<?php
/**
 * gpx.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 \DateTimeInterface;

/**
 * A GPX file.
 *
 * @see https://www.topografix.com/gpx.asp
 *
 * @author Andy Street <andy@street.me.uk>
 */
class GPX implements Geographic
{

  /**
   * The program that created the GPX file.
   *
   * @var string
   */
  protected $creator;

  /**
   * The name of the GPX file.
   *
   * @var string
   */
  protected $name;

  /**
   * A description of the contents of the GPX file.
   *
   * @var string
   */
  protected $desc;

  /**
   * The person or organization who created the GPX file.
   *
   * @var Person
   */
  protected $author;

  /**
   * Copyright and license information governing use of the file.
   *
   * @var Copyright
   */
  protected $copyright;

  /**
   * Links to other resources that describe this GPX file.
   *
   * @var TypedDoublyLinkedList (Link)
   */
  protected $links;

  /**
   * The creation time of the file.
   *
   * @var DateTimeInterface
   */
  protected $time;

  /**
   * A list of keywords classifying this GPX file.
   *
   * @var TypedDoublyLinkedList (string)
   */
  protected $keywords;

  /**
   * A list of XML snippets describing unsupported metadata.
   *
   * @var TypedDoublyLinkedList (string)
   */
  protected $metadataExtensions;

  /**
   * A list of waypoints.
   *
   * @var TypedDoublyLinkedList (Point)
   */
  protected $waypoints;

  /**
   * A list of routes.
   *
   * @var TypedDoublyLinkedList (Route)
   */
  protected $routes;

  /**
   * A list of tracks.
   *
   * @var TypedDoublyLinkedList (Track)
   */
  protected $tracks;

  /**
   * A list of XML snippets describing unsupported elements.
   *
   * @var TypedDoublyLinkedList (string)
   */
  protected $extensions;

  /**
   * Fetch the name of the program that created the GPX file.
   *
   * @return string|null The creator or null if not set.
   */
  public function getCreator()
  {
    return $this->creator;
  }

  /**
   * Set the name of the program that created the GPX file.
   *
   * @param string|null $creator The program name or null to delete.
   * @return void
   */
  public function setCreator(string $creator = null)
  {
    $this->creator = $creator;
  }

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

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

  /**
   * Fetch the description of the file.
   *
   * @return string|null The description or null if not set.
   */
  public function getDesc()
  {
    return $this->desc;
  }

  /**
   * Set the description of the file.
   *
   * @param string|null $desc The description or null to delete.
   * @return void
   */
  public function setDesc(string $desc = null)
  {
    $this->desc = $desc;
  }

  /**
   * Fetch the author of the file.
   *
   * @return Person|null The author or null if not set.
   */
  public function getAuthor()
  {
    return $this->author;
  }

  /**
   * Set the author of the file.
   *
   * @param Person|null $author The author or null to delete.
   * @return void
   */
  public function setAuthor(Person $author = null)
  {
    $this->author = $author;
  }

  /**
   * Fetch the copyright details for the file.
   *
   * @return Copyright|null The copyright or null if not set.
   */
  public function getCopyright()
  {
    return $this->copyright;
  }

  /**
   * Set the copyright details for the file.
   *
   * @param Copyright|null $copyright The copyright detail or null to delete.
   * @return void
   */
  public function setCopyright(Copyright $copyright = null)
  {
    $this->copyright = $copyright;
  }

  /**
   * Fetch links to other resources.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList
   */
  public function getLinks(bool $create = true)
  {
    if ($create && $this->links === null)
      $this->links = new TypedDoublyLinkedList('libgpx\Link');
    return $this->links;
  }

  /**
   * Fetch the time the GPX file was created.
   *
   * @return DateTimeInterface|null A timestamp or null if not set.
   */
  public function getTime()
  {
    return $this->time;
  }

  /**
   * Set the time at which the file was created.
   *
   * @param DateTimeInterface $time The creation time or null to delete.
   */
  public function setTime(DateTimeInterface $time = null)
  {
    $this->time = $time;
  }

  /**
   * Fetch a list of keywords for this GPX file.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList The keywords
   */
  public function getKeywords(bool $create = true)
  {
    if ($create && $this->keywords === null)
      $this->keywords = new TypedDoublyLinkedList('string');
    return $this->keywords;
  }

  /**
   * Fetch a list of XML snippets describing unsupported metadata.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList The keywords
   */
  public function getMetadataExtensions(bool $create = true)
  {
    if ($create && $this->metadataExtensions === null)
        $this->metadataExtensions = new TypedDoublyLinkedList('string');
    return $this->metadataExtensions;
  }

  /**
   * Fetch a list of waypoints.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList A list of waypoints.
   */
  public function getWaypoints(bool $create = true)
  {
    if ($create && $this->waypoints === null)
      $this->waypoints = new TypedDoublyLinkedList('libgpx\Point');
    return $this->waypoints;
  }

  /**
   * Fetch a list of routes.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList A list of routes.
   */
  public function getRoutes(bool $create = true)
  {
    if ($create && $this->routes === null)
      $this->routes = new TypedDoublyLinkedList('libgpx\Route');
    return $this->routes;
  }

  /**
   * Fetch a list of tracks.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList A list of tracks.
   */
  public function getTracks(bool $create = true)
  {
    if ($create && $this->tracks === null)
      $this->tracks = new TypedDoublyLinkedList('libgpx\Track');
    return $this->tracks;
  }

  /**
   * Fetch a list of protocol extensions as raw XML.
   *
   * @param boolean $create Create the list if it does not already exist.
   * @return TypedDoublyLinkedList A list of protocol extensions.
   */
  public function getExtensions(bool $create = true)
  {
    if ($create && $this->extensions === null)
      $this->extensions = new TypedDoublyLinkedList('string');
    return $this->extensions;
  }

  /**
   * 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()
  {
    $result = null;
    $lists = [
      $this->waypoints,
      $this->routes,
      $this->tracks
    ];
    foreach ($lists as $list) {
      if ($list === null) continue;
      foreach ($list as $geo) {
        $bounds = $geo->getBounds();
        if ($bounds === null) continue;
        if ($result === null) {
          $result = $bounds;
        } else {
          $result->extend($bounds);
        }
      }
    }
    return $result;
  }

  /**
   * Fetch the length of all features in this GPX file.
   *
   * @return float The length in meters.
   */
  public function getLength()
  {
    $length = 0;
    $lists = [
      $this->routes,
      $this->tracks
    ];
    foreach ($lists as $list) {
      if ($list === null) continue;
      foreach ($list as $geo) {
        $length += $geo->getLength();
      }
    }
    return $length;
  }

}