<?php

namespace app\common;

use think\Db;
use think\Env;
use think\Queue;
use think\Exception;

/**
 * 查重业务层：把 TurnitinService 的低层调用包装成"按 article 查重"的高层流程，
 * 并维护 t_plagiarism_check 状态机。
 *
 * 状态流：
 *   submit()                    → state=1（上传中），入队 PlagiarismRun
 *   PlagiarismRun               → 创建 submission + 上传文件 → 入队 PlagiarismWaitIngest
 *   PlagiarismWaitIngest        → 单次 GET submission 状态；就绪则入队 PlagiarismTriggerSimilarity，否则延迟再入队
 *   PlagiarismTriggerSimilarity → PUT similarity → state=2（比对中），入队 PlagiarismPoll
 *   PlagiarismPoll              → 轮询 similarity，完成后下载 PDF → state=3（完成）
 *   任意环节抛异常               → state=4（失败），写 error_msg
 *
 * Worker：请用 `queue:work` 消费队列 **plagiarism**（整条链与轮询均在此队列；若此前单独监听 PlagiarismRun / PlagiarismPoll，需改为 plagiarism）。
 */
class PlagiarismService
{
    /**
     * 报告 PDF 本地保存目录（相对于项目根，永久保留）
     */
    const REPORT_DIR = 'public/plagiarism';

    /** Run / WaitIngest / TriggerSimilarity / Poll 共用队列名 */
    const QUEUE_CHAIN = 'plagiarism';

    const JOB_WAIT_INGEST = 'app\\api\\job\\PlagiarismWaitIngest';
    const JOB_TRIGGER_SIM = 'app\\api\\job\\PlagiarismTriggerSimilarity';
    const JOB_POLL = 'app\\api\\job\\PlagiarismPoll';

    /**
     * 轮询间隔（秒）。Turnitin 一般 1-5 分钟出结果，30 秒一次比较合适
     */
    const POLL_INTERVAL = 30;

    /**
     * 最长轮询次数（30s × 60 = 30 分钟）
     */
    const MAX_POLL_ATTEMPTS = 60;

    private $logFile;

    public function __construct()
    {
        $this->logFile = ROOT_PATH . 'runtime' . DS . 'plagiarism_task.log';
    }

    // ---------- 顶层入口 ----------

    /**
     * 提交查重（入队，立即返回 check_id）
     *
     * @param int    $articleId   投稿 ID
     * @param string $filePath    本地可读的 PDF/DOCX 绝对路径
     * @param int    $triggeredBy 触发人 user_id（手工触发时编辑后台的 user_id）
     * @param string $source      'manual' / 'auto_xxx'
     * @return int   check_id
     */
    public function submit($articleId, $filePath, $triggeredBy = 0, $source = 'manual')
    {
        if (!is_file($filePath) || !is_readable($filePath)) {
            throw new Exception("File not readable: {$filePath}");
        }

        $journalId = (int) Db::name('article')
            ->where('article_id', $articleId)
            ->value('journal_id');

        $this->log("plagiarism submit is running");
        $now = time();
        $checkId = Db::name('plagiarism_check')->insertGetId([
            'article_id'       => $articleId,
            'journal_id'       => $journalId,
            'triggered_by'     => $triggeredBy,
            'trigger_source'   => $source,
            'state'            => 1,           // 上传中
            'source_file_name' => basename($filePath),
            'source_file_size' => filesize($filePath) ?: 0,
            'ctime'            => $now,
            'utime'            => $now,
        ]);
        Queue::push(
            'app\\api\\job\\PlagiarismRun',
            ['check_id' => $checkId, 'file_path' => $filePath],
            self::QUEUE_CHAIN
        );

        return (int)$checkId;
    }

    /**
     * Job 调用：仅创建 submission + 上传文件，随后由 PlagiarismWaitIngest 链式轮询 ingest，再 PlagiarismTriggerSimilarity。
     */
    public function runUploadOnly($checkId, $filePath)
    {
        $check = $this->mustGetCheck($checkId);
        $this->log('runUploadOnly start check_id=' . $checkId);
        $tii = new TurnitinService();

        $articleTitle = (string) Db::name('article')
            ->where('article_id', $check['article_id'])
            ->value('title');
        if ($articleTitle === '') {
            $articleTitle = 'Article #' . $check['article_id'];
        }

