woocommerce/includes/class-wc-tax.php

<?php
/**
 * Performs tax calculations and loads tax rates.
 *
 * @class 		WC_Tax
 * @version		2.0.0
 * @package		WooCommerce/Classes
 * @category	Class
 * @author 		WooThemes
 */
class WC_Tax {

	/** @var array */
	public $matched_rates;


	var $log = array();

	/**
	 * __construct function.
	 *
	 * @access public
	 */
	public function __construct() {
		$this->precision         = WC_ROUNDING_PRECISION;
		$this->dp                = (int) get_option( 'woocommerce_price_num_decimals' );
		$this->round_at_subtotal = get_option('woocommerce_tax_round_at_subtotal') == 'yes';
	}

	/**
	 * Calculate tax for a line
	 * @param  float  $price              Price to calc tax on
	 * @param  array  $rates              Rates to apply
	 * @param  boolean $price_includes_tax Whether the passed price has taxes included
	 * @param  boolean $suppress_rounding  Whether to suppress any rounding from taking place
	 * @return array                      Array of rates + prices after tax
	 */
	public function calc_tax( $price, $rates, $price_includes_tax = false, $suppress_rounding = false ) {
		// Work in pence to X precision
		$price = $this->precision( $price );

		if ( $price_includes_tax )
			$taxes = $this->calc_inclusive_tax( $price, $rates );
		else
			$taxes = $this->calc_exclusive_tax( $price, $rates );

		// Round to precision
		if ( ! $this->round_at_subtotal && ! $suppress_rounding ) {
			$taxes = array_map( 'round', $taxes ); // Round to precision
		}

		// Remove precision
		$price     = $this->remove_precision( $price );
		$taxes     = array_map( array( $this, 'remove_precision' ), $taxes );

		return apply_filters( 'woocommerce_calc_tax', $taxes, $price, $rates, $price_includes_tax, $suppress_rounding );
	}

	/**
	 * Calculate the shipping tax using a passed array of rates.
	 *
	 * @param   float		Price
	 * @param	array		Taxation Rate
	 * @return  array
	 */
	public function calc_shipping_tax( $price, $rates ) {
		return $this->calc_exclusive_tax( $price, $rates );
	}

	/**
	 * Multiply cost by pow precision
	 * @param  float $price
	 * @return float
	 */
	private function precision( $price ) {
		return $price * ( pow( 10, $this->precision ) );
	}

	/**
	 * Divide cost by pow precision
	 * @param  float $price
	 * @return float
	 */
	private function remove_precision( $price ) {
		return $price / ( pow( 10, $this->precision ) );
	}

	/**
	 * Round to precision.
	 *
	 * Filter example: to return rounding to .5 cents you'd use:
	 *
	 * public function euro_5cent_rounding( $in ) {
	 *      return round( $in / 5, 2 ) * 5;
	 * }
	 * add_filter( 'woocommerce_tax_round', 'euro_5cent_rounding' );
	 */
	public function round( $in ) {
		return apply_filters( 'woocommerce_tax_round', round( $in, $this->precision ), $in );
	}

	/**
	 * Calc tax from inclusive price
	 *
	 * @param  float $price
	 * @param  array $rates
	 * @return array
	 */
	private function calc_inclusive_tax( $price, $rates ) {
		$taxes = array();

		$regular_tax_rates = $compound_tax_rates = 0;

		foreach ( $rates as $key => $rate )
			if ( $rate['compound'] == 'yes' )
				$compound_tax_rates = $compound_tax_rates + $rate['rate'];
			else
				$regular_tax_rates  = $regular_tax_rates + $rate['rate'];

		$regular_tax_rate 	= 1 + ( $regular_tax_rates / 100 );
		$compound_tax_rate 	= 1 + ( $compound_tax_rates / 100 );
		$non_compound_price = $price / $compound_tax_rate;

		foreach ( $rates as $key => $rate ) {
			if ( ! isset( $taxes[ $key ] ) )
				$taxes[ $key ] = 0;

			$the_rate      = $rate['rate'] / 100;

			if ( $rate['compound'] == 'yes' ) {
				$the_price = $price;
				$the_rate  = $the_rate / $compound_tax_rate;
			} else {
				$the_price = $non_compound_price;
				$the_rate  = $the_rate / $regular_tax_rate;
			}

			$net_price       = $price - ( $the_rate * $the_price );
			$tax_amount      = $price - $net_price;
			$taxes[ $key ]   += apply_filters( 'woocommerce_price_inc_tax_amount', $tax_amount, $key, $rate, $price );
		}

		return $taxes;
	}

	/**
	 * Calc tax from exclusive price
	 *
	 * @param  float $price
	 * @param  array $rates
	 * @return array
	 */
	private function calc_exclusive_tax( $price, $rates ) {
		$taxes = array();

