<?php
/** Explicit public query connections. @package ThreeTaskPostOrder */
namespace ThreeTask\PostOrder;

use WP_Query;
use WP_REST_Request;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Query {
	/**
	 * Public contexts read in this request.
	 *
	 * @var array<int,array<string,mixed>|null>
	 */
	private static $seen = array();

	/**
	 * Archive context IDs found in this request.
	 *
	 * @var array<string,int>
	 */
	private static $archives = array();
	public static function init(): void {
		add_action( 'threepo_order_changed', array( self::class, 'forget' ), 0 );

		add_action( 'pre_get_posts', array( self::class, 'prepare' ) );

		add_filter( 'posts_clauses', array( self::class, 'clauses' ), 20, 2 );

		add_filter( 'query_loop_block_query_vars', array( self::class, 'block' ), 20, 2 );

		add_filter( 'terms_clauses', array( self::class, 'terms' ), 20, 3 );

		add_action( 'init', array( self::class, 'rest_hooks' ), 30 );
	}

	/**
	 * @return array<string,mixed>|null
	 */
	public static function public_context( int $id ): ?array {
		$c = self::stored( $id );

		return $c && in_array( $c['scope'], array( 'block', 'archive' ), true ) ? $c : null;
	}

	/**
	 * Any stored context, public or not, read once per request.
	 *
	 * @return array<string,mixed>|null
	 */
	public static function stored( int $id ): ?array {
		if ( ! array_key_exists( $id, self::$seen ) ) {
			self::$seen[ $id ] = Store::get( $id );
		}

		return self::$seen[ $id ];
	}

	/** Drop per-request lookups after a confirmed change, so later queries use the new revision. */
	public static function forget(): void {
		self::$seen     = array();
		self::$archives = array();
	}

	public static function rest_hooks(): void {
		foreach ( get_post_types( array( 'show_in_rest' => true ) ) as $type ) {
			add_filter(
				'rest_' . $type . '_collection_params',
				static function ( $params ) {
					$params['threepo_context'] = array(
						'type'        => 'integer',
						'minimum'     => 1,
						'description' => __( 'Connected Post Order context.', '3task-post-order' ),
					);
					return $params;
				}
			);

			add_filter( 'rest_' . $type . '_query', array( self::class, 'rest' ), 20, 2 );
		}
	}

	/**
	 * @param array<string,mixed> $args Validated values.
	 * @return array<string,mixed>
	 */
	public static function rest( array $args, WP_REST_Request $r ): array {
		if ( $r['threepo_context'] ) {
			$args['threepo_context'] = (int) $r['threepo_context'];
		}

		return $args;
	}

	/**
	 * @param array<string,mixed> $args Validated values.
	 * @param \WP_Block $block WordPress boundary value.
	 * @return array<string,mixed>
	 */
	public static function block( array $args, $block ): array {
		$id = (int) ( $block->context['query']['threepo_context'] ?? 0 );

		if ( $id ) {
			$args['threepo_context'] = $id;
		}

		return $args;
	}

	public static function prepare( WP_Query $q ): void {
		$id = (int) $q->get( 'threepo_context' );

		if ( ! $id && ! is_admin() && $q->is_main_query() && ! $q->is_search() && ! $q->is_feed() && ! $q->is_singular() && ! $q->get( 'orderby' ) ) {
			global $wpdb;

			$term    = $q->get_queried_object();
			$tax     = '';
			$term_id = 0;

			if ( $term instanceof \WP_Term ) {
				$tax     = $term->taxonomy;
				$term_id = $term->term_id;
			}

			if ( $term_id || $q->is_home() || $q->is_post_type_archive() ) {
				$type = ( $q->get( 'post_type' ) ? $q->get( 'post_type' ) : 'post' );

				if ( is_string( $type ) ) {
					$key = $type . ':' . $tax . ':' . $term_id;

					if ( ! isset( self::$archives[ $key ] ) ) {
						self::$archives[ $key ] = (int) $wpdb->get_var( $wpdb->prepare( "SELECT id FROM %i WHERE kind='post' AND object_type=%s AND taxonomy=%s AND term_id=%d AND parent_id=0 AND scope='archive' LIMIT 1", Store::table( 'contexts' ), $type, $tax, $term_id ) );
					}

