<?php
/**
 * BlogSearchService —— 博客文章检索（ES 增强，默认 LIKE 降级）
 */
declare(strict_types=1);

namespace addon\blog\service;

use addon\blog\model\BlogArticle;
use think\facade\Db;
use ywxapp\library\Search\EsSearch;

class BlogSearchService
{
    protected static function conf(): array
    {
        return [
            'engine' => config('blog.search_engine', 'like'),
            'host'   => config('blog.es_host', 'http://127.0.0.1:9200'),
            'index'  => config('blog.es_index', 'ywxapp_blog'),
        ];
    }

    /**
     * 前台搜索：status=1 + audit_status=2 通过的文章
     * @return \think\Paginator
     */
    public static function search(string $kw, int $page = 1, int $size = 12)
    {
        $kw = trim($kw);
        if ($kw === '') {
            return BlogArticle::with(['user', 'category'])
                ->where('status', 1)->where('audit_status', 2)
                ->order('create_at', 'desc')->paginate($size, false, ['page' => $page]);
        }

        $cfg = self::conf();
        if ($cfg['engine'] === 'es') {
            try {
                EsSearch::ensureIndex($cfg['host'], $cfg['index'], ['title', 'content', 'summary']);
                $ids = EsSearch::search($cfg['host'], $cfg['index'], $kw, ['title', 'content', 'summary'], 200);
                if (!empty($ids)) {
                    $list = BlogArticle::with(['user', 'category'])
                        ->where('status', 1)
                        ->where('audit_status', 2)
                        ->whereIn('id', $ids)
                        ->select()
                        ->all();
                    $order = array_flip($ids);
                    $list = collect($list)->sortBy(function ($m) use ($order) {
                        return $order[$m->id] ?? PHP_INT_MAX;
                    })->values();
                    return new \think\Paginator($list, $size, $page);
                }
            } catch (\RuntimeException $e) {
                // 降级 LIKE
            }
        }

        return BlogArticle::with(['user', 'category'])
            ->where('title|content|summary', 'like', '%' . $kw . '%')
            ->where('status', 1)
            ->where('audit_status', 2)
            ->order('create_at', 'desc')
            ->paginate($size, false, ['page' => $page]);
    }

    /**
     * 后台/会员中心文章搜索（按 uid 可选限定）
     */
    public static function searchAdmin(string $kw, int $page = 1, int $size = 15, int $uid = 0)
    {
        $kw = trim($kw);
        $query = BlogArticle::with(['user', 'category']);
        if ($uid > 0) {
            $query->where('uid', $uid);
        }

        if ($kw === '') {
            return $query->order('create_at', 'desc')->paginate($size, false, ['page' => $page]);
        }

        $cfg = self::conf();
        if ($cfg['engine'] === 'es') {
            try {
                EsSearch::ensureIndex($cfg['host'], $cfg['index'], ['title', 'content', 'summary']);
                $ids = EsSearch::search($cfg['host'], $cfg['index'], $kw, ['title', 'content', 'summary'], 200);
                if (!empty($ids)) {
                    $q = BlogArticle::with(['user', 'category'])->whereIn('id', $ids);
                    if ($uid > 0) {
                        $q->where('uid', $uid);
                    }
                    $list = $q->select()->all();
                    $order = array_flip($ids);
                    $list = collect($list)->sortBy(fn($m) => $order[$m->id] ?? PHP_INT_MAX)->values();
                    return new \think\Paginator($list, $size, $page);
                }
            } catch (\RuntimeException $e) {
            }
        }

        if ($uid > 0) {
            $query->where('uid', $uid);
        }
        return $query->where('title|content', 'like', '%' . $kw . '%')
            ->order('create_at', 'desc')
            ->paginate($size, false, ['page' => $page]);
    }

