<?php

namespace app\common;

use think\Env;

/**
 * 参考文献元数据聚合：PubMed 优先，Crossref 补全。
 *
 * 医学期刊的著录信息以 PubMed（NLM 人工校订）更贴合期次著录：
 * - 年份：PubMed 取期次年；Crossref 的 issued 是线上/线下较早者，在线优先出版会偏早一年
 * - 期刊名：PubMed 的 ISOAbbreviation / MedlineTA 就是排版要的规范缩写
 * - 卷期页：PubMed 覆盖完整；Crossref 在 ahead-of-print 阶段常缺失
 *
 * Crossref 负责非 MEDLINE 收录文献的兜底，并提供 ORCID 作者明细与撤稿关系。
 */
class ReferenceMetadataService
{
    /** @var PubmedService */
    private $pubmed;

    /** @var CrossrefService */
    private $crossref;

    /** @var ReferenceTypeClassifier */
    private $classifier;

    public function __construct()
    {
        $this->pubmed = new PubmedService();
        $this->crossref = new CrossrefService([
            'mailto' => trim((string)Env::get('crossref_mailto', '')),
        ]);
        $this->classifier = new ReferenceTypeClassifier(['use_llm' => false]);
    }

    /**
     * 按 DOI 聚合元数据
     *
     * @return array|null 两个源都查不到时返回 null
     */
    public function fetchByDoi($doi)
    {
        $doi = $this->normalizeDoi($doi);
        if ($doi === '') {
            return null;
        }

        $pub = null;
        try {
            $pub = $this->pubmed->fetchByDoi($doi);
        } catch (\Throwable $e) {
            $pub = null;
        }
        if (!is_array($pub)) {
            $pub = null;
        }

        $cr = $this->crossref->fetchWorkSummary($doi);
        if (!is_array($cr)) {
            $cr = null;
        }

        if ($pub === null && $cr === null) {
            return null;
        }

        $sources = [];
        if ($pub !== null) $sources[] = 'pubmed';
        if ($cr !== null) $sources[] = 'crossref';

        $title  = $this->pickTitle($pub, $cr);
        $joura  = $this->pickJournal($pub, $cr);
        $author = $this->pickAuthor($pub, $cr);
        $dateno = $this->pickDateno($pub, $cr);

        $doilink = trim((string)($cr['doilink'] ?? ''));
        if ($doilink === '') {
            $doilink = 'https://doi.org/' . $doi;
        }

        $crossrefType = trim((string)($cr['raw']['type'] ?? ''));
        $type = $this->pickType($pub, $crossrefType);

        $retract = $this->pickRetraction($pub, $cr);

        return [
            'doi'              => $doi,
            'pmid'             => trim((string)($pub['pmid'] ?? '')),
            'title'            => $title,
            'author'           => $author,
            'joura'            => $joura,
            'dateno'           => $dateno,
            'doilink'          => $doilink,
            'type'             => $type,
            'crossref_type'    => $crossrefType,
            'is_retracted'     => $retract['is_retracted'],
            'retract_reason'   => $retract['reason'],
            'has_cjk'          => $this->crossref->hasCjk($title)
                || $this->crossref->hasCjk($joura)
                || $this->crossref->hasCjk($author),
            'sources'          => $sources,
            'crossref_summary' => $cr,
            'pubmed'           => $pub,
        ];
    }

    /**
     * 标题：PubMed 优先。非英文原文在 PubMed 里是括号包裹的英译标题，去掉括号更贴合排版。
     */
    private function pickTitle($pub, $cr)
    {
        $title = trim((string)($pub['title'] ?? ''));
        if ($title !== '') {
            $title = rtrim($title, '.');
            if (preg_match('/^\[(.+)\]$/s', $title, $m)) {
                $title = trim($m[1]);
            }
            return $title;
        }
        return trim((string)($cr['title'] ?? ''));
    }

