<?php
/**
 * Tax conversions for fees.
 *
 * @package Extrova
 */

declare( strict_types=1 );

namespace Extrova\Pricing;

use Extrova\Core\Context;

defined( 'ABSPATH' ) || exit;

/**
 * WooCommerce always adds fees as net amounts. When the store enters prices including tax,
 * the configured amount is converted to net the same way WooCommerce does for products:
 *
 * - `woocommerce_adjust_non_base_location_prices` true (default): base-location rates are removed.
 * - false: the customer's rates are removed, so every customer pays the same gross amount.
 *
 * @since 1.0.0
 */
final class TaxHelper {

	/**
	 * Converts an amount entered by the store to net (rounding precision, not price decimals).
	 *
	 * @param float   $amount    Amount as entered.
	 * @param bool    $taxable   Taxable.
	 * @param string  $tax_class Tax class.
	 * @param Context $context   Context.
	 */
	public function to_net( float $amount, bool $taxable, string $tax_class, Context $context ): float {
		if ( ! $taxable || ! wc_tax_enabled() || ! wc_prices_include_tax() ) {
			return round( $amount, wc_get_price_decimals() );
		}

		if ( apply_filters( 'woocommerce_adjust_non_base_location_prices', true ) ) { // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Core WooCommerce filter.
			$rates = \WC_Tax::get_base_tax_rates( $tax_class );
		} else {
			$rates = \WC_Tax::get_rates( $tax_class, $context->customer );
		}

		// Not rounded to the price decimals: like product lines with prices including tax, the net
		// keeps WooCommerce's rounding precision so net + rounded tax is exactly the amount entered
		// (1.99 → 1.644628 + 0.35). WC_Cart_Totals rounds the totals afterwards.
		$taxes = \WC_Tax::calc_inclusive_tax( $amount, $rates );
		return round( $amount - (float) array_sum( $taxes ), wc_get_rounding_precision() );
	}

	/**
	 * Estimated tax for a net amount and the current customer.
	 *
	 * @param float   $net       Net amount.
	 * @param bool    $taxable   Taxable.
	 * @param string  $tax_class Tax class.
	 * @param Context $context   Context.
	 */
	public function tax_for( float $net, bool $taxable, string $tax_class, Context $context ): float {
		if ( ! $taxable || ! wc_tax_enabled() || $net <= 0 ) {
			return 0.0;
		}
		if ( $context->customer && $context->customer->get_is_vat_exempt() ) {
			return 0.0;
		}
		$rates = \WC_Tax::get_rates( $tax_class, $context->customer );
		$taxes = \WC_Tax::calc_tax( $net, $rates, false );
		return round( (float) array_sum( $taxes ), wc_get_price_decimals() );
	}

	/**
	 * Whether prices are displayed including tax in the cart/checkout.
	 *
	 * @param Context $context Context.
	 */
	public function display_including_tax( Context $context ): bool {
		if ( $context->cart ) {
			return (bool) $context->cart->display_prices_including_tax();
		}
		return 'incl' === get_option( 'woocommerce_tax_display_cart' );
	}
}