<?php
/**
 * Geo Information Tools: Neighbour
 *
 * @author gERD Schaufelberger <gerd@php-tools.de>
 * @package WB
 * @subpackage geo
 */

WBClass::load('WBGeo');

/**
 * Geo Information Tools: Neighbour
 *
 * @todo this is alpha
 * @version 0.2.0
 * @package WB
 * @subpackage geo
 */
class WBGeo_Neighbour extends WBStdClass
{
    /**
     * Maxiumum Distance Of Neighbour
     * @var int
     */
    private $maxDistance    =   1000;

    /**
     * Center Point
     * @var WBGeo_Point
     */
    private $center;

    /**
     * Position of Bounding Box Edges
     *
     * North, east, south, west
     *
     * @var array
     */
    private $bounding   =   array(0,0,0,0);

    /**
     * Constructor
     *
     * @param array
     */
    public function __construct($parameter = array())
    {
    }

    public function setCenter(WBGeo_Point $point)
    {
        $this->center   =   $point;
        $this->updateBoundings();
    }

    /**
     * Set Maxiumum Distance
     *
     * @param int meter
     */
    public function setMaxDistance($distance = 1000)
    {
        $this->maxDistance  =   $distance;
        $this->updateBoundings();
    }

    /**
     * Is Point in Neighbourhood?
     *
     * See if point's coordinates are within bounding box
     *
     * @param WBGeo_Point
     * @return bool
     */
    public function check(WBGeo_Point $point)
    {
        $lat    =   $point->getLatitude(false);
        if ($lat > $this->bounding[0] || $lat < $this->bounding[2]) {
            return false;
        }

        $lon    =   $point->getLongitude(false);
        if ($lon > $this->bounding[1] || $lon < $this->bounding[3]) {
            return false;
        }

        return true;
    }

    /**
     * Get Bounding Box Coordinates
     *
     * @param bool convert to deg
     * @return array
     */
    public function getBoundingBoxCoordinates($deg = true)
    {
        if (!$deg) {
            return $this->bounding;
        }

        $box    =   array();
        foreach ($this->bounding as $b) {
            $box[]  =   WBGeo::rad2deg($b);
        }
        return $box;
    }

    /**
     * Recalculate Bounding Box
     *
     * @todo juggle with negative values?
     */
    private function updateBoundings()
    {
        $this->bounding =   array(0,0,0,0);

        if (empty($this->center)) {
            return;
        }

        $lat    =   $this->center->getLatitude(false);
        $lon    =   $this->center->getLongitude(false);

        // north / south offset
        $cir    =   WBGeo::EARTH_RADIUS * 2 * M_PI;
        $offset =   2 * M_PI * $this->maxDistance / $cir;
        $this->bounding[0]  =   $lat + $offset;
        $this->bounding[2]  =   $lat - $offset;

        $rad    =   cos($lat) * WBGeo::EARTH_RADIUS;
        $cir    =   $rad * 2 * M_PI;
        $offset =   2 * M_PI * $this->maxDistance / $cir;
        $this->bounding[1]  =   $lon + $offset;
        $this->bounding[3]  =   $lon - $offset;

        // swap
        if ($this->bounding[0] > $this->bounding[2]) {
            $tmp    =   $this->bounding[0];
            $this->bounding[0]  =   $this->bounding[2];
            $this->bounding[2]  =   $tmp;
        }

        if ($this->bounding[1] > $this->bounding[3]) {
            $tmp    =   $this->bounding[1];
            $this->bounding[1]  =   $this->bounding[3];
            $this->bounding[3]  =   $tmp;
        }
    }
}