<?php

namespace app\common;

use app\common\service\LLMService;

/**
 * 参考文献类型识别器
 *
 * 识别顺序（分层，从权威到兜底）：
 *   1. CrossRef 的 type 字段（若有 DOI 且命中）——最权威
 *   2. 英文规则启发式（基于作者原文特征词/结构）
 *   3. 大模型兜底（规则判为 other 或低置信度时）
 *   4. 仍无法判定 → other
 *
 * 支持类型：journal / book / conference / thesis / web / other
 */
class ReferenceTypeClassifier
{
    const TYPE_JOURNAL    = 'journal';
    const TYPE_BOOK       = 'book';
    const TYPE_CONFERENCE = 'conference';
    const TYPE_THESIS     = 'thesis';
    const TYPE_WEB        = 'web';
    const TYPE_OTHER      = 'other';

    /** 是否允许使用大模型兜底 */
    private $useLlm = true;

    public function __construct($config = [])
    {
        if (is_array($config) && isset($config['use_llm'])) {
            $this->useLlm = (bool)$config['use_llm'];
        }
    }

    /**
     * 主入口：根据作者原文（可选 CrossRef type）识别类型
     *
     * @param string $referContent 作者提供的原始参考文献字符串
     * @param string $crossrefType CrossRef 返回的 type（可选）
     * @return array ['type' => string, 'confidence' => float, 'source' => string]
     */
    public function classify($referContent, $crossrefType = '')
    {
        $text = trim((string)$referContent);

        // 1. CrossRef type 优先
        $byCrossref = $this->mapCrossrefType($crossrefType);
        if ($byCrossref !== '') {
            return ['type' => $byCrossref, 'confidence' => 0.95, 'source' => 'crossref'];
        }

        if ($text === '') {
            return ['type' => self::TYPE_OTHER, 'confidence' => 0.0, 'source' => 'fallback'];
        }

        // 2. 规则启发式
        $byRule = $this->classifyByRule($text);
        if ($byRule['type'] !== self::TYPE_OTHER && $byRule['confidence'] >= 0.8) {
            return ['type' => $byRule['type'], 'confidence' => $byRule['confidence'], 'source' => 'rule'];
        }

        // 3. 大模型兜底
        if ($this->useLlm) {
            $byLlm = $this->classifyByLlm($text);
            if ($byLlm !== '') {
                return ['type' => $byLlm, 'confidence' => 0.7, 'source' => 'llm'];
            }
        }

        // 规则给出的弱结果（若有）优先于纯兜底
        if ($byRule['type'] !== self::TYPE_OTHER) {
            return ['type' => $byRule['type'], 'confidence' => $byRule['confidence'], 'source' => 'rule'];
        }

        // 4. 兜底
        return ['type' => self::TYPE_OTHER, 'confidence' => 0.0, 'source' => 'fallback'];
    }

    /**
     * CrossRef type → 内部枚举映射；未命中返回空串
     */
    public function mapCrossrefType($crossrefType)
    {
        $t = strtolower(trim((string)$crossrefType));
        if ($t === '') {
            return '';
        }

        $map = [
            // 期刊
            'journal-article' => self::TYPE_JOURNAL,
            'journal'         => self::TYPE_JOURNAL,
            'journal-volume'  => self::TYPE_JOURNAL,
            'journal-issue'   => self::TYPE_JOURNAL,
            // 图书
            'book'            => self::TYPE_BOOK,
            'book-chapter'    => self::TYPE_BOOK,
            'book-part'       => self::TYPE_BOOK,
            'book-section'    => self::TYPE_BOOK,
            'book-set'        => self::TYPE_BOOK,
            'book-series'     => self::TYPE_BOOK,
            'book-track'      => self::TYPE_BOOK,
            'reference-book'  => self::TYPE_BOOK,
            'edited-book'     => self::TYPE_BOOK,
            'monograph'       => self::TYPE_BOOK,
            // 会议
            'proceedings-article' => self::TYPE_CONFERENCE,
            'proceedings'         => self::TYPE_CONFERENCE,
            'proceedings-series'  => self::TYPE_CONFERENCE,
            // 学位论文
            'dissertation'    => self::TYPE_THESIS,
            // 在线/预印本
            'posted-content'  => self::TYPE_WEB,
        ];

        return isset($map[$t]) ? $map[$t] : '';
    }

    /**
     * 英文规则启发式：按「最独特 → 最普通」顺序判定
     *
     * @return array ['type' => string, 'confidence' => float]
     */
    public function classifyByRule($text)
    {
        $hasDoi = (bool)preg_match('/\bdoi:\s*10\./i', $text) || (bool)preg_match('#doi\.org/#i', $text);
        $hasUrl = (bool)preg_match('#https?://#i', $text);
        // 期刊卷期页结构，如 2020;382(8):727-733 或 2020;10:100
        $hasJournalVol = (bool)preg_match('/\b(19|20)\d{2}\s*[;:]\s*\d+\s*(\(\d+\))?\s*:\s*[A-Za-z]?\d+/', $text);

