<?php

namespace app\api\controller;

use think\Db;

/**
 * 用户端 · 首页与展示（Module-HOME）
 * 路由：
 *   GET /api/v1/home/banners        H1 轮播广告位
 *   GET /api/v1/home/categories     H2 分类导航
 *   GET /api/v1/home/search/hot     H3 热门搜索
 *   GET /api/v1/home/feed           H4 信息流（支持 lat/lng + sort=nearby 距离排序）
 */
class Home extends V1
{
    /**
     * H1 首页轮播广告位
     * GET /api/v1/home/banners  →  [{id,title,image,link,color}]
     * 规则：仅 enabled=1，按 sort asc；image 为空返回 ''
     */
    public function banners()
    {
        $rows = Db::name('fc_banner')
            ->where('enabled', 1)
            ->order('sort asc')
            ->select();

        $list = [];
        foreach ($rows as $row) {
            $list[] = [
                'id'    => (int)$row['id'],
                'title' => (string)$row['title'],
                'image' => (string)$row['image'],
                'link'  => (string)$row['link'],
                'color' => (string)$row['color'],
            ];
        }
        $this->ok($list);
    }

    /**
     * H2 分类导航
     * GET /api/v1/home/categories  →  [{id,name,iconKey,icon,color,count}]
     * 规则：仅 enabled=1，按 sort asc；icon 为固定 /static/icons/ 文件名（按 id 映射）
     */
    public function categories()
    {
        $rows = Db::name('fc_category')
            ->where('enabled', 1)
            ->order('sort asc')
            ->select();

        $list = [];
        foreach ($rows as $row) {
            $id = (int)$row['id'];
            $list[] = [
                'id'      => $id,
                'name'    => (string)$row['name'],
                'iconKey' => (string)$row['icon_key'],
                'icon'    => '/static/icons/' . $this->iconFile($id),
                'color'   => (string)$row['color'],
                'count'   => (int)$row['post_count'],
            ];
        }
        $this->ok($list);
    }

    /**
     * H3 热门搜索
     * GET /api/v1/home/search/hot  →  [string]
     * 规则：读配置 home.hotKeywords，未配置则返回默认
     */
    public function hotKeywords()
    {
        $default = ['租房 一室一厅', '二手电动车', '急招快递员', '钢琴家教', '空调维修'];
        $keywords = $this->cfg('home.hotKeywords', $default);
        if (!is_array($keywords) || !$keywords) {
            $keywords = $default;
        }
        $this->ok(array_values($keywords));
    }

    /**
     * H4 信息流
     * GET /api/v1/home/feed  {categoryId?,keyword?,area?,sort?,lat?,lng?,page,size}
     *   →  {list,page,size,total,hasMore}
     * 规则：仅 audit_status=1 AND status=1 AND deletetime IS NULL
     *   - sort=nearby 时按距离升序（无坐标的信息排最后；请求未带 lat/lng 则回落发布时间倒序）；
     *   - 列表项 distance 为 km（一位小数），请求未带坐标 / 信息未定位时为 null。
     */
    public function feed()
    {
        list($page, $size) = $this->pager();

        $categoryId = (int)$this->input('categoryId', 0);
        $keyword = trim((string)$this->input('keyword', ''));
        $area = trim((string)$this->input('area', ''));
        $sort = (string)$this->input('sort', '');

        $query = Db::name('fc_post')
            ->where('audit_status', 1)
            ->where('status', 1)
            ->whereNull('deletetime');
        if ($categoryId > 0) {
            $query->where('category_id', $categoryId);
        }
        if ($keyword !== '') {
            $query->where('title', 'like', '%' . $keyword . '%');
        }
        if ($area !== '') {
            $query->where('area', $area);
        }

        $counter = Db::name('fc_post')
            ->where('audit_status', 1)
            ->where('status', 1)
            ->whereNull('deletetime');
        if ($categoryId > 0) {
            $counter->where('category_id', $categoryId);
        }
        if ($keyword !== '') {
            $counter->where('title', 'like', '%' . $keyword . '%');
        }
        if ($area !== '') {
            $counter->where('area', $area);
        }
        $total = $counter->count();

        // 「附近」：距离在 PHP 内用 Haversine 计算后排序（不用 SQL 距离函数，避免 MySQL 兼容问题）；
        // 因排序依赖计算结果，这里取全量匹配行排序后再做**内存分页**，保证 page/size/total 一致。
        if ($sort === 'nearby') {
            $rows = $query->order('createtime desc')->select();
            $items = [];
            foreach ($rows as $row) {
                $items[] = [
                    'item'     => $this->buildPost($row),
                    'distance' => $this->postDistance($row),
                    'ct'       => (int)$row['createtime'],
                ];
            }
            usort($items, function ($a, $b) {
                $na = $a['distance'] === null;
                $nb = $b['distance'] === null;
                if ($na !== $nb) {
                    return $na ? 1 : -1;          // 无坐标的排最后
                }
                if (!$na && $a['distance'] != $b['distance']) {
                    return $a['distance'] < $b['distance'] ? -1 : 1;
                }
                return $b['ct'] - $a['ct'];       // 距离相同（或都无坐标）：新的在前
            });
            $list = [];
            foreach ($items as $it) {
                $list[] = $it['item'];
            }
            $this->ok($this->paginateArray($list, $page, $size));
        }

        if ($sort === 'price') {
            $query->order('is_top desc, price asc');
        } elseif ($sort === 'hot') {
            $query->order('is_top desc, views desc');
        } else {
            // 后台「置顶」优先展示，其余按发布时间倒序
            $query->order('is_top desc, createtime desc');
        }

