<?php
/**
 * Post Page Metadata Builder class
 *
 * @package Parsely
 * @since 3.4.0
 */

declare(strict_types=1);

namespace Parsely\Metadata;

use Parsely\Parsely;
use WP_Post;
use WP_User;

/**
 * Implements abstract Metadata Builder class to generate the metadata array
 * for a post page.
 *
 * @since 3.4.0
 */
class Post_Builder extends Metadata_Builder {
	/**
	 * Post object to generate the metadata for.
	 *
	 * @var WP_Post
	 */
	private $post;

	/**
	 * Constructor.
	 *
	 * @param Parsely $parsely Instance of Parsely class.
	 * @param WP_Post $post Post object to generate the metadata for.
	 */
	public function __construct( Parsely $parsely, WP_Post $post ) {
		parent::__construct( $parsely );
		$this->post = $post;
	}

	/**
	 * Generates the metadata object by calling the build_* methods and
	 * returns the value.
	 *
	 * @since 3.4.0
	 *
	 * @return array<string, mixed>
	 */
	public function get_metadata(): array {
		$this->build_basic();
		$this->build_headline();
		$this->build_url();

		$this->build_type();
		$this->build_main_entity();
		$this->build_thumbnail_url();
		$this->build_image();
		$this->build_article_section();
		$this->build_author();
		$this->build_publisher();
		$this->build_keywords();
		$this->build_metadata_post_times();

		return $this->metadata;
	}

	/**
	 * Populates the `headline` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_headline(): void {
		$this->metadata['headline'] = $this->clean_value( get_the_title( $this->post ) );
	}

	/**
	 * Populates the `url` field in the metadata object by getting the current page's URL.
	 *
	 * @since 3.4.0
	 */
	protected function build_url(): void {
		$this->metadata['url'] = $this->get_current_url( 'post', $this->post->ID );
	}

	/**
	 * Populates the `@type` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_type(): void {
		/**
		 * Filters the JSON-LD @type.
		 *
		 * @param array $jsonld_type JSON-LD @type value, default is NewsArticle.
		 * @param int $id Post ID.
		 * @param string $post_type The Post type in WordPress.
		 *
		 * @since 2.5.0
		 */
		$type = (string) apply_filters( 'wp_parsely_post_type', 'NewsArticle', $this->post->ID, $this->post->post_type );

		// TODO: Merge only once, not every execution.
		$supported_types = array_merge( Parsely::SUPPORTED_JSONLD_POST_TYPES, Parsely::SUPPORTED_JSONLD_NON_POST_TYPES );

		// Validate type before passing it further as an invalid type will not be recognized by Parse.ly.
		if ( ! in_array( $type, $supported_types, true ) ) {
			$error = sprintf(
			/* translators: 1: JSON @type like NewsArticle, 2: URL */
				__( '@type %1$s is not supported by Parse.ly. Please use a type mentioned in %2$s', 'wp-parsely' ),
				$type,
				'https://www.parse.ly/help/integration/jsonld#distinguishing-between-posts-and-pages'
			);
			// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
			trigger_error( esc_html( $error ), E_USER_WARNING );
			$type = 'NewsArticle';
		}

		$this->metadata['@type'] = $type;
	}

	/**
	 * Populates the `mainEntityOfPage` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_main_entity(): void {
		$this->metadata['mainEntityOfPage'] = array(
			'@type' => 'WebPage',
			'@id'   => $this->get_current_url( 'post' ),
		);
	}

	/**
	 * Populates the `thumbnailUrl` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_thumbnail_url(): void {
		$thumb_url = get_the_post_thumbnail_url( $this->post, 'thumbnail' );
		if ( ! is_string( $thumb_url ) ) {
			$thumb_url = '';
		}
		$this->metadata['thumbnailUrl'] = $thumb_url;
	}

	/**
	 * Populates the `image` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_image(): void {
		$image_url = get_the_post_thumbnail_url( $this->post, 'full' );
		if ( ! is_string( $image_url ) ) {
			$image_url = '';
		}
		$this->metadata['image'] = array(
			'@type' => 'ImageObject',
			'url'   => $image_url,
		);
	}

	/**
	 * Populates the `articleSection` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_article_section(): void {
		$this->metadata['articleSection'] = $this->get_category_name( $this->post, $this->parsely->get_options() );
	}

