<?php
/**
 * Schema.org JSON-LD graph for a page.
 *
 * @package OrbitstemSEO
 */

namespace Orbitstem\SEO\Schema;

use Orbitstem\SEO\Content\TemplateEngine;
use Orbitstem\SEO\Core\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Builds one connected @graph per page: WebSite, Organization or Person,
 * the page itself, its primary image, an Article where configured, and the
 * BreadcrumbList. Nodes refer to each other by @id instead of repeating data.
 */
class Graph {

	const ARTICLE_TYPES = array( 'Article', 'BlogPosting', 'NewsArticle' );

	/**
	 * Settings service.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * SEO fields (rich-result schema per post).
	 *
	 * @var \Orbitstem\SEO\Content\MetaRepository|null
	 */
	private $meta;

	/**
	 * Local business details.
	 *
	 * @var LocalBusiness|null
	 */
	private $local;

	/**
	 * Constructor.
	 *
	 * @param Settings                                   $settings Settings.
	 * @param \Orbitstem\SEO\Content\MetaRepository|null $meta     Meta.
	 * @param LocalBusiness|null                         $local    Local business.
	 */
	public function __construct( Settings $settings, $meta = null, $local = null ) {
		$this->settings = $settings;
		$this->meta     = $meta;
		$this->local    = $local;
	}

	/**
	 * Builds the payload for resolved page data.
	 *
	 * @param array $data  Resolver output.
	 * @param array $trail Breadcrumb trail for the page.
	 * @return array JSON-LD document with @context and @graph.
	 */
	public function build( array $data, array $trail ) {
		$home      = home_url( '/' );
		$site_id   = $home . '#website';
		$publisher = $this->publisher_node( $home );
		$graph     = array();

		$website = array(
			'@type'           => 'WebSite',
			'@id'             => $site_id,
			'url'             => $home,
			'name'            => TemplateEngine::plain( get_bloginfo( 'name' ) ),
			'inLanguage'      => get_bloginfo( 'language' ),
			'publisher'       => array( '@id' => $publisher['@id'] ),
			'potentialAction' => array(
				'@type'       => 'SearchAction',
				'target'      => array(
					'@type'       => 'EntryPoint',
					'urlTemplate' => add_query_arg( 's', '{search_term_string}', $home ),
				),
				'query-input' => 'required name=search_term_string',
			),
		);
		$tagline = TemplateEngine::plain( get_bloginfo( 'description' ) );
		if ( '' !== $tagline ) {
			$website['description'] = $tagline;
		}
		$graph[] = $website;
		$graph[] = $publisher;

		$url = $data['url'];
		if ( '404' === $data['object_type'] || '' === $url ) {
			return $this->document( $graph );
		}

		$page_id = $url . '#webpage';
		$page    = array(
			'@type'      => $this->page_type( $data ),
			'@id'        => $page_id,
			'url'        => $url,
			'name'       => $data['title'],
			'isPartOf'   => array( '@id' => $site_id ),
			'inLanguage' => get_bloginfo( 'language' ),
		);
		if ( '' !== $data['description'] ) {
			$page['description'] = $data['description'];
		}
		if ( 'front' === $data['object_type'] ) {
			$page['about'] = array( '@id' => $publisher['@id'] );
		}

		$post = 'post' === $data['object_type'] || ( 'front' === $data['object_type'] && $data['object_id'] ) ? get_post( $data['object_id'] ) : null;
		if ( $post ) {
			$page['datePublished'] = get_post_time( 'c', true, $post );
			$page['dateModified']  = get_post_modified_time( 'c', true, $post );
		}

		$image_id = '';
		if ( '' !== $data['image'] ) {
			$image_id = $url . '#primaryimage';
			$graph[]  = $this->image_node( $image_id, $data['image'], $post ? (int) get_post_thumbnail_id( $post ) : 0 );

