<?php

use Swoole\Coroutine\Http\Server;
use Swoole\Coroutine\Http\Client;
use function Swoole\Coroutine\run;

// 常量定义
const CACHE_DIR_NAME = '.cache';
const DEFAULT_PORT = 9001;
const DEFAULT_API_ENDPOINT = 'http://183.6.121.121:9519/api';
const CACHE_EXPIRY_MS = 24 * 60 * 60 * 1000; // 24小时
const CACHE_CLEANUP_INTERVAL_MS = 60 * 60 * 1000; // 1小时
const API_TIMEOUT_MS = 5000;
const USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36';

// HTTP状态码
const HTTP_STATUS = [
    'OK' => 200,
    'NO_CONTENT' => 204,
    'REDIRECT' => 302,
    'NOT_MODIFIED' => 304,
    'BAD_REQUEST' => 400,
    'NOT_FOUND' => 404,
    'INTERNAL_SERVER_ERROR' => 500,
    'BAD_GATEWAY' => 502,
];

// 初始化变量
$cacheDir = __DIR__ . '/' . CACHE_DIR_NAME;
$pathIndex = [];
$port = DEFAULT_PORT;
$apiEndpoint = DEFAULT_API_ENDPOINT;

// 访问计数器
$viewsInfo = [
    'request' => 0,
    'cacheHit' => 0,
    'apiCall' => 0,
    'cacheCall' => 0,
    'cacheReadError' => 0,
    'fetchApiError' => 0,
    'fetchApiWarning' => 0,
];

// 解析命令行参数
function parseArguments() {
    global $port, $apiEndpoint;

    $options = getopt('', ['port:', 'api:']);

    if (isset($options['port'])) {
        $parsedPort = intval($options['port']);
        if ($parsedPort > 0) {
            $port = $parsedPort;
        }
    }

    if (isset($options['api'])) {
        $apiEndpoint = $options['api'];
    }
}

// 初始化应用
function initializeApp() {
    global $cacheDir;

    parseArguments();

    if (!file_exists($cacheDir)) {
        try {
            mkdir($cacheDir, 0777, true);
            echo "Cache directory created: {$cacheDir}\n";
        } catch (Exception $e) {
            echo "Error creating cache directory {$cacheDir}: " . $e->getMessage() . "\n";
            exit(1);
        }
    }
}

// 发送错误响应
function sendErrorResponse($res, int $statusCode, string $message) {
    if (!$res->isWritable()) {
        return;
    }
    $res->status($statusCode);
    $res->header('Content-Type', 'text/plain;charset=UTF-8');
    $res->end($message);
}

// 处理favicon请求
function handleFavicon($req, $res) {
    $res->status(HTTP_STATUS['NO_CONTENT']);
    $res->end();
}

// 处理endpoint请求
function handleEndpoint($req, $res, array $queryParams) {
    global $apiEndpoint, $port, $cacheDir, $pathIndex, $viewsInfo;

    if (isset($queryParams['api'])) {
        $urlRegex = '/^(https?:\/\/)?([\da-z.-]+)\.([a-z.]{2,6})([\/\w.-]*)*\/?$/';
        if (preg_match($urlRegex, $queryParams['api'])) {
            $apiEndpoint = $queryParams['api'];
            echo "API endpoint updated to: {$apiEndpoint}\n";
        }
    }

    $res->status(HTTP_STATUS['OK']);
    $res->header('Content-Type', 'application/json; charset=utf-8');
    $res->end(json_encode([
        'code' => HTTP_STATUS['OK'],
        'data' => [
            'api' => $apiEndpoint,
            'port' => $port,
            'cacheDir' => $cacheDir,
            'pathIndexCount' => count($pathIndex),
            'viewsInfo' => $viewsInfo
        ]
    ]));
}

// 处理API重定向
function handleApiRedirect($res, array $apiData) {
    $res->status(HTTP_STATUS['REDIRECT']);
    $res->header('Location', $apiData['data']['url']);
    $res->end();
}

// 检查缓存头并返回是否为304
function checkCacheHeaders($req, string $cacheMetaFile) {
    try {
        $metaContent = file_get_contents($cacheMetaFile);
        $cacheData = json_decode($metaContent, true);
        $ifNoneMatch = isset($req->header['if-none-match']) ? $req->header['if-none-match'] : null;
        $ifModifiedSince = isset($req->header['if-modified-since']) ? $req->header['if-modified-since'] : null;