	/**
	 * Populates the `author` and `creator` fields in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_author(): void {
		$authors        = $this->get_author_names( $this->post );
		$author_objects = array();
		foreach ( $authors as $author ) {
			$author_tag       = array(
				'@type' => 'Person',
				'name'  => $author,
			);
			$author_objects[] = $author_tag;
		}
		$this->metadata['author']  = $author_objects;
		$this->metadata['creator'] = $authors;
	}

	/**
	 * Populates the `publisher` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_publisher(): void {
		$this->metadata['publisher'] = array(
			'@type' => 'Organization',
			'name'  => get_bloginfo( 'name' ),
			'logo'  => $this->parsely->get_options()['logo'],
		);
	}

	/**
	 * Populates the `keywords` field in the metadata object.
	 *
	 * @since 3.4.0
	 */
	private function build_keywords(): void {
		$options = $this->parsely->get_options();
		$tags    = $this->get_tags( $this->post->ID );
		if ( $options['cats_as_tags'] ) {
			$tags = array_merge( $tags, $this->get_categories( $this->post->ID ) );
			// add custom taxonomy values.
			$tags = array_merge( $tags, $this->get_custom_taxonomy_values( $this->post ) );
		}
		// The function 'mb_strtolower' is not enabled by default in php, so this check
		// falls back to the native php function 'strtolower' if necessary.
		if ( function_exists( 'mb_strtolower' ) ) {
			$lowercase_callback = 'mb_strtolower';
		} else {
			$lowercase_callback = 'strtolower';
		}
		if ( $options['lowercase_tags'] ) {
			$tags = array_map( $lowercase_callback, $tags );
		}

		/**
		 * Filters the post tags that are used as metadata keywords.
		 *
		 * @param array<string> $tags Post tags.
		 * @param int $ID Post ID.
		 *
		 * @since 1.8.0
		 */
		$tags = apply_filters( 'wp_parsely_post_tags', $tags, $this->post->ID );
		$tags = array_map( array( $this, 'clean_value' ), $tags );

		$this->metadata['keywords'] = array_values( array_unique( $tags ) );
	}

	/**
	 * Sets all metadata values related to post time.
	 *
	 * @since 3.0.2
	 * @since 3.3.0 Moved to class-metadata
	 */
	private function build_metadata_post_times(): void {
		$date_format      = 'Y-m-d\TH:i:s\Z';
		$post_created_gmt = get_post_time( $date_format, true, $this->post );

		if ( false === $post_created_gmt ) {
			return;
		}

		$this->metadata['dateCreated']   = $post_created_gmt;
		$this->metadata['datePublished'] = $post_created_gmt;
		$this->metadata['dateModified']  = $post_created_gmt;

		$post_modified_gmt = get_post_modified_time( $date_format, true, $this->post );

		if ( false !== $post_modified_gmt && $post_modified_gmt > $post_created_gmt ) {
			$this->metadata['dateModified'] = $post_modified_gmt;
		}
	}

	/**
	 * Returns a properly cleaned category/taxonomy value and will optionally
	 * use the top-level category/taxonomy value, if so instructed via the
	 * `use_top_level_cats` option.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param WP_Post              $post_obj The object for the post.
	 * @param array<string, mixed> $parsely_options The parsely options.
	 * @return string Cleaned category name for the post in question.
	 */
	private function get_category_name( WP_Post $post_obj, array $parsely_options ): string {
		$taxonomy_dropdown_choice = get_the_terms( $post_obj->ID, $parsely_options['custom_taxonomy_section'] );
		// Get top-level taxonomy name for chosen taxonomy and assign to $parent_name; it will be used
		// as the category value if 'use_top_level_cats' option is checked.
		// Assign as the default category name if no value is checked for the chosen taxonomy.
		$category_name = get_cat_name( get_option( 'default_category' ) );
		if ( ! empty( $taxonomy_dropdown_choice ) && ! is_wp_error( $taxonomy_dropdown_choice ) ) {
			if ( $parsely_options['use_top_level_cats'] ) {
				$first_term = array_shift( $taxonomy_dropdown_choice );
				$term_name  = $this->get_top_level_term( $first_term->term_id, $first_term->taxonomy );
			} else {
				$term_name = $this->get_bottom_level_term( $post_obj->ID, $parsely_options['custom_taxonomy_section'] );
			}

			if ( is_string( $term_name ) && 0 < strlen( $term_name ) ) {
				$category_name = $term_name;
			}
		}