		// Multiple taxes
		foreach ( $rates as $key => $rate ) {

			if ( $rate['compound'] == 'yes' )
				continue;

			$tax_amount = $price * ( $rate['rate'] / 100 );

			// ADVANCED: Allow third parties to modify this rate
			$tax_amount = apply_filters( 'woocommerce_price_ex_tax_amount', $tax_amount, $key, $rate, $price );

			// Add rate
			if ( ! isset( $taxes[ $key ] ) )
				$taxes[ $key ] = $tax_amount;
			else
				$taxes[ $key ] += $tax_amount;
		}

		$pre_compound_total = array_sum( $taxes );

		// Compound taxes
		if ( $rates ) {
			foreach ( $rates as $key => $rate ) {

				if ( $rate['compound'] == 'no' )
					continue;

				$the_price_inc_tax = $price + ( $pre_compound_total * 100 );

				$tax_amount = $the_price_inc_tax * ( $rate['rate'] / 100 );

				// ADVANCED: Allow third parties to modify this rate
				$tax_amount = apply_filters( 'woocommerce_price_ex_tax_amount', $tax_amount, $key, $rate, $price, $the_price_inc_tax, $pre_compound_total );

				// Add rate
				if ( ! isset( $taxes[ $key ] ) )
					$taxes[ $key ] = $tax_amount;
				else
					$taxes[ $key ] += $tax_amount;
			}
		}

		return $taxes;
	}

	/**
	 * Searches for all matching country/state/postcode tax rates.
	 *
	 * @access public
	 * @param array $args
	 * @return array
	 */
	public function find_rates( $args = array() ) {
		global $wpdb;

		$defaults = array(
			'country' 	=> '',
			'state' 	=> '',
			'city' 		=> '',
			'postcode' 	=> '',
			'tax_class'	=> ''
		);

		$args = wp_parse_args( $args, $defaults );

		extract( $args, EXTR_SKIP );

		if ( ! $country )
			return array();

		// Handle postcodes
		$valid_postcodes 	= array( '*', strtoupper( wc_clean( $postcode ) ) );

		// Work out possible valid wildcard postcodes
		$postcode_length	= strlen( $postcode );
		$wildcard_postcode	= strtoupper( wc_clean( $postcode ) );

		for ( $i = 0; $i < $postcode_length; $i ++ ) {

			$wildcard_postcode = substr( $wildcard_postcode, 0, -1 );

			$valid_postcodes[] = $wildcard_postcode . '*';
		}

		// Build transient key and try to retrieve them from cache
		$rates_transient_key = 'wc_tax_rates_' . md5( sprintf( '%s+%s+%s+%s+%s', $country, $state, $city, implode( ',', $valid_postcodes), $tax_class ) );
		$matched_tax_rates = get_transient( $rates_transient_key );

		if ( false === $matched_tax_rates ) {

			// Run the query
			$found_rates = $wpdb->get_results( $wpdb->prepare( "
				SELECT * FROM (
					SELECT tax_rates.* FROM
						{$wpdb->prefix}woocommerce_tax_rates as tax_rates
					LEFT OUTER JOIN
						{$wpdb->prefix}woocommerce_tax_rate_locations as locations ON tax_rates.tax_rate_id = locations.tax_rate_id
					LEFT OUTER JOIN
						{$wpdb->prefix}woocommerce_tax_rate_locations as locations2 ON tax_rates.tax_rate_id = locations2.tax_rate_id
					WHERE
						tax_rate_country IN ( %s, '' )
						AND tax_rate_state IN ( %s, '' )
						AND tax_rate_class = %s
						AND
						(
							(
								locations.location_type IS NULL
							)
							OR
							(
								locations.location_type = 'postcode'
								AND locations.location_code IN ('" . implode( "','", $valid_postcodes ) . "')
								AND locations2.location_type = 'city'
								AND locations2.location_code = %s
							)
							OR
							(
								locations.location_type = 'postcode'
								AND locations.location_code IN ('" . implode( "','", $valid_postcodes ) . "')
								AND 0 = (
									SELECT COUNT(*) FROM {$wpdb->prefix}woocommerce_tax_rate_locations as sublocations
									WHERE sublocations.location_type = 'city'
									AND sublocations.tax_rate_id = tax_rates.tax_rate_id
								)
							)
							OR
							(
								locations.location_type = 'city'
								AND locations.location_code = %s
								AND 0 = (
									SELECT COUNT(*) FROM {$wpdb->prefix}woocommerce_tax_rate_locations as sublocations
									WHERE sublocations.location_type = 'postcode'
									AND sublocations.tax_rate_id = tax_rates.tax_rate_id
								)
							)
						)
					GROUP BY
						tax_rate_id
					ORDER BY
						tax_rate_priority, tax_rate_order
				) as ordered_taxes
				GROUP BY
					tax_rate_priority
				",
				strtoupper( $country ),
				strtoupper( $state ),
				sanitize_title( $tax_class ),
				strtoupper( $city ),
				strtoupper( $city )
			) );

