<?php

namespace app\common;

use app\common\service\LLMService;

/**
 * 图书类参考文献著录解析：原文字符串 → author / title / publisher / year / edition …
 *
 * 注意 refer_content 存的是带序号的原文（"1. "、"[1] "、"1) "），
 * 直接按第一个句点切分会把序号当作者、把作者当标题，所以必须先剥序号再解析。
 *
 * 规则解析拿不准时（缺标题、或标题看着像作者名单）再交给大模型兜底。
 */
class BookCitationParser
{
    /** @var bool */
    private $useLlm;

    public function __construct(array $config = [])
    {
        $this->useLlm = isset($config['use_llm']) ? (bool)$config['use_llm'] : true;
    }

    /**
     * @return array author/title/publisher/place/year/edition/pages/isbn/container
     */
    public function parse($content)
    {
        $out = [
            'author'    => '',
            'title'     => '',
            'publisher' => '',
            'place'     => '',
            'year'      => '',
            'edition'   => '',
            'pages'     => '',
            'isbn'      => '',
            'container' => '',
        ];

        $clean = $this->normalize($content);
        if ($clean === '') {
            return $out;
        }

        $out['isbn'] = $this->matchIsbn($clean);
        $clean = $this->stripTail($clean);

        // 章节引用："章节作者. 章节名. In: 编者. 书名. 版次. 地点: 出版社; 年. 页码"
        // 出版信息属于 In: 之后的那本书，必须分开解析，否则会把编者当成书名
        if (preg_match('/^(.*?)\bIn\s*:\s*(.+)$/isu', $clean, $m) && trim($m[1]) !== '' && trim($m[2]) !== '') {
            $chapter = trim($m[1]);
            $book = trim($m[2]);

            $this->parseSegments($this->takeAuthor($chapter, $out['author']), $out);

            $bookOut = $out;
            $bookOut['title'] = '';
            $editors = '';
            $this->parseSegments($this->takeAuthor($book, $editors), $bookOut);

            $out['container'] = $bookOut['title'];
            foreach (['publisher', 'place', 'year', 'edition', 'pages'] as $field) {
                if ($out[$field] === '') {
                    $out[$field] = $bookOut[$field];
                }
            }
            if ($out['author'] === '') {
                $out['author'] = $editors;
            }
        } else {
            $this->parseSegments($this->takeAuthor($clean, $out['author']), $out);
        }

        if ($this->needsLlm($out)) {
            $out = $this->refineByLlm($clean, $out);
        }

        return $out;
    }

    /**
     * 去掉条目序号："1. " / "[1] " / "(1) " / "1) " / "1、"
     */
    public function stripIndex($content)
    {
        return preg_replace('/^\s*(?:\[\d{1,4}\]|\(\d{1,4}\)|\d{1,4}\s*[\.\)\]、,])\s*/u', '', (string)$content);
    }

    private function normalize($content)
    {
        $content = trim((string)$content);
        $content = str_replace(
            ['：', '；', '，', '（', '）', '［', '］', '　', '．'],
            [':', ';', ',', '(', ')', '[', ']', ' ', '.'],
            $content
        );
        $content = preg_replace('/\s+/u', ' ', $content);
        $content = $this->stripIndex($content);
        // 中文句号统一成英文句点，便于按同一套规则切分
        $content = str_replace('。', '. ', $content);

        return trim(preg_replace('/\s+/u', ' ', $content));
    }

    /**
     * 去掉尾部的获取途径（Available at / Accessed / URL / DOI），它们会干扰分段
     */
    private function stripTail($text)
    {
        $text = preg_replace('/\s*(?:Available\s*(?:at|from)|Retrieved\s+from|Accessed\s+(?:on\s+)?)\s*:?.*$/iu', '', $text);
        $text = preg_replace('/\s*https?:\/\/\S+/iu', '', $text);
        $text = preg_replace('/\s*\bdoi\s*:\s*\S+/iu', '', $text);
        $text = preg_replace('/\s*\bISBN(?:-1[03])?\s*:?\s*[\d\-\sXx]{10,20}\.?/iu', '', $text);

        return trim($text);
    }

    private function matchIsbn($text)
    {
        if (!preg_match('/\bISBN(?:-1[03])?[:\s]*([0-9][0-9\-\s]{8,20}[0-9Xx])/i', $text, $m)) {
            return '';
        }

        return preg_replace('/[^0-9Xx]/', '', $m[1]);
    }

    // ------------------------------------------------------------------
    // 作者
    // ------------------------------------------------------------------

