<?php
/**
 * AMP carousel component use to handle gallery
 *
 * Class Amp_WP_Carousel_Component
 *
 * @since 1.0.0
 */
class Amp_WP_Carousel_Component extends Amp_WP_Component_Base implements Amp_WP_Component_Interface {

    /**
     * Just Implement contact
     *
     *
     * @since 1.0.0
     *
     * @param Amp_WP_Html_Util $instance
     *
     * @return Amp_WP_Html_Util
     */
    public function transform( Amp_WP_Html_Util $instance ) {
        return $instance;
    }

    /**
     * Register shortcode to display galleries as carousel on amp version
     *
     * @since 1.0.0
     *
     * @return array
     */
    public function config() {
        return array(
            'shortcodes' => array(
                'gallery' => array( $this, 'handle_gallery' ),
                'amp-wp-slider' => array( $this, 'handle_slider' ),
            ),
            'scripts' => array(
                'amp-carousel' => 'https://cdn.ampproject.org/v0/amp-carousel-0.1.js'
            )
        );
    }

    /**
     * Gallery shortcode handler
     *
     * @param array $attr
     *
     * @since 1.0.0
     *
     * @return string
     */
    public function handle_gallery( $attr ) {
        global $post;
        if( !empty( $attr['ids'] ) ) {
            
            // 'ids' is explicitly ordered, unless you specify otherwise.
            if ( empty( $attr['orderby'] ) ) {
                $attr['orderby'] = 'post__in';
            }
            $attr['include'] = $attr['ids'];
        }
        $atts = shortcode_atts( array(
                'order'   => 'ASC',
                'orderby' => 'menu_order ID',
                'id'      => $post ? $post->ID : 0,
                'size'    => 'thumbnail',
                'include' => '',
                'exclude' => '',
                'link'    => '',
        ), $attr, 'gallery' );
        return $this->gallery_attachments( $atts );
    }


    /**
     * Slider shortcode handler
     *
     * @param array $attr
     *
     * @since 1.0.0
     *
     * @return string
     */
    public function handle_slider( $attr ) {
        $atts = shortcode_atts(
            array(
                'posts' => '',
            ),
            $attr,
            'gallery'
        );
        return $this->slider_posts( $atts );
    }


    /**
     * @param array $atts
     *
     * @since 1.0.0
     *
     * @return string
     */
    protected function slider_posts( $atts ) {
        if ( empty( $atts['posts'] ) ) {
            return '';
        }
        query_posts(
            array(
                'post__in' => explode( ',', $atts['posts'] )
            ) 
        );
        $return = $this->locate_template( 'shortcodes/amp-slider.php' );
        wp_reset_query();
        $this->enable_enqueue_scripts = true;
        return $return;
    }


    /**
     * @param array $atts
     *
     * @since 1.0.0
     *
     * @return string
     */
    protected function gallery_attachments( $atts ) {
        $id = intval( $atts['id'] );
        if( !empty( $atts['include'] ) ) {
            $_attachments = get_posts( array(
                'include'        => $atts['include'],
                'post_status'    => 'inherit',
                'post_type'      => 'attachment',
                'post_mime_type' => 'image',
                'order'          => $atts['order'],
                'orderby'        => $atts['orderby']
            ));
            $attachments = array();
            foreach ( $_attachments as $key => $val ) {
                $attachments[ $val->ID ] = $_attachments[ $key ];
            }
        } elseif ( !empty( $atts['exclude'] ) ) {
            $attachments = get_children( array(
                'post_parent'    => $id,
                'exclude'        => $atts['exclude'],
                'post_status'    => 'inherit',
                'post_type'      => 'attachment',
                'post_mime_type' => 'image',
                'order'          => $atts['order'],
                'orderby'        => $atts['orderby']
            ));
        } else {
            $attachments = get_children( array(
                'post_parent'    => $id,
                'post_status'    => 'inherit',
                'post_type'      => 'attachment',
                'post_mime_type' => 'image',
                'order'          => $atts['order'],
                'orderby'        => $atts['orderby']
            ));
        }
        if( empty( $attachments ) ) {
            return '';
        }
        $this->enable_enqueue_scripts = true;
        return $this->locate_template( 'shortcodes/gallery.php', compact( 'attachments' ), true, false );
    }
}
// Register component class
amp_wp_register_component( 'Amp_WP_Carousel_Component' );