			// Put results into array
			$matched_tax_rates = array();

			foreach ( $found_rates as $found_rate )
				$matched_tax_rates[ $found_rate->tax_rate_id ] = array(
					'rate'     => $found_rate->tax_rate,
					'label'    => $found_rate->tax_rate_name,
					'shipping' => $found_rate->tax_rate_shipping ? 'yes' : 'no',
					'compound' => $found_rate->tax_rate_compound ? 'yes' : 'no'
				);

			$matched_tax_rates = apply_filters( 'woocommerce_matched_tax_rates', $matched_tax_rates, $country, $state, $postcode, $city, $tax_class );

			set_transient( $rates_transient_key, $matched_tax_rates, DAY_IN_SECONDS );
		}

		return $matched_tax_rates;
	}

	/**
	 * Get's an array of matching rates for a tax class.
	 * @param string $tax_class
	 * @return  array
	 */
	public function get_rates( $tax_class = '' ) {

		$tax_class = sanitize_title( $tax_class );

		/* Checkout uses customer location for the tax rates. Also, if shipping has been calculated, use the customers address. */
		if ( ( defined('WOOCOMMERCE_CHECKOUT') && WOOCOMMERCE_CHECKOUT ) || ( ! empty( WC()->customer ) && WC()->customer->has_calculated_shipping() ) ) {

			list( $country, $state, $postcode, $city ) = WC()->customer->get_taxable_address();

			$matched_tax_rates = $this->find_rates( array(
				'country' 	=> $country,
				'state' 	=> $state,
				'postcode' 	=> $postcode,
				'city' 		=> $city,
				'tax_class' => $tax_class
			) );

		} else {

			// Prices which include tax should always use the base rate if we don't know where the user is located
			// Prices excluding tax however should just not add any taxes, as they will be added during checkout.
			// The woocommerce_default_customer_address option (when set to base) is also used here.
			$matched_tax_rates = get_option( 'woocommerce_prices_include_tax' ) == 'yes' || get_option( 'woocommerce_default_customer_address' ) == 'base'
				? $this->get_shop_base_rate( $tax_class )
				: array();

		}

		return apply_filters('woocommerce_matched_rates', $matched_tax_rates, $tax_class);
	}

	/**
	 * Get's an array of matching rates for the shop's base country.
	 *
	 * @param   string	Tax Class
	 * @return  array
	 */
	public function get_shop_base_rate( $tax_class = '' ) {
		return $this->find_rates( array(
			'country' 	=> WC()->countries->get_base_country(),
			'state' 	=> WC()->countries->get_base_state(),
			'postcode' 	=> WC()->countries->get_base_postcode(),
			'city' 		=> WC()->countries->get_base_city(),
			'tax_class' => $tax_class
		) );
	}

	/**
	 * Gets an array of matching shipping tax rates for a given class.
	 *
	 * @param   string	Tax Class
	 * @return  mixed
	 */
	public function get_shipping_tax_rates( $tax_class = null ) {

		// See if we have an explicitly set shipping tax class
		if ( $shipping_tax_class = get_option( 'woocommerce_shipping_tax_class' ) ) {
			$tax_class = $shipping_tax_class == 'standard' ? '' : $shipping_tax_class;
		}

		if ( ( defined('WOOCOMMERCE_CHECKOUT') && WOOCOMMERCE_CHECKOUT ) || ( ! empty( WC()->customer ) && WC()->customer->has_calculated_shipping() ) ) {

			list( $country, $state, $postcode, $city ) = WC()->customer->get_taxable_address();

		} else {

			// Prices which include tax should always use the base rate if we don't know where the user is located
			// Prices excluding tax however should just not add any taxes, as they will be added during checkout
			if ( get_option( 'woocommerce_prices_include_tax' ) == 'yes' || get_option( 'woocommerce_default_customer_address' ) == 'base' ) {
				$country 	= WC()->countries->get_base_country();
				$state 		= WC()->countries->get_base_state();
				$postcode   = '';
				$city		= '';
			} else {
				return array();
			}

		}

		// If we are here then shipping is taxable - work it out
		if ( ! is_null( $tax_class ) ) {

			$matched_tax_rates = array();

