<?php
/**
 * FAQ query builder.
 *
 * @package AccordionFaq
 */

namespace AccordionFaq\Frontend;

defined( 'ABSPATH' ) || exit;

use AccordionFaq\Setup\PostType;
use AccordionFaq\Setup\Taxonomy;
use AccordionFaq\Setup\Meta;

/**
 * Class Query
 */
class Query {

	/**
	 * Build and run a WP_Query for FAQs from normalized args.
	 *
	 * @param array $args Normalized render args (see Renderer::normalize()).
	 * @return \WP_Query
	 */
	public function run( array $args ) {
		$query_args = array(
			'post_type'           => PostType::POST_TYPE,
			'post_status'         => 'publish',
			'posts_per_page'      => (int) $args['limit'],
			'ignore_sticky_posts' => true,
			'no_found_rows'       => true,
		);

		// Ordering.
		switch ( $args['orderby'] ) {
			case 'title':
				$query_args['orderby'] = 'title';
				break;
			case 'order':
				// Include posts with and without the order meta; treat missing as 0.
				$query_args['orderby']    = 'meta_value_num';
				$query_args['meta_key']   = Meta::META_ORDER; // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
				$query_args['meta_query']  = array( // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
					'relation' => 'OR',
					array(
						'key'     => Meta::META_ORDER,
						'compare' => 'EXISTS',
					),
					array(
						'key'     => Meta::META_ORDER,
						'compare' => 'NOT EXISTS',
					),
				);
				break;
			case 'date':
			default:
				$query_args['orderby'] = 'date';
				break;
		}

		$query_args['order'] = ( 'DESC' === $args['order'] ) ? 'DESC' : 'ASC';

		// Explicit post IDs win over taxonomy filters.
		if ( ! empty( $args['ids'] ) ) {
			$query_args['post__in'] = array_map( 'absint', $args['ids'] );
			$query_args['orderby']  = 'post__in';
		} else {
			$tax_query = $this->build_tax_query( $args );
			if ( ! empty( $tax_query ) ) {
				$query_args['tax_query'] = $tax_query; // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_tax_query
			}
		}

		/**
		 * Filter the WP_Query arguments used to fetch FAQs.
		 *
		 * @param array $query_args WP_Query args.
		 * @param array $args       Normalized render args.
		 */
		$query_args = apply_filters( 'accordion_faq_query_args', $query_args, $args );

		return new \WP_Query( $query_args );
	}

	/**
	 * Build the tax_query from term IDs and/or category slugs.
	 *
	 * @param array $args Normalized render args.
	 * @return array
	 */
	private function build_tax_query( array $args ) {
		$clauses = array();

		if ( ! empty( $args['term'] ) ) {
			$clauses[] = array(
				'taxonomy' => Taxonomy::TAXONOMY,
				'field'    => 'term_id',
				'terms'    => array_map( 'absint', (array) $args['term'] ),
			);
		}

		if ( ! empty( $args['category'] ) ) {
			$clauses[] = array(
				'taxonomy' => Taxonomy::TAXONOMY,
				'field'    => 'slug',
				'terms'    => (array) $args['category'],
			);
		}

		if ( count( $clauses ) > 1 ) {
			$clauses['relation'] = 'OR';
		}

		return $clauses;
	}
}