<?php

namespace app\common;

use PhpOffice\PhpWord\IOFactory;
use PhpOffice\PhpWord\PhpWord;
use think\Exception;

/**
 * 从投稿 Word 稿件生成「仅正文」版本：去掉文前题名/作者/单位等，去掉参考文献及之后内容。
 */
class ManuscriptBodyExtractor
{
    const BODY_SUBDIR = 'public/plagiarism/body_only';

    /** @var array<int,string> */
    private $lines = [];

    /**
     * @return array{path:string, rel_path:string, line_count:int, ref_start:int, body_start:int, warnings:array}
     */
    public function buildBodyOnlyDocx($sourcePath, $articleId = 0)
    {
        $sourcePath = trim((string) $sourcePath);
        if (!is_file($sourcePath) || !is_readable($sourcePath)) {
            throw new Exception('Manuscript not readable: ' . $sourcePath);
        }
        $ext = strtolower(pathinfo($sourcePath, PATHINFO_EXTENSION));
        if ($ext !== 'docx') {
            throw new Exception('body_only check requires DOCX manuscript, got: ' . $ext);
        }

        $this->lines = ArticleParserService::collectParagraphLines($sourcePath);
        if (empty($this->lines)) {
            throw new Exception('No text extracted from manuscript');
        }

        $refStart = $this->findReferenceStartIndex();
        $bodyStart = $this->findBodyStartIndex();
        $warnings = [];

        if ($refStart < 0) {
            $warnings[] = 'references_heading_not_found; using document end';
            $refStart = count($this->lines);
        }
        if ($bodyStart >= $refStart) {
            throw new Exception('Could not locate main body (front matter may include entire document)');
        }

        $bodyLines = array_slice($this->lines, $bodyStart, $refStart - $bodyStart);
        $bodyLines = $this->normalizeBodyLines($bodyLines);
        if (count($bodyLines) < 3) {
            throw new Exception('Body text too short after extraction (' . count($bodyLines) . ' paragraphs)');
        }

        $relPath = $this->writeBodyDocx($bodyLines, $articleId);
        $rootDir = rtrim(ROOT_PATH ?: dirname(dirname(__DIR__)), '/\\');
        $absPath = $rootDir . DIRECTORY_SEPARATOR . str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $relPath);

        return [
            'path'       => $absPath,
            'rel_path'   => $relPath,
            'line_count' => count($bodyLines),
            'ref_start'  => $refStart,
            'body_start' => $bodyStart,
            'warnings'   => $warnings,
        ];
    }

    private function findReferenceStartIndex()
    {
        $stopKeywords = [
            'acknowledgements', 'acknowledgments', 'funding', 'appendix', 'supplementary',
            'conflict of interest', 'competing interests', 'author contributions',
            '致谢', '基金', '附录', '补充材料', '利益冲突', '作者贡献',
        ];

        foreach ($this->lines as $i => $line) {
            $t = trim($line);
            if ($t === '') {
                continue;
            }
            if (preg_match('/^\s*(references|reference|bibliography|参考文献|文献)\b\s*[:：]?\s*/iu', $t)) {
                return $i;
            }
            $lower = strtolower($t);
            foreach ($stopKeywords as $sk) {
                $skLower = strtolower($sk);
                if ($lower === $skLower || $lower === $skLower . ':' || $lower === $skLower . '：') {
                    if ($i > count($this->lines) * 0.4) {
                        return $i;
                    }
                }
            }
        }
        return -1;
    }

    private function findBodyStartIndex()
    {
        $n = count($this->lines);
        $introIdx = -1;
        $keywordsIdx = -1;

        for ($i = 0; $i < $n; $i++) {
            $t = trim($this->lines[$i]);
            if ($t === '') {
                continue;
            }
            if ($introIdx < 0 && $this->isIntroductionHeading($t)) {
                $introIdx = $i;
            }
            if ($keywordsIdx < 0 && preg_match('/^\s*keywords?\b\s*[:：]?/iu', $t)) {
                $keywordsIdx = $i;
            }
        }

