<?php
/**
 * MLP5 content relations writer.
 *
 * Creates relationship groups in MLP5 from MLP2 source data.
 *
 * MLP5 schema:
 *   mlp_relationships      (id BIGINT PK AUTO_INCREMENT, type VARCHAR(36))
 *   mlp_content_relations  (relationship_id BIGINT, site_id BIGINT, content_id BIGINT, PK(relationship_id, site_id))
 *
 * @package Robotstxt_Mlp2_Mlp5
 */

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

/**
 * Class Robotstxt_Mlp2_Mlp5_Writer_Content_Relations
 */
class Robotstxt_Mlp2_Mlp5_Writer_Content_Relations {

	/**
	 * Check whether any MLP5 relationship already references a given (site_id, content_id) pair.
	 *
	 * Used for idempotency: if the pair is already in MLP5, the group is skipped.
	 *
	 * @param int $site_id    Site ID.
	 * @param int $content_id Post or term ID.
	 * @return bool
	 */
	public static function pair_exists_in_mlp5( int $site_id, int $content_id ): bool {
		global $wpdb;

		$mlp5  = new Robotstxt_Mlp2_Mlp5_Detector_Mlp5();
		$table = $mlp5->get_content_relations_table();

		if ( '' === $table ) {
			return false;
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$found = (int) $wpdb->get_var(
			$wpdb->prepare(
				// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				"SELECT COUNT(*) FROM `{$table}` WHERE site_id = %d AND content_id = %d",
				$site_id,
				$content_id
			)
		);

		return $found > 0;
	}

	/**
	 * Create a relationship group in MLP5 for the given members.
	 *
	 * Inserts one row into mlp_relationships and one row per member into
	 * mlp_content_relations. Wrapped in a transaction for atomicity.
	 *
	 * @param string  $type    WordPress content type: post type slug or taxonomy name.
	 *                         Pass 'post' for standard posts, 'term' for terms.
	 * @param array[] $members Array of ['site_id' => int, 'element_id' => int].
	 * @return bool True on success, false on any DB error.
	 */
	public static function create_group( string $type, array $members ): bool {
		global $wpdb;

		$mlp5       = new Robotstxt_Mlp2_Mlp5_Detector_Mlp5();
		$rel_table  = $mlp5->get_relationships_table();
		$cont_table = $mlp5->get_content_relations_table();

		if ( '' === $rel_table || '' === $cont_table ) {
			return false;
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$wpdb->query( 'START TRANSACTION' );

		// Insert relationship group.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$inserted = $wpdb->insert(
			$rel_table,
			array( 'type' => $type ),
			array( '%s' )
		);

		if ( false === $inserted ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
			$wpdb->query( 'ROLLBACK' );
			return false;
		}

		$relationship_id = (int) $wpdb->insert_id;

		// Insert each member.
		foreach ( $members as $member ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
			$ok = $wpdb->insert(
				$cont_table,
				array(
					'relationship_id' => $relationship_id,
					'site_id'         => (int) $member['site_id'],
					'content_id'      => (int) $member['element_id'],
				),
				array( '%d', '%d', '%d' )
			);

			if ( false === $ok ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
				$wpdb->query( 'ROLLBACK' );
				return false;
			}
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$wpdb->query( 'COMMIT' );
		return true;
	}
}