taxes/tax_calc.inc

   1 <?php
   2 /**********************************************************************
   3     Copyright (C) FrontAccounting, LLC.
   4         Released under the terms of the GNU General Public License, GPL,
   5         as published by the Free Software Foundation, either version 3
   6         of the License, or (at your option) any later version.
   7     This program is distributed in the hope that it will be useful,
   8     but WITHOUT ANY WARRANTY; without even the implied warranty of
   9     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  10     See the License here <http://www.gnu.org/licenses/gpl-3.0.html>.
  11 ***********************************************************************/
  12 include_once($path_to_root . "/taxes/db/tax_groups_db.inc");
  13 include_once($path_to_root . "/taxes/db/tax_types_db.inc");
  14 include_once($path_to_root . "/taxes/db/item_tax_types_db.inc");
  15
  16 //---------------------------------------------------------------------------------
  17
  18 // returns the price of a given item minus any included taxes
  19 // for item $stock_id with line price $price,
  20 // with applicable tax rates $tax_group_array or group id $tax_group
  21
  22 function get_tax_free_price_for_item($stock_id, $price, $tax_group, $tax_included, $tax_group_array=null)
  23 {
  24         // if price is zero, then can't be taxed !
  25         if ($price == 0)
  26                 return 0;
  27
  28         if ($tax_included==0) return $price;
  29
  30         // if array already read, then make a copy and use that
  31         if ($tax_group_array)
  32                 $ret_tax_array = $tax_group_array;
  33         else
  34                 $ret_tax_array = get_tax_group_items_as_array($tax_group);
  35
  36         $tax_array = get_taxes_for_item($stock_id, $ret_tax_array);
  37
  38         // if no exemptions or taxgroup is empty, then no included/excluded taxes
  39         if ($tax_array == null)
  40                 return $price;
  41
  42         // to avoid rounding errors we have to just subtract taxes from tax_included price.
  43         $tax_multiplier = 0;
  44         foreach ($tax_array as $taxitem)
  45         {
  46                 $tax_multiplier += $taxitem["rate"];
  47         }
  48
  49         $tax = 0;
  50         foreach ($tax_array as $taxitem)
  51         {
  52                 $tax += round($price*$taxitem['rate']/(100+$tax_multiplier), user_price_dec());
  53         }
  54         return $price-$tax;
  55 }
  56 //
  57 //      Full price (incl. VAT) for item $stock_id with line price $price,
  58 //      with tax rates $tax_group_array or applicable group $tax_group
  59 //
  60 function get_full_price_for_item($stock_id, $price, $tax_group, $tax_included, $tax_group_array=null)
  61 {
  62         // if price is zero, then can't be taxed !
  63         if ($price == 0)
  64                 return 0;
  65
  66         if ($tax_included==1) return $price;
  67
  68         // if array already read, then make a copy and use that
  69         if ($tax_group_array)
  70                 $ret_tax_array = $tax_group_array;
  71         else
  72                 $ret_tax_array = get_tax_group_items_as_array($tax_group);
  73
  74         //print_r($ret_tax_array);
  75
  76         $tax_array = get_taxes_for_item($stock_id, $ret_tax_array);
  77         // if no exemptions or taxgroup is empty, then no included/excluded taxes
  78         if ($tax_array == null)
  79                 return $price;
  80
  81         $tax_multiplier = 0;
  82
  83         // loop for all items
  84
  85         foreach ($tax_array as $taxitem)
  86         {
  87                         $tax_multiplier += $taxitem["rate"];
  88         }
  89
  90         return round($price * (1 + ($tax_multiplier / 100)),  user_price_dec());
  91 }
  92
  93 //---------------------------------------------------------------------------------
  94 // return an array of (tax_type_id, tax_type_name, sales_gl_code, purchasing_gl_code, rate)
  95
  96 function get_taxes_for_item($stock_id, $tax_group_items_array)
  97 {
  98         $item_tax_type = get_item_tax_type_for_item($stock_id);
  99
 100         // if the item is exempt from all taxes then return 0
 101         if ($item_tax_type["exempt"])
 102                 return null;
 103
 104         // get the exemptions for this item tax type
 105         $item_tax_type_exemptions_db = get_item_tax_type_exemptions($item_tax_type["id"]);
 106
 107         // read them all into an array to minimize db querying
 108         $item_tax_type_exemptions = array();
 109         while ($item_tax_type_exemp = db_fetch($item_tax_type_exemptions_db))
 110         {
 111                 $item_tax_type_exemptions[] = $item_tax_type_exemp["tax_type_id"];
 112         }
 113
 114         $ret_tax_array = array();
 115
 116         // if any of the taxes of the tax group are in the exemptions, then skip
 117         foreach ($tax_group_items_array as $tax_group_item)
 118         {
 119
 120                 $skip = false;
 121
 122                 // if it's in the exemptions, skip
 123                 foreach ($item_tax_type_exemptions as $exemption)
 124                 {
 125                         if (($tax_group_item['tax_type_id'] == $exemption))
 126                         {
 127                         $skip = true;
 128                         break;
 129                         }
 130                 }
 131
 132                 if (!$skip)
 133                 {
 134                         $index = $tax_group_item['tax_type_id'];
