<?php

namespace App\Services\Brief;

use App\Models\News;
use App\Models\Paper;
use App\Models\Teacher;
use App\Models\WeeklyBrief;
use Carbon\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Str;

class WeeklyBriefService
{
    /** @var array<string, string> */
    protected const TRACKS = [
        'physics' => 'Physics',
        'math' => 'Mathematics',
        'cs' => 'Computer Science',
        'eess' => 'Electrical Engineering and Systems Science',
    ];

    /** @var list<string> */
    protected const HIGH_VALUE_KEYWORDS = [
        '产业化', '量产', '中试', '小试', '落地', '商用', '专利', '转化', '示范', '试点',
        'prototype', 'commercial', 'deployment', 'industrial', 'pilot', 'scale-up',
    ];

    /** @var list<string> */
    protected const COOP_KEYWORDS = [
        '校企', '产学研', '联合研究', '联合实验室', '产业资本', '投资', '融资', '合作',
        '签约', '落地', '试点', '示范', '转化', '专利', '孵化',
    ];

    /**
     * @return array{0: Carbon, 1: Carbon}
     */
    public function resolvePreviousWeek(?Carbon $reference = null): array
    {
        return $this->resolveWeekByOffset(1, $reference);
    }

    /**
     * @return array{0: Carbon, 1: Carbon}
     */
    public function resolveWeekByOffset(int $offset = 0, ?Carbon $reference = null): array
    {
        $ref = ($reference ?? now())->copy()->timezone('Asia/Shanghai')->startOfDay();
        $weekStart = $ref->copy()->startOfWeek(Carbon::MONDAY)->subWeeks($offset);
        if ($offset === 0) {
            $weekEnd = $ref->copy()->endOfDay();
        } else {
            $weekEnd = $weekStart->copy()->endOfWeek(Carbon::SUNDAY)->endOfDay();
        }

        return [$weekStart, $weekEnd];
    }

    /**
     * @return list<array{offset:int,label:string,week_start:string,week_end:string}>
     */
    public function weekOptions(int $count = 8, ?Carbon $reference = null): array
    {
        $options = [];
        for ($offset = 0; $offset < $count; $offset++) {
            [$start, $end] = $this->resolveWeekByOffset($offset, $reference);
            $options[] = [
                'offset' => $offset,
                'label' => $offset === 0 ? '本周（截至今日）' : ($offset === 1 ? '上周' : "前{$offset}周"),
                'week_start' => $start->toDateString(),
                'week_end' => $end->toDateString(),
            ];
        }

        return $options;
    }

    public function generate(Carbon $weekStart, Carbon $weekEnd, ?int $adminUserId = null, bool $replace = true): WeeklyBrief
    {
        $weekStart = $weekStart->copy()->timezone('Asia/Shanghai')->startOfDay();
        $weekEnd = $weekEnd->copy()->timezone('Asia/Shanghai')->endOfDay();

        $papers = $this->fetchPapers($weekStart, $weekEnd);
        $newsItems = $this->fetchNews($weekStart, $weekEnd);
        $teachers = $this->fetchTeachers($weekStart, $weekEnd);

        $scoredPapers = $papers->map(fn (Paper $paper) => [
            'paper' => $paper,
            'track' => $this->resolvePaperTrack($paper),
            'score' => $this->scorePaper($paper),
            'maturity' => $this->assessMaturity($paper),
        ])->sortByDesc('score')->values();

        $trackCounts = $scoredPapers->groupBy('track')->map->count();
        $highValuePapers = $scoredPapers->filter(fn ($row) => $row['score'] >= 60)->values();
        $topTracks = $trackCounts->sortDesc()->take(3)->keys()->all();

        $generatedAt = now()->timezone('Asia/Shanghai');
        $titleDate = $this->formatChineseDate($generatedAt);
        $periodLabel = $weekStart->format('Y年n月j日').' - '.$weekEnd->format('Y年n月j日');

        $title = "高校科技成果周报 | {$titleDate}";

