<?php
/**
 * point.php
 *
 * Copyright 2018 Andy Street <andy@street.me.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 *
 *
 */

namespace libgpx;

use \DomainException;
use \DateTimeInterface;

/**
 * A geographic point.
 *
 * @see https://www.topografix.com/GPX/1/1/#type_wptType
 *
 * @author Andy Street <andy@street.me.uk>
 */
class Point extends DataType implements Geographic
{

  /**
   * The latitude of the point.
   *
   * @var float
   */
  protected $lat;

  /**
   * The longitude of the point.
   *
   * @var float
   */
  protected $lon;

  /**
   * Elevation (in meters) of the point.
   *
   * @var float
   */
  protected $ele;

  /**
   * Creation/modification timestamp for element.
   *
   * Date and time in are in Univeral Coordinated Time (UTC), not local time!
   * Conforms to ISO 8601 specification for date/time representation.
   * Fractional seconds are allowed for millisecond timing in tracklogs.
   *
   * @var DateTimeInterface
   */
  protected $time;

  /**
   * Magnetic variation (in degrees) at the point.
   *
   * @var float
   */
  protected $magvar;

  /**
   * Height (in meters) of geoid (mean sea level) above WGS84 earth ellipsoid.
   * As defined in NMEA GGA message.
   *
   * @var float
   */
  protected $geoidheight;

  /**
   * Text of GPS symbol name.
   *
   * For interchange with other programs, use the exact spelling of the symbol
   * as displayed on the GPS. If the GPS abbreviates words, spell them out.
   *
   * @var string
   */
  protected $symbol;

  /**
   * Type of GPS fix.
   *
   * "none", "2d", "3d", "dgps" or "pps".
   *
   * None means GPS had no fix. To signify "the fix info is unknown, leave out
   * fixType entirely. pps = military signal used.
   *
   * @var string
   */
  protected $fix;

  /**
   * Number of satellites used to calculate the GPX fix.
   *
   * @var int
   */
  protected $satellites;

  /**
   * Horizontal dilution of precision.
   *
   * @var float
   */
  protected $hdop;

  /**
   * Vertical dilution of precision.
   *
   * @var float
   */
  protected $vdop;

  /**
   * Position dilution of precision.
   *
   * @var float
   */
  protected $pdop;

  /**
   * Number of seconds since last DGPS update.
   *
   * @var float
   */
  protected $ageofdgpsdata;

  /**
   * ID of DGPS station used in differential correction.
   *
   * @var int
   */
  protected $dgpsid;

  /**
   * Create a new point.
   *
   * @param float $lat Latitude
   * @param float $lon Longitude
   * @throws DomainException If not a valid latitude or longitude.
   */
  public function __construct(float $lat, float $lon)
  {
    $this->setLatitude($lat);
    $this->setLongitude($lon);
  }

  /**
   * Fetch the latitude of the point.
   *
   * @return float
   */
  public function getLatitude()
  {
    return $this->lat;
  }

  /**
   * Set the latitude of the point.
   *
   * @param float $lat Latitude
   * @return void
   * @throws DomainException If not a valid latitude.
   */
  public function setLatitude(float $lat)
  {
    if ($lat < -90 || $lat > 90)
      throw new DomainException(
        sprintf('Value %s is not in the range -90-+90.', $lat)
      );
    $this->lat = $lat;
  }

  /**
   * Fetch the longitude of the point.
   *
   * @return float
   */
  public function getLongitude()
  {
    return $this->lon;
  }

  /**
   * Set the longitude of the point.
   *
   * @param float $lon Longitude
   * @return void
   * @throws DomainException If not a valid longitude.
   */
  public function setLongitude(float $lon)
  {
    if ($lon < -180 || $lon > 180)
      throw new DomainException(
        sprintf('Value %s is not in the range -180-+180.', $lon)
      );
    $this->lon = $lon;
  }

  /**
   * Fetch the elevation of the point.
   *
   * @return float|null The elevation in meters or null if not set.
   */
  public function getEle()
  {
    return $this->ele;
  }

  /**
   * Set the elevation of the point.
   *
   * @param float $ele The elevation in meters or null to delete.
   * @return void
   */
  public function setEle(float $ele = null)
  {
    $this->ele = $ele;
  }

  /**
   * Fetch the creation time of the point.
   *
   * @return DateTimeInterface|null The time or null if not set.
   */
  public function getTime()
  {
    return $this->time;
  }

  /**
   * Set the creation time of the point.
   *
   * @param DateTimeInterface $time The creation time or null to delete.
   * @return void
   */
  public function setTime(DateTimeInterface $time = null)
  {
    $this->time = $time;
  }

  /**
   * Fetch the magnetic variation.
   *
   * @return float|null The magnetic variation in degrees or null if not set.
   */
  public function getMagvar()
  {
    return $this->magvar;
  }

  /**
   * Set the magnetic variation.
   *
   * @param float $magvar The magnetic variation in degrees or null to delete.
   * @return void
   * @throws DomainException if not in range 0 <= value < 360
   */
  public function setMagvar(float $magvar = null)
  {
    if (
      $magvar !== null
      && ($magvar < 0 || $magvar >= 360)
    ) {
      throw new DomainException(
        sprintf('Value %s is not in the range 0 <= value < 360.', $lon)
      );
    }
    $this->magvar = $magvar;
  }

