<?php
namespace Admirly\Domain;

/**
 * Card labels built from the settings-driven field definitions.
 */
final class Labels {
	/** Label for a slug; the slug itself when it is no longer configured; '' for ''. @param array<int,array{slug:string,label:string}> $items */
	public static function lookup( array $items, string $slug ): string {
		if ( $slug === '' ) {
			return '';
		}
		return FieldConfig::labels( $items )[ $slug ] ?? $slug;
	}

	/** Subtitle parts [role label, sub label]; extensions may append their own before join(). @param array<string,mixed> $fields @return string[] */
	public static function parts( array $fields, string $role, string $sub ): array {
		return [
			self::lookup( $fields['roles'] ?? [], $role ),
			self::lookup( $fields['sub']['options'] ?? [], $sub ),
		];
	}

	/** "A · B · C" with empty parts skipped. @param string[] $parts */
	public static function join( array $parts ): string {
		return implode(
			' · ',
			array_filter(
				$parts,
				static function ( $s ) {
					return $s !== '';
				}
			)
		);
	}

	/** Card subtitle "Role · Sub". @param array<string,mixed> $fields Normalized FieldConfig. */
	public static function card( array $fields, string $role, string $sub ): string {
		return self::join( self::parts( $fields, $role, $sub ) );
	}
}