		/**
		 * Filters the constructed category name.
		 *
		 * @since 1.8.0
		 *
		 * @param string  $category    Category name.
		 * @param WP_Post $post_obj    Post object.
		 * @param array<string, mixed> $parsely_options The Parsely options.
		 */
		$category_name = apply_filters( 'wp_parsely_post_category', $category_name, $post_obj, $parsely_options );

		return $this->clean_value( $category_name );
	}

	/**
	 * Returns the top-most category/taxonomy value in a hierarchy given a
	 * taxonomy value's ID.
	 *
	 * (WordPress calls taxonomy values 'terms').
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param int    $term_id       The ID of the top level term.
	 * @param string $taxonomy_name The name of the taxonomy.
	 * @return string|false $parent The top level name of the category / taxonomy.
	 */
	private function get_top_level_term( int $term_id, string $taxonomy_name ) {
		$parent = get_term_by( 'id', $term_id, $taxonomy_name );
		while ( false !== $parent && 0 !== $parent->parent ) {
			$parent = get_term_by( 'id', $parent->parent, $taxonomy_name );
		}
		return $parent ? $parent->name : false;
	}

	/**
	 * Returns the bottom-most category/taxonomy value in a hierarchy given a
	 * post ID.
	 *
	 * (WordPress calls taxonomy values 'terms').
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param int    $post_id       The post id you're interested in.
	 * @param string $taxonomy_name The name of the taxonomy.
	 * @return string Name of the custom taxonomy.
	 */
	private function get_bottom_level_term( int $post_id, string $taxonomy_name ): string {
		$terms = get_the_terms( $post_id, $taxonomy_name );

		if ( ! is_array( $terms ) ) {
			return '';
		}

		$term_ids = wp_list_pluck( $terms, 'term_id' );
		$parents  = array_filter( wp_list_pluck( $terms, 'parent' ) );

		// Get array of IDs of terms which are not parents.
		$term_ids_not_parents = array_diff( $term_ids, $parents );
		// Get corresponding term objects, which are mapped to array index keys.
		$terms_not_parents = array_intersect_key( $terms, $term_ids_not_parents );
		// remove array index keys.
		$terms_not_parents_cleaned = array_values( $terms_not_parents );

		if ( ! empty( $terms_not_parents_cleaned ) ) {
			// If you assign multiple child terms in a custom taxonomy, will only return the first.
			return $terms_not_parents_cleaned[0]->name ?? '';
		}

		return '';
	}

	/**
	 * Retrieves all the authors for a post as an array. Can include multiple
	 * authors if the Co-Authors Plus plugin is in use.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param WP_Post $post The post object.
	 * @return array<string>
	 */
	private function get_author_names( WP_Post $post ): array {
		$authors = $this->get_coauthor_names( $post->ID );
		if ( 0 === count( $authors ) ) {
			$post_author = get_user_by( 'id', $post->post_author );
			if ( false !== $post_author ) {
				$authors = array( $post_author );
			}
		}

		/**
		 * Filters the list of author WP_User objects for a post.
		 *
		 * @since 1.14.0
		 *
		 * @param array<WP_User> $authors One or more authors as WP_User objects.
		 * @param WP_Post        $post    Post object.
		 */
		$authors = apply_filters( 'wp_parsely_pre_authors', $authors, $post );

		// Getting the author name for each author.
		$authors = array_map( array( $this, 'get_author_name' ), $authors );

		/**
		 * Filters the list of author names for a post.
		 *
		 * @since 1.14.0
		 *
		 * @param array<string> $authors One or more author names.
		 * @param WP_Post       $post    Post object.
		 */
		$authors = apply_filters( 'wp_parsely_post_authors', $authors, $post );

		return array_map( array( $this, 'clean_value' ), $authors );
	}

	/**
	 * Returns a list of coauthors for a post assuming the Co-Authors Plus plugin
	 * is installed.
	 *
	 * Borrowed from
	 * https://github.com/Automattic/Co-Authors-Plus/blob/master/template-tags.php#L3-35
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param int $post_id The ID of the post.
	 * @return array<WP_User> List of coauthors, or an empty array if the Co-Authors Plus plugin is not active.
	 */
	private function get_coauthor_names( int $post_id ): array {
		$coauthors = array();
		if ( class_exists( 'coauthors_plus' ) ) {
			global $post, $post_ID, $coauthors_plus;