        if ($introIdx >= 0) {
            return $introIdx;
        }

        if ($keywordsIdx >= 0) {
            $afterKw = $this->indexAfterKeywordsBlock($keywordsIdx);
            if ($afterKw < $n) {
                return $afterKw;
            }
        }

        return $this->indexAfterFrontMatterFallback();
    }

    private function isIntroductionHeading($t)
    {
        if (preg_match('/^\s*(introduction|background|materials and methods|materials & methods|methods and materials)\b\s*[:：]?/iu', $t)) {
            return true;
        }
        if (preg_match('/^\s*(引言|前言|背景|材料与方法|资料与方法|研究方法)\b\s*[:：]?/iu', $t)) {
            return true;
        }
        if (preg_match('/^\s*1[\.\s、]+(introduction|引言|前言)\b/iu', $t)) {
            return true;
        }
        return false;
    }

    private function indexAfterKeywordsBlock($kwIdx)
    {
        $n = count($this->lines);
        for ($i = $kwIdx + 1; $i < $n; $i++) {
            $t = trim($this->lines[$i]);
            if ($t === '') {
                continue;
            }
            if ($this->isIntroductionHeading($t)) {
                return $i;
            }
            if (preg_match('/^\s*abstract\b/iu', $t)) {
                continue;
            }
            if (mb_strlen($t) >= 30 && !$this->looksLikeAffiliationLine($t)) {
                return $i;
            }
        }
        return min($kwIdx + 1, $n - 1);
    }

    private function indexAfterFrontMatterFallback()
    {
        $n = count($this->lines);
        $maxSkip = min(20, (int) floor($n * 0.15));
        for ($i = 0; $i < $maxSkip && $i < $n; $i++) {
            $t = trim($this->lines[$i]);
            if ($t === '') {
                continue;
            }
            if ($this->isIntroductionHeading($t)) {
                return $i;
            }
        }
        return min(8, max(0, $n - 1));
    }

    private function looksLikeAffiliationLine($t)
    {
        if (preg_match('/@|mailto:|correspond|univ|university|hospital|institute|department|^\d+[\s,，]/iu', $t)) {
            return true;
        }
        if (preg_match('/^\s*abstract\b/iu', $t) || preg_match('/^\s*keywords?\b/iu', $t)) {
            return true;
        }
        return false;
    }

    /**
     * @param array<int,string> $bodyLines
     * @return array<int,string>
     */
    private function normalizeBodyLines(array $bodyLines)
    {
        $out = [];
        foreach ($bodyLines as $line) {
            $line = trim($line);
            if ($line === '') {
                continue;
            }
            if (preg_match('/^\{\s*ADDIN\s+EN\.REFLIST\s*\}$/i', $line)) {
                continue;
            }
            $out[] = $line;
        }
        return $out;
    }

    /**
     * @param array<int,string> $bodyLines
     */
    private function writeBodyDocx(array $bodyLines, $articleId)
    {
        $rootDir = rtrim(ROOT_PATH ?: dirname(dirname(__DIR__)), '/\\');
        $dir = $rootDir . DIRECTORY_SEPARATOR . self::BODY_SUBDIR;
        if (!is_dir($dir)) {
            @mkdir($dir, 0755, true);
        }

        $name = sprintf('body_article_%d_%s.docx', intval($articleId), date('Ymd_His'));
        $absPath = $dir . DIRECTORY_SEPARATOR . $name;

        $phpWord = new PhpWord();
        $section = $phpWord->addSection();
        foreach ($bodyLines as $line) {
            $section->addText($line);
        }
        $writer = IOFactory::createWriter($phpWord, 'Word2007');
        $writer->save($absPath);

        if (!is_file($absPath) || filesize($absPath) < 200) {
            throw new Exception('Failed to write body-only docx');
        }

        return self::BODY_SUBDIR . '/' . $name;
    }
}