			// This will be per item shipping
			$rates = $this->find_rates( array(
				'country' 	=> $country,
				'state' 	=> $state,
				'postcode' 	=> $postcode,
				'city' 		=> $city,
				'tax_class' => $tax_class
			) );

			if ( $rates )
				foreach ( $rates as $key => $rate )
					if ( isset( $rate['shipping'] ) && $rate['shipping'] == 'yes' )
						$matched_tax_rates[ $key ] = $rate;

			if ( sizeof( $matched_tax_rates ) == 0 ) {
				// Get standard rate
				$rates = $this->find_rates( array(
					'country' 	=> $country,
					'state' 	=> $state,
					'city' 		=> $city,
					'postcode' 	=> $postcode,
				) );

				if ( $rates )
					foreach ( $rates as $key => $rate )
						if ( isset( $rate['shipping'] ) && $rate['shipping'] == 'yes' )
							$matched_tax_rates[ $key ] = $rate;
			}

			return $matched_tax_rates;

		} else {

			// This will be per order shipping - loop through the order and find the highest tax class rate
			$found_tax_classes = array();
			$matched_tax_rates = array();
			$rates = false;

			// Loop cart and find the highest tax band
			if ( sizeof( WC()->cart->get_cart() ) > 0 )
				foreach ( WC()->cart->get_cart() as $item )
					$found_tax_classes[] = $item['data']->get_tax_class();

			$found_tax_classes = array_unique( $found_tax_classes );

			// If multiple classes are found, use highest
			if ( sizeof( $found_tax_classes ) > 1 ) {

				if ( in_array( '', $found_tax_classes ) ) {
					$rates = $this->find_rates( array(
						'country' 	=> $country,
						'state' 	=> $state,
						'city' 		=> $city,
						'postcode' 	=> $postcode,
					) );
				} else {
					$tax_classes = array_filter( array_map( 'trim', explode( "\n", get_option( 'woocommerce_tax_classes' ) ) ) );

					foreach ( $tax_classes as $tax_class ) {
						if ( in_array( $tax_class, $found_tax_classes ) ) {
							$rates = $this->find_rates( array(
								'country' 	=> $country,
								'state' 	=> $state,
								'postcode' 	=> $postcode,
								'city' 		=> $city,
								'tax_class' => $tax_class
							) );
							break;
						}
					}
				}

			// If a single tax class is found, use it
			} elseif ( sizeof( $found_tax_classes ) == 1 ) {

				$rates = $this->find_rates( array(
					'country' 	=> $country,
					'state' 	=> $state,
					'postcode' 	=> $postcode,
					'city' 		=> $city,
					'tax_class' => $found_tax_classes[0]
				) );

			}

			// If no class rate are found, use standard rates
			if ( ! $rates )
				$rates = $this->find_rates( array(
					'country' 	=> $country,
					'state' 	=> $state,
					'postcode' 	=> $postcode,
					'city' 		=> $city,
				) );

			if ( $rates )
				foreach ( $rates as $key => $rate )
					if ( isset( $rate['shipping'] ) && $rate['shipping'] == 'yes' )
						$matched_tax_rates[ $key ] = $rate;

			return $matched_tax_rates;
		}

		return array(); // return false
	}

	/**
	 * Return true/false depending on if a rate is a compound rate.
	 *
	 * @param   int		key
	 * @return  bool
	 */
	public function is_compound( $key ) {
		global $wpdb;
		return $wpdb->get_var( $wpdb->prepare( "SELECT tax_rate_compound FROM {$wpdb->prefix}woocommerce_tax_rates WHERE tax_rate_id = %s", $key ) ) ? true : false;
	}

	/**
	 * Return a given rates label.
	 *
	 * @param   int		key
	 * @return  string
	 */
	public function get_rate_label( $key ) {
		global $wpdb;

		$rate_name = $wpdb->get_var( $wpdb->prepare( "SELECT tax_rate_name FROM {$wpdb->prefix}woocommerce_tax_rates WHERE tax_rate_id = %s", $key ) );

		if ( ! $rate_name )
			$rate_name = WC()->countries->tax_or_vat();

		return apply_filters( 'woocommerce_rate_label', $rate_name, $key, $this );
	}

	/**
	 * Get a rates code. Code is made up of COUNTRY-STATE-NAME-Priority. E.g GB-VAT-1, US-AL-TAX-1
	 *
	 * @access public
	 * @param mixed $key
	 * @return string
	 */
	public function get_rate_code( $key ) {
		global $wpdb;

		$rate = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->prefix}woocommerce_tax_rates WHERE tax_rate_id = %s", $key ) );

		$code = array();

		$code[] = $rate->tax_rate_country;
		$code[] = $rate->tax_rate_state;
		$code[] = $rate->tax_rate_name ? $rate->tax_rate_name : 'TAX';
		$code[] = absint( $rate->tax_rate_priority );

		return apply_filters( 'woocommerce_rate_code', strtoupper( implode( '-', array_filter( $code ) ) ), $key, $this );
	}

	/**
	 * Round tax lines and return the sum.
	 *
	 * @param   array
	 * @return  float
	 */
	public function get_tax_total( $taxes ) {
		return array_sum( array_map( array( $this, 'round' ), $taxes ) );
	}
}