<?php
/* * *
 * Library for json-ld support
 *
 * @since 1.0.0
 */

class Amp_WP_Json_Ld_Generator {

    /**
     * Configurations
     *
     * @var array
     */
    protected static $config = array(
        'active' => TRUE,
        'media_field_id' => '_featured_embed_code', // AMP WP Media Meta ID
        'logo' => '', // Logo for organization
    );

    /**
     * Store json-LD Generator Callback
     *
     * @var array
     */
    protected static $generators = array();

    /**
     * Global json-ld properties that is need in every data types
     *
     * @var array
     *
     * @since 1.0.0
     */
    protected static $global_params = array(
        '@context' => 'http://schema.org',
    );

    /**
     * Initialize library
     *
     * @since 1.0.0
     */
    public static function init() {

        // Prepare data
        add_action('template_redirect', 'Amp_WP_Json_Ld_Generator::prepare_data');
    }
    
    /**
     * Generate JSON-LD Information
     *
     * @since 1.0.0
     */
    public static function prepare_data() {
        self::$config = apply_filters( 'amp_wp_json_ld_config', self::$config );
        if( empty( self::$config['active'] ) ) {
            return;
        }

        // Organization
        if( !empty( self::$config['logo'] ) ) {
            self::$generators[] = array(
                'type' => 'organization',
                'callback' => array('Amp_WP_Json_Ld_Generator', 'generate_organization_schema'),
            );
        }

        // Homepage
        if( is_home() || is_front_page() ) {
            self::$generators[] = array(
                'type' => 'website',
                'callback' => array('Amp_WP_Json_Ld_Generator', 'generate_website_schema'),
            );
        }

        // Single Items
        if( is_singular() && !is_front_page() ) {
            $type = 'single';
            if( function_exists('is_product') && is_product() ) {
                $type = 'product';
            } else if ( is_page() ) {
                $type = 'page';
            }

            $callback = array('Amp_WP_Json_Ld_Generator', sprintf('generate_%s_schema', $type));

            if( $type != 'single' && !is_callable( $callback ) ) {
                $callback = array('Amp_WP_Json_Ld_Generator', sprintf( 'generate_single_schema', $type ) );
            }

            self::$generators[] = array(
                'type' => 'single',
                'callback' => $callback
            );
        }

        // Print data
        if( !empty( self::$generators ) ) {
            add_action('wp_head', 'Amp_WP_Json_Ld_Generator::print_output');
            add_action('amp_wp_template_head', 'Amp_WP_Json_Ld_Generator::print_output');
        }
    }
    
    /**
     * Generate Organization Schema
     *
     * @since   1.0.0
     * @return  array
     */
    public static function generate_organization_schema() {
        return array(
            "@context" => "http://schema.org/",
            '@type' => 'organization',
            '@id' => '#organization',
            'logo' => array(
                '@type' => 'ImageObject',
                'url' => self::$config['logo'],
            ),
            'url' => get_bloginfo('url'),
            'name' => get_bloginfo('name'),
            'description' => self::esc_text( get_bloginfo( 'description' ) )
        );
    }

    /**
     * callback: Print json-ld output
     *
     * action: wp_head
     *
     * @since 1.0.0
     */
    public static function print_output() {
        foreach( self::$generators as $generator ) {
            if( empty( $generator['type'] ) || empty( $generator['callback'] ) || !is_callable( $generator['callback'] ) ) {
                continue;
            }

            $filter = sprintf('amp_wp_json_ld_%s_', $generator['type']);
            if( !$data = apply_filters( $filter, call_user_func( $generator['callback'] ) ) ) {
                continue;
            }
            echo '<script type="application/ld+json">', wp_json_encode( $data, JSON_PRETTY_PRINT ), '</script>', PHP_EOL;
        }
    }

    /**
     * Get the Post Author
     *
     * @since   1.0.0
     * @return  string
     */
    public static function get_the_author() {
        global $post;

        $display_name = get_the_author_meta('display_name', $post->post_author);
        if( $display_name && $display_name !== get_the_author_meta( 'login', $post->post_author ) ) {
            return $display_name;
        }
        return '';
    }

