<?php
/**
 * route.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 \ArrayAccess;
use \Countable;
use \DomainException;
use \IteratorAggregate;

/**
 * The GPX route type.
 *
 * @see https://www.topografix.com/GPX/1/1/#type_rteType
 *
 * @author Andy Street <andy@street.me.uk>
 */
class Route extends DataType
  implements Geographic, ArrayAccess, Countable, IteratorAggregate
{

  /**
   * GPS route number.
   *
   * @var int
   */
  protected $number;

  /**
   * A list of route points.
   *
   * @var DoublyLinkedList (Point)
   */
  protected $points;

  /**
   * Fetch the route number.
   *
   * @return int|null The route number or null if not set.
   */
  public function getNumber()
  {
    return $this->number;
  }

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

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

  /**
   * 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()
  {
    $result = null;
    if ($this->points !== null) {
      foreach ($this->points as $point) {
        $bounds = $point->getBounds();
        if ($result === null) {
          $result = $bounds;
        } else {
          $result->extend($bounds);
        }
      }
    }
    return $result;
  }

  /**
   * Fetch the length of a route.
   *
   * @return float The length in meters.
   */
  public function getLength()
  {
    $length = 0;
    $points = $this->getPoints(false);
    if ($points !== null && !$points->isEmpty()) {
      $last_point = null;
      foreach ($points as $current_point) {
        if ($last_point !== null)
          $length += libgpx::distance(
            $last_point->getLatitude(),
            $last_point->getLongitude(),
            $current_point->getLatitude(),
            $current_point->getLongitude()
          );
        $last_point = $current_point;
      }
    }
    return $length;
  }

  /**
   * Check if an offset holds a value.
   *
   * @see ArrayAccess::offsetExists
   *
   * @param mixed $offset The offset to search
   * @return boolean
   */
  public function offsetExists($offset)
  {
    return $this->getPoints()->offsetExists($offset);
  }

  /**
   * Fetch a point from this route.
   *
   * @see ArrayAccess::offsetGet
   *
   * @param mixed $offset The offset to retrieve
   * @return Point
   */
  public function offsetGet($offset)
  {
    return $this->getPoints()->offsetGet($offset);
  }

  /**
   * Set the point at an offset.
   *
   * @see ArrayAccess::offsetSet
   *
   * @param mixed $offset Where to store the point.
   * @param Point $value The point to store.
   * @return void
   */
  public function offsetSet($offset, $value)
  {
    return $this->getPoints()->offsetSet($offset, $value);
  }

  /**
   * Remove a point.
   *
   * @see ArrayAccess::offsetUnset
   *
   * @param mixed $offset Which point to remove
   * @return void
   */
  public function offsetUnset($offset)
  {
    return $this->getPoints()->offsetUnset($offset);
  }

  /**
   * Count the number of points in this route.
   *
   * @return int
   */
  public function count()
  {
    return ($this->points === null ? 0 : $this->points->count());
  }

  /**
   * Fetch an iterator for the points contained in this route.
   *
   * @return \Iterator
   */
  public function getIterator() {
    return $this->getPoints();
  }

}