			$page['primaryImageOfPage'] = array( '@id' => $image_id );
		}

		if ( count( $trail ) > 1 ) {
			$page['breadcrumb'] = array( '@id' => $url . '#breadcrumb' );
		}
		$graph[] = $page;

		if ( $post && 'post' === $data['object_type'] && in_array( $data['schema'], self::ARTICLE_TYPES, true ) ) {
			$graph[] = $this->article_node( $post, $data, $url, $page_id, $publisher['@id'], $image_id );
		}
		// A static front page is a page too: its FAQ, video or product schema belongs on the homepage.
		// Password-protected content stays hidden: FAQ answers or video details would give it away.
		if ( $post && in_array( $data['object_type'], array( 'post', 'front' ), true ) && '' === $post->post_password ) {
			foreach ( $this->extra_nodes( $post, $data, $page_id, $publisher['@id'] ) as $node ) {
				$graph[] = $node;
			}
		}
		if ( 'front' === $data['object_type'] && $this->local ) {
			$business = $this->local->node( $publisher['@id'], (string) $this->settings->get( 'knowledge_logo' ) );
			if ( $business ) {
				$graph[] = $business;
			}
		}

		if ( count( $trail ) > 1 ) {
			$graph[] = $this->breadcrumb_node( $url . '#breadcrumb', $trail );
		}

		return $this->document( $graph );
	}

	/**
	 * Rich-result node chosen in the editor, WooCommerce product, and videos
	 * found in the content.
	 *
	 * @param \WP_Post $post         Post.
	 * @param array    $data         Resolver output.
	 * @param string   $page_id      WebPage @id.
	 * @param string   $publisher_id Publisher @id.
	 * @return array<int,array>
	 */
	private function extra_nodes( $post, array $data, $page_id, $publisher_id ) {
		$nodes = array();
		$rich  = $this->meta ? RichTypes::decode( $this->meta->get_post( $post->ID, 'rich_schema' ) ) : null;
		if ( $rich ) {
			$node = RichTypes::node(
				$rich['type'],
				$rich['data'],
				$post,
				$data,
				array(
					'page'      => $page_id,
					'publisher' => $publisher_id,
				)
			);
			if ( $node ) {
				$nodes[] = $node;
			}
		}
		if ( ( ! $rich || 'Product' !== $rich['type'] ) && $this->settings->get( 'woo_schema' ) ) {
			$product = Woo::product_node( $post, $data, $page_id );
			if ( $product ) {
				$nodes[] = $product;
			}
		}
		if ( ( ! $rich || 'VideoObject' !== $rich['type'] ) && $this->settings->get( 'video_schema' ) ) {
			foreach ( RichTypes::detected_videos( $post, $data ) as $video ) {
				$nodes[] = $video;
			}
		}
		return $nodes;
	}

	/**
	 * JSON for a script tag. JSON_HEX_TAG turns "<" and ">" into escapes, so
	 * values can never close the script element.
	 *
	 * @param array $document JSON-LD document.
	 * @return string
	 */
	public static function to_json( array $document ) {
		return (string) wp_json_encode( $document, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_HEX_TAG );
	}

	/**
	 * Wraps nodes in a document.
	 *
	 * @param array $graph Nodes.
	 * @return array
	 */
	private function document( array $graph ) {
		$document = array(
			'@context' => 'https://schema.org',
			'@graph'   => $graph,
		);

		/**
		 * Filters the JSON-LD document before output.
		 *
		 * @param array $document Document with @context and @graph.
		 */
		return apply_filters( 'orbitstem_seo_schema', $document );
	}

	/**
	 * The schema.org type for the page node.
	 *
	 * @param array $data Resolver output.
	 * @return string
	 */
	private function page_type( array $data ) {
		switch ( $data['object_type'] ) {
			case 'search':
				return 'SearchResultsPage';
			case 'author':
				return 'ProfilePage';
			case 'term':
			case 'archive':
			case 'date':
				return 'CollectionPage';
			case 'front':
				return 'CollectionPage' === $data['schema'] ? 'CollectionPage' : 'WebPage';
			default:
				return 'WebPage';
		}
	}

	/**
	 * Organization or Person behind the site.
	 *
	 * @param string $home Home URL.
	 * @return array
	 */
	private function publisher_node( $home ) {
		$name   = (string) $this->settings->get( 'knowledge_name' );
		$name   = '' !== $name ? $name : TemplateEngine::plain( get_bloginfo( 'name' ) );
		$logo   = (string) $this->settings->get( 'knowledge_logo' );
		$same   = (array) $this->settings->get( 'knowledge_same_as' );
		$person = 'person' === $this->settings->get( 'knowledge_type' );