        $createResp = $tii->createSubmission([
            'title'     => mb_substr($articleTitle, 0, 250),
            'owner'     => 'editor_' . $check['triggered_by'],
            'submitter' => 'editor_' . $check['triggered_by'],
            'metadata'  => [
                'article_id' => (string) $check['article_id'],
                'check_id'   => (string) $check['check_id'],
            ],
        ]);
        $submissionId = isset($createResp['id']) ? $createResp['id'] : '';
        if ($submissionId === '') {
            throw new Exception('Turnitin createSubmission returned empty id: ' . json_encode($createResp));
        }

        $this->updateCheck($checkId, [
            'tii_submission_id' => $submissionId,
            'raw_response'      => json_encode($createResp, JSON_UNESCAPED_UNICODE),
        ]);

        $tii->uploadFile($submissionId, $filePath, basename($filePath));
        $firstDelay = $this->ingestChainFirstDelaySec();
        Queue::later(
            $firstDelay,
            self::JOB_WAIT_INGEST,
            ['check_id' => $checkId, 'attempt' => 1],
            self::QUEUE_CHAIN
        );
    }

    /**
     * 单次 ingest 检查（由 PlagiarismWaitIngest 调用）。不在本方法内 sleep 长循环。
     */
    public function runIngestPollStep($checkId, $attempt = 1)
    {
        $check = $this->mustGetCheck($checkId);
        if (empty($check['tii_submission_id'])) {
            $this->markFailed($checkId, '[ingest] tii_submission_id empty');
            return;
        }
        $this->log("runIngestPollStep is running");
        $maxAttempts = $this->ingestChainMaxAttempts();
        $interval    = $this->ingestChainPollIntervalSec();
        $tii         = new TurnitinService();

        try {
            $parsed = $tii->parseSubmissionIngestState($check['tii_submission_id']);
        } catch (\Throwable $e) {
            if ($attempt >= $maxAttempts) {
                $this->markFailed($checkId, '[ingest] request failed after ' . $attempt . ' tries: ' . $e->getMessage());
                return;
            }
            Queue::later($interval, self::JOB_WAIT_INGEST, ['check_id' => $checkId, 'attempt' => $attempt + 1], self::QUEUE_CHAIN);
            return;
        }

        if (!empty($parsed['failed'])) {
            $this->markFailed($checkId, '[ingest] submission failed status=' . $parsed['status'] . ' ' . $parsed['snippet']);
            return;
        }
        if (!empty($parsed['ready'])) {
            Queue::push(self::JOB_TRIGGER_SIM, ['check_id' => $checkId, 'ingest_attempt' => $attempt], self::QUEUE_CHAIN);
            return;
        }
        if ($attempt >= $maxAttempts) {
            $this->markFailed($checkId, '[ingest] timeout last_status=' . ($parsed['status'] !== '' ? $parsed['status'] : '(empty)'));
            return;
        }
        Queue::later($interval, self::JOB_WAIT_INGEST, ['check_id' => $checkId, 'attempt' => $attempt + 1], self::QUEUE_CHAIN);
    }

    /**
     * 在 ingest 就绪后触发 similarity，并入队 PlagiarismPoll。
     * 若仍返回 409，则重新入队 PlagiarismWaitIngest（不抛异常，避免误标失败）。
     *
     * @param int $ingestAttempt 来自 WaitIngest 的 attempt，供 409 时继续轮询
     */
    public function runTriggerSimilarityOnly($checkId, $ingestAttempt = 1)
    {
        $check = $this->mustGetCheck($checkId);
        if (empty($check['tii_submission_id'])) {
            $this->markFailed($checkId, '[similarity] tii_submission_id empty');
            return;
        }

        $this->log("runTriggerSimilarityOnly is running");
        $tii = new TurnitinService();
        $sid = $check['tii_submission_id'];

        try {
            $simResp = $tii->triggerSimilarity($sid);
        } catch (\Throwable $e) {
            $msg = $e->getMessage();
            $is409 = (stripos($msg, '409') !== false || stripos($msg, 'CONFLICT') !== false)
                && (stripos($msg, 'not been completed') !== false || stripos($msg, 'completed yet') !== false);
            if ($is409) {
                $maxAttempts = $this->ingestChainMaxAttempts();
                $next        = $ingestAttempt + 1;
                if ($next > $maxAttempts) {
                    $this->markFailed($checkId, '[similarity] still not ready after ingest attempts: ' . $msg);
                    return;
                }
                $delay = max($this->ingestChainPollIntervalSec(), 20);
                Queue::later($delay, self::JOB_WAIT_INGEST, ['check_id' => $checkId, 'attempt' => $next], self::QUEUE_CHAIN);
                return;
            }
            throw $e;
        }

