<?php

/**
 * Exif
 *
 * Reads exif data from a given media object
 *
 * @package   Kirby Toolkit
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      http://getkirby.com
 * @copyright Bastian Allgeier
 * @license   http://www.opensource.org/licenses/mit-license.php MIT License
 */
class Exif {

  // the parent media object
  protected $media = null;

  // the raw exif array
  protected $data = null;

  // the camera object with model and make
  protected $camera = null;

  // the location object
  protected $location = null;

  // the timestamp
  protected $timestamp = null;

  // the exposure value
  protected $exposure = null;

  // the aperture value
  protected $aperture = null;

  // iso value
  protected $iso = null;

  // focal length
  protected $focalLength = null;

  // color or black/white
  protected $isColor = null;

  /**
   * Constructor
   *
   * @param Media $media
   */
  public function __construct(Media $media) {
    $this->media = $media;
    $this->parse();
  }

  /**
   * Returns the raw data array from the parser
   *
   * @return array
   */
  public function data() {
    return $this->data;
  }

  /**
   * Returns the Camera object
   *
   * @return object KirbyExifCamera
   */
  public function camera() {

    if(!is_null($this->camera)) return $this->camera;

    // check for valid exif data
    if(!is_array($this->data)) return null;

    // initialize and return it
    return $this->camera = new Exif\Camera($this->data);

  }

  /**
   * Returns the location object
   *
   * @return object ExifLocation
   */
  public function location() {

    if(!is_null($this->location)) return $this->location;

    // check for valid exif data
    if(!is_array($this->data)) return null;

    // initialize and return it
    return $this->location = new Exif\Location($this->data);

  }

  /**
   * Returns the timestamp
   *
   * @return string
   */
  public function timestamp() {
    return $this->timestamp;
  }

  /**
   * Returns the exposure
   *
   * @return string
   */
  public function exposure() {
    return $this->exposure;
  }

  /**
   * Returns the aperture
   *
   * @return string
   */
  public function aperture() {
    return $this->aperture;
  }

  /**
   * Returns the iso value
   *
   * @return int
   */
  public function iso() {
    return $this->iso;
  }

  /**
   * Checks if this is a color picture
   *
   * @return boolean
   */
  public function isColor() {
    return $this->isColor;
  }

  /**
   * Checks if this is a bw picture
   *
   * @return boolean
   */
  public function isBW() {
    return !$this->isColor;
  }

  /**
   * Returns the focal length
   *
   * @return string
   */
  public function focalLength() {
    return $this->focalLength;
  }

  /**
   * Pareses and stores all relevant exif data
   */
  protected function parse() {

    // read the exif data of the media object if possible
    $this->data = @read_exif_data($this->media->root());

    // stop on invalid exif data
    if(!is_array($this->data)) return false;

    // store the timestamp when the picture has been taken
    if(isset($this->data['DateTimeOriginal'])) {
      $this->timestamp = strtotime($this->data['DateTimeOriginal']);
    } else {
      $this->timestamp = a::get($this->data, 'FileDateTime', $this->media->modified());
    }

    // exposure
    $this->exposure = a::get($this->data, 'ExposureTime');

    // iso
    $this->iso = a::get($this->data, 'ISOSpeedRatings');

    // focal length
    if(isset($this->data['FocalLength'])) {
      $this->focalLength = $this->data['FocalLength'];
    } else if(isset($this->data['FocalLengthIn35mmFilm'])) {
      $this->focalLength = $this->data['FocalLengthIn35mmFilm'];
    }

    // aperture
    $this->aperture = @$this->data['COMPUTED']['ApertureFNumber'];

    // color or bw
    $this->isColor = @$this->data['COMPUTED']['IsColor'] == true;

  }

  /**
   * Converts the object into a nicely readable array
   *
   * @return array
   */
  public function toArray() {

    return array(
      'camera'      => $this->camera()->toArray(),
      'location'    => $this->location()->toArray(),
      'timestamp'   => $this->timestamp(),
      'exposure'    => $this->exposure(),
      'aperture'    => $this->aperture(),
      'iso'         => $this->iso(),
      'focalLength' => $this->focalLength(),
      'isColor'     => $this->isColor()
    );

  }

}