        $lines = [];
        $lines[] = "# {$title}";
        $lines[] = '';
        $lines[] = "> 统计周期：{$periodLabel}（Asia/Shanghai）";
        $lines[] = '';
        $lines[] = '---';
        $lines[] = '';

        $refIndex = 1;
        $references = [];

        $lines[] = '## 一、总览';
        $lines[] = '';
        $lines[] = '### 1、赛道热度拐点';
        $lines[] = '';
        if ($topTracks === []) {
            $lines[] = '_本周暂无足够论文数据识别赛道拐点。_';
        } else {
            foreach ($topTracks as $trackKey) {
                $label = self::TRACKS[$trackKey] ?? $trackKey;
                $count = (int) ($trackCounts[$trackKey] ?? 0);
                $lines[] = "- **{$label}**：本周入库 {$count} 篇，技术突破相对集中";
            }
        }
        $lines[] = '';

        $lines[] = '### 2、核心突破';
        $lines[] = '';
        $coreBreakthroughs = $highValuePapers->take(5);
        if ($coreBreakthroughs->isEmpty()) {
            $lines[] = '_本周暂无可落地、可商业化的关键技术进展。_';
        } else {
            foreach ($coreBreakthroughs as $row) {
                /** @var Paper $paper */
                $paper = $row['paper'];
                $trackLabel = self::TRACKS[$row['track']] ?? $row['track'];
                $lines[] = '- **'.$this->truncate($paper->title, 120).'**（'.$trackLabel.'）：'.$this->truncate($this->extractInnovation($paper), 160);
            }
        }
        $lines[] = '';

        $lines[] = '### 3、项目机会';
        $lines[] = '';
        $projectHints = $this->buildProjectOpportunities($scoredPapers, $teachers);
        if ($projectHints === []) {
            $lines[] = '_本周暂无新增值得跟踪的高校创业团队或可转化实验室成果。_';
        } else {
            foreach ($projectHints as $hint) {
                $lines[] = '- '.$hint;
            }
        }
        $lines[] = '';

        $lines[] = '### 4、数据总结';
        $lines[] = '';
        $total = $papers->count();
        $highValueCount = $highValuePapers->count();
        $lines[] = "- 本周有效检索论文总量：**{$total}** 篇";
        $lines[] = "- 高价值产业级论文数量：**{$highValueCount}** 篇";
        $lines[] = '- 各赛道分布占比：'.$this->formatTrackDistribution($trackCounts, $total);
        $lines[] = '';

        $lines[] = '---';
        $lines[] = '';
        $lines[] = '## 二、技术突破盘点';
        $lines[] = '';
        foreach (self::TRACKS as $trackKey => $trackLabel) {
            $trackPapers = $scoredPapers->where('track', $trackKey)->take(5)->values();
            $lines[] = "### {$trackLabel}";
            $lines[] = '';
            if ($trackPapers->isEmpty()) {
                $lines[] = '_本周该赛道暂无论文入库。_';
                $lines[] = '';

                continue;
            }

            $lines[] = '**1、技术突破**';
            $lines[] = '';
            $idx = 1;
            foreach ($trackPapers as $row) {
                /** @var Paper $paper */
                $paper = $row['paper'];
                $lines[] = "{$idx}. **{$paper->title}**";
                $lines[] = '   - 核心创新点：'.$this->extractInnovation($paper);
                if ($paper->authors) {
                    $lines[] = '   - 作者团队：'.$this->truncate($this->cleanText($paper->authors), 100);
                }
                $source = $this->appendReference($paper->source_site ?: '论文来源', $paper->url, $refIndex, $references);
                $lines[] = '   - 来源：'.$source;
                $lines[] = '';
                $idx++;
            }

            $lines[] = '**2、产业化成熟度判定**';
            $lines[] = '';
            $maturityGroups = $trackPapers->groupBy('maturity');
            foreach (['可直接量产落地', '中试优化', '小试可行', '实验室原理验证'] as $level) {
                $count = $maturityGroups->get($level)?->count() ?? 0;
                if ($count > 0) {
                    $lines[] = "- {$level}：{$count} 篇";
                }
            }
            $lines[] = '';

