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

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

	/**
	 * Searches for all matching country/state/postcode tax rates.
	 *
	 * @access public
	 * @param string $args (default: '')
	 * @return array
	 */
	function find_rates( $args = '' ) {
		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( woocommerce_clean( $postcode ) ) );

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

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

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

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

		// Run the query
		$found_rates = $wpdb->get_results( $wpdb->prepare( "
			SELECT tax_rates.* FROM
				{$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
			WHERE
				tax_rate_country IN ( %s, '' )
				AND tax_rate_state IN ( %s, '' )
				AND tax_rate_class = %s
				AND (
					(
						locations.location_type = 'postcode' AND locations.location_code IN ('" . implode( "','", $valid_postcodes ) . "')
					)
					OR
					(
						locations.location_type = 'city' AND locations.location_code = %s
					)
					OR locations.location_type IS null
				)
			GROUP BY
				tax_rate_priority
			ORDER BY
				tax_rate_priority, tax_rate_order
			",
			strtoupper( $country ),
			strtoupper( $state ),
			sanitize_title( $tax_class ),
			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'
			);

		/*
		echo '<pre>' . __( 'Matched tax rates:', 'woocommerce' );
		var_dump( $matched_tax_rates );
		echo '</pre>';
		*/

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

	/**
	 * Get's an array of matching rates for a tax class.
	 *
	 * @param   object	Tax Class
	 * @return  array
	 */
	function get_rates( $tax_class = '' ) {
		global $woocommerce;

		$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 ) || $woocommerce->customer->has_calculated_shipping() ) {

			list( $country, $state, $postcode, $city ) = $woocommerce->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 exlcuding tax however should just not add any taxes, as they will be added during checkout
			$matched_tax_rates = $woocommerce->cart->prices_include_tax
				? $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
	 */
	function get_shop_base_rate( $tax_class = '' ) {
		global $woocommerce;

		$country 	= $woocommerce->countries->get_base_country();
		$state 		= $woocommerce->countries->get_base_state();

		return $this->find_rates( array(
			'country' 	=> $country,
			'state' 	=> $state,
			'tax_class' => $tax_class
		) );
	}

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

		// 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 ) || $woocommerce->customer->has_calculated_shipping() ) {

			list( $country, $state, $postcode, $city ) = $woocommerce->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 exlcuding tax however should just not add any taxes, as they will be added during checkout
			if ( $woocommerce->cart->prices_include_tax ) {
				$country 	= $woocommerce->countries->get_base_country();
				$state 		= $woocommerce->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( $woocommerce->cart->get_cart() ) > 0 )
				foreach ( $woocommerce->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
	}

	/**
	 * Calculate the tax using a passed array of rates.
	 *
	 * @param   float	price
	 * @param   array	rates
	 * @param	bool	passed price includes tax
	 * @return  array	array of rates/amounts
	 */
	function calc_tax( $price, $rates, $price_includes_tax = true, $supress_rounding = false ) {

		$price = $price * 100;	// To avoid float rounding errors, work with integers (pence)

		// Taxes array
		$taxes = array();

		// Price inc tax
		if ( $price_includes_tax ) {

			$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 );
			$tax_rate 			= $regular_tax_rate * $compound_tax_rate;
			$non_compound_price = ( $price / $compound_tax_rate );

			foreach ( $rates as $key => $rate ) {

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

				if ( $rate['compound'] == 'yes' )
					$tax_amount = ( $the_rate / $compound_tax_rate ) * $price;
				else
					$tax_amount = ( $the_rate / $regular_tax_rate ) * $non_compound_price;

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

				// Back to pounds
				$tax_amount = ( $tax_amount / 100 );

				// Rounding
				if ( get_option( 'woocommerce_tax_round_at_subtotal' ) == 'no' && ! $supress_rounding ) {
					$decimals = ( '' != get_option( 'woocommerce_price_num_decimals' ) ) ? get_option( 'woocommerce_price_num_decimals' ) : 0;
					$tax_amount = round( $tax_amount, $decimals );
				}

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

			}

		// Prices ex tax
		} else {

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

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

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

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

				// Back to pounds
				$tax_amount = ( $tax_amount / 100 );

				// Rounding
				if ( get_option( 'woocommerce_tax_round_at_subtotal' ) == 'no' && ! $supress_rounding ) {
					$decimals = ( '' != get_option( 'woocommerce_price_num_decimals' ) ) ? get_option( 'woocommerce_price_num_decimals' ) : 0;
					$tax_amount = round( $tax_amount, $decimals );
				}

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

			}

			$pre_compound_total = array_sum( $taxes );

			// Compound taxes
			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 modifiy this rate
				$tax_amount = apply_filters( 'woocommerce_price_ex_tax_amount', $tax_amount, $key, $rate, $price, $the_price_inc_tax, $pre_compound_total );

				// Back to pounds
				$tax_amount = ( $tax_amount / 100 );

				// Rounding
				if ( get_option( 'woocommerce_tax_round_at_subtotal' ) == 'no' && ! $supress_rounding ) {
					$decimals = ( '' != get_option( 'woocommerce_price_num_decimals' ) ) ? get_option( 'woocommerce_price_num_decimals' ) : 0;
					$tax_amount = round( $tax_amount, $decimals );
				}

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

			}

		}

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

	/**
	 * Calculate the shipping tax using a passed array of rates.
	 *
	 * @param   int		Price
	 * @param	int		Taxation Rate
	 * @return  int
	 */
	function calc_shipping_tax( $price, $rates ) {

		// Taxes array
		$taxes = array();

		// Multiple taxes
		foreach ($rates as $key => $rate) :
			if ($rate['compound']=='yes') continue;

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

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

		endforeach;

		$pre_compound_total = array_sum($taxes);

		// Compound taxes
		foreach ($rates as $key => $rate) :
			if ($rate['compound']=='no') continue;

			$the_price_inc_tax = $price + $pre_compound_total;

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

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

		endforeach;

		return $taxes;
	}

	/**
	 * Return true/false depending on if a rate is a compound rate.
	 *
	 * @param   int		key
	 * @return  bool
	 */
	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
	 */
	function get_rate_label( $key ) {
		global $wpdb;
		return apply_filters( 'woocommerce_rate_label', $wpdb->get_var( $wpdb->prepare( "SELECT tax_rate_name FROM {$wpdb->prefix}woocommerce_tax_rates WHERE tax_rate_id = %s", $key ) ), $key, $this );
	}

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

	/**
	 * Round to currency DP.
	 */
	function round( $in ) {
		$decimals = ( '' != get_option( 'woocommerce_price_num_decimals' ) ) ? get_option( 'woocommerce_price_num_decimals' ) : 0;
		return round( $in, $decimals );
	}

}