<?php
/** Currency display metadata; canonical monetary storage always uses hundredths. */
namespace Abientot\Support;
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Currency {
	/**
	 * ISO 4217 minor units, SIX List One published 2026-09-17.
	 * Codes with no defined minor unit and retained unknown historical codes use 2.
	 * https://www.six-group.com/en/products-services/financial-information/market-reference-data/data-standards.html
	 */
	public static function precision( string $currency ): int {
		$currency = strtoupper( trim( $currency ) );
		return self::precisions()[ $currency ] ?? 2;
	}
	/** Non-default precisions shared with client formatters; other codes use 2. */
	public static function precisions(): array {
		return array_merge(
			array_fill_keys( array( 'BIF', 'CLP', 'DJF', 'GNF', 'ISK', 'JPY', 'KMF', 'KRW', 'PYG', 'RWF', 'UGX', 'UYI', 'VND', 'VUV', 'XAF', 'XOF', 'XPF' ), 0 ),
			array_fill_keys( array( 'BHD', 'IQD', 'JOD', 'KWD', 'LYD', 'OMR', 'TND' ), 3 ),
			array(
				'CLF' => 4,
				'UYW' => 4
			)
		);
	}
	/** Preserve fractional historical amounts even for whole-unit currencies. */
	public static function display_precision( int $cents, string $currency ): int {
		$precision = self::precision( $currency );
		return $precision === 0 && $cents % 100 !== 0 ? 2 : $precision;
	}
	/** Locale formats the number; ISO codes remain clear across PHP and JS. */
	public static function format( int $cents, string $currency ): string {
		return Locale::currency( $cents / 100, strtoupper( trim( $currency ) ), self::display_precision( $cents, $currency ) );
	}
	/** Whether a new amount can be written without rounding or rescaling. */
	public static function representable( int $cents, string $currency ): bool {
		return $cents >= 0 && $cents <= 2147483647 && ( self::precision( $currency ) !== 0 || $cents % 100 === 0 );
	}
	/** Shared appointment write guard; preserve unchanged retained and past imported prices. */
	public static function validate_booking( array $after, ?array $before = null ): void {
		if ( $before && (int) $after['price_cents'] === (int) $before['price_cents'] && (string) $after['currency'] === (string) $before['currency'] ) {
			return;
		}
		if ( ! $before && ( $after['source'] ?? '' ) === 'import' ) {
			$end = \DateTimeImmutable::createFromFormat( '!Y-m-d H:i:s', (string) ( $after['end_utc'] ?? '' ), new \DateTimeZone( 'UTC' ) );
			if ( $end && $end->format( 'Y-m-d H:i:s' ) === $after['end_utc'] && $end->getTimestamp() <= time() ) {
				return;
			}
		}
		self::validate( (int) $after['price_cents'], (string) $after['currency'] );
	}
	/** Call on new monetary writes; do not apply to historical read access. */
	public static function validate( int $cents, string $currency ): void {
		if ( $cents < 0 || $cents > 2147483647 ) {
			throw new \InvalidArgumentException( 'money_input' );
		}
		if ( ! self::representable( $cents, $currency ) ) {
			throw new \InvalidArgumentException( 'money_precision' );
		}
	}
}