  /**
   * Fetch the geoid height at the point.
   *
   * @return float The geoid height in meters.
   */
  public function getGeoidHeight()
  {
    return $this->geoidheight;
  }

  /**
   * Set the geoid height at the point.
   *
   * @param float $geoidheight The geoid height in meters.
   * @return void
   */
  public function setGeoidHeight(float $geoidheight = null)
  {
    $this->geoidheight = $geoidheight;
  }

  /**
   * Fetch the waypoint symbol.
   *
   * @return string|null The symbol or null if not set.
   */
  public function getSymbol()
  {
    return $this->symbol;
  }

  /**
   * Set the symbol representing this point.
   *
   * @param string $symbol The name of the symbol or null to delete.
   * @return void
   */
  public function setSymbol(string $symbol = null)
  {
    $this->symbol = $symbol;
  }

  /**
   * Fetch the fix type for this point.
   *
   * @return string|null The fix type or null if not set.
   */
  public function getFix()
  {
    return $this->fix;
  }

  /**
   * Set the fix type.
   *
   * @param string $fix "none", "2d", "3d", "dgps", "pps" or null to delete.
   * @return void
   * @throws DomainException If an invalid fix type is passed.
   */
  public function setFix(string $fix = null)
  {
    if ($fix !== null && !in_array($fix, ['none', '2d', '3d', 'dgps', 'pps']))
      throw new DomainException(sprintf('Unknown fix type "%s"', $fix));
    $this->fix = $fix;
  }

  /**
   * Fetch the number of satellites used to calculate the fix.
   *
   * @return int The number of satellites or null if not set.
   */
  public function getSatellites()
  {
    return $this->satellites;
  }

  /**
   * Set the number of satellites used to calculate the fix.
   *
   * @param int $satellites The number if satellites or null to delete.
   * @return void
   * @throws DomainException If $satellites < 0
   */
  public function setSatellites(int $satellites = null)
  {
    if ($satellites !== null && $satellites < 0)
      throw new DomainException(
        sprintf('Satellites must be >= 0 but got %s', $satellites)
      );
    $this->satellites = $satellites;
  }

  /**
   * Fetch the hdop of the point.
   *
   * @return float|null The hdop or null if not set.
   */
  public function getHdop()
  {
    return $this->hdop;
  }

  /**
   * Set the hdop of the point.
   *
   * @param float $hdop The hdop or null to delete.
   * @return void
   */
  public function setHdop(float $hdop = null)
  {
    $this->hdop = $hdop;
  }

  /**
   * Fetch the vdop of the point.
   *
   * @return float|null The vdop or null if not set.
   */
  public function getVdop()
  {
    return $this->vdop;
  }

  /**
   * Set the vdop of the point.
   *
   * @param float $vdop The vdop or null to delete.
   * @return void
   */
  public function setVdop(float $vdop = null)
  {
    $this->vdop = $vdop;
  }

  /**
   * Fetch the pdop of the point.
   *
   * @return float|null The pdop or null if not set.
   */
  public function getPdop()
  {
    return $this->pdop;
  }

  /**
   * Set the pdop of the point.
   *
   * @param float $pdop The pdop or null to delete.
   * @return void
   */
  public function setPdop(float $pdop = null)
  {
    $this->pdop = $pdop;
  }

  /**
   * Fetch the age of the DGPS data.
   *
   * @return float The age of DGPS data in seconds or null if not set.
   */
  public function getAgeOfDGPSData()
  {
    return $this->ageofdgpsdata;
  }

  /**
   * Set the age of the DGPS data.
   *
   * @param float $ageofdgpsdata The age in seconds or null to delete.
   * @return void
   */
  public function setAgeOfDGPSData(float $ageofdgpsdata = null)
  {
    $this->ageofdgpsdata = $ageofdgpsdata;
  }

  /**
   * Fetch the id of the DGPS station.
   *
   * @return int The DGPS id or null if not set.
   */
  public function getDGPSId()
  {
    return $this->dgpsid;
  }

  /**
   * Set the id of the DGPS station.
   *
   * @param int $dgpsid The station id.
   * @return void
   * @throws DomainException If the station id < 0 or > 1023.
   */
  public function setDGPSId(int $dgpsid = null)
  {
    if ($dgpsid !== null && ($dgpsid < 0 || $dgpsid > 1023))
      throw new DomainException(
        sprintf('DGPS id must be >= 0 and <= 1023 but got %s', $dgpsid)
      );
    return $this->dgpsid = $dgpsid;
  }

  /**
   * Fetch a bounding box that covers the feature.
   *
   * @return Bounds|null A bounding box covering the extent of the feature or
   *         null if not applicable.
   */
  public function getBounds()
  {
    return new Bounds($this->lat, $this->lon, $this->lat, $this->lon);
  }

  /**
   * Fetch the length of a point.
   *
   * Note: Length is the distance between two points so calling this function
   *       on a single point makes little sense. It is implemented to complete
   *       the `Geographic` interface and will always return a value of 0.
   *
   * @return float The length in meters.
   */
  public function getLength()
  {
    return 0.0;
  }

  /**
   * Find the distance to another point.
   *
   * @param Point $point The point to find the distance to.
   * @return float The distance in meters.
   */
  public function distanceTo(Point $point)
  {
    return libgpx::distance(
      $this->lat,
      $this->lon,
      $point->getLatitude(),
      $point->getLongitude()
    );
  }

}