    /**
     * Escape shortcodes and tags of text
     *
     * @param   string  $text
     * @param   int     $limit
     * @since   1.0.0
     *
     * @return  string  $text
     */
    private static function esc_text($text, $limit = 0) {
        $text = strip_tags($text);
        $text = strip_shortcodes($text);
        $text = str_replace(array("\r", "\n"), '', $text);

        if( $limit ) {
            return self::substr_text($text, $limit);
        } else {
            return $text;
        }
    }

    /**
     * Return a pice of text
     *
     * @param   string  $text
     * @param   int     $length
     * @since   1.0.0
     *
     * @return string $text
     */
    private static function substr_text( $text = '', $length = 110 ) {
        if( empty( $text ) ) {
            return $text;
        }

        return mb_substr($text, 0, $length, 'UTF-8');
    }

    /**
     * Generate Website Schema
     *
     * @since 1.0.0
     * @return array
     */
    public static function generate_website_schema() {

        return array(
            "@context" => "http://schema.org/",
            '@type' => 'WebSite',
            '@id' => '#website',
            'url' => get_bloginfo('url'),
            'name' => get_bloginfo('name'),
            'description' => self::esc_text( get_bloginfo( 'description' ) ),
            'potentialAction' => array(
                '@type' => 'SearchAction',
                'target' => get_search_link() . '{search_term}',
                'query-input' => 'required name=search_term'
            ),
        );
    }

    /**
     * Generate WebPage Schema
     *
     * @since 1.0.0
     * @return array
     */
    public static function generate_page_schema() {
        return self::get_singular_schema('WebPage', array('add_date' => FALSE));
    }

    /**
     * Generate WooCommerce Schema
     *
     * @since 1.0.0
     * @return array
     *
     *
     * @check http://jsonld.com/product/
     */
    public static function generate_product_schema() {

        $product = wc_get_product();
        $schema = self::get_singular_schema( 'Product', FALSE );

        // Change to product to be valid!
        $schema['@type'] = 'Product';
        $schema['name'] = $schema['headline'];
        $schema['brand'] = $schema['publisher'];
        $schema['productionDate'] = $schema['datePublished'];
        unset(
            $schema['headline'], $schema['publisher'], $schema['dateModified'], $schema['datePublished'], $schema['author']
        );

        if ($rating_count = (int) $product->get_rating_count()) {
            $schema['aggregateRating'] = array(
                '@type' => 'AggregateRating',
                'ratingValue' => wc_format_decimal( $product->get_average_rating(), 2 ),
                'reviewCount' => $rating_count,
            );
        }

        $schema['offers'] = array(
            '@type' => 'Offer',
            'priceCurrency' => get_woocommerce_currency(),
            'price' => $product->get_price(),
            'availability' => 'http://schema.org/' . ( $product->is_in_stock() ? 'InStock' : 'OutOfStock' ),
        );

        return $schema;
    }

    /**
     * Generate  Single Post Schema
     *
     * @since 1.0.0
     * @return array
     */
    public static function generate_single_schema() {
        return self::get_singular_schema('BlogPosting');
    }

    /**
     * Get Singular Post Schema
     *
     * @param string $type
     * @param array  $args
     *
     * @since 1.0.0
     *
     * @return array
     */
    public static function get_singular_schema( $type = 'BlogPosting', $args = array() ) {

        global $post;
        if( !isset($args['add_search'] ) ) {
            $args['add_search'] = TRUE;
        }

        if( !isset($args['add_date'] ) ) {
            $args['add_date'] = TRUE;
        }

        if( !isset($args['add_image'] ) ) {
            $args['add_image'] = TRUE;
        }
        $permalink = get_permalink($post->ID);
        $schema = array(
            "@context" => "http://schema.org/",
            '@type' => $type,
            'url' => $permalink,
            'headline' => $post->post_title,
            'publisher' => array(
                '@id' => '#organization',
            ),
            'mainEntityOfPage' => array(
                '@type' => 'WebPage',
                '@id' => $permalink,
            ),
        );

