<?php
/**
 * The prompt line for the variant the shopper selected.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Prompt;

defined( 'ABSPATH' ) || exit;

/**
 * Many stores keep one product photo and sell colours as attributes only; without this line the
 * preview would show the photo's colour, not the chosen one.
 *
 * The text comes from the store's own catalogue (attribute names and values), never from the
 * shopper. It is still cleaned to letters, digits and a few separators and shortened, so a stray
 * value cannot add instructions or break the prompt. Size is left out: how a size fits is not
 * something the model can show reliably.
 */
final class VariantText {

	/**
	 * Longest name or value kept, in characters.
	 */
	public const MAX_LENGTH = 30;

	/**
	 * Attributes kept at most.
	 */
	public const MAX_ATTRIBUTES = 4;

	private const SIZE_WORDS = array( 'size', 'sizes', 'razmer', 'размер', 'olcham', 'lcham' );

	/**
	 * One sentence for the prompt, or '' when there is nothing to say.
	 *
	 * @param array<string, string> $attributes Attribute names (labels) and selected values.
	 */
	public static function line( array $attributes ): string {
		$parts = array();

		foreach ( $attributes as $name => $value ) {
			$name  = self::clean( (string) $name );
			$value = self::clean( (string) $value );

			if ( '' === $name || '' === $value || self::is_size( $name ) ) {
				continue;
			}

			$parts[] = $name . ': ' . $value;
			if ( count( $parts ) >= self::MAX_ATTRIBUTES ) {
				break;
			}
		}

		if ( array() === $parts ) {
			return '';
		}

		return 'The shopper selected this variant of the product: ' . implode( '; ', $parts ) . '. Show the product in this variant, even if image 2 shows another one.';
	}

	/**
	 * Letters, digits, spaces, hyphens, apostrophes, ampersands and slashes only; shortened.
	 *
	 * @param string $text Name or value.
	 */
	private static function clean( string $text ): string {
		$text = (string) preg_replace( "/[^\\p{L}\\p{N}\\-'&\\/ ]+/u", ' ', $text );
		$text = trim( (string) preg_replace( '/\s+/u', ' ', $text ) );

		return trim( function_exists( 'mb_substr' ) ? mb_substr( $text, 0, self::MAX_LENGTH ) : substr( $text, 0, self::MAX_LENGTH ) );
	}

	/**
	 * Whether an attribute name means size.
	 *
	 * @param string $name Cleaned name.
	 */
	private static function is_size( string $name ): bool {
		$lower = function_exists( 'mb_strtolower' ) ? mb_strtolower( $name ) : strtolower( $name );

		foreach ( (array) preg_split( "/[\\s\\-'\\/&]+/u", $lower ) as $word ) {
			if ( in_array( $word, self::SIZE_WORDS, true ) ) {
				return true;
			}
		}

		return false;
	}
}