        $this->updateCheck($checkId, [
            'state'             => 2,
            'tii_report_status' => 'PROCESSING',
            'raw_response'      => json_encode($simResp, JSON_UNESCAPED_UNICODE),
        ]);

        Queue::later(
            self::POLL_INTERVAL,
            self::JOB_POLL,
            ['check_id' => $checkId, 'attempt' => 1],
            self::QUEUE_CHAIN
        );
    }

    /**
     * @deprecated 与 runUploadOnly 等价；长耗时 ingest 已拆到队列 PlagiarismWaitIngest，勿在本方法内同步 wait。
     */
    public function runUploadAndTrigger($checkId, $filePath)
    {
        $this->runUploadOnly($checkId, $filePath);
    }

    /**
     * Job 调用：轮询 similarity 状态，完成后下载 PDF。未完成则重新入队。
     */
    public function runPollStatus($checkId, $attempt = 1)
    {
        $check = $this->mustGetCheck($checkId);
        if (empty($check['tii_submission_id'])) {
            $this->markFailed($checkId, '[poll] tii_submission_id empty');
            return;
        }

//        try {
            $tii = new TurnitinService();
            $statusResp = $tii->getSimilarityStatus($check['tii_submission_id']);
            $status = isset($statusResp['status']) ? strtoupper($statusResp['status']) : '';

            $this->updateCheck($checkId, [
                'tii_report_status' => $status,
                'attempts'          => $attempt,
                'raw_response'      => json_encode($statusResp, JSON_UNESCAPED_UNICODE),
            ]);

            if ($status === 'COMPLETE') {
                $score = isset($statusResp['overall_match_percentage'])
                    ? floatval($statusResp['overall_match_percentage']) : 0;

                // 下载 PDF + 取在线查看 URL
                $localPdf = $this->downloadAndStorePdf($tii, $check['tii_submission_id'], $checkId);
                $viewerInfo = $this->refreshViewerUrl($tii, $check['tii_submission_id']);

                $this->updateCheck($checkId, [
                    'state'                => 3,
                    'similarity_score'     => $score,
                    'pdf_local_path'       => $localPdf,
                    'view_only_url'        => $viewerInfo['url'],
                    'view_only_url_expire' => $viewerInfo['expire'],
                    'error_msg'            => '',
                ]);
                return;
            }

            if ($status === 'ERROR') {
                $errMsg = isset($statusResp['error_code']) ? (string)$statusResp['error_code'] : 'Turnitin reported ERROR';
                $this->markFailed($checkId, '[poll] ' . $errMsg);
                return;
            }

            // PROCESSING 或其它中间态：继续轮询
            if ($attempt >= self::MAX_POLL_ATTEMPTS) {
                $this->markFailed($checkId, '[poll] timeout after ' . $attempt . ' attempts');
                return;
            }
            Queue::later(
                self::POLL_INTERVAL,
                self::JOB_POLL,
                ['check_id' => $checkId, 'attempt' => $attempt + 1],
                self::QUEUE_CHAIN
            );
//        } catch (\Throwable $e) {
//            // 网络抖动不要直接 fail，给一定容错次数
//            if ($attempt < self::MAX_POLL_ATTEMPTS) {
//                Queue::later(
//                    self::POLL_INTERVAL,
//                    self::JOB_POLL,
//                    ['check_id' => $checkId, 'attempt' => $attempt + 1],
//                    self::QUEUE_CHAIN
//                );
//                $this->updateCheck($checkId, [
//                    'attempts'  => $attempt,
//                    'error_msg' => '[poll] transient: ' . $e->getMessage(),
//                ]);
//                return;
//            }
//            $this->markFailed($checkId, '[poll] exhausted: ' . $e->getMessage());
//            throw $e;
//        }
    }

