<?php
/**
 * Fills the {placeholders} of a title or description template. Pure PHP.
 *
 * @package Tidelist
 */

namespace Tidelist\Build;

/**
 * Template renderer.
 */
final class Template {

	/**
	 * Replaces every {name} with its value; unknown placeholders become empty.
	 *
	 * @param string $template Template.
	 * @param array  $values   Placeholder name => text.
	 */
	public static function render( string $template, array $values ): string {
		return (string) preg_replace_callback(
			'/\{([a-z_]+)\}/',
			static function ( $m ) use ( $values ) {
				return (string) ( $values[ $m[1] ] ?? '' );
			},
			$template
		);
	}

	/**
	 * Placeholders a template uses.
	 *
	 * @param string $template Template.
	 * @return string[]
	 */
	public static function placeholders( string $template ): array {
		preg_match_all( '/\{([a-z_]+)\}/', $template, $m );
		return array_values( array_unique( $m[1] ) );
	}
}