            $lines[] = '**3、商业价值**';
            $lines[] = '';
            $sample = $trackPapers->first();
            /** @var Paper|null $samplePaper */
            $samplePaper = $sample['paper'] ?? null;
            if ($samplePaper) {
                $lines[] = $this->assessCommercialValue($samplePaper);
            } else {
                $lines[] = '_待进一步评估。_';
            }
            $lines[] = '';
        }

        $lines[] = '---';
        $lines[] = '';
        $lines[] = '## 三、产业级重磅论文';
        $lines[] = '';
        $lines[] = '筛选本周具备投资影响力的核心论文前 10 篇：';
        $lines[] = '';
        $topTen = $scoredPapers->take(10);
        if ($topTen->isEmpty()) {
            $lines[] = '_本周暂无符合条件的论文。_';
        } else {
            $index = 1;
            foreach ($topTen as $row) {
                /** @var Paper $paper */
                $paper = $row['paper'];
                $trackLabel = self::TRACKS[$row['track']] ?? $row['track'];
                $lines[] = "### {$index}. {$paper->title}";
                $lines[] = '- **发表期刊/平台**：'.($paper->source_site ?: 'arXiv / 预印本');
                $lines[] = '- **作者团队**：'.($this->cleanText($paper->authors) ?: '待补充');
                $lines[] = '- **所属高校/实验室**：'.($paper->school_name ?: '待关联');
                if ($paper->published_at) {
                    $lines[] = '- **发表时间**：'.$paper->published_at->format('Y年n月j日');
                }
                $lines[] = '- **所属赛道**：'.$trackLabel;
                $lines[] = '- **可转化落地可能性**：'.$this->assessConversionPotential($row['score'], $row['maturity']);
                $source = $this->appendReference('论文链接', $paper->url, $refIndex, $references);
                $lines[] = '- **来源**：'.$source;
                $lines[] = '';
                $index++;
            }
        }

        $lines[] = '---';
        $lines[] = '';
        $lines[] = '## 四、潜在项目挖掘';
        $lines[] = '';
        $lines = array_merge($lines, $this->renderPotentialProjects($scoredPapers, $teachers));

        $lines[] = '---';
        $lines[] = '';
        $lines[] = '## 五、专利&产学研联动动态';
        $lines[] = '';
        $coopNews = $newsItems->filter(fn (News $n) => $this->matchesKeywords($n->title.' '.($n->summary ?? ''), self::COOP_KEYWORDS));
        if ($coopNews->isEmpty()) {
            $lines[] = '_本周暂无产学研合作或技术转化公开动态。_';
        } else {
            $index = 1;
            foreach ($coopNews->take(12) as $news) {
                $lines = array_merge($lines, $this->renderCoopNewsEntry($index, $news, $refIndex, $references));
                $index++;
            }
        }

        $lines[] = '---';
        $lines[] = '';
        $lines[] = '## 参考来源汇总';
        $lines[] = '';
        foreach ($references as $i => $ref) {
            $num = $i + 1;
            $lines[] = "{$num}. {$ref['label']} {$ref['url']}";
        }
        if ($references === []) {
            $lines[] = '_本周暂无外部来源链接。_';
        }

        $lines[] = '';
        $lines[] = '---';
        $lines[] = '';
        $lines[] = '*简报生成时间：'.$generatedAt->format('Y年n月j日 H:i').' (Asia/Shanghai)*';

        $markdown = implode("\n", $lines);

