<?php
/**********************************************************************
	Copyright (C) NotrinosERP.
	Released under the terms of the GNU General Public License, GPL, 
	as published by the Free Software Foundation, either version 3 
	of the License, or (at your option) any later version.
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
	See the License here <http://www.gnu.org/licenses/gpl-3.0.html>.
***********************************************************************/
include_once($path_to_root . '/taxes/db/tax_groups_db.inc');
include_once($path_to_root . '/taxes/db/tax_types_db.inc');
include_once($path_to_root . '/taxes/db/item_tax_types_db.inc');

//---------------------------------------------------------------------------------

// returns the price of a given item minus any included taxes
// for item $stock_id with line price $price,
// with applicable tax rates $tax_group_array or group id $tax_group

function get_tax_free_price_for_item($stock_id, $price, $tax_group, $tax_included, $tax_group_array=null) {
	// if price is zero, then can't be taxed !
	if ($price == 0)
		return 0;

	if ($tax_included==0) return $price;
	
	// if array already read, then make a copy and use that
	if ($tax_group_array)
		$ret_tax_array = $tax_group_array;
	else
		$ret_tax_array = get_tax_group_items_as_array($tax_group);
	
	$tax_array = get_taxes_for_item($stock_id, $ret_tax_array);

	// if no exemptions or taxgroup is empty, then no included/excluded taxes
	if ($tax_array == null)
		return $price;

	// to avoid rounding errors we have to just subtract taxes from tax_included price.
	$tax_multiplier = 0;
	foreach ($tax_array as $taxitem) {
		$tax_multiplier += $taxitem['rate'];
	}

	$tax = 0;
	foreach ($tax_array as $taxitem) {
		$tax += round($price*$taxitem['rate']/(100+$tax_multiplier), user_price_dec());
	}
	return $price-$tax;
}
//
//	Full price (incl. VAT) for item $stock_id with line price $price,
//	with tax rates $tax_group_array or applicable group $tax_group
//
function get_full_price_for_item($stock_id, $price, $tax_group, $tax_included, $tax_group_array=null) {
	// if price is zero, then can't be taxed !
	if ($price == 0)
		return 0;

	if ($tax_included==1) return $price;

	// if array already read, then make a copy and use that
	if ($tax_group_array)
		$ret_tax_array = $tax_group_array;
	else
		$ret_tax_array = get_tax_group_items_as_array($tax_group);
	
	//print_r($ret_tax_array);

	$tax_array = get_taxes_for_item($stock_id, $ret_tax_array);
	// if no exemptions or taxgroup is empty, then no included/excluded taxes
	if ($tax_array == null)
		return $price;
	
	$tax_multiplier = 0;

	// loop for all items

	foreach ($tax_array as $taxitem) {
		$tax_multiplier += $taxitem['rate'];
	}
	
	return round($price * (1 + ($tax_multiplier / 100)),  user_price_dec());
}

//---------------------------------------------------------------------------------
// return an array of (tax_type_id, tax_type_name, sales_gl_code, purchasing_gl_code, rate)

function get_taxes_for_item($stock_id, $tax_group_items_array) {
	$item_tax_type = get_item_tax_type_for_item($stock_id);
	
	// if the item is exempt from all taxes then return 0
	if ($item_tax_type['exempt'])
		return null;
		
	// get the exemptions for this item tax type
	$item_tax_type_exemptions_db = get_item_tax_type_exemptions($item_tax_type['id']);
	
	// read them all into an array to minimize db querying
	$item_tax_type_exemptions = array();
	while ($item_tax_type_exemp = db_fetch($item_tax_type_exemptions_db)) {
		$item_tax_type_exemptions[] = $item_tax_type_exemp['tax_type_id'];
	}
	
	$ret_tax_array = array();
	
	// if any of the taxes of the tax group are in the exemptions, then skip
	foreach ($tax_group_items_array as $tax_group_item) {
		
		$skip = false;
		
