fenleixinxi/application/common/library/NationalArea.php

<?php

namespace app\common\library;

use think\Db;

/**
 * 全国标准省/市/区县服务区域工具类
 *
 * 规则：
 *   - 默认全国所有省、市、区县全部开通，无需后台手动维护；
 *   - 数据源取自 application/extra/national_areas.json（由全国行政区划字典构建，涵盖全国 34 个省级行政区、全部地级市及区县）；
 *   - 同时合并 fa_fc_area 表中历史自定义记录，确保旧 ID 与历史数据 100% 兼容。
 */
class NationalArea
{
    /** @var array|null 内存级缓存 */
    protected static $allCache = null;

    /**
     * 获取全国全部省/市/区县平铺列表
     *
     * @return array<int, array{id:int,province:string,city:string,district:string,lat:float|null,lng:float|null}>
     */
    public static function all()
    {
        if (self::$allCache !== null) {
            return self::$allCache;
        }

        $jsonFile = APP_PATH . 'extra' . DS . 'national_areas.json';
        $list = [];
        if (is_file($jsonFile)) {
            $decoded = json_decode((string)file_get_contents($jsonFile), true);
            if (is_array($decoded)) {
                $list = $decoded;
            }
        }

        // 合并数据库中已有的自定义启用区域（避免重复）
        try {
            $dbRows = Db::name('fc_area')
                ->where('enabled', 1)
                ->order('sort asc, id asc')
                ->select();
            $seenKey = [];
            $seenId = [];
            foreach ($list as $idx => $item) {
                $k = $item['province'] . '|' . $item['city'] . '|' . $item['district'];
                $seenKey[$k] = $idx;
                $seenId[(int)$item['id']] = $idx;
            }
            foreach ($dbRows as $row) {
                $p = (string)$row['province'];
                $c = (string)$row['city'];
                $d = (string)$row['district'];
                $k = $p . '|' . $c . '|' . $d;
                $id = (int)$row['id'];
                if (isset($seenKey[$k])) {
                    $targetIdx = $seenKey[$k];
                    if ($row['lat'] !== null && $row['lng'] !== null) {
                        $list[$targetIdx]['lat'] = (float)$row['lat'];
                        $list[$targetIdx]['lng'] = (float)$row['lng'];
                    }
                    continue;
                }
                if (!isset($seenId[$id])) {
                    $list[] = [
                        'id'       => $id,
                        'province' => $p,
                        'city'     => $c,
                        'district' => $d,
                        'lat'      => $row['lat'] !== null ? (float)$row['lat'] : null,
                        'lng'      => $row['lng'] !== null ? (float)$row['lng'] : null,
                    ];
                }
            }
        } catch (\Throwable $e) {
            // 忽略数据库读取异常，以全国静态字典兜底
        }

        self::$allCache = $list;
        return self::$allCache;
    }

    /**
     * 按区域 ID 查找单条省/市/区县记录
     *
     * @param int $areaId 区县ID
     * @return array|null
     */
    public static function findById($areaId)
    {
        $areaId = (int)$areaId;
        if ($areaId <= 0) {
            return null;
        }
        foreach (self::all() as $row) {
            if ((int)$row['id'] === $areaId) {
                return $row;
            }
        }
        return null;
    }

    /**
     * 按区县名称（及可选省/市）查找匹配记录
     *
     * @param string $district 区县名称
     * @param string $city     可选城市名称
     * @param string $province 可选省份名称
     * @return array|null
     */
    public static function findByName($district, $city = '', $province = '')
    {
        $district = trim((string)$district);
        $city = trim((string)$city);
        $province = trim((string)$province);
        if ($district === '') {
            return null;
        }
        foreach (self::all() as $row) {
            if ($row['district'] === $district) {
                if ($city !== '' && $row['city'] !== $city) {
                    continue;
                }
                if ($province !== '' && $row['province'] !== $province) {
                    continue;
                }
                return $row;
            }
        }
        return null;
    }

    /**
     * 按经纬度坐标（gcj02）匹配最近的全国区县
     *
     * @param float $lat 纬度
     * @param float $lng 经度
     * @return array|null {areaId, province, city, district, distance}
     */
    public static function locate($lat, $lng)
    {
        $best = null;
        foreach (self::all() as $row) {
            if ($row['lat'] === null || $row['lng'] === null) {
                continue;
            }
            $dist = self::haversine($lat, $lng, (float)$row['lat'], (float)$row['lng']);
            if ($best === null || $dist < $best['distance']) {
                $best = ['row' => $row, 'distance' => $dist];
            }
        }
        if (!$best || $best['distance'] > 1000) {
            return null;
        }
        $area = $best['row'];
        return [
            'areaId'   => (int)$area['id'],
            'province' => (string)$area['province'],
            'city'     => (string)$area['city'],
            'district' => (string)$area['district'],
            'distance' => $best['distance'],
        ];
    }

    /**
     * 计算两点间 Haversine 球面距离（km，保留 1 位小数）
     *
     * @param float $lat1
     * @param float $lng1
     * @param float $lat2
     * @param float $lng2
     * @return float
     */
    public static function haversine($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);
    }
}