introduce WC_Round_Tax class

includes/class-wc-round-tax.php

@@ -0,0 +1,183 @@
+<?php
+/**
+ * WooCommerce tax calculation class.
+ *
+ * @class   WC_Round_Tax
+ * @package WooCommerce/Classes
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * WC_Round_Tax class.
+ */
+class WC_Round_Tax {
+	/**
+	 * Precision.
+	 *
+	 * @var int
+	 */
+	protected $precision = 0;
+
+	/**
+	 * Tax inclusive.
+	 *
+	 * @var bool
+	 */
+	protected $inclusive = false;
+
+	/**
+	 * Tax rate.
+	 *
+	 * @var float
+	 */
+	protected $tax_rate = 0.0;
+
+	/**
+	 * Before tax amount.
+	 *
+	 * @var float
+	 */
+	protected $before_tax;
+
+	/**
+	 * Total including tax.
+	 *
+	 * @var float
+	 */
+	protected $total;
+
+	/**
+	 * Calculated before tax amount.
+	 *
+	 * @var float
+	 */
+	protected $calculated_before_tax;
+
+	/**
+	 * Calculated tax amount.
+	 *
+	 * @var float
+	 */
+	protected $calculated_tax;
+	/**
+	 * Calculated total including tax.
+	 *
+	 * @var float
+	 */
+	protected $calculated_total;
+
+	/**
+	 * Recalculate amounts.
+	 */
+	public function calculate() {
+		if ( $this->inclusive ) {
+			$this->calculate_tax_inclusive();
+		} else {
+			$this->calculate_tax_exclusive();
+		}
+	}
+
+	/**
+	 * Recalculate amounts when tax is inclusive.
+	 */
+	private function calculate_tax_inclusive() {
+		if ( is_null( $this->total ) || 0 == ( $this->tax_rate - 1.0 ) ) {
+			return;
+		}
+
+		$this->calculated_total      = null;
+		$this->calculated_before_tax = $this->round( $this->total / ( 1.0 + $this->tax_rate ) );
+		$this->calculated_tax        = $this->total - $this->calculated_tax;
+	}
+
+	/**
+	 * Recalculate amounts when tax is exclusive.
+	 */
+	private function calculate_tax_exclusive() {
+		if ( is_null( $this->before_tax ) ) {
+			return;
+		}
+
+		$this->calculated_before_tax = null;
+		$this->calculated_tax        = $this->round( $this->before_tax * $this->tax_rate );
+		$this->calculated_total      = $this->before_tax + $this->calculated_tax;
+	}
+
+	/**
+	 * Before tax amount getter.
+	 *
+	 * @return float $before_tax.
+	 */
+	public function get_before_tax() {
+		return ! is_null( $this->calculated_before_tax ) ? $this->calculated_before_tax : $this->before_tax;
+	}
+
+	/**
+	 * Tax amount getter.
+	 */
+	public function get_tax_amount() {
+		return (float) $this->calculated_tax;
+	}
+
+	/**
+	 * Total including tax getter.
+	 */
+	public function get_total() {
+		return ! is_null( $this->calculated_total ) ? $this->calculated_total : $this->total;
+	}
+
+	/**
+	 * Precision setter.
+	 *
+	 * @param int $precision Rounding precision.
+	 */
+	public function set_precision( $precision ) {
+		$this->precision = (int) $precision;
+	}
+
+	/**
+	 * Inclusive setter.
+	 *
+	 * @param bool $inclusive Calculate taxes inclusive.
+	 */
+	public function set_inclusive( $inclusive ) {
+		$this->inclusive = (bool) $inclusive;
+	}
+
+	/**
+	 * Tax rate setter.
+	 *
+	 * @param float $tax_rate Tax rate for calculation.
+	 */
+	public function set_tax_rate( $tax_rate ) {
+		$this->tax_rate = (float) $tax_rate;
+	}
+
+	/**
+	 * Before tax amount setter.
+	 *
+	 * @param float $before_tax Before tax amount.
+	 */
+	public function set_before_tax( $before_tax ) {
+		$this->before_tax = $this->round( (float) $before_tax );
+	}
+
+	/**
+	 * Total including tax setter.
+	 *
+	 * @param float $total Tax inclusive total.
+	 */
+	public function set_total( $total ) {
+		$this->total = $this->round( (float) $total );
+	}
+
+	/**
+	 * Round to precision.
+	 *
+	 * @param float $amount Amount to be rounded.
+	 */
+	protected function round( $amount ) {
+		return round( $amount, $this->precision );
+	}
+}