the ThinkPHP route to QUERY_STRING during its internal rewrite.
    // REQUEST_URI keeps the browser's original URI, so use it to detect real args.
    if (strpos($requestUri, '?') !== false) {
        return false;
    }
    $path = parse_url($requestUri, PHP_URL_PATH);
    if (!is_string($path) || !preg_match('#^/app_games/index([1-9][0-9]*)[.]html$#D', rawurldecode($path), $matches)) {
        return false;
    }
    return intval($matches[1]);
}

function xxiaw_list_cache_serve($file, $state)
{
    $html = @file_get_contents($file);
    if ($html === false) {
        return false;
    }
    header('Content-Type: text/html; charset=UTF-8');
    header('X-Xxiaw-List-Cache: ' . $state);
    echo $html;
    return true;
}

function xxiaw_list_cache_bootstrap()
{
    if (PHP_SAPI === 'cli') {
        return false;
    }
    $page = xxiaw_list_cache_page_number($_SERVER);
    if ($page === false) {
        return false;
    }

    $ttl = 60;
    $staleTtl = 300;
    $cacheDir = dirname(__DIR__) . '/Runtime/XxiawListPageCache';
    if (!is_dir($cacheDir) && !@mkdir($cacheDir, 0750, true) && !is_dir($cacheDir)) {
        return false;
    }
    $cacheFile = $cacheDir . '/app-games-page-' . $page . '.html';
    clearstatcache(true, $cacheFile);
    $modified = @filemtime($cacheFile);
    if ($modified !== false && $modified >= time() - $ttl && @filesize($cacheFile) > 1000) {
        if (xxiaw_list_cache_serve($cacheFile, 'HIT')) {
            exit;
        }
    }

    $lock = @fopen($cacheFile . '.lock', 'c');
    if ($lock === false) {
        return false;
    }
    if (!@flock($lock, LOCK_EX | LOCK_NB)) {
        if ($modified !== false && $modified >= time() - $staleTtl && @filesize($cacheFile) > 1000) {
            @fclose($lock);
            if (xxiaw_list_cache_serve($cacheFile, 'STALE')) {
                exit;
            }
        }
        $deadline = microtime(true) + 0.20;
        do {
            usleep(20000);
            clearstatcache(true, $cacheFile);
            if (@filemtime($cacheFile) >= time() - $ttl && @filesize($cacheFile) > 1000) {
                @fclose($lock);
                if (xxiaw_list_cache_serve($cacheFile, 'HIT')) {
                    exit;
                }
            }
        } while (microtime(true) < $deadline);
        @fclose($lock);
        return false;
    }

    header('X-Xxiaw-List-Cache: MISS');
    ob_start(function ($html) use ($cacheDir, $cacheFile, $lock) {
        $status = http_response_code();
        if (($status === false || $status < 400) && strlen($html) > 1000 && strpos($html, 'class="jshwarticle"') !== false) {
            $temporary = @tempnam($cacheDir, '.list-cache-');
            if ($temporary !== false) {
                if (@file_put_contents($temporary, $html, LOCK_EX) !== false) {
                    @chmod($temporary, 0640);
                    @rename($temporary, $cacheFile);
                }
                if (is_file($temporary)) {
                    @unlink($temporary);
                }
            }
        }
        @flock($lock, LOCK_UN);
        @fclose($lock);
        return $html;
    });
    return true;
}