        // 检查ETag
        if ($ifNoneMatch && isset($cacheData['uniqid']) && $ifNoneMatch === $cacheData['uniqid']) {
            return ['cacheData' => $cacheData, 'isNotModified' => true];
        }

        // 检查If-Modified-Since
        if ($ifModifiedSince && isset($cacheData['headers']['last-modified'])) {
            try {
                $lastModifiedDate = strtotime($cacheData['headers']['last-modified']);
                $ifModifiedSinceDate = strtotime($ifModifiedSince);

                if ($lastModifiedDate <= $ifModifiedSinceDate) {
                    return ['cacheData' => $cacheData, 'isNotModified' => true];
                }
            } catch (Exception $e) {
                echo "Error parsing date for cache header check ({$cacheMetaFile}): " . $e->getMessage() . "\n";
            }
        }

        return ['cacheData' => $cacheData, 'isNotModified' => false];
    } catch (Exception $e) {
        echo "Error reading or parsing cache meta file {$cacheMetaFile} in checkCacheHeaders: " . $e->getMessage() . "\n";
        return ['cacheData' => null, 'isNotModified' => false];
    }
}

// 检查缓存是否有效
function isCacheValid(string $cacheMetaFile, string $cacheContentFile) {
    if (!file_exists($cacheMetaFile) || !file_exists($cacheContentFile)) {
        return false;
    }

    try {
        $metaContent = file_get_contents($cacheMetaFile);
        $cacheData = json_decode($metaContent, true);

        return isset($cacheData['expiration']) && is_numeric($cacheData['expiration']) && $cacheData['expiration'] > time() * 1000;
    } catch (Exception $e) {
        echo "Error reading or parsing cache meta file {$cacheMetaFile} for validation: " . $e->getMessage() . "\n";
        return false;
    }
}

// 从API获取数据
function fetchApiData(string $reqPath, string $token, string $sign) {
    global $apiEndpoint;

    $queryParams = http_build_query([
        'type' => $reqPath,
        'sign' => $sign
    ]);

    $apiUrl = "{$apiEndpoint}?{$queryParams}";
    $parsedApiUrl = parse_url($apiUrl);

    $client = new Client($parsedApiUrl['host'], $parsedApiUrl['port'] ?? ($parsedApiUrl['scheme'] === 'https' ? 443 : 80), $parsedApiUrl['scheme'] === 'https');
    $client->setHeaders([
        'Accept' => 'application/json; charset=utf-8',
        'User-Agent' => USER_AGENT,
        'token' => $token
    ]);
    $client->set(['timeout' => API_TIMEOUT_MS / 1000]);

    $path = isset($parsedApiUrl['path']) ? $parsedApiUrl['path'] : '/';
    if (isset($parsedApiUrl['query'])) {
        $path .= '?' . $parsedApiUrl['query'];
    }

    $client->get($path);

    if ($client->statusCode >= 400) {
        echo "API request to {$apiUrl} failed with status {$client->statusCode}: {$client->body}\n";
        $errorPayload = ['code' => $client->statusCode, 'message' => "API Error: {$client->statusCode}"];

        try {
            $parsedError = json_decode($client->body, true);
            if ($parsedError && isset($parsedError['message'])) {
                $errorPayload['message'] = $parsedError['message'];
            }
        } catch (Exception $e) {
            // Ignore if response is not JSON
        }

        return $errorPayload;
    }

    try {
        return json_decode($client->body, true);
    } catch (Exception $e) {
        echo "Error parsing JSON response from {$apiUrl}: " . $e->getMessage() . ", {$client->body}\n";
        throw new Exception("Failed to parse API response: " . $e->getMessage());
    }
}

// 从缓存中读取数据并返回
function serveFromCache(array $cacheData, string $cacheContentFile, string $cacheMetaFile, $res) {
    global $viewsInfo;

    if (!$cacheData) {
        echo "serveFromCache called with null cacheData for {$cacheContentFile}\n";
        sendErrorResponse($res, HTTP_STATUS['INTERNAL_SERVER_ERROR'], 'Cache metadata unavailable.');
        return;
    }

    $viewsInfo['cacheCall']++;

    try {
        $fileContent = file_get_contents($cacheContentFile);

        if ($fileContent === false) {
            throw new Exception("Failed to read cache file");
        }