    /**
     * 期刊名：PubMed 的规范缩写优先，其次 Crossref
     */
    private function pickJournal($pub, $cr)
    {
        $abbr = trim((string)($pub['journal_iso_abbr'] ?? ''));
        if ($abbr === '') {
            $abbr = trim((string)($pub['journal_medline_ta'] ?? ''));
        }
        if ($abbr !== '') {
            return $abbr;
        }
        return trim((string)($cr['joura'] ?? ''));
    }

    private function pickAuthor($pub, $cr)
    {
        $authors = isset($pub['authors']) && is_array($pub['authors']) ? $pub['authors'] : [];
        if (!empty($authors)) {
            $citation = $this->pubmed->authorsCitation($authors);
            if ($citation !== '') {
                return $citation;
            }
        }
        return $this->crossref->getAuthorsCitation($cr['raw'] ?? []);
    }

    /**
     * 卷期页：PubMed 有卷或页时以 PubMed 为准，否则用 Crossref
     *
     * 格式与 citation.doi.org 路径一致：Year;Volume(Issue):Pages
     */
    private function pickDateno($pub, $cr)
    {
        $volume = trim((string)($pub['volume'] ?? ''));
        $pages  = $this->expandPageRange((string)($pub['pages'] ?? ''));
        if ($volume === '' && $pages === '') {
            return trim((string)($cr['dateno'] ?? ''));
        }

        if ($volume !== '') {
            $issue = trim((string)($pub['issue'] ?? ''));
            $volume .= $issue !== '' ? "({$issue})" : '';
        }

        $tail = $volume;
        if ($pages !== '') {
            $tail = $tail !== '' ? $tail . ':' . $pages : $pages;
        }

        $year = trim((string)($pub['year'] ?? ''));
        if ($year === '' || $tail === '') {
            return $year !== '' ? $year : $tail;
        }
        return $year . ';' . $tail;
    }

    /**
     * 展开 NLM 缩写式尾页：210-8 表示 210-218
     */
    private function expandPageRange($pages)
    {
        $pages = trim((string)$pages);
        if ($pages === '' || strpos($pages, '-') === false) {
            return $pages;
        }

        $parts = explode('-', $pages, 2);
        $start = trim($parts[0]);
        $end   = trim($parts[1]);
        if ($start === '' || $end === '') {
            return $pages;
        }

        if (ctype_digit($start) && ctype_digit($end) && strlen($end) < strlen($start)) {
            $end = substr($start, 0, strlen($start) - strlen($end)) . $end;
        }

        return $start . '-' . $end;
    }

    /**
     * 类型：Crossref 的 type 最权威，PubMed 的 publication_types 兜底
     */
    private function pickType($pub, $crossrefType)
    {
        $mapped = $this->classifier->mapCrossrefType($crossrefType);
        if ($mapped !== '') {
            return $mapped;
        }

        $types = isset($pub['publication_types']) && is_array($pub['publication_types'])
            ? $pub['publication_types'] : [];
        foreach ($types as $t) {
            $t = strtolower(trim((string)$t));
            if ($t === '') {
                continue;
            }
            if (strpos($t, 'congress') !== false) {
                return ReferenceTypeClassifier::TYPE_CONFERENCE;
            }
            if (strpos($t, 'journal article') !== false
                || strpos($t, 'review') !== false
                || strpos($t, 'clinical trial') !== false
                || strpos($t, 'meta-analysis') !== false
                || strpos($t, 'case reports') !== false
                || strpos($t, 'observational study') !== false
                || strpos($t, 'comparative study') !== false
                || strpos($t, 'multicenter study') !== false
                || strpos($t, 'editorial') !== false
                || strpos($t, 'letter') !== false) {
                return ReferenceTypeClassifier::TYPE_JOURNAL;
            }
        }

        return '';
    }

    private function pickRetraction($pub, $cr)
    {
        $types = isset($pub['publication_types']) && is_array($pub['publication_types'])
            ? $pub['publication_types'] : [];
        foreach ($types as $t) {
            if (stripos((string)$t, 'retract') !== false) {
                return ['is_retracted' => 1, 'reason' => 'PubMed 标记：' . trim((string)$t)];
            }
        }

        return [
            'is_retracted'   => !empty($cr['is_retracted']) ? 1 : 0,
            'reason'         => (string)($cr['retract_reason'] ?? ''),
        ];
    }

    public function normalizeDoi($doi)
    {
        $doi = preg_replace('#^https?://(dx\.)?doi\.org/#i', '', trim((string)$doi));
        return trim($doi, " \t\n\r\0\x0B/");
    }
}