					$id = self::$archives[ $key ];
				}
			}
		}

		if ( ! $id ) {
			return;
		}

		$native = is_admin() && $q->is_main_query() && $q->get( 'threepo_native' );
		$c      = $native ? Store::get( $id ) : self::public_context( $id );
		$type   = ( $q->get( 'post_type' ) ? $q->get( 'post_type' ) : 'post' );

		$q->set( 'threepo_fallback', false );

		if ( ! $c ) {
			$stored = $native ? null : self::stored( $id );

			if ( $stored && 'post' === $stored['kind'] && $type === $stored['object_type'] ) {
				// Not connected right now (admin only, import preview): keep the order's selection, use the query's own sorting.
				$q->set( 'threepo_context', $id );
				$q->set( 'threepo_fallback', true );

				return;
			}

			// Deleted order: the query runs as written instead of returning an empty list.
			$q->set( 'threepo_context', 0 );

			return;
		}

		// A connection never broadens statuses; for another kind or content type it is ignored.
		if ( 'post' !== $c['kind'] || $type !== $c['object_type'] ) {
			$q->set( 'threepo_context', 0 );

			return;
		}

		$q->set( 'threepo_context', $id );
		$q->set( 'threepo_revision', $c['revision'] );
		$q->set( 'ignore_sticky_posts', true );
	}

	/**
	 * @param array<string,mixed> $clauses Validated values.
	 * @return array<string,mixed>
	 */
	public static function clauses( array $clauses, WP_Query $q ): array {
		$id = (int) $q->get( 'threepo_context' );

		if ( ! $id ) {
			return $clauses;
		}

		global $wpdb;

		if ( $q->get( 'threepo_fallback' ) ) {
			$c = self::stored( $id );

			if ( $c && 'post' === $c['kind'] ) {
				$s                 = Order::source( $c );
				$clauses['where'] .= ' AND EXISTS (SELECT 1 FROM ' . $s['from'] . ' WHERE ' . $s['where'] . ' AND ' . $s['id'] . '=' . $wpdb->posts . '.ID)';
			}

			return $clauses;
		}

		$c = ( is_admin() && $q->is_main_query() && $q->get( 'threepo_native' ) ) ? Store::get( $id ) : self::public_context( $id );

		if ( ! $c || 'post' !== $c['kind'] ) {
			return $clauses;
		}

		$s                  = Order::source( $c );
		$clauses['join']   .= $wpdb->prepare( ' LEFT JOIN %i threepo_rank ON threepo_rank.object_id=%i.ID AND threepo_rank.context_id=%d AND %d=%d', Store::table( 'entries' ), $wpdb->posts, $id, $c['revision'], $c['revision'] );
		$clauses['where']  .= ' AND EXISTS (SELECT 1 FROM ' . $s['from'] . ' WHERE ' . $s['where'] . ' AND ' . $s['id'] . '=' . $wpdb->posts . '.ID)';
		$clauses['orderby'] = '(threepo_rank.rank_value IS NULL),threepo_rank.rank_value ASC,' . $wpdb->posts . '.post_date DESC,' . $wpdb->posts . '.ID DESC';

		return $clauses;
	}

	/**
	 * @param array<string,mixed> $clauses Validated values.
	 * @param list<string> $taxonomies Validated values.
	 * @param array<string,mixed> $args Validated values.
	 * @return array<string,mixed>
	 */
	public static function terms( array $clauses, array $taxonomies, array $args ): array {
		$id = (int) ( $args['threepo_context'] ?? 0 );

		if ( ! $id ) {
			return $clauses;
		}

		$c = is_admin() && Native::context() && Native::context()['id'] === $id ? Native::context() : self::public_context( $id );

		if ( ! $c || 'term' !== $c['kind'] || array( $c['object_type'] ) !== $taxonomies ) {
			return $clauses;
		}

		global $wpdb;

		$clauses['join']   .= $wpdb->prepare( ' LEFT JOIN %i threepo_rank ON threepo_rank.object_id=t.term_id AND threepo_rank.context_id=%d AND %d=%d', Store::table( 'entries' ), $id, $c['revision'], $c['revision'] );
		$clauses['where']  .= $wpdb->prepare( ' AND tt.parent=%d', $c['parent_id'] );
		$clauses['orderby'] = 'ORDER BY (threepo_rank.rank_value IS NULL),threepo_rank.rank_value ASC,t.name ASC,t.term_id ASC';
		$clauses['order']   = '';

		return $clauses;
	}
}