<?php

namespace app\common;

use think\Db;

/**
 * 模板句规则检测（t_ai_template_sentence）
 */
class AiTemplateSentenceRuleDetectService
{
    /** @var array<int,array>|null */
    private static $ruleCache;

    /**
     * @param array<string,string> $sectionTexts 键：abstract/introduction/...
     * @return array{hits:array,rule_score:int}
     */
    public function detect(array $sectionTexts): array
    {
        $rules = $this->loadActiveRules();
        $hits = [];
        $ruleScore = 0;

        $normalized = [];
        foreach ($sectionTexts as $key => $text) {
            $section = strtolower(trim((string) $key));
            if ($section === '') {
                continue;
            }
            $normalized[$section] = ManuscriptTextCleanService::clean((string) $text);
        }
        $allText = ManuscriptTextCleanService::clean(implode("\n\n", array_filter($normalized)));

        foreach ($rules as $rule) {
            $section = strtolower(trim((string) ($rule['section'] ?? '')));
            $pattern = trim((string) ($rule['sentence_pattern'] ?? ''));
            if ($pattern === '') {
                continue;
            }

            $targetText = '';
            if ($section === 'all') {
                $targetText = $allText;
            } elseif (isset($normalized[$section])) {
                $targetText = $normalized[$section];
            } else {
                continue;
            }
            if ($targetText === '') {
                continue;
            }

            $matches = $this->matchPattern($targetText, $pattern);
            foreach ($matches as $matchedText) {
                $sentence = $this->extractSentenceContaining($targetText, $matchedText);
                $hitScore = max(1, intval($rule['weight'] ?? 1)) * max(1, intval($rule['risk_level'] ?? 1));
                $hits[] = [
                    'section'  => $section,
                    'type'     => '模板化表达',
                    'sentence' => $sentence !== '' ? $sentence : $matchedText,
                    'pattern'  => $pattern,
                    'score'    => $hitScore,
                    'remark'   => (string) ($rule['remark'] ?? ''),
                ];
                $ruleScore += $hitScore;
            }
        }

        return [
            'hits'       => $hits,
            'rule_score' => min(100, $ruleScore),
        ];
    }

    /**
     * @return array<int,array>
     */
    private function loadActiveRules(): array
    {
        if (self::$ruleCache !== null) {
            return self::$ruleCache;
        }
        try {
            self::$ruleCache = Db::name('ai_template_sentence')
                ->where('status', 1)
                ->field('id,sentence_pattern,section,language,risk_level,weight,remark')
                ->order('section asc,id asc')
                ->select();
        } catch (\Throwable $e) {
            self::$ruleCache = [];
        }
        return self::$ruleCache;
    }

    /**
     * @return array<int,string>
     */
    private function matchPattern(string $text, string $pattern): array
    {
        // 支持 regex: 前缀；否则优先按正则，失败则按字面量匹配
        $raw = $pattern;
        $forceRegex = false;
        if (stripos($pattern, 'regex:') === 0) {
            $raw = trim(substr($pattern, 6));
            $forceRegex = true;
        }

        $out = $this->runPregMatchAll($text, '#' . $raw . '#iu');
        if (!empty($out) || $forceRegex) {
            return $out;
        }

        // 字面量回退（库内普通句子）
        return $this->runPregMatchAll($text, '#' . preg_quote($raw, '#') . '#iu');
    }

    /**
     * @return array<int,string>
     */
    private function runPregMatchAll(string $text, string $regex): array
    {
        $error = null;
        set_error_handler(function ($errno, $errstr) use (&$error) {
            $error = $errstr;
            return true;
        });
        $ok = preg_match_all($regex, $text, $matches);
        restore_error_handler();
        if ($ok === false || $error !== null || empty($matches[0])) {
            return [];
        }

        $out = [];
        foreach ($matches[0] as $match) {
            $match = trim((string) $match);
            if ($match !== '') {
                $out[] = $match;
            }
        }
        return $out;
    }

    private function extractSentenceContaining(string $text, string $needle): string
    {
        $pos = mb_stripos($text, $needle);
        if ($pos === false) {
            return '';
        }

        $before = mb_substr($text, 0, $pos);
        $after = mb_substr($text, $pos);

        $start = $before;
        if (preg_match('/.*[.!?。！？]\s*/us', $before, $m)) {
            $start = substr($before, strlen($m[0]));
        }

        $sentence = $start . $after;
        if (preg_match('/^(.+?[.!?。！？])/us', $sentence, $m)) {
            return trim($m[1]);
        }
        if (preg_match('/^.{1,500}/us', $sentence, $m)) {
            return trim($m[0]);
        }
        return trim(mb_substr($sentence, 0, 300));
    }
}