        $rows = $query->page($page, $size)->select();

        $list = [];
        foreach ($rows as $row) {
            $list[] = $this->buildPost($row);
        }

        $this->ok($this->paginate($list, $total, $page, $size));
    }

    /**
     * Haversine 距离（km，一位小数）—— 与 Post 控制器同一算法
     * @return float
     */
    protected function haversine($lat1, $lng1, $lat2, $lng2)
    {
        $earth = 6371.0;
        $rad = M_PI / 180;
        $dLat = ($lat2 - $lat1) * $rad;
        $dLng = ($lng2 - $lng1) * $rad;
        $a = sin($dLat / 2) * sin($dLat / 2)
            + cos($lat1 * $rad) * cos($lat2 * $rad) * sin($dLng / 2) * sin($dLng / 2);
        $c = 2 * asin(min(1.0, sqrt($a)));
        return round($earth * $c, 1);
    }

    /**
     * 列表项距离（km，一位小数；请求未带坐标 / 信息未定位 = null）
     * @param array $row fc_post 行
     * @return float|null
     */
    protected function postDistance($row)
    {
        $lat = $this->input('lat', null);
        $lng = $this->input('lng', null);
        if (!is_numeric($lat) || !is_numeric($lng)) {
            return null;
        }
        $lat = (float)$lat;
        $lng = (float)$lng;
        if ($lat == 0.0 && $lng == 0.0) {
            return null;
        }
        $plat = isset($row['lat']) && $row['lat'] !== null ? (float)$row['lat'] : 0.0;
        $plng = isset($row['lng']) && $row['lng'] !== null ? (float)$row['lng'] : 0.0;
        if ($plat == 0.0 && $plng == 0.0) {
            return null;
        }
        return $this->haversine($lat, $lng, $plat, $plng);
    }

    /**
     * 组装 Post 结构（与前端 mock 数据字段严格对齐）
     * @param array $row fc_post 行
     * @return array
     */
    protected function buildPost($row)
    {
        $categoryName = '';
        if (!empty($row['category_id'])) {
            $cat = Db::name('fc_category')->where('id', $row['category_id'])->find();
            if ($cat) {
                $categoryName = (string)$cat['name'];
            }
        }

        $publisher = ['id' => 0, 'name' => '', 'avatar' => '', 'isMerchant' => false, 'verified' => false];
        if (!empty($row['user_id'])) {
            $pub = Db::name('user')->where('id', $row['user_id'])->find();
            if ($pub) {
                $pubExt = Db::name('fc_user_ext')->where('user_id', $pub['id'])->find();
                $isMerchant = $pubExt && (int)$pubExt['user_type'] === 2;
                $publisher = [
                    'id'         => (int)$pub['id'],
                    'name'       => (string)$pub['nickname'],
                    'avatar'     => (string)$pub['avatar'],
                    'isMerchant' => (bool)$isMerchant,
                    'verified'   => (bool)$isMerchant,
                ];
            }
        }

        $tags = [];
        if (!empty($row['tags'])) {
            foreach (explode(',', (string)$row['tags']) as $tag) {
                $tag = trim($tag);
                if ($tag !== '') {
                    $tags[] = $tag;
                }
            }
        }

        return [
            'id'           => (int)$row['id'],
            'categoryId'   => (int)$row['category_id'],
            'categoryName' => $categoryName,
            'title'        => (string)$row['title'],
            'content'      => (string)$row['content'],
            'cover'        => (string)$row['cover'],
            'price'        => (float)$row['price'],
            'priceUnit'    => (string)$row['price_unit'],
            'area'         => (string)$row['area'],
            'address'      => (string)$row['address'],
            'contact'      => $this->maskPhone($row['phone']),
            'views'        => (int)$row['views'],
            'likes'        => (int)$row['likes'],
            'isPaid'       => (int)$row['is_paid'] === 1,
            'isTop'        => (int)$row['is_top'] === 1,
            'auditStatus'  => (int)$row['audit_status'],
            'createdAt'    => $this->iso($row['createtime']),
            'tags'         => $tags,
            'publisher'    => $publisher,
            'commentCount' => (int)$row['comment_count'],
            'distance'     => $this->postDistance($row),
        ];
    }

    /**
     * 分类 id → 固定图标文件名
     * @param int $id
     * @return string
     */
    protected function iconFile($id)
    {
        $map = [
            1 => 'cat-job.png',
            2 => 'cat-house.png',
            3 => 'cat-goods.png',
            4 => 'cat-car.png',
            5 => 'cat-service.png',
            6 => 'cat-education.png',
            7 => 'cat-clean.png',
            8 => 'cat-friend.png',
        ];
        return isset($map[$id]) ? $map[$id] : 'cat-job.png';
    }
}