        $baseHeaders = [
            'Cloud-Type' => $cacheData['cloudtype'] ?? 'unknown',
            'Cloud-Expiration' => $cacheData['expiration'] ?? 0,
            'ETag' => $cacheData['uniqid'] ?? '',
            'Cache-Control' => 'public, max-age=31536000',
            'Expires' => gmdate('D, d M Y H:i:s', time() + 31536000) . ' GMT',
            'Accept-Ranges' => 'bytes',
            'Connection' => 'keep-alive',
            'Date' => gmdate('D, d M Y H:i:s') . ' GMT',
            'Last-Modified' => isset($cacheData['headers']['last-modified']) ? $cacheData['headers']['last-modified'] : gmdate('D, d M Y H:i:s', filemtime($cacheMetaFile)) . ' GMT',
        ];

        $isVideo = isset($cacheData['path']) && is_string($cacheData['path']) && strpos($cacheData['path'], '.mp4') !== false;
        $contentType = isset($cacheData['headers']['Content-Type']) ? $cacheData['headers']['Content-Type'] : ($isVideo ? 'video/mp4' : 'application/octet-stream');

        $responseHeaders = array_merge($baseHeaders, [
            'Content-Type' => $contentType,
        ]);

        foreach ($responseHeaders as $key => $value) {
            $res->header($key, $value);
        }

        $res->status(HTTP_STATUS['OK']);
        $res->end($fileContent);
    } catch (Exception $e) {
        $viewsInfo['cacheReadError']++;
        echo "Error reading from cache {$cacheContentFile}: " . $e->getMessage() . "\n";
        sendErrorResponse($res, HTTP_STATUS['INTERNAL_SERVER_ERROR'], "Failed to read from cache: " . $e->getMessage());
    }
}

// 从真实URL获取数据并写入缓存
function fetchAndServe(array $data, string $tempCacheContentFile, string $cacheContentFile, string $cacheMetaFile, $res) {
    global $viewsInfo;

    $parsedUrl = parse_url($data['realUrl']);
    $client = new Client($parsedUrl['host'], $parsedUrl['port'] ?? ($parsedUrl['scheme'] === 'https' ? 443 : 80), $parsedUrl['scheme'] === 'https');
    $client->setHeaders([
        'User-Agent' => USER_AGENT
    ]);

    $path = isset($parsedUrl['path']) ? $parsedUrl['path'] : '/';
    if (isset($parsedUrl['query'])) {
        $path .= '?' . $parsedUrl['query'];
    }

    $client->get($path);

    if ($client->statusCode !== 200) {
        echo "Error fetching from {$data['realUrl']}: HTTP status {$client->statusCode}\n";
        sendErrorResponse($res, HTTP_STATUS['BAD_GATEWAY'], "Bad Gateway: Failed to fetch content from source");
        return;
    }

    $isVideo = isset($data['path']) && is_string($data['path']) && strpos($data['path'], '.mp4') !== false;

    // 检查content-length
    $contentLength = isset($client->headers['content-length']) ? $client->headers['content-length'] : null;
    if ($contentLength) {
        // contentLength小于2KB且与缓存文件大小不一致时，重新获取
        if ($contentLength < 2048 && isset($data['headers']['content-length']) && $data['headers']['content-length'] !== $contentLength) {
            echo "Warning: content-length is different for the response from: {$data['realUrl']}\n";
            sendErrorResponse($res, HTTP_STATUS['BAD_GATEWAY'], "Bad Gateway: Content-Length mismatch for {$data['realUrl']}");
            return;
        }
        // 更新data到缓存cacheMetaFile
        file_put_contents($cacheMetaFile, json_encode($data));
    } else {
        echo "Warning: content-length is undefined for the response from: {$data['realUrl']}\n";
    }

    // 写入临时缓存文件
    file_put_contents($tempCacheContentFile, $client->body);

    // 重命名临时文件为正式缓存文件
    try {
        $targetDir = dirname($cacheContentFile);
        if (!file_exists($targetDir)) {
            mkdir($targetDir, 0777, true);
        }
        rename($tempCacheContentFile, $cacheContentFile);
        echo "Successfully cached: {$cacheContentFile}\n";
    } catch (Exception $e) {
        echo "Error renaming temp cache file {$tempCacheContentFile} to {$cacheContentFile}: " . $e->getMessage() . "\n";
        // 如果重命名失败，尝试删除临时文件以避免混乱
        if (file_exists($tempCacheContentFile)) {
            unlink($tempCacheContentFile);
        }
    }