        $stats = [
            'papers_count' => $papers->count(),
            'high_value_papers_count' => $highValueCount,
            'news_count' => $newsItems->count(),
            'teachers_count' => $teachers->count(),
            'references_count' => count($references),
            'track_distribution' => $trackCounts->all(),
            'sections' => [
                'overview' => 1,
                'breakthrough' => $scoredPapers->count(),
                'top_papers' => $topTen->count(),
                'projects' => min(8, $teachers->count() + $scoredPapers->take(5)->count()),
                'coop' => $coopNews->count(),
            ],
        ];

        if ($replace) {
            WeeklyBrief::query()
                ->whereDate('week_start', $weekStart->toDateString())
                ->whereDate('week_end', $weekEnd->toDateString())
                ->delete();
        }

        return WeeklyBrief::query()->create([
            'week_start' => $weekStart->toDateString(),
            'week_end' => $weekEnd->toDateString(),
            'title' => $title,
            'markdown' => $markdown,
            'stats_json' => $stats,
            'admin_user_id' => $adminUserId,
            'generated_at' => $generatedAt,
        ]);
    }

    /**
     * @return Collection<int, Paper>
     */
    protected function fetchPapers(Carbon $weekStart, Carbon $weekEnd): Collection
    {
        return Paper::query()
            ->with('crawlJob')
            ->whereNotNull('crawl_job_id')
            ->whereBetween('created_at', [$weekStart, $weekEnd])
            ->orderByDesc('published_at')
            ->orderByDesc('id')
            ->limit(200)
            ->get();
    }

    /**
     * @return Collection<int, News>
     */
    protected function fetchNews(Carbon $weekStart, Carbon $weekEnd): Collection
    {
        return News::query()
            ->with('categoryItem')
            ->whereNotNull('crawl_job_id')
            ->whereBetween('created_at', [$weekStart, $weekEnd])
            ->orderByDesc('published_at')
            ->orderByDesc('id')
            ->limit(80)
            ->get();
    }

    /**
     * @return Collection<int, Teacher>
     */
    protected function fetchTeachers(Carbon $weekStart, Carbon $weekEnd): Collection
    {
        return Teacher::query()
            ->with(['university', 'researchDirections'])
            ->whereBetween('created_at', [$weekStart, $weekEnd])
            ->orderByDesc('id')
            ->limit(30)
            ->get();
    }

    protected function resolvePaperTrack(Paper $paper): string
    {
        $url = strtolower((string) ($paper->crawlJob?->request_url ?? ''));
        foreach (array_keys(self::TRACKS) as $track) {
            if (preg_match('#/list/'.$track.'(?:/|$|[?&#])#', $url)) {
                return $track;
            }
            if (preg_match('#categories?/'.$track.'#', $url)) {
                return $track;
            }
        }

        $haystack = strtolower($paper->title.' '.($paper->summary ?? '').' '.($paper->url ?? ''));
        if (str_contains($haystack, 'physics') || str_contains($haystack, 'quantum')) {
            return 'physics';
        }
        if (str_contains($haystack, 'math')) {
            return 'math';
        }
        if (str_contains($haystack, 'eess') || str_contains($haystack, 'electrical')) {
            return 'eess';
        }

        return 'cs';
    }

    protected function scorePaper(Paper $paper): int
    {
        $score = 40;
        $text = $paper->title.' '.($paper->summary ?? '');

        if ($paper->school_name) {
            $score += 10;
        }
        if ($paper->authors) {
            $score += 8;
        }
        if ($paper->published_at) {
            $score += 5;
        }
        if ($this->matchesKeywords($text, self::HIGH_VALUE_KEYWORDS)) {
            $score += 20;
        }
        if (mb_strlen($this->cleanText($paper->summary)) >= 120) {
            $score += 7;
        }

        return min(100, $score);
    }

    protected function assessMaturity(Paper $paper): string
    {
        $text = $paper->title.' '.($paper->summary ?? '');
        if ($this->matchesKeywords($text, ['量产', '部署', '商用', '落地应用', 'production', 'deployed'])) {
            return '可直接量产落地';
        }
        if ($this->matchesKeywords($text, ['中试', 'pilot plant', 'scale-up', '示范线'])) {
            return '中试优化';
        }
        if ($this->matchesKeywords($text, ['小试', 'prototype', '样机', '验证平台'])) {
            return '小试可行';
        }

