<?php
/**
 * Article, BlogPosting and NewsArticle.
 *
 * @package ElevenRank
 * @since   1.0.0
 */

namespace ElevenRank\Modules\Schema;

use WP_Post;

defined( 'ABSPATH' ) || exit;

/**
 * Taken from the post: headline, dates, author, publisher, image and word count.
 *
 * @since 1.0.0
 */
final class Article_Node extends Content_Node {

	/**
	 * Longest headline Google shows.
	 *
	 * @since 1.0.0
	 *
	 * @var int
	 */
	const HEADLINE_LENGTH = 110;

	/**
	 * Builds the node.
	 *
	 * @since 1.0.0
	 *
	 * @param string               $type   Article, BlogPosting or NewsArticle.
	 * @param array<string, mixed> $fields Field values.
	 * @param WP_Post              $post   The post.
	 * @param Node_Context         $c      Page information.
	 * @param Graph                $graph  The graph.
	 * @return array<string, mixed>|null
	 */
	public function build( string $type, array $fields, WP_Post $post, Node_Context $c, Graph $graph ): ?array {
		$headline = $this->text( $fields, 'headline', $this->title( $post ) );

		if ( '' === $headline ) {
			return null;
		}

		if ( mb_strlen( $headline ) > self::HEADLINE_LENGTH ) {
			$headline = rtrim( mb_substr( $headline, 0, self::HEADLINE_LENGTH - 1 ) ) . '…';
		}

		return array(
			'@type'            => $type,
			'@id'              => $c->id( 'article' ),
			'isPartOf'         => array( '@id' => $c->id( 'webpage' ) ),
			'mainEntityOfPage' => array( '@id' => $c->id( 'webpage' ) ),
			'headline'         => $headline,
			'description'      => $this->text( $fields, 'description', $this->description( $post, $c ) ),
			'datePublished'    => get_post_time( 'c', false, $post ),
			'dateModified'     => get_post_modified_time( 'c', false, $post ),
			'author'           => $this->author( $post, $graph ),
			'publisher'        => array( '@id' => $c->entity_id() ),
			'image'            => $graph->has( $c->id( 'primaryimage' ) ) ? array( '@id' => $c->id( 'primaryimage' ) ) : null,
			'wordCount'        => $this->word_count( $post ),
			'articleSection'   => $this->text( $fields, 'section', $this->first_category( $post ) ),
			'inLanguage'       => get_bloginfo( 'language' ),
		);
	}

	/**
	 * Number of words in the post's text.
	 *
	 * @since 1.0.0
	 *
	 * @param WP_Post $post Post.
	 * @return int
	 */
	private function word_count( WP_Post $post ): int {
		$text = trim( wp_strip_all_tags( strip_shortcodes( $post->post_content ) ) );

		$words = '' === $text ? false : preg_split( '/\s+/u', $text );

		return is_array( $words ) ? count( $words ) : 0;
	}

	/**
	 * Name of the first category of a post.
	 *
	 * @since 1.0.0
	 *
	 * @param WP_Post $post Post.
	 * @return string
	 */
	private function first_category( WP_Post $post ): string {
		if ( ! is_object_in_taxonomy( $post->post_type, 'category' ) ) {
			return '';
		}

		$terms = get_the_terms( $post, 'category' );

		return is_array( $terms ) && $terms ? html_entity_decode( (string) $terms[0]->name, ENT_QUOTES, 'UTF-8' ) : '';
	}
}