<?php

class site_point {

  private $base_dir;

  private $name = false;

  private $prefix = false;

  private $params = false;

  private $zooms;

  public function __construct($dir) {

    $this->base_dir = $dir;

    $dir_fd = opendir($this->base_dir);

    while (false !== ($file = readdir($dir_fd))) {

       if (preg_match('/(.*)_[0-9]+_[0-9]+_[0-9]+\.jpg$/', $file, $reg)) {

         $this->prefix = $reg[1];

         break;

       }

    }

    closedir($dir_fd);

    if ($this->prefix === false) return false;

    $pfname = $this->base_dir.'/'.$this->prefix.'.params';

    if (is_file($pfname)) {

      $this->params = @parse_ini_file($pfname);

    }

  }

  public function get_params() {

    return $this->params;

  }

  public function get_name() {

    return basename($this->base_dir);

  }

  public function get_prefix() {

    return $this->prefix;

  }

  public function get_magnifications() {

    $dir_fd = opendir($this->base_dir);

    while (false !== ($file = readdir($dir_fd))) {                // extraction des paramètres de grossissement par le serveur

       //echo $file;

       if (preg_match('/(.*)_([0-9]+)_([0-9]+)_([0-9]+)\.jpg$/', $file, $reg)) {

         $prefix = $reg[1];

         if ($prefix == $this->prefix) {

           $zoom = (int)$reg[2];

           $posx = (int)$reg[3]+1;

           $posy = (int)$reg[4]+1;

           if (!isset($zoom_array[$zoom]['nx']) || $zoom_array[$zoom]['nx'] < $posx) $zoom_array[$zoom]['nx'] = $posx;

           if (!isset($zoom_array[$zoom]['ny']) || $zoom_array[$zoom]['ny'] < $posy) $zoom_array[$zoom]['ny'] = $posy;

         }

       }

    }

    $this->zooms = $zoom_array;

    return $this->zooms;

  }

  public function coordsToCap($lat, $lon, $alt) {

    if (!isset($this->params['latitude']) || !isset($this->params['longitude'])) return false;

    $rt = 6371;  // Rayon de la terre

    $alt1 = isset($this->params['altitude']) ? $this->params['altitude'] : $alt;

    $lat1 = $this->params['latitude']*M_PI/180;

    $lon1 = $this->params['longitude']*M_PI/180;

    $alt2 = $alt;

    $lat2 = $lat * M_PI/180;

    $lon2 = $lon * M_PI/180;

    $dLat = $lat2-$lat1;

    $dLon = $lon2-$lon1;

    $a = sin($dLat/2) * sin($dLat/2) + sin($dLon/2) * sin($dLon/2) * cos($lat1) * cos($lat2); 

    $angle = 2 * atan2(sqrt($a), sqrt(1-$a));

    $d = $angle * $rt;                    // distance du point en Kms

    $y = sin($dLon)*cos($lat2);

    $x = cos($lat1)*sin($lat2) - sin($lat1)*cos($lat2)*cos($dLon);

    $cap = atan2($y, $x);                 // cap pour atteindre le point en radians

    $e = atan2(($alt2 - $alt1)/1000 - $d*$d/(2*$rt), $d);  // angle de l'élévation en radians

    //    printf("%s, %s, %s, %s\n",$lat1, $this->params['latitude'], $lat, $dLat);

    return array($d, $cap*180/M_PI, $e*180/M_PI);   // les résultats sont en degrés

  }

}