    /**
     * 从头部切出作者，返回剩余部分
     */
    private function takeAuthor($text, &$author)
    {
        $author = '';

        // 温哥华格式：Surname AB, Surname CD, et al.（可带 editor/eds 标记）
        $name = '\p{Lu}[\p{L}\'\x{2019}\-]+(?:\s+\p{Lu}[\p{L}\'\x{2019}\-]+)*\s+\p{Lu}{1,4}';
        $pattern = '/^((?:' . $name . ')(?:\s*,\s*(?:' . $name . '))*'
            . '(?:\s*,?\s*et\s+al\.?)?)(?:\s*,\s*(?:eds?|editors?))?\s*[\.,]\s+/u';
        if (preg_match($pattern, $text, $m)) {
            $author = trim($m[1], " ,.");
            return trim(substr($text, strlen($m[0])));
        }

        // 机构作者
        $org = '/^([\p{Lu}][\p{L}\s&\-,\.]{4,90}?(?:Organization|Organisation|Association|Society|Institute'
            . '|Institutes|Ministry|Committee|Council|Administration|Agency|Department|Bureau|Foundation'
            . '|Academy|Commission|Centers?|WHO|CDC|NIH|FDA|NICE|UNICEF|OECD))\.\s+/u';
        if (preg_match($org, $text, $m)) {
            $author = trim($m[1], " ,.");
            return trim(substr($text, strlen($m[0])));
        }

        // 中文作者：张三, 李四, 等.
        $cn = '/^([\x{4e00}-\x{9fff}·]{2,10}(?:\s*[,、;]\s*[\x{4e00}-\x{9fff}·]{2,10})*(?:\s*,?\s*等)?)\s*[\.,]\s*/u';
        if (preg_match($cn, $text, $m)) {
            $author = trim($m[1], " ,.");
            return trim(substr($text, strlen($m[0])));
        }

        // 兜底：第一个句点之前
        $parts = preg_split('/\.\s+/u', $text, 2);
        if (is_array($parts) && count($parts) === 2 && mb_strlen($parts[0], 'UTF-8') <= 120) {
            $author = trim($parts[0], " ,.");
            return trim($parts[1]);
        }

        return $text;
    }

    // ------------------------------------------------------------------
    // 分段与归类
    // ------------------------------------------------------------------

    private function parseSegments($text, array &$out)
    {
        foreach ($this->splitSegments($text) as $seg) {
            $seg = trim($seg, " .,;");
            if ($seg === '') {
                continue;
            }

            // "6th ed. New York: Garland Science; 2015" 里版次和出版信息粘在一段，
            // 摘掉版次再往下判，否则出版地会变成 "6th ed. New York"
            $edition = $this->matchEdition($seg);
            if ($edition !== '') {
                if ($out['edition'] === '') {
                    $out['edition'] = $edition;
                }
                $seg = trim($this->stripEdition($seg), " .,;");
                if ($seg === '') {
                    continue;
                }
            }

            if ($out['pages'] === '' && preg_match('/^(?:p{1,2}\.?|pages?)\s*([\divxlcIVXLC][\divxlcIVXLC\-\x{2013}]*)$/iu', $seg, $m)) {
                $out['pages'] = $m[1];
                continue;
            }

            if ($this->takePublication($seg, $out)) {
                continue;
            }

            if ($out['title'] === '') {
                $out['title'] = $this->cleanTitle($seg);
            }
        }

        if ($out['year'] === '' && preg_match_all('/\b(?:19|20)\d{2}\b/', $text, $ym)) {
            $out['year'] = end($ym[0]);
        }
    }