    /**
     * 重新生成在线查看 URL（已有的过期了用）
     *
     * @return array{url:string, expire:int, local_pdf:string}
     */
    public function refreshViewerUrlFor($checkId)
    {
        $check = $this->mustGetCheck($checkId);
        if (empty($check['tii_submission_id'])) {
            throw new Exception('check has no tii_submission_id');
        }
        $tii = new TurnitinService();
        $info = $this->refreshViewerUrl($tii, $check['tii_submission_id']);
        $this->updateCheck($checkId, [
            'view_only_url'        => $info['url'],
            'view_only_url_expire' => $info['expire'],
        ]);
        return [
            'url'       => $info['url'],
            'expire'    => $info['expire'],
            'local_pdf' => $check['pdf_local_path'],
        ];
    }

    // ---------- 内部 ----------

    private function refreshViewerUrl($tii, $submissionId)
    {
        $resp = $tii->getViewerUrl($submissionId);
        $url = '';
        if (isset($resp['viewer_url'])) {
            $url = (string)$resp['viewer_url'];
        } elseif (isset($resp['url'])) {
            $url = (string)$resp['url'];
        }
        // 默认 2 小时过期，保守起见
        return ['url' => $url, 'expire' => time() + 7200];
    }

    /**
     * 触发生成 + 轮询 + 下载 PDF 到本地，返回相对路径
     */
    private function downloadAndStorePdf($tii, $submissionId, $checkId)
    {
        // 1. 请求生成
        $req = $tii->requestPdfReport($submissionId);
        $pdfId = isset($req['id']) ? $req['id'] : '';
        if ($pdfId === '') {
            throw new Exception('requestPdfReport empty id: ' . json_encode($req));
        }

        // 2. 内联轮询 PDF 状态（最多 3 分钟，每 6 秒一次）
        $maxLoops = 30;
        for ($i = 0; $i < $maxLoops; $i++) {
            $st = $tii->getPdfReportStatus($submissionId, $pdfId);
            $stCode = isset($st['status']) ? strtoupper($st['status']) : '';
            if ($stCode === 'SUCCESS') {
                break;
            }
            if ($stCode === 'FAILED') {
                throw new Exception('PDF report generation failed: ' . json_encode($st));
            }
            sleep(6);
        }
        // 3. 下载
        $binary = $tii->downloadPdfReport($submissionId, $pdfId);
        if (!is_string($binary) || strlen($binary) < 100) {
            throw new Exception('downloaded pdf is empty/too small');
        }

        // 4. 落盘
        $rootDir = ROOT_PATH ?: dirname(dirname(__DIR__));
        $absDir  = rtrim($rootDir, '/\\') . DIRECTORY_SEPARATOR . self::REPORT_DIR;
        if (!is_dir($absDir)) {
            @mkdir($absDir, 0755, true);
        }
        $filename = sprintf('check_%d_%s.pdf', $checkId, date('Ymd_His'));
        $absPath  = $absDir . DIRECTORY_SEPARATOR . $filename;
        $bytes    = file_put_contents($absPath, $binary);
        if ($bytes === false || $bytes < 100) {
            throw new Exception('failed to save pdf to ' . $absPath);
        }
        return self::REPORT_DIR . '/' . $filename;
    }

    private function mustGetCheck($checkId)
    {
        $row = Db::name('plagiarism_check')->where('check_id', $checkId)->find();
        if (!$row) {
            throw new Exception("plagiarism_check #{$checkId} not found");
        }
        return $row;
    }

    private function updateCheck($checkId, array $data)
    {
        $data['utime'] = time();
        Db::name('plagiarism_check')->where('check_id', $checkId)->update($data);
    }

    public function markFailed($checkId, $errMsg)
    {
        $this->log('markFailed check_id=' . $checkId);
        $this->updateCheck($checkId, [
            'state'     => 4,
            'error_msg' => mb_substr($errMsg, 0, 1000),
        ]);
    }

    private function ingestChainFirstDelaySec()
    {
        return max(3, (int) Env::get('turnitin.ingest_chain_first_delay', 10));
    }

    private function ingestChainPollIntervalSec()
    {
        return max(60, (int) Env::get('turnitin.ingest_chain_poll_interval', 15));
    }

    private function ingestChainMaxAttempts()
    {
        return max(10, (int) Env::get('turnitin.ingest_chain_max_attempts', 80));
    }