        return '实验室原理验证';
    }

    protected function extractInnovation(Paper $paper): string
    {
        $summary = $this->cleanText($paper->summary);
        if ($summary !== '') {
            return $this->truncate($summary, 220);
        }

        return '围绕「'.$this->truncate($paper->title, 80).'」提出方法或系统层面的创新，具备进一步工程化验证价值。';
    }

    protected function assessCommercialValue(Paper $paper): string
    {
        $text = $this->cleanText($paper->summary);
        if ($text === '') {
            return '- 降本/提效空间与下游应用场景需结合实验数据进一步量化；建议关注头部团队复现与工程化进度。';
        }

        return '- 降本提效：'.$this->truncate($text, 120)."\n".
            '- 替代现有方案：需对照行业 baseline 评估性能/成本拐点'."\n".
            '- 下游场景：'.($paper->school_name ? $paper->school_name.'相关方向' : '待结合赛道进一步拆解');
    }

    protected function assessConversionPotential(int $score, string $maturity): string
    {
        if ($score >= 75 && in_array($maturity, ['可直接量产落地', '中试优化'], true)) {
            return '高（接近工程化/产业化窗口）';
        }
        if ($score >= 60) {
            return '中（具备跟踪价值，需验证复现与场景）';
        }

        return '低（偏基础研究，可作为技术雷达储备）';
    }

    /**
     * @param  Collection<string, int>  $trackCounts
     */
    protected function formatTrackDistribution(Collection $trackCounts, int $total): string
    {
        if ($total <= 0) {
            return '暂无数据';
        }

        $parts = [];
        foreach (self::TRACKS as $key => $label) {
            $count = (int) ($trackCounts[$key] ?? 0);
            $percent = (int) round($count / $total * 100);
            $parts[] = "{$label} {$percent}%（{$count}篇）";
        }

        return implode('；', $parts);
    }

    /**
     * @param  Collection<int, array{paper: Paper, track: string, score: int, maturity: string}>  $scoredPapers
     * @param  Collection<int, Teacher>  $teachers
     * @return list<string>
     */
    protected function buildProjectOpportunities(Collection $scoredPapers, Collection $teachers): array
    {
        $hints = [];
        foreach ($teachers->take(5) as $teacher) {
            $uni = $teacher->university?->name ?: $teacher->university_text ?: '国内高校';
            $dirs = $teacher->researchDirections->pluck('name')->join('、') ?: '细分方向待补充';
            $hints[] = "新增团队：**{$uni} · {$teacher->name}**（{$dirs}），建议纳入长期跟踪池";
        }

        foreach ($scoredPapers->take(3) as $row) {
            /** @var Paper $paper */
            $paper = $row['paper'];
            if ($row['score'] < 55) {
                continue;
            }
            $trackLabel = self::TRACKS[$row['track']] ?? $row['track'];
            $hints[] = "可转化成果：**{$paper->title}**（{$trackLabel}），成熟度：{$row['maturity']}";
        }

        return $hints;
    }

    /**
     * @param  Collection<int, array{paper: Paper, track: string, score: int, maturity: string}>  $scoredPapers
     * @param  Collection<int, Teacher>  $teachers
     * @return list<string>
     */
    protected function renderPotentialProjects(Collection $scoredPapers, Collection $teachers): array
    {
        $lines = [];
        if ($teachers->isEmpty() && $scoredPapers->isEmpty()) {
            $lines[] = '_本周暂无高辨识度核心团队或高价值成果。_';
            $lines[] = '';

            return $lines;
        }

        $index = 1;
        foreach ($teachers->take(8) as $teacher) {
            $uni = $teacher->university?->name ?: $teacher->university_text ?: '国内高校';
            $dirs = $teacher->researchDirections->pluck('name')->join('、') ?: '待补充';
            $lines[] = "### {$index}. {$uni} · {$teacher->name}";
            $lines[] = '- **团队背景**：'.($teacher->bio ? $this->truncate($this->cleanText($teacher->bio), 180) : ($teacher->title ?: '职称/履历待补充'));
            $lines[] = '- **技术稀缺性**：长期深耕「'.$dirs.'」，可对比行业现有方案评估差异化';
            $lines[] = '- **技术进度**：'.$teacher->created_at?->format('Y-m-d').' 入库，建议结合论文/专利进一步核验';
            $lines[] = '';
            $index++;
        }