    $baseHeaders = [
        'Cloud-Type' => $data['cloudtype'] ?? 'unknown',
        'Cloud-Expiration' => $data['expiration'] ?? 0,
        'ETag' => $data['uniqid'] ?? '',
        'Cache-Control' => 'public, max-age=31536000',
        'Expires' => gmdate('D, d M Y H:i:s', time() + 31536000) . ' GMT',
        'Accept-Ranges' => 'bytes',
        'Connection' => 'keep-alive',
        'Date' => gmdate('D, d M Y H:i:s') . ' GMT',
        'Last-Modified' => isset($data['headers']['last-modified']) ?
            $data['headers']['last-modified'] :
            gmdate('D, d M Y H:i:s', filemtime($cacheMetaFile)) . ' GMT',
    ];

    $responseHeaders = array_merge($baseHeaders, [
        'Content-Type' => isset($client->headers['content-type']) ? $client->headers['content-type'] : ($isVideo ? 'video/mp4' : 'application/octet-stream'),
    ], $data['headers']);

    foreach ($responseHeaders as $key => $value) {
        $res->header($key, $value);
    }

    $res->status(HTTP_STATUS['OK']);
    $res->end($client->body);
}

// 尝试从过期缓存提供服务或返回错误
function tryServeFromStaleCacheOrError(string $uniqidhex, $res, string $errorMessage = null) {
    global $pathIndex, $cacheDir;

    if (isset($pathIndex[$uniqidhex])) {
        $cacheMetaFile = $cacheDir . '/' . $uniqidhex . '.meta';
        $cacheContentFile = $cacheDir . '/' . $pathIndex[$uniqidhex]['uniqid'] . '.content';

        if (file_exists($cacheMetaFile) && file_exists($cacheContentFile)) {
            echo "API call failed or returned non-200. Serving stale cache for {$uniqidhex}\n";

            try {
                $cacheData = json_decode(file_get_contents($cacheMetaFile), true);
                serveFromCache($cacheData, $cacheContentFile, $cacheMetaFile, $res);
                return;
            } catch (Exception $e) {
                echo "Error parsing stale meta file {$cacheMetaFile}: " . $e->getMessage() . "\n";
                // 如果过期缓存也损坏，则返回通用错误
            }
        }
    }

    sendErrorResponse($res, HTTP_STATUS['BAD_GATEWAY'], $errorMessage ?: 'Bad Gateway');
}

// 处理主请求
function handleMainRequest($req, $res) {
    global $pathIndex, $cacheDir, $viewsInfo;

    $url = preg_replace('/\/{2,}/', '/', $req->server['request_uri']);
    $parsedUrl = parse_url($url);
    $queryParams = [];

    if (isset($parsedUrl['query'])) {
        parse_str($parsedUrl['query'], $queryParams);
    }

    $sign = $queryParams['sign'] ?? '';
    $pathParts = explode('/', trim($parsedUrl['path'], '/'));
    $reqPath = $pathParts[0] ?? '';
    $token = implode('/', array_slice($pathParts, 1));

    if ($reqPath === 'favicon.ico') {
        return handleFavicon($req, $res);
    }

    if ($reqPath === 'endpoint') {
        return handleEndpoint($req, $res, $queryParams);
    }

    if (!$token && $reqPath) {
        $token = $reqPath;
        $reqPath = 'app'; // 默认为'app'，如果只提供了一个路径段
    }

    $allowedPaths = ['avatar', 'go', 'bbs', 'www', 'url', 'thumb', 'app'];
    if (!in_array($reqPath, $allowedPaths) || !$token) {
        return sendErrorResponse($res, HTTP_STATUS['BAD_REQUEST'], "Bad Request: Invalid path or missing token.");
    }