 135                         $ret_tax_array[$index] = $tax_group_item;
 136                 }
 137         }
 138
 139         return $ret_tax_array;
 140 }
 141 //-----------------------------------------------------------------------------------
 142 // return an array of (tax_type_id, tax_type_name, sales_gl_code, purchasing_gl_code, rate, included_in_price, Value)
 143
 144 function get_tax_for_items($items, $prices, $shipping_cost, $tax_group, $tax_included=null, $tax_items_array=null, $tax_algorithm = null)
 145 {
 146         if (!$tax_algorithm)
 147                 $tax_algorithm = get_company_pref('tax_algorithm');
 148         // first create and set an array with all the tax types of the tax group
 149         if($tax_items_array!=null)
 150                 $ret_tax_array = $tax_items_array;
 151         else
 152                 $ret_tax_array = get_tax_group_items_as_array($tax_group);
 153
 154         $dec = user_price_dec();
 155
 156         $fully_exempt = true;
 157         foreach($ret_tax_array as $k=>$t)
 158         {
 159                 if ($t['rate'] !== null)
 160                         $fully_exempt = false;
 161                 $ret_tax_array[$k]['Net'] = 0;
 162         }
 163
 164         $ret_tax_array['exempt'] = array('Value'=>0, 'Net'=>0, 'rate' => null, 'tax_type_id' => '', 'sales_gl_code' => '');
 165         $dec = user_price_dec();
 166         // loop for all items
 167         for ($i = 0; $i < count($items); $i++)
 168         {
 169                 $item_taxes = get_taxes_for_item($items[$i], $ret_tax_array);
 170                 if ($item_taxes == null || $fully_exempt)
 171                 {
 172                           $ret_tax_array['exempt']['Value'] += round2(0, $dec);
 173                           $ret_tax_array['exempt']['Net'] += $prices[$i];
 174                 }
 175                 else
 176                 {
 177                         $tax_multiplier = 0;
 178                         foreach ($item_taxes as $taxitem)
 179                         {
 180                                 $tax_multiplier += $taxitem['rate'];
 181                         }
 182                         foreach ($item_taxes as $item_tax)
 183                         {
 184                                 if ($item_tax['rate'] !== null) {
 185                                         $index = $item_tax['tax_type_id'];
 186                                         if ($tax_included == 1) {
 187                                                 $ret_tax_array[$index]['Value'] += round2($prices[$i]*$item_tax['rate']/(100+$tax_multiplier), $dec);
 188                                                 $ret_tax_array[$index]['Net'] += round2($prices[$i]*100/(100+$tax_multiplier), $dec);
 189                                         } else {
 190                                                 $ret_tax_array[$index]['Value'] += round2($prices[$i] * $item_tax['rate'] / 100, $dec);
 191                                                 $ret_tax_array[$index]['Net'] += $prices[$i];
 192                                         }
 193                                 }
 194                         }
 195                 }
 196         }
 197         // add the shipping taxes, only if non-zero, and only if tax group taxes shipping
 198         if ($shipping_cost != 0)
 199         {
 200                 $item_taxes = get_shipping_tax_as_array($tax_group);
 201                 if ($item_taxes != null)
 202                 {
 203                         if ($tax_included == 1)
 204                         {
 205                                 $tax_rate = 0;
 206                                 foreach ($item_taxes as $item_tax)
 207                                 {
 208                                         $index = $item_tax['tax_type_id'];
 209                                         if(isset($ret_tax_array[$index])) {
 210                                                 $tax_rate += $item_tax['rate'];
 211                                         }
 212                                 }
 213                                 $shipping_net = round2($shipping_cost*100/(100+$tax_rate), $dec);
 214                         }
 215                         foreach ($item_taxes as $item_tax)
 216                         {
 217                                 $index = $item_tax['tax_type_id'];
 218                                 if ($item_tax['rate'] !== null && $ret_tax_array[$index]['rate'] !== null) {
 219                                         if($tax_included==1) {
 220                                                 $ret_tax_array[$index]['Value'] += round2($shipping_cost*$item_tax['rate']/(100+$tax_rate), $dec);
 221                                                 $ret_tax_array[$index]['Net'] += $shipping_net;
 222                                         } else {
 223                                                 $ret_tax_array[$index]['Value'] += round2($shipping_cost * $item_tax['rate'] / 100, $dec);
 224                                                 $ret_tax_array[$index]['Net'] += $shipping_cost;
 225                                         }
 226                                 }
 227                         }
 228                 }
 229         }
 230
 231         if ($tax_algorithm == TCA_TOTALS ) {
 232                 // update taxes with
 233                 foreach($ret_tax_array as $index => $item_tax) {
 234                         $ret_tax_array[$index]['Value'] = round2($item_tax['Net'] * $item_tax['rate'] / 100, $dec);
 235                 }
 236         }
 237
 238         return $ret_tax_array;
 239 }
 240