        // 1) 学位论文
        if (preg_match('/\[(ph\.?d\.?|master(\'s)?|doctoral|masters)?\s*(thesis|dissertation)\]/i', $text)
            || preg_match('/\b(ph\.?d\.?|master\'?s|doctoral|doctorate)\b[^.]{0,40}\b(thesis|dissertation)\b/i', $text)
            || preg_match('/\b(thesis|dissertation)\b/i', $text)) {
            return ['type' => self::TYPE_THESIS, 'confidence' => 0.9];
        }

        // 2) 会议论文
        if (preg_match('/\bproceedings\b/i', $text)
            || preg_match('/\bin:\s*proc\b/i', $text)
            || preg_match('/\b(conference|symposium|workshop|congress)\b/i', $text)
            || preg_match('/\bannual meeting\b/i', $text)) {
            return ['type' => self::TYPE_CONFERENCE, 'confidence' => 0.85];
        }

        // 3) 网页 / 在线资源
        if (preg_match('/\[(internet|online)\]/i', $text)
            || preg_match('/\baccessed\b/i', $text)
            || preg_match('/\bavailable\s+(from|at)\b/i', $text)
            || preg_match('/\bcited\s+(19|20)\d{2}/i', $text)
            || ($hasUrl && !$hasDoi && !$hasJournalVol)) {
            return ['type' => self::TYPE_WEB, 'confidence' => 0.8];
        }

        // 4) 图书
        if (preg_match('/\b\d+(st|nd|rd|th)\s+ed(ition)?\.?/i', $text)
            || preg_match('/\bisbn\b/i', $text)
            || preg_match('/\b(press|publisher|publishing house)\b/i', $text)
            || preg_match('/[A-Z][A-Za-z .]+:\s*[A-Z][A-Za-z .&]+;\s*(19|20)\d{2}/', $text)) {
            // 期刊卷期结构更强时不判为书
            if (!$hasJournalVol) {
                return ['type' => self::TYPE_BOOK, 'confidence' => 0.8];
            }
        }

        // 5) 期刊
        if ($hasJournalVol || $hasDoi
            || preg_match('/\bvol\.?\s*\d+/i', $text)
            || preg_match('/\bpp?\.\s*\d+/i', $text)) {
            return ['type' => self::TYPE_JOURNAL, 'confidence' => $hasJournalVol ? 0.85 : 0.6];
        }

        return ['type' => self::TYPE_OTHER, 'confidence' => 0.0];
    }

    /**
     * 大模型兜底：只返回枚举值之一，失败返回空串
     */
    public function classifyByLlm($text)
    {
        try {
            $llm = new LLMService();
            $system = 'You are a bibliography classifier. Classify the reference into exactly one type. '
                . 'Allowed types: journal, book, conference, thesis, web, other. '
                . 'journal=journal article; book=book or book chapter; conference=conference/proceedings paper; '
                . 'thesis=dissertation/thesis; web=website or online resource; other=none of the above. '
                . 'Respond with ONLY a JSON object: {"type":"<one of the allowed types>"}. No explanation.';
            $user = "Reference:\n" . mb_substr($text, 0, 2000);

            $content = $llm->requestChat([
                ['role' => 'system', 'content' => $system],
                ['role' => 'user', 'content' => $user],
            ], 0);

            if ($content === null || $content === '') {
                return '';
            }

            $parsed = $llm->parseJsonResponse($content);
            $type = '';
            if (is_array($parsed) && isset($parsed['type'])) {
                $type = strtolower(trim((string)$parsed['type']));
            } else {
                // 兜底：直接从文本里找枚举词
                if (preg_match('/\b(journal|book|conference|thesis|web|other)\b/i', $content, $m)) {
                    $type = strtolower($m[1]);
                }
            }

            $allowed = [
                self::TYPE_JOURNAL, self::TYPE_BOOK, self::TYPE_CONFERENCE,
                self::TYPE_THESIS, self::TYPE_WEB, self::TYPE_OTHER,
            ];
            return in_array($type, $allowed, true) ? $type : '';
        } catch (\Throwable $e) {
            return '';
        }
    }
}