    $viewsInfo['request']++;
    $uniqidhex = md5($reqPath . $token . $sign);
    $cacheMetaFile = '';
    $cacheContentFile = '';

    if (isset($pathIndex[$uniqidhex])) {
        $cacheMetaFile = $cacheDir . '/' . $uniqidhex . '.meta';
        $cacheContentFile = $cacheDir . '/' . $pathIndex[$uniqidhex]['uniqid'] . '.content';
    }

    if (isset($pathIndex[$uniqidhex]) && isCacheValid($cacheMetaFile, $cacheContentFile)) {
        $cacheResult = checkCacheHeaders($req, $cacheMetaFile);

        if ($cacheResult['isNotModified']) {
            $res->status(HTTP_STATUS['NOT_MODIFIED']);
            $res->end();
        } else {
            $viewsInfo['cacheHit']++;
            serveFromCache($cacheResult['cacheData'], $cacheContentFile, $cacheMetaFile, $res);
        }
    } else {
        try {
            $viewsInfo['apiCall']++;
            $apiData = fetchApiData($reqPath, $token, $sign);

            if (isset($apiData['code']) && ($apiData['code'] === HTTP_STATUS['REDIRECT'] || $apiData['code'] === 301)) {
                return handleApiRedirect($res, $apiData);
            }

            if (isset($apiData['code']) && $apiData['code'] === HTTP_STATUS['OK'] && isset($apiData['data']) && isset($apiData['data']['url'])) {
                $data = [
                    'realUrl' => $apiData['data']['url'],
                    'cloudtype' => $apiData['data']['cloudtype'] ?? '',
                    'expiration' => isset($apiData['data']['expiration']) ? $apiData['data']['expiration'] * 1000 : 0,
                    'path' => $apiData['data']['path'] ?? '',
                    'headers' => $apiData['data']['headers'] ?? [],
                    'uniqid' => $apiData['data']['uniqid'] ?? '',
                    'thumb' => $apiData['data']['thumb'] ?? ''
                ];

                $pathIndex[$uniqidhex] = ['uniqid' => $data['uniqid'], 'timestamp' => time() * 1000];
                $cacheMetaFile = $cacheDir . '/' . $uniqidhex . '.meta';
                $cacheContentFile = $cacheDir . '/' . $data['uniqid'] . '.content';
                $tempCacheContentFile = $cacheDir . '/' . $data['uniqid'] . '_' . bin2hex(random_bytes(16)) . '.temp';

                try {
                    file_put_contents($cacheMetaFile, json_encode($data));
                } catch (Exception $e) {
                    echo "Error writing meta file {$cacheMetaFile}: " . $e->getMessage() . "\n";
                    sendErrorResponse($res, HTTP_STATUS['INTERNAL_SERVER_ERROR'], 'Failed to write cache metadata.');
                    return;
                }

                if (file_exists($cacheContentFile)) {
                    $contentLength = filesize($cacheContentFile);
                    if ($contentLength < 2048 && isset($data['headers']['content-length']) && intval($data['headers']['content-length']) !== $contentLength) {
                        echo "Content length mismatch for {$cacheContentFile}. API: {$data['headers']['content-length']}, Cache: {$contentLength}. Re-fetching.\n";
                        fetchAndServe($data, $tempCacheContentFile, $cacheContentFile, $cacheMetaFile, $res);
                    } else {
                        serveFromCache($data, $cacheContentFile, $cacheMetaFile, $res);
                    }
                } else {
                    fetchAndServe($data, $tempCacheContentFile, $cacheContentFile, $cacheMetaFile, $res);
                }
            } else {
                $viewsInfo['fetchApiWarning']++;
                tryServeFromStaleCacheOrError($uniqidhex, $res, $apiData['message'] ?? null);
            }
        } catch (Exception $e) {
            $viewsInfo['fetchApiError']++;
            echo "Error in API call or processing: " . $e->getMessage() . "\n";
            tryServeFromStaleCacheOrError($uniqidhex, $res, "Bad Gateway: API request failed. " . $e->getMessage());
        }
    }
}

// 定时清理过期缓存数据
function cleanupExpiredCache() {
    global $pathIndex;

    $currentTime = time() * 1000;
    foreach ($pathIndex as $key => $value) {
        if ($currentTime - $value['timestamp'] > CACHE_EXPIRY_MS) {
            unset($pathIndex[$key]);
        }
    }
}

// 主函数
function main() {
    global $port;

    initializeApp();

    // 创建服务器
    $server = new Server('0.0.0.0', $port);

    echo "Server started at http://0.0.0.0:{$port}\n";

    // 设置定时器清理过期缓存
    Swoole\Timer::tick(CACHE_CLEANUP_INTERVAL_MS, function () {
        cleanupExpiredCache();
    });

    // 处理请求
    $server->handle('/', function ($req, $res) {
        handleMainRequest($req, $res);
    });

    $server->start();
}

// 启动服务器
run(function () {
    main();
});