<?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.fire       → 上传 + 触发 similarity → state=2（比对中），入队 PlagiarismPoll
 *   PlagiarismPoll.fire      → 轮询 status，完成后下载 PDF → state=3（完成）
 *   任意环节抛异常           → state=4（失败），写 error_msg
 */
class PlagiarismService
{
    /**
     * 报告 PDF 本地保存目录（相对于项目根，永久保留）
     */
    const REPORT_DIR = 'runtime/plagiarism';

    /**
     * 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;

    // ---------- 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');

        $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,
        ]);

        // 入队执行：上传 + 触发 similarity
        Queue::push(
            'app\\api\\job\\PlagiarismRun',
            ['check_id' => $checkId, 'file_path' => $filePath],
            'plagiarism'
        );

        return (int)$checkId;
    }

    /**
     * Job 调用：上传文件到 Turnitin 并触发 similarity，然后入队 PlagiarismPoll
     */
    public function runUploadAndTrigger($checkId, $filePath)
    {
        $check = $this->mustGetCheck($checkId);

        try {
            $tii = new TurnitinService();

            // 1. 创建 submission
            $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),
            ]);

            // 2. 上传文件
            $tii->uploadFile($submissionId, $filePath, basename($filePath));

            // 3. 触发 similarity
            $simResp = $tii->triggerSimilarity($submissionId);

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

            // 4. 排队首次轮询（晚一点开始，让 Turnitin 先处理）
            Queue::later(
                self::POLL_INTERVAL,
                'app\\api\\job\\PlagiarismPoll',
                ['check_id' => $checkId, 'attempt' => 1],
                'plagiarism'
            );
        } catch (\Throwable $e) {
            $this->markFailed($checkId, '[upload] ' . $e->getMessage());
            throw $e;
        }
    }

    /**
     * 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,
                'app\\api\\job\\PlagiarismPoll',
                ['check_id' => $checkId, 'attempt' => $attempt + 1],
                'plagiarism'
            );
        } 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,
                    'app\\api\\job\\PlagiarismPoll',
                    ['check_id' => $checkId, 'attempt' => $attempt + 1],
                    'plagiarism'
                );
                $this->updateCheck($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);
    }

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

    /**
     * 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', $articleId)
            ->where('type_name', 'manuscirpt')   // 历史拼写
            ->order('article_file_id desc')
            ->find();
        if (!$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();
    }
}