		// if it's in the exemptions, skip
		foreach ($item_tax_type_exemptions as $exemption) {
			if (($tax_group_item['tax_type_id'] == $exemption)) {
				$skip = true;
				break;
			}
		}
		
		if (!$skip) {
			$index = $tax_group_item['tax_type_id'];
			$ret_tax_array[$index] = $tax_group_item;
		}
	}
	
	return $ret_tax_array;
}
//-----------------------------------------------------------------------------------
// return an array of (tax_type_id, tax_type_name, sales_gl_code, purchasing_gl_code, rate, included_in_price, Value) 

function get_tax_for_items($items, $prices, $shipping_cost, $tax_group, $tax_included=null, $tax_items_array=null, $tax_algorithm=null) {
	if (!$tax_algorithm)
		$tax_algorithm = get_company_pref('tax_algorithm');
	// first create and set an array with all the tax types of the tax group
	if($tax_items_array!=null)
		$ret_tax_array = $tax_items_array;
	else
		$ret_tax_array = get_tax_group_items_as_array($tax_group);

	$dec = user_price_dec();

	$fully_exempt = true;
	foreach($ret_tax_array as $k=>$t) {
		if ($t['rate'] !== null)
			$fully_exempt = false;
		$ret_tax_array[$k]['Net'] = 0;
	}
	
	$ret_tax_array['exempt'] = array('Value'=>0, 'Net'=>0, 'rate' => null, 'tax_type_id' => '', 'sales_gl_code' => '');
	$dec = user_price_dec();
	// loop for all items
	for ($i = 0; $i < count($items); $i++) {
		$item_taxes = get_taxes_for_item($items[$i], $ret_tax_array);
		if ($item_taxes == null || $fully_exempt) {
			  $ret_tax_array['exempt']['Value'] += round2(0, $dec);
			  $ret_tax_array['exempt']['Net'] += $prices[$i];
		}
		else {
			$tax_multiplier = 0;
			foreach ($item_taxes as $taxitem) {
				$tax_multiplier += $taxitem['rate'];
			}
			foreach ($item_taxes as $item_tax) {
				if ($item_tax['rate'] !== null) {
					$index = $item_tax['tax_type_id'];
					if ($tax_included == 1) {
						$ret_tax_array[$index]['Value'] += round2($prices[$i]*$item_tax['rate']/(100+$tax_multiplier), $dec);
						$ret_tax_array[$index]['Net'] += round2($prices[$i]*100/(100+$tax_multiplier), $dec);
					}
					else {
						$ret_tax_array[$index]['Value'] += round2($prices[$i] * $item_tax['rate'] / 100, $dec);
						$ret_tax_array[$index]['Net'] += $prices[$i];
					}
				}
			}
		}
	}
	// add the shipping taxes, only if non-zero, and only if tax group taxes shipping
	if ($shipping_cost != 0) {
		$item_taxes = get_shipping_tax_as_array($tax_group);
		if ($item_taxes != null) {
			if ($tax_included == 1) {
				$tax_rate = 0;
				foreach ($item_taxes as $item_tax) {
					$index = $item_tax['tax_type_id'];
					if(isset($ret_tax_array[$index]))
						$tax_rate += $item_tax['rate'];
				}
				$shipping_net = round2($shipping_cost*100/(100+$tax_rate), $dec);
			}
			foreach ($item_taxes as $item_tax) {
				$index = $item_tax['tax_type_id'];
				if ($item_tax['rate'] !== null && $ret_tax_array[$index]['rate'] !== null) {
					if($tax_included==1) {
						$ret_tax_array[$index]['Value'] += round2($shipping_cost*$item_tax['rate']/(100+$tax_rate), $dec);
						$ret_tax_array[$index]['Net'] += $shipping_net;
					}
					else {
						$ret_tax_array[$index]['Value'] += round2($shipping_cost * $item_tax['rate'] / 100, $dec);
						$ret_tax_array[$index]['Net'] += $shipping_cost;
					}
				}
			}
		}
	}

	if ($tax_algorithm == TCA_TOTALS ) {
		// update taxes with 
		foreach($ret_tax_array as $index => $item_tax) {
			$ret_tax_array[$index]['Value'] = round2($item_tax['Net'] * $item_tax['rate'] / 100, $dec);
		}
	}

	return $ret_tax_array;
}
