<?php

namespace Yoast\WP\SEO\Helpers;

use WP_Taxonomy;
use WP_Term;
use WPSEO_Taxonomy_Meta;

/**
 * A helper object for terms.
 */
class Taxonomy_Helper {

	/**
	 * The options helper.
	 *
	 * @var Options_Helper
	 */
	private $options;

	/**
	 * The string helper.
	 *
	 * @var String_Helper
	 */
	private $string;

	/**
	 * Taxonomy_Helper constructor.
	 *
	 * @codeCoverageIgnore It only sets dependencies.
	 *
	 * @param Options_Helper $options       The options helper.
	 * @param String_Helper  $string_helper The string helper.
	 */
	public function __construct( Options_Helper $options, String_Helper $string_helper ) {
		$this->options = $options;
		$this->string  = $string_helper;
	}

	/**
	 * Checks if the requested term is indexable.
	 *
	 * @param string $taxonomy The taxonomy slug.
	 *
	 * @return bool True when taxonomy is set to index.
	 */
	public function is_indexable( $taxonomy ) {
		return ! $this->options->get( 'noindex-tax-' . $taxonomy, false );
	}

	/**
	 * Returns an array with the public taxonomies.
	 *
	 * @param string $output The output type to use.
	 *
	 * @return string[]|WP_Taxonomy[] Array with all the public taxonomies.
	 *                                The type depends on the specified output variable.
	 */
	public function get_public_taxonomies( $output = 'names' ) {
		return \get_taxonomies( [ 'public' => true ], $output );
	}

	/**
	 * Retrieves the term description (without tags).
	 *
	 * @param int $term_id Term ID.
	 *
	 * @return string Term description (without tags).
	 */
	public function get_term_description( $term_id ) {
		return $this->string->strip_all_tags( \term_description( $term_id ) );
	}

	/**
	 * Retrieves the taxonomy term's meta values.
	 *
	 * @codeCoverageIgnore We have to write test when this method contains own code.
	 *
	 * @param WP_Term $term Term to get the meta value for.
	 *
	 * @return array|bool Array of all the meta data for the term.
	 *                    False if the term does not exist or the $meta provided is invalid.
	 */
	public function get_term_meta( $term ) {
		return WPSEO_Taxonomy_Meta::get_term_meta( $term, $term->taxonomy, null );
	}

	/**
	 * Gets the passed taxonomy's slug.
	 *
	 * @param string $taxonomy The name of the taxonomy.
	 *
	 * @return string The slug for the taxonomy. Returns the taxonomy's name if no slug could be found.
	 */
	public function get_taxonomy_slug( $taxonomy ) {
		$taxonomy_object = \get_taxonomy( $taxonomy );

		if ( $taxonomy_object && \property_exists( $taxonomy_object, 'rewrite' ) && \is_array( $taxonomy_object->rewrite ) && isset( $taxonomy_object->rewrite['slug'] ) ) {
			return $taxonomy_object->rewrite['slug'];
		}

		return \strtolower( $taxonomy_object->name );
	}

	/**
	 * Returns an array with the custom taxonomies.
	 *
	 * @param string $output The output type to use.
	 *
	 * @return string[]|WP_Taxonomy[] Array with all the custom taxonomies.
	 *                                The type depends on the specified output variable.
	 */
	public function get_custom_taxonomies( $output = 'names' ) {
		return \get_taxonomies( [ '_builtin' => false ], $output );
	}

	/**
	 * Returns an array of taxonomies that are excluded from being indexed for the
	 * indexables.
	 *
	 * @return array The excluded taxonomies.
	 */
	public function get_excluded_taxonomies_for_indexables() {
		/**
		 * Filter: 'wpseo_indexable_excluded_taxonomies' - Allow developers to prevent a certain taxonomy
		 * from being saved to the indexable table.
		 *
		 * @param array $excluded_taxonomies The currently excluded taxonomies.
		 */
		$excluded_taxonomies = \apply_filters( 'wpseo_indexable_excluded_taxonomies', [] );

		// Failsafe, to always make sure that `excluded_taxonomies` is an array.
		if ( ! \is_array( $excluded_taxonomies ) ) {
			return [];
		}

		return $excluded_taxonomies;
	}

	/**
	 * Checks if the taxonomy is excluded.
	 *
	 * @param string $taxonomy The taxonomy to check.
	 *
	 * @return bool If the taxonomy is excluded.
	 */
	public function is_excluded( $taxonomy ) {
		return \in_array( $taxonomy, $this->get_excluded_taxonomies_for_indexables(), true );
	}

	/**
	 * This builds a list of indexable taxonomies.
	 *
	 * @return array The indexable taxonomies.
	 */
	public function get_indexable_taxonomies() {
		$public_taxonomies   = $this->get_public_taxonomies();
		$excluded_taxonomies = $this->get_excluded_taxonomies_for_indexables();

		// `array_values`, to make sure that the keys are reset.
		return \array_values( \array_diff( $public_taxonomies, $excluded_taxonomies ) );
	}

	/**
	 * Returns an array of complete taxonomy objects for all indexable taxonomies.
	 *
	 * @return array List of indexable indexables objects.
	 */
	public function get_indexable_taxonomy_objects() {
		$taxonomy_objects     = [];
		$indexable_taxonomies = $this->get_indexable_taxonomies();
		foreach ( $indexable_taxonomies as $taxonomy ) {
			$taxonomy_object = \get_taxonomy( $taxonomy );
			if ( ! empty( $taxonomy_object ) ) {
				$taxonomy_objects[ $taxonomy ] = $taxonomy_object;
			}
		}

		return $taxonomy_objects;
	}
}