<?php

namespace App\Services\Coordinates;

class CoordinateService
{
    /**
     * Computes the distance between two coordinates.
     *
     * Implementation based on reverse engineering of
     * <code>google.maps.geometry.spherical.computeDistanceBetween()</code>.
     *
     * @param float $lat1   latitude from the first point
     * @param float $lng1   longitude from the first point
     * @param float $lat2   latitude from the second point
     * @param float $lng2   longitude from the second point
     * @param float $radius (optional) Radius in meters
     *
     * @return float distance in meters
     */
    public function computeDistance($lat1, $lng1, $lat2, $lng2, $radius = 6378137)
    {
        static $x = M_PI / 180;
        $lat1 *= $x;
        $lng1 *= $x;
        $lat2 *= $x;
        $lng2 *= $x;
        $distance = 2 * asin(sqrt(pow(sin(($lat1 - $lat2) / 2), 2) + cos($lat1)
        * cos($lat2) * pow(sin(($lng1 - $lng2) / 2), 2)));

        return $distance * $radius;
    }

    /*
     * Algorithm based on the spherical law of cosines.
     * https://developers.google.com/maps/solutions/store-locator/clothing-store-locator#creating-the-map
     *
     *To count in miles change 6371 to 3959
     */
    public function pointsInRadiusQuery(array $data)
    {
        return '*,
                (
                    6371 *
                    acos(cos(radians('.$data['latitude'].')) *
                    cos(radians(`latitude`)) *
                    cos(radians(`longitude`) -
                    radians('.$data['longitude'].')) +
                    sin(radians('.$data['latitude'].')) *
                    sin(radians(`latitude` )))
                )
                AS distance';
    }
}