<?php

namespace App\Services\DropOff;

use App\Models\DropOffPoint;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;

class DropOffPointFinder
{
    /**
     * Return active DOPs within $radiusKm of the given coordinates,
     * ordered by distance ascending. Each result has a `distance_meters`
     * attribute attached.
     *
     * @return Collection<int, DropOffPoint>
     */
    public function nearby(float $latitude, float $longitude, float $radiusKm = 5.0, int $limit = 25): Collection
    {
        $radiusMeters = $radiusKm * 1000;

        $rows = DB::table('drop_off_points')
            ->whereNull('deleted_at')
            ->where('status', DropOffPoint::STATUS_ACTIVE)
            ->select('id')
            ->selectRaw(
                'ST_Distance_Sphere(coordinates, ST_SRID(POINT(?, ?), 4326)) AS distance_meters',
                [$longitude, $latitude],
            )
            ->whereRaw(
                'ST_Distance_Sphere(coordinates, ST_SRID(POINT(?, ?), 4326)) <= ?',
                [$longitude, $latitude, $radiusMeters],
            )
            ->orderBy('distance_meters')
            ->limit($limit)
            ->get();

        if ($rows->isEmpty()) {
            return collect();
        }

        $distancesById = $rows->pluck('distance_meters', 'id');
        $points = DropOffPoint::with('barangay')
            ->whereIn('id', $rows->pluck('id'))
            ->get()
            ->keyBy('id');

        return $rows->map(function ($r) use ($points, $distancesById) {
            $p = $points->get($r->id);
            if ($p) {
                $p->distance_meters = (float) $distancesById->get($r->id);
            }

            return $p;
        })->filter()->values();
    }

    public function nearest(float $latitude, float $longitude, float $maxKm = 25.0): ?DropOffPoint
    {
        return $this->nearby($latitude, $longitude, $maxKm, 1)->first();
    }
}