			if ( ! $post_id && $post_ID ) {
				$post_id = $post_ID;
			}

			if ( ! $post_id && $post ) {
				$post_id = $post->ID;
			}

			if ( $post_id ) {
				$coauthor_terms = get_the_terms( $post_id, $coauthors_plus->coauthor_taxonomy );

				if ( is_array( $coauthor_terms ) ) {
					foreach ( $coauthor_terms as $coauthor ) {
						$coauthor_slug = preg_replace( '#^cap-#', '', $coauthor->slug );
						$post_author   = $coauthors_plus->get_coauthor_by( 'user_nicename', $coauthor_slug );
						// In case the user has been deleted while plugin was deactivated.
						if ( ! empty( $post_author ) ) {
							$coauthors[] = new WP_User( $post_author );
						}
					}
				} elseif ( ! $coauthors_plus->force_guest_authors ) {
					if ( $post && $post_id === $post->ID ) {
						$post_author = get_userdata( $post->post_author );
					}
					if ( ! empty( $post_author ) ) {
						$coauthors[] = $post_author;
					}
				}
				// The empty else case is because if we force guest authors, we don't ever care what value wp_posts.post_author has.
			}
		}
		return $coauthors;
	}

	/**
	 * Determines author name from display name, falling back to firstname
	 * lastname, then nickname and finally the nicename.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param ?WP_User $author The author of the post.
	 * @return string An author name.
	 */
	private function get_author_name( ?WP_User $author ): string {
		// Gracefully handle situation where no author is available.
		if ( null === $author ) {
			return '';
		}

		if ( ! empty( $author->display_name ) ) {
			return $author->display_name;
		}

		$author_name = $author->user_firstname . ' ' . $author->user_lastname;
		if ( ' ' !== $author_name ) {
			return $author_name;
		}

		if ( ! empty( $author->nickname ) ) {
			return $author->nickname;
		}

		if ( ! empty( $author->user_nicename ) ) {
			return $author->user_nicename;
		}

		return '';
	}

	/**
	 * Returns the tags associated with this page or post.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param int $post_id   The ID of the post you're trying to get tags for.
	 * @return array<string> The tags of the post represented by the post id.
	 */
	private function get_tags( int $post_id ): array {
		$tags      = array();
		$post_tags = wp_get_post_tags( $post_id );
		if ( ! is_wp_error( $post_tags ) ) {
			foreach ( $post_tags as $wp_tag ) {
				$tags[] = $wp_tag->name;
			}
		}
		return $tags;
	}

	/**
	 * Returns an array of all the child categories for the current post.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 *
	 * @param int    $post_id   The ID of the post you're trying to get categories for.
	 * @param string $delimiter What character will delimit the categories.
	 * @return array<string> All the child categories of the current post.
	 */
	private function get_categories( int $post_id, string $delimiter = '/' ): array {
		$tags = array();
		foreach ( get_the_category( $post_id ) as $category ) {
			$hierarchy = get_category_parents( $category->term_id, false, $delimiter );
			if ( ! is_wp_error( $hierarchy ) ) {
				$tags[] = rtrim( $hierarchy, '/' );
			}
		}
		// Take last element in the hierarchy, a string representing the full parent->child tree,
		// and split it into individual category names.
		$last_tag = end( $tags );
		if ( false !== $last_tag ) {
			$tags = explode( '/', $last_tag );
		}

		// Remove default category name from tags if needed.
		$default_category_name = get_cat_name( get_option( 'default_category' ) );
		return array_diff( $tags, array( $default_category_name ) );
	}

	/**
	 * Gets all term names from all custom taxonomies assigned to a post.
	 *
	 * @since 3.3.0 Moved to class-metadata
	 * @since 3.4.0 Moved to class-post-builder
	 *
	 * @param WP_Post $post_obj The post object to find the terms for.
	 * @return array<string> Term names.
	 */
	private function get_custom_taxonomy_values( WP_Post $post_obj ): array {
		// Filter out default WordPress taxonomies.
		$all_taxonomies = array_diff( get_taxonomies(), array( 'post_tag', 'nav_menu', 'author', 'link_category', 'post_format' ) );
		$all_values     = array();

		foreach ( $all_taxonomies as $taxonomy ) {
			$custom_taxonomy_objects = get_the_terms( $post_obj->ID, $taxonomy );
			if ( is_array( $custom_taxonomy_objects ) ) {
				foreach ( $custom_taxonomy_objects as $custom_taxonomy_object ) {
					$all_values[] = $custom_taxonomy_object->name;
				}
			}
		}

		return $all_values;
	}
}