    /**
     * 缩写后的句点不是分段边界（ed. / vol. / p. / Inc. / 姓名缩写）
     *
     * @return string[]
     */
    private function splitSegments($text)
    {
        $abbr = 'ed|eds|edn|vol|vols|no|nos|pp|p|st|mt|dr|prof|inc|ltd|co|jr|sr|al|rev|suppl|fig|ch|pt|approx';
        $masked = preg_replace('/\b(' . $abbr . ')\.(?=\s)/iu', '$1' . "\x01", $text);
        // "Kumar V. Abbas AK." 这类姓名缩写之间的点
        $masked = preg_replace('/\b(\p{Lu})\.(?=\s*\p{Lu}\b)/u', '$1' . "\x01", $masked);

        $segments = preg_split('/\.\s+|\.$/u', $masked);
        $out = [];
        foreach ((array)$segments as $seg) {
            $out[] = str_replace("\x01", '.', $seg);
        }

        return $out;
    }

    private function matchEdition($seg)
    {
        if (preg_match('/\b(\d{1,2})\s*(?:st|nd|rd|th|d)?\s*(?:ed\.?|edn\.?|edition)\b/iu', $seg, $m)) {
            return $m[1];
        }
        if (preg_match('/\b(first|second|third|fourth|fifth|sixth|seventh|eighth|ninth|tenth)\s+(?:ed\.?|edn\.?|edition)\b/iu', $seg, $m)) {
            return strtolower($m[1]);
        }
        if (preg_match('/(?:第\s*)?(\d{1,2})\s*版/u', $seg, $m)) {
            return $m[1];
        }

        return '';
    }

    private function stripEdition($seg)
    {
        $seg = preg_replace('/\b\d{1,2}\s*(?:st|nd|rd|th|d)?\s*(?:ed\.?|edn\.?|edition)\b[\.,;]?/iu', '', $seg);
        $seg = preg_replace('/\b(?:first|second|third|fourth|fifth|sixth|seventh|eighth|ninth|tenth)\s+(?:ed\.?|edn\.?|edition)\b[\.,;]?/iu', '', $seg);
        $seg = preg_replace('/(?:第\s*)?\d{1,2}\s*版/u', '', $seg);

        return $seg;
    }

    /**
     * 出版信息段：Place: Publisher; Year / Publisher, Year / 北京: 人民卫生出版社, 2018
     */
    private function takePublication($seg, array &$out)
    {
        $hasYear = preg_match('/\b((?:19|20)\d{2})\b/', $seg, $ym);
        $hasPlace = preg_match('/^([^:]{2,60}):\s*(.+)$/u', $seg, $pm);
        if (!$hasYear && !$hasPlace) {
            return false;
        }

        // "Depression in adults: treatment and management" 是带副标题的书名，不是"地点: 出版社"
        if ($hasPlace && !$hasYear && ($out['title'] === '' || !$this->looksLikePublisher($pm[2]))) {
            return false;
        }

        // 标题里出现年份（如 "Global tuberculosis report 2020"）不算出版信息段
        if ($hasYear && !$hasPlace && $out['title'] === '' && !preg_match('/^\W*(?:19|20)\d{2}\W*$/', $seg)) {
            $withoutYear = trim(preg_replace('/\b(?:19|20)\d{2}\b/', '', $seg), " .,;");
            if ($withoutYear !== '' && !$this->looksLikePublisher($withoutYear)) {
                return false;
            }
        }

        if ($hasYear && $out['year'] === '') {
            $out['year'] = $ym[1];
        }