        foreach ($scoredPapers->take(5) as $row) {
            /** @var Paper $paper */
            $paper = $row['paper'];
            $lines[] = "### {$index}. {$paper->title}";
            $lines[] = '- **团队背景**：'.($this->cleanText($paper->authors) ?: '作者信息待补充');
            $lines[] = '- **技术稀缺性**：'.self::TRACKS[$row['track']].' 赛道，'.$this->assessConversionPotential($row['score'], $row['maturity']);
            $lines[] = '- **技术进度**：'.$row['maturity'];
            $lines[] = '';
            $index++;
        }

        return $lines;
    }

    /**
     * @param  list<array{label: string, url: string}>  $references
     * @return list<string>
     */
    protected function renderCoopNewsEntry(int $index, News $news, int &$refIndex, array &$references): array
    {
        $lines = [];
        $lines[] = "### {$index}. {$news->title}";

        $summary = $this->cleanText($news->summary);
        if ($summary !== '') {
            $lines[] = '- **合作/转化进展**：'.$this->truncate($summary, 240);
        }

        $text = $news->title.' '.$summary;
        $flags = [];
        if ($this->matchesKeywords($text, ['头部企业', '联合研究', '联合实验室'])) {
            $flags[] = '与头部企业联合研究';
        }
        if ($this->matchesKeywords($text, ['投资', '融资', '产业资本', '基金'])) {
            $flags[] = '产业资本介入';
        }
        if ($this->matchesKeywords($text, ['试点', '示范', '落地', '应用'])) {
            $flags[] = '落地试点应用';
        }
        if ($flags !== []) {
            $lines[] = '- **产学研信号**：'.implode('；', $flags);
        }

        if ($news->published_at) {
            $lines[] = '- **时间**：'.$news->published_at->timezone('Asia/Shanghai')->format('Y年n月j日');
        }

        $label = $news->source_site ?: ($news->source ?: '资讯来源');
        $source = $this->appendReference($label, $news->source_url ?: $news->cover_url, $refIndex, $references);
        $lines[] = '- **来源**：'.$source;
        $lines[] = '';

        return $lines;
    }

    /**
     * @param  list<string>  $keywords
     */
    protected function matchesKeywords(string $text, array $keywords): bool
    {
        foreach ($keywords as $keyword) {
            if ($keyword !== '' && Str::contains($text, $keyword)) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param  list<array{label: string, url: string}>  $references
     */
    protected function appendReference(string $label, ?string $url, int &$refIndex, array &$references): string
    {
        $label = $this->cleanText($label) ?: '来源';
        $url = trim((string) $url);
        if ($url === '' || ! preg_match('#^https?://#i', $url)) {
            return $label;
        }

        foreach ($references as $ref) {
            if ($ref['url'] === $url) {
                return "[{$label}]({$url})";
            }
        }

        $references[] = ['label' => $label.' - '.$this->briefTitleFromUrl($url), 'url' => $url];
        $refIndex++;

        return "[{$label}]({$url})";
    }

    protected function briefTitleFromUrl(string $url): string
    {
        $host = parse_url($url, PHP_URL_HOST) ?: $url;

        return Str::limit($host, 48, '');
    }

    protected function formatChineseDate(Carbon $date): string
    {
        return $date->format('Y年n月j日');
    }

    protected function cleanText(?string $text): string
    {
        if ($text === null || trim($text) === '') {
            return '';
        }

        return trim(preg_replace('/\s+/u', ' ', strip_tags($text)) ?? '');
    }

    protected function truncate(string $text, int $limit): string
    {
        if (mb_strlen($text) <= $limit) {
            return $text;
        }

        return mb_substr($text, 0, $limit - 1).'…';
    }
}