<?php
/**
 * The Image Sizes library.
 *
 * @package jetpack
 */

jetpack_require_lib( 'class.jetpack-photon-image' );

/**
 * Class Jetpack_Photon_ImageSizes
 *
 * Manages image resizing via Jetpack CDN Service.
 */
class Jetpack_Photon_ImageSizes {

	/**
	 * @var array $data Attachment metadata.
	 */
	public $data;

	/**
	 * @var Image Image to be resized.
	 */
	public $image;

	/**
	 * @var null|array $sizes Intermediate sizes.
	 */
	public static $sizes = null;

	/**
	 * Construct new sizes meta
	 *
	 * @param int   $attachment_id Attachment ID.
	 * @param array $data          Attachment metadata.
	 */
	public function __construct( $attachment_id, $data ) {
		$this->data  = $data;
		$this->image = new Jetpack_Photon_Image( $data, get_post_mime_type( $attachment_id ) );
		$this->generate_sizes();
	}

	/**
	 * Generate sizes for attachment.
	 *
	 * @return array Array of sizes; empty array as failure fallback.
	 */
	protected function generate_sizes() {

		// There is no need to generate the sizes a new for every single image.
		if ( null !== self::$sizes ) {
			return self::$sizes;
		}

		/*
		 * The following logic is copied over from wp_generate_attachment_metadata
		 */
		$_wp_additional_image_sizes = wp_get_additional_image_sizes();

		$sizes = array();

		$intermediate_image_sizes = get_intermediate_image_sizes();

		foreach ( $intermediate_image_sizes as $s ) {
			$sizes[ $s ] = array(
				'width'  => '',
				'height' => '',
				'crop'   => false,
			);
			if ( isset( $_wp_additional_image_sizes[ $s ]['width'] ) ) {
				// For theme-added sizes.
				$sizes[ $s ]['width'] = intval( $_wp_additional_image_sizes[ $s ]['width'] );
			} else {
				// For default sizes set in options.
				$sizes[ $s ]['width'] = get_option( "{$s}_size_w" );
			}

			if ( isset( $_wp_additional_image_sizes[ $s ]['height'] ) ) {
				// For theme-added sizes.
				$sizes[ $s ]['height'] = intval( $_wp_additional_image_sizes[ $s ]['height'] );
			} else {
				// For default sizes set in options.
				$sizes[ $s ]['height'] = get_option( "{$s}_size_h" );
			}

			if ( isset( $_wp_additional_image_sizes[ $s ]['crop'] ) ) {
				// For theme-added sizes.
				$sizes[ $s ]['crop'] = $_wp_additional_image_sizes[ $s ]['crop'];
			} else {
				// For default sizes set in options.
				$sizes[ $s ]['crop'] = get_option( "{$s}_crop" );
			}
		}

		self::$sizes = $sizes;

		return $sizes;
	}

	/**
	 * @return array
	 */
	public function filtered_sizes() {
		// Remove filter preventing the creation of advanced sizes.
		remove_filter(
			'intermediate_image_sizes_advanced',
			array( 'Jetpack_Photon', 'filter_photon_noresize_intermediate_sizes' )
		);

		/** This filter is documented in wp-admin/includes/image.php */
		$sizes = apply_filters( 'intermediate_image_sizes_advanced', self::$sizes, $this->data );

		// Re-add the filter removed above.
		add_filter(
			'intermediate_image_sizes_advanced',
			array( 'Jetpack_Photon', 'filter_photon_noresize_intermediate_sizes' )
		);

		return (array) $sizes;
	}

	/**
	 * Standardises and validates the size_data array.
	 *
	 * @param array $size_data Size data array - at least containing height or width key. Can contain crop as well.
	 *
	 * @return array Array with populated width, height and crop keys; empty array if no width and height are provided.
	 */
	public function standardize_size_data( $size_data ) {
		$has_at_least_width_or_height = ( isset( $size_data['width'] ) || isset( $size_data['height'] ) );
		if ( ! $has_at_least_width_or_height ) {
			return array();
		}

		$defaults = array(
			'width'  => null,
			'height' => null,
			'crop'   => false,
		);

		return array_merge( $defaults, $size_data );
	}

	/**
	 * Get sizes for attachment post meta.
	 *
	 * @return array ImageSizes for attachment postmeta.
	 */
	public function generate_sizes_meta() {

		$metadata = array();

		foreach ( $this->filtered_sizes() as $size => $size_data ) {

			$size_data = $this->standardize_size_data( $size_data );

			if ( true === empty( $size_data ) ) {
				continue;
			}

			$resized_image = $this->resize( $size_data );

			if ( true === is_array( $resized_image ) ) {
				$metadata[ $size ] = $resized_image;
			}
		}

		return $metadata;
	}

	/**
	 * @param array $size_data
	 *
	 * @return array|\WP_Error Array for usage in $metadata['sizes']; WP_Error on failure.
	 */
	protected function resize( $size_data ) {

		return $this->image->get_size( $size_data );

	}
}