        $body = $hasPlace ? trim($pm[2]) : $seg;
        if ($hasPlace && $out['place'] === '') {
            $out['place'] = trim($pm[1], " .,;");
        }
        $body = trim(preg_replace('/\b(?:19|20)\d{2}\b/', '', $body), " .,;:");
        if ($body !== '' && $out['publisher'] === '') {
            $out['publisher'] = $body;
        }

        return true;
    }

    private function looksLikePublisher($text)
    {
        return (bool)preg_match(
            '/(Press|Publish\w*|Books?|Elsevier|Springer|Wiley|Saunders|Mosby|Lippincott|Williams|Wilkins'
            . '|McGraw|Academic|University|Univ\b|出版社|书局|WHO|Organization)/iu',
            $text
        );
    }

    private function cleanTitle($title)
    {
        $title = trim((string)$title);
        // GB/T 7714 的文献类型标识：[M] [M/OL] [C] 等
        $title = preg_replace('/\s*\[[A-Z]{1,2}(?:\/[A-Z]{1,2})?\]\s*/u', ' ', $title);
        $title = preg_replace('/\s+/u', ' ', $title);

        return trim($title, " .,;:");
    }

    // ------------------------------------------------------------------
    // 大模型兜底
    // ------------------------------------------------------------------

    private function needsLlm(array $out)
    {
        if (!$this->useLlm) {
            return false;
        }
        if ($out['title'] === '' || $out['author'] === '') {
            return true;
        }
        // 分段错位时标题里会留下一串人名
        return $this->looksLikeAuthorList($out['title']);
    }

    private function looksLikeAuthorList($text)
    {
        $text = trim((string)$text);
        if ($text === '') {
            return false;
        }
        $name = '\p{Lu}[\p{L}\'\-]+\s+\p{Lu}{1,4}';

        return (bool)preg_match('/^(?:' . $name . ')(?:\s*,\s*(?:' . $name . '))*(?:\s*,?\s*et\s+al\.?)?$/u', $text);
    }

    private function refineByLlm($content, array $out)
    {
        try {
            $llm = new LLMService();
            $system = 'You extract bibliographic fields from a single book (or book chapter) reference string. '
                . 'Return ONLY a JSON object with these keys: '
                . '{"author":"","title":"","publisher":"","place":"","year":"","edition":"","pages":""}. '
                . 'Rules: author = the author or editor list exactly as written, without a trailing period; '
                . 'title = the title of the cited work only, without edition, publisher, place or year; '
                . 'for a chapter reference, title = the chapter title; '
                . 'publisher = publisher name only, no place; year = 4-digit publication year; '
                . 'edition = the edition number as digits only (e.g. "6"), empty if not stated; '
                . 'pages = page range if stated. Use an empty string for anything not stated. '
                . 'Do not translate, do not invent, do not add explanation.';
            $user = "Reference:\n" . mb_substr($content, 0, 1500);

            $reply = $llm->requestChat([
                ['role' => 'system', 'content' => $system],
                ['role' => 'user', 'content' => $user],
            ], 0);
            if ($reply === null || $reply === '') {
                return $out;
            }

            $parsed = $llm->parseJsonResponse($reply);
            if (!is_array($parsed)) {
                return $out;
            }

            foreach (['author', 'title', 'publisher', 'place', 'year', 'edition', 'pages'] as $field) {
                $value = trim((string)($parsed[$field] ?? ''));
                if ($value === '') {
                    continue;
                }
                // 模型不得改写原文里没有的内容
                if ($field === 'year' && !preg_match('/^(?:19|20)\d{2}$/', $value)) {
                    continue;
                }
                if ($field === 'edition') {
                    $value = preg_match('/\d{1,2}/', $value, $m) ? $m[0] : '';
                    if ($value === '') {
                        continue;
                    }
                }
                if ($field === 'title' && $this->looksLikeAuthorList($value)) {
                    continue;
                }
                $out[$field] = $field === 'title' ? $this->cleanTitle($value) : $value;
            }
        } catch (\Throwable $e) {
            \think\Log::write('book citation llm parse failed: ' . $e->getMessage(), 'error');
        }

        return $out;
    }
}