        // Post Excerpt or Content
        if( $post->post_excerpt ) {
            $schema['description'] = $post->post_excerpt;
        } else {
            $schema['description'] = self::esc_text( $post->post_content, 250 );
        }
        
        // Add Date
        if( $args['add_date'] ) {
            $schema['datePublished'] = get_the_date('Y-m-d');
            $schema['dateModified'] = get_post_modified_time('Y-m-d');

            // No need if it was not modified!
            if( $schema['datePublished'] == $schema['dateModified'] ) {
                unset($schema['dateModified']);
            }
        }
        
        // Add Thumbnail
        if( $args['add_image'] ) {
            $featured_image = wp_get_attachment_image_src(get_post_thumbnail_id(), 'full');
            if( !empty( $featured_image[0] ) ) {
                $schema['image'] = array(
                    '@type' => 'ImageObject',
                    'url' => $featured_image[0],
                );

                // Add width and height
                if( !empty($featured_image[1] ) && !empty( $featured_image[2] ) ) {
                    $schema['image']['width'] = $featured_image[1];
                    $schema['image']['height'] = $featured_image[2];
                }
            }
        }
        
        // Author
        if( $author = self::get_the_author() ) {
            $schema['author'] = array(
                '@type' => 'Person',
                '@id' => '#person-' . $author,
                'name' => $author,
            );
            $author = sanitize_html_class( $author );
            $schema['author']['@id'] = '#person-' . $author;
        }
        
        // Change type to advanced format
        if( 'post' === $post->post_type ) {
            $format = get_post_format();
            switch( $format ) {
                // Audio type
                case 'audio':
                    $schema['@type'] = 'AudioObject';

                    // Add Media
                    if( $media = get_post_meta( $post->ID, self::$config['media_field_id'], TRUE ) ) {
                        $schema['contentUrl'] = $media;
                    }
                break;
                
                // Video type
                case 'video':
                    $schema['@type'] = 'VideoObject';
                    // Add Media
                    if( $media = get_post_meta( $post->ID, self::$config['media_field_id'], TRUE) ) {
                        $schema['contentUrl'] = $media;
                    }
                    
                    // Change to product to be valid!
                    $schema['name'] = $schema['headline'];
                    $schema['thumbnailUrl'] = $schema['image'] ? $schema['image']['url'] : '';
                    $schema['uploadDate'] = $schema['datePublished'];
                    unset(
                        $schema['headline'], $schema['datePublished'], $schema['image']
                    );
                break;

                // Image & Gallery type
                case 'image':
                case 'gallery':
                    $schema['@type'] = 'ImageObject';
                    break;
            }
        } // Image attachment
        elseif ('attachment' === $post->post_type && wp_attachment_is_image()) {
            $schema['@type'] = 'ImageObject';
        } // Audio attachment
        elseif ('attachment' === $post->post_type && wp_attachment_is('audio')) {
            $schema['@type'] = 'AudioObject';
            $schema['contentUrl'] = wp_get_attachment_url();
        } // Video attachment
        elseif ('attachment' === $post->post_type && wp_attachment_is('video')) {
            $schema['@type'] = 'VideoObject';
            $schema['contentUrl'] = wp_get_attachment_url();
        }
        
        // Comments Count
        if( $post->post_type != 'product' && $post->post_type != 'WebPage' && post_type_supports($post->post_type, 'comments' ) ) {
            $schema['interactionStatistic'][] = array(
                '@type' => 'InteractionCounter',
                'interactionType' => 'http://schema.org/CommentAction',
                'userInteractionCount' => get_comments_number($post),
            );
        }
        
        // Add Search for Pages
        if( $type === 'WebPage' ) {
            $search_link = get_search_link();
            if( !strstr( $search_link, '?' ) ) {
                $search_link = trailingslashit( $search_link );
            }

            $schema['potentialAction']['comments'] = array(
                '@type' => 'SearchAction',
                'target' => $search_link . '{search_term}',
                'query-input' => 'required name=search_term'
            );
        }

        return array_filter($schema);
    }
}
Amp_WP_Json_Ld_Generator::init();