    /**
     * 同步单条到 ES
     */
    public static function sync(int $articleId): void
    {
        $cfg = self::conf();
        if ($cfg['engine'] !== 'es') {
            return;
        }
        try {
            $a = BlogArticle::find($articleId);
            if (!$a) {
                return;
            }
            EsSearch::ensureIndex($cfg['host'], $cfg['index'], ['title', 'content', 'summary']);
            if ((int) $a->status !== 1 || (int) $a->audit_status !== 2) {
                EsSearch::deleteDoc($cfg['host'], $cfg['index'], $articleId);
                return;
            }
            EsSearch::indexDoc($cfg['host'], $cfg['index'], $articleId, [
                'title'   => $a->title,
                'content' => $a->content,
                'summary' => $a->summary,
            ]);
        } catch (\RuntimeException $e) {
        }
    }

    public static function remove(int $articleId): void
    {
        $cfg = self::conf();
        if ($cfg['engine'] !== 'es') {
            return;
        }
        try {
            EsSearch::deleteDoc($cfg['host'], $cfg['index'], $articleId);
        } catch (\RuntimeException $e) {
        }
    }

    /**
     * 相关文章推荐：优先 ES more_like_this，未启用 ES 时降级为「同分类 + 标签重叠」
     * @return \addon\blog\model\BlogArticle[]
     */
    public static function related(int $articleId, int $limit = 6): array
    {
        $article = BlogArticle::find($articleId);
        if (!$article) {
            return [];
        }
        $cfg = self::conf();
        if ($cfg['engine'] === 'es') {
            try {
                EsSearch::ensureIndex($cfg['host'], $cfg['index'], ['title', 'content', 'summary']);
                $ids = EsSearch::moreLikeThis(
                    $cfg['host'], $cfg['index'],
                    $article->title . "\n" . $article->summary . "\n" . $article->content,
                    ['title', 'content', 'summary'], $articleId, $limit
                );
                if (!empty($ids)) {
                    return BlogArticle::with(['user', 'category'])
                        ->where('status', 1)
                        ->where('audit_status', 2)
                        ->whereIn('id', $ids)
                        ->select()
                        ->all();
                }
            } catch (\RuntimeException $e) {
                // 降级
            }
        }

        // 降级：同分类最新文章（或标签重叠）
        $tagIds = $article->tags()->column('id');
        if (!empty($tagIds)) {
            $rel = BlogArticle::with(['user', 'category'])
                ->alias('a')
                ->join('blog_article_tag t', 't.article_id = a.id')
                ->where('a.id', '<>', $articleId)
                ->where('a.status', 1)
                ->where('a.audit_status', 2)
                ->whereIn('t.tag_id', $tagIds)
                ->order('a.create_at', 'desc')
                ->limit($limit)
                ->select()
                ->all();
            if ($rel->count() >= $limit) {
                return $rel->all();
            }
        }
        return BlogArticle::with(['user', 'category'])
            ->where('id', '<>', $articleId)
            ->where('status', 1)
            ->where('audit_status', 2)
            ->where('cid', $article->cid)
            ->order('create_at', 'desc')
            ->limit($limit)
            ->select()
            ->all();
    }

    /**
     * 附近文章（GEO/LBS）：Haversine 球面距离过滤，零外部依赖
     * @param float $lat 纬度
     * @param float $lng 经度
     * @param float $radiusKm 半径(千米)，默认 10
     * @param int $limit 返回数量
     * @return \addon\blog\model\BlogArticle[]
     */
    public static function nearby(float $lat, float $lng, float $radiusKm = 10.0, int $limit = 20): array
    {
        if ($lat == 0.0 && $lng == 0.0) {
            return [];
        }
        $lat = (float) $lat;
        $lng = (float) $lng;
        $R = 6371;
        return BlogArticle::with(['user', 'category'])
            ->where('status', 1)
            ->where('audit_status', 2)
            ->where('lat', '<>', 0)
            ->where('lng', '<>', 0)
            ->fieldRaw("*, ({$R} * acos(cos(radians({$lat})) * cos(radians(lat)) * cos(radians(lng) - radians({$lng})) + sin(radians({$lat})) * sin(radians(lat)))) AS distance_km")
            ->having('distance_km <= ' . floatval($radiusKm))
            ->order('distance_km', 'asc')
            ->limit($limit)
            ->select()
            ->all();
    }
}