Activated strict SQL mode, minor SQL injection fix, fixed _vl() debug helper.
[fa-stable.git] / sales / includes / cart_class.inc
index 25de205d1b4f280e12d5a20cbd0065f9c9caea78..1bc3db242f5b0528d2f98a2a65bde6275125bd14 100644 (file)
@@ -1,5 +1,14 @@
 <?php
-
+/**********************************************************************
+    Copyright (C) FrontAccounting, LLC.
+       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>.
+***********************************************************************/
 /* Definition of the cart class
 this class can hold all the information for:
 
@@ -12,77 +21,403 @@ iv)  a delivery note
 include_once($path_to_root . "/inventory/includes/inventory_db.inc");
 include_once($path_to_root . "/taxes/tax_calc.inc");
 
-class cart
+class Cart
 {
-
-       var $line_items; /*array of objects of class line_details using the product id as the pointer */
-
-       var $delivery_date;
-       var $default_sales_type; // set to the customer's sales type
+       var $trans_type; // invoice, order, quotation, delivery note ...
+       var $trans_no = array();// array (num1=>ver1,..) or 0 for new
+       var $so_type = 0;               // for sales order: simple=0 template=1
+       var $cart_id;           // used to detect multi-tab edition conflits
+       var $line_items;  //array of objects of class line_details
+
+       var $src_docs = array();        // array of arrays(num1=>ver1,...) or 0 for no src
+       var $src_date;                  // src document date (for info only)
+
+       var $document_date;
+       var $due_date;
+       var $sales_type; // set to the customer's sales type
        var $sales_type_name; // set to customer's sales type name
+       var $tax_included;
+
        var $customer_currency; // set to the customer's currency
        var $default_discount; // set to the customer's discount %
-       var $trans_type; // invoice, order, delivery note ...
-       var $memo_; // memo_ on direct invoicing
+       var $customer_name;
+       var $customer_id;
+       var $Branch;
+       var $email;
 
        var $deliver_to;
        var $delivery_address;
        var $phone;
 
-       var $email;
        var $cust_ref;
+       var $reference;
        var $Comments;
        var $Location;
        var $location_name;
-       var $order_no; // the original order number     
-       var $trans_no;// transaction number
-
-       var $customer_name;
-       var $customer_id;
-       var $Branch;
-
-       var $orig_order_date;
+       var $order_no;          // the original order number
 
        var $ship_via;
-       var $freight_cost;
+       var $freight_cost = 0;
 
        var $tax_group_id;
        var $tax_group_name;
-
-       function Cart($type = 'order')
-       {
+       var $tax_group_array = null; // saves db queries
+       var $price_factor;       // ditto for price calculations
+
+       var     $pos;                   // user assigned POS
+       var $cash_account;
+       var $account_name;
+       var $cash_discount;     // not used as of FA 2.1
+       var $dimension_id;
+       var $dimension2_id;
+       var $payment;
+       var $payment_terms; // cached payment terms
+       var $credit;
+       // prepayment mode:
+       var $prepaid=false;     // true for documents issued in prepayment mode
+       var $prep_amount=0;     // prepayment required for SO, invoiced amount for prepaiament invoice
+       var $sum_paid;          // sum of all allocated prepayments both to order and related invoices
+       var $alloc;             // sum of payments allocated to this document
+       var $prepayments = array(); // allocation records for this document
+       var $ex_rate;
+
+       var $fixed_asset = false;
+
+       //-------------------------------------------------------------------------
+       //
+       //  $trans_no==0 => open new/direct document
+       //  $trans_no!=0 && $prepare_child==false => update with parent constarints for reedition
+       //  $trans_no!=0 && $prepare_child==true => prepare for child doc entry
+       //      $prepare_child is set to ST_SALESINVOICE for prepayment invoices
+       //
+       function __construct($type, $trans_no=0, $prepare_child=false) {
                /*Constructor function initialises a new shopping cart */
                $this->line_items = array();
-               $this->default_sales_type = "";
-               $this->trans_type = $type;
+               $this->sales_type = "";
+               if ($type == ST_SALESQUOTE)
+                       $this->trans_type = $type;
+               else    
+                       $this->trans_type = ST_SALESORDER;
+               $this->dimension_id = 0;
+               $this->dimension2_id = 0;
+               $this->pos = get_sales_point(user_pos());
+               $this->read($type, $trans_no, $prepare_child);
+               $this->cart_id = uniqid('');
        }
 