    /**
     * 从 t_article_file 找到投稿主稿（manuscirpt）的本地绝对路径。
     * file_url 在系统里可能是 URL 或相对路径，调用方负责保证可读。
     *
     * @return string 文件绝对路径，找不到时抛异常
     */
    public function locateArticleManuscript($articleId)
    {
        $row = Db::name('article_file')
            ->where('article_id', $articleId)
            ->where('type_name', 'manuscirpt')   // 历史拼写
            ->order('file_id desc')
            ->find();
        if (!$row || empty($row['file_url'])) {
            throw new Exception("article #{$articleId} has no manuscirpt file");
        }
        return $this->resolveFileUrlToLocal($row['file_url']);
    }

    /**
     * 把 file_url（可能是 http URL 或相对路径）解析成本地绝对路径。
     * 不同环境部署可能有差异，这里用 .env 配置的 STATIC_ROOT 作前缀。
     */
    public function resolveFileUrlToLocal($fileUrl)
    {
        $fileUrl = trim((string)$fileUrl);
        if ($fileUrl === '') {
            throw new Exception('empty file_url');
        }
        // 已是绝对路径
        if (preg_match('/^([a-zA-Z]:[\\\\\/]|\/)/', $fileUrl) && is_file($fileUrl)) {
            return $fileUrl;
        }

        $staticRoot = trim((string)Env::get('plagiarism.static_root', ''));
        $cdnPrefix  = trim((string)Env::get('plagiarism.cdn_prefix', ''));

        // 是 http URL：先试着剥掉 cdn 前缀，映射到本地
        if (preg_match('#^https?://#i', $fileUrl)) {
            if ($cdnPrefix !== '' && stripos($fileUrl, $cdnPrefix) === 0) {
                $rel = ltrim(substr($fileUrl, strlen($cdnPrefix)), '/');
                $local = rtrim($staticRoot, '/\\') . DIRECTORY_SEPARATOR . $rel;
                if (is_file($local)) {
                    return $local;
                }
            }
            // 实在不行，下载到 runtime/plagiarism/tmp 临时目录
            return $this->downloadRemoteFile($fileUrl);
        }

        // 相对路径：拼 static_root
        if ($staticRoot !== '') {
            $local = rtrim($staticRoot, '/\\') . DIRECTORY_SEPARATOR . ltrim($fileUrl, '/\\');
            if (is_file($local)) {
                return $local;
            }
        }

        throw new Exception("cannot resolve file_url to local path: {$fileUrl} (set [plagiarism] STATIC_ROOT/CDN_PREFIX in .env)");
    }

    private function downloadRemoteFile($url)
    {
        $rootDir = ROOT_PATH ?: dirname(dirname(__DIR__));
        $tmpDir  = rtrim($rootDir, '/\\') . DIRECTORY_SEPARATOR . self::REPORT_DIR . DIRECTORY_SEPARATOR . 'tmp';
        if (!is_dir($tmpDir)) {
            @mkdir($tmpDir, 0755, true);
        }
        $ext = pathinfo(parse_url($url, PHP_URL_PATH), PATHINFO_EXTENSION) ?: 'pdf';
        $local = $tmpDir . DIRECTORY_SEPARATOR . md5($url) . '_' . time() . '.' . $ext;

        $ch = curl_init($url);
        $fh = fopen($local, 'wb');
        curl_setopt_array($ch, [
            CURLOPT_FILE => $fh,
            CURLOPT_FOLLOWLOCATION => true,
            CURLOPT_TIMEOUT => 120,
            CURLOPT_SSL_VERIFYPEER => false,
        ]);
        $ok = curl_exec($ch);
        $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        fclose($fh);
        if (!$ok || $code !== 200 || filesize($local) < 100) {
            @unlink($local);
            throw new Exception("download failed url={$url} http={$code}");
        }
        return $local;
    }

    public function getCheck($checkId)
    {
        return Db::name('plagiarism_check')->where('check_id', $checkId)->find();
    }

    public function log($msg)
    {
        $line = date('Y-m-d H:i:s') . ' ' . $msg . PHP_EOL;
        @file_put_contents($this->logFile, $line, FILE_APPEND);
    }
}