<?php
/**
 * Finite display policy for local Amazon discount snapshots.
 *
 * @package Affilun\Application\AmazonDiscount
 */

declare(strict_types=1);

namespace Affilun\Application\AmazonDiscount;

use DateTimeImmutable;

/**
 * Uses the existing 24-hour fresh TTL as a conservative maximum, without grace.
 * This is a local display limit, not a statement of provider legal requirements.
 */
final class AmazonDiscountDisplayPolicy {

	public const MAX_AGE_SECONDS = 86400;

	/**
	 * Old rows were not verified against the selected price listing.
	 * Namespace new collections so they alone are readable until resynchronization.
	 */
	public const STORAGE_PREFIX = 'v2:';

	/**
	 * Return the exclusive oldest acceptable fetch instant.
	 *
	 * @param DateTimeImmutable $now Current instant.
	 */
	public static function cutoff( DateTimeImmutable $now ): DateTimeImmutable {
		return $now->setTimestamp( $now->getTimestamp() - self::MAX_AGE_SECONDS );
	}

	/**
	 * Apply the same confirmation and freshness rules before repository limits.
	 *
	 * @param AmazonDiscountProduct $product Stored snapshot.
	 * @param DateTimeImmutable     $now     Current instant.
	 */
	public static function allows( AmazonDiscountProduct $product, DateTimeImmutable $now ): bool {
		$saving = $product->savingsPercentage();
		return $saving !== null
			&& $saving >= max( AmazonDiscountSyncService::DEFAULT_MIN_SAVING_PERCENT, $product->minSavingPercent() )
			&& $saving <= 100
			&& $product->fetchedAt() > self::cutoff( $now )
			&& $product->fetchedAt() <= $now;
	}
}