		$node = array(
			'@type' => $person ? 'Person' : 'Organization',
			'@id'   => $home . ( $person ? '#person' : '#organization' ),
			'name'  => $name,
			'url'   => $home,
		);
		if ( '' !== $logo ) {
			$image = array(
				'@type'      => 'ImageObject',
				'@id'        => $home . '#logo',
				'url'        => $logo,
				'contentUrl' => $logo,
			);
			if ( $person ) {
				$node['image'] = $image;
			} else {
				$node['logo']  = $image;
				$node['image'] = array( '@id' => $home . '#logo' );
			}
		}
		if ( $same ) {
			$node['sameAs'] = array_values( $same );
		}
		return $node;
	}

	/**
	 * ImageObject node, with dimensions when the image is a local attachment.
	 *
	 * @param string $id            Node @id.
	 * @param string $url           Image URL.
	 * @param int    $attachment_id Attachment ID or 0.
	 * @return array
	 */
	private function image_node( $id, $url, $attachment_id ) {
		$node = array(
			'@type'      => 'ImageObject',
			'@id'        => $id,
			'url'        => $url,
			'contentUrl' => $url,
		);
		// Size and caption describe the featured image, so they are only added when that is the image used
		// (a separate social image has its own size).
		$size = '';
		if ( $attachment_id ) {
			foreach ( array_merge( array( 'full', 'large' ), get_intermediate_image_sizes() ) as $candidate ) {
				$src = wp_get_attachment_image_src( $attachment_id, $candidate );
				if ( $src && $src[0] === $url ) {
					$size = $candidate;
					break;
				}
			}
		}
		if ( '' !== $size ) {
			$node['width']  = (int) $src[1];
			$node['height'] = (int) $src[2];

			$alt = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );
			if ( is_string( $alt ) && '' !== $alt ) {
				$node['caption'] = TemplateEngine::plain( $alt );
			}
		}
		return $node;
	}

	/**
	 * Article-family node.
	 *
	 * @param \WP_Post $post         Post.
	 * @param array    $data         Resolver output.
	 * @param string   $url          Page URL.
	 * @param string   $page_id      WebPage @id.
	 * @param string   $publisher_id Publisher @id.
	 * @param string   $image_id     Image @id or ''.
	 * @return array
	 */
	private function article_node( $post, array $data, $url, $page_id, $publisher_id, $image_id ) {
		$headline = TemplateEngine::plain( $post->post_title );
		if ( mb_strlen( $headline ) > 110 ) {
			$headline = mb_substr( $headline, 0, 109 ) . "\u{2026}";
		}
		$node = array(
			'@type'            => $data['schema'],
			'@id'              => $url . '#article',
			'isPartOf'         => array( '@id' => $page_id ),
			'mainEntityOfPage' => array( '@id' => $page_id ),
			'headline'         => $headline,
			'datePublished'    => get_post_time( 'c', true, $post ),
			'dateModified'     => get_post_modified_time( 'c', true, $post ),
			'author'           => array(
				'@type' => 'Person',
				'name'  => TemplateEngine::plain( get_the_author_meta( 'display_name', (int) $post->post_author ) ),
				'url'   => get_author_posts_url( (int) $post->post_author ),
			),
			'publisher'        => array( '@id' => $publisher_id ),
			'inLanguage'       => get_bloginfo( 'language' ),
		);
		if ( '' !== $image_id ) {
			$node['image'] = array( '@id' => $image_id );
		}
		if ( '' !== $data['description'] ) {
			$node['description'] = $data['description'];
		}
		return $node;
	}

	/**
	 * BreadcrumbList node. The last item omits "item", as it is the page itself.
	 *
	 * @param string $id    Node @id.
	 * @param array  $trail Trail.
	 * @return array
	 */
	private function breadcrumb_node( $id, array $trail ) {
		$items = array();
		$last  = count( $trail ) - 1;
		foreach ( array_values( $trail ) as $i => $crumb ) {
			$item = array(
				'@type'    => 'ListItem',
				'position' => $i + 1,
				'name'     => $crumb['name'],
			);
			if ( $i !== $last && '' !== $crumb['url'] ) {
				$item['item'] = $crumb['url'];
			}
			$items[] = $item;
		}
		return array(
			'@type'           => 'BreadcrumbList',
			'@id'             => $id,
			'itemListElement' => $items,
		);
	}
}