/**
	 * Returns a list of date archives that can be included.
	 *
	 * @since 4.1.3
	 *
	 * @return array The date archives.
	 */
	public function archives() {
		$result = aioseo()->core->db
			->start( 'posts', false, 'SELECT DISTINCT' )
			->select( 'YEAR(post_date) AS year, MONTH(post_date) AS month' )
			->where( 'post_type', 'post' )
			->where( 'post_status', 'publish' )
			->whereRaw( "post_password=''" )
			->orderBy( '`year` DESC, `month` DESC' )
			->run()
			->result();

		$dates = [];
		foreach ( $result as $date ) {
			$dates[ $date->year ][ $date->month ] = 1;
		}

		return $dates;
	}

	/**
	 * Returns the publish date for a given term.
	 * This is the publish date of the oldest post that is assigned to the term.
	 *
	 * @since 4.1.3
	 *
	 * @param  int $termId The term ID.
	 * @return int         The publish date timestamp.
	 */
	public function getTermPublishDate( $termId ) {
		$termRelationshipsTable = aioseo()->core->db->db->prefix . 'term_relationships';

		$post = aioseo()->core->db
			->start( 'posts as p' )
			->select( 'MIN(`p`.`post_date_gmt`) as publish_date' )
			->whereRaw( "
			( `p`.`ID` IN
				(
					SELECT `tr`.`object_id`
					FROM `$termRelationshipsTable` as tr
					WHERE `tr`.`term_taxonomy_id` = '$termId'
				)
			)" )
			->run()
			->result();

		return ! empty( $post[0]->publish_date ) ? strtotime( $post[0]->publish_date ) : 0;
	}

	/**
	 * Returns a comma-separated string of excluded object IDs.
	 *
	 * @since 4.1.3
	 *
	 * @param  array   $attributes The attributes.
	 * @param  boolean $posts      Whether the objects are posts.
	 * @return string              The excluded object IDs.
	 */
	private function getExcludedObjects( $attributes, $posts = true ) {
		$excludedObjects = $posts
			? aioseo()->sitemap->helpers->excludedPosts()
			: aioseo()->sitemap->helpers->excludedTerms();
		$key             = $posts ? 'excluded_posts' : 'excluded_terms';

		if ( ! empty( $attributes[ $key ] ) ) {
			$ids = explode( ',', $excludedObjects );

			$extraIds = [];
			if ( is_array( $attributes[ $key ] ) ) {
				$extraIds = $attributes[ $key ];
			}
			if ( is_string( $attributes[ $key ] ) ) {
				$extraIds = array_map( 'trim', explode( ',', $attributes[ $key ] ) );
			}

			$ids = array_filter( array_merge( $ids, $extraIds ), 'is_numeric' );

			$excludedObjects = esc_sql( implode( ', ', $ids ) );
		}

		return $excludedObjects;
	}
}