-       function add_to_cart($stock_id, $qty, $price, $disc, $qty_done=0, $standard_cost=0, $description=null, $id=0)
+       /*
+               Optional sorting items by stock_id.
+       */
+       function _cmp_lines($a, $b)
        {
-               if (isset($stock_id) && $stock_id != "" && isset($qty)/* && $qty > 0*/)
-               {
-                       $this->line_items[] = new line_details($stock_id, $qty, $price, $disc, 
-                               $qty_done,  $standard_cost, $description, $id);
-                       return 1;
+               return strcmp($a->stock_id, $b->stock_id);
+       }
+
+       /*
+               Returns items array optionally sorted by item code.
+       */
+       function get_items()
+       {
+               global $SysPrefs;
+
+               $items = $this->line_items;
+               if (@$SysPrefs->sort_sales_items)
+                       uasort($items, array($this, '_cmp_lines'));
+
+               return $items;
+       }
+       //
+       //      Prepare cart to new child document entry, just after initial parent doc read.
+       //
+       function prepare_child($type)
+       {
+               global $Refs;
+
+               if ($type === true)
+                       $type = get_child_type($this->trans_type);
+
+               $this->trans_type = $type;
+               $this->reference = $Refs->get_next($this->trans_type, null, array('date' => $this->document_date,
+                       'customer' => $this->customer_id, 'branch' => $this->Branch));
+               if ($type == ST_CUSTCREDIT)
+                   $this->src_date = $this->document_date;
+
+               $this->document_date = new_doc_date();
+
+               for($line_no = 0; $line_no < count($this->line_items); $line_no++) {
+                       $line = &$this->line_items[$line_no];
+                       $line->src_id = $line->id; // save src line ids for update
+                       $line->qty_dispatched = $type == ST_CUSTCREDIT ? '0' : 
+                                (($this->prepaid && $type == ST_SALESINVOICE) ? $line->quantity : $line->quantity - $line->qty_done);
+                       $line->qty_old = 0;
                }
-               else
-               {
-                       // shouldn't come here under normal circumstances
-                       display_db_error("unexpected - adding an invalid item or null quantity", "", true);
+               unset($line);
+               
+               if ($type == ST_CUSTDELIVERY) {
+                       $this->order_no = key($this->trans_no);
+                       $cust = get_customer($this->customer_id);
+                       $this->dimension_id = $cust['dimension_id'];
+                       $this->dimension2_id = $cust['dimension2_id'];
                }
-               return 0;
+               if ($type == ST_SALESINVOICE) {
+                       $this->due_date = get_invoice_duedate($this->payment, $this->document_date);
+               }
+
+               $this->src_docs = $this->trans_no;
+               $this->trans_no = 0;
        }
 
-       function update_cart_item($line_no, $qty, $price, $disc)
-       {
+       //
+       //      Prepares transaction for reedition updating with parent transaction data 
+       //
+       function set_parent_constraints($sodata, $src_no) {
+
+               $srcdetails = get_sales_parent_lines($this->trans_type, $src_no);
+               $src_type = get_parent_type($this->trans_type);
+
+               // calculate & save: qtys on other docs and free qtys on src doc
+               $line_no = 0; $src_docs = array();
+               // Loop speed optimisation below depends on fact 
+               // that child line_items contains subset of parent lines in _the_same_ order !
+               while (($line_no < count($this->line_items)) && ($srcline = db_fetch($srcdetails))) {
+                       $line = &$this->line_items[$line_no];
+                       $src_docs[] = $src_type == ST_SALESORDER ?  $srcline['order_no'] : $srcline['debtor_trans_no'];
+                       while($srcline['id'] != $line->src_id) // Logic : This will increment the line_items array till sales_order line is matched.
+                       {       // Fixes Delivery note bug : Parent constraints not working if sales order line deleted after delivery 
+                       $line_no++;
+                       $line = &$this->line_items[$line_no];
+                       }
+                       if ($srcline['id'] == $line->src_id) {
+                               if ($this->trans_type == ST_SALESINVOICE)
+                                       $line->src_no = $srcline['debtor_trans_no'];
+                               $line->qty_old = $line->qty_dispatched = $line->quantity;
+                               $line->quantity += $srcline['quantity'] - 
+                                       ($src_type==ST_SALESORDER ? $srcline['qty_sent'] : $srcline['qty_done']); // add free qty on src doc
+                               $line_no++;
+                       }
+               }
 
-               if ($qty > 0)
+               if ($src_type == ST_SALESORDER || $src_type == 0) {
+                       $this->src_docs = array( $sodata['order_no']=>$sodata['version']);
+               } else {
+                       // get src_data from debtor_trans
+                       $this->src_docs = get_customer_trans_version($src_type, array_unique($src_docs));
+               }
+       }
+       //-------------------------------------------------------------------------
+       // Reading document into cart
+       //
+       function read($type, $trans_no=0, $prepare_child=false) {
+
+               global $SysPrefs, $Refs;
+
+               if (!is_array($trans_no)) $trans_no = array($trans_no);
+
+               if ($trans_no[0]) { // read old transaction
+                       if ($type == ST_SALESORDER || $type == ST_SALESQUOTE) { // sales order || sales quotation
+                               read_sales_order($trans_no[0], $this, $type);
+                       } else {        // other type of sales transaction
+                               read_sales_trans($type, $trans_no, $this);
+                               $this->prepayments = get_payments_for($trans_no[0], $type, $this->customer_id);
+                               $this->update_payments();
+                               if ($this->order_no) { // free hand credit notes have no order_no
+                                       $sodata = get_sales_order_header($this->order_no, ST_SALESORDER);
+                                       $this->cust_ref = $sodata["customer_ref"];
+                               // currently currency is hard linked to debtor account
+                                       $this->delivery_to = $sodata["deliver_to"];
+                                       $this->delivery_address = $sodata["delivery_address"];
+                               // child transaction reedition - update with parent info unless it is freehand
+                               if (!$this->is_prepaid() && !$prepare_child) // this is read for view/reedition
+                                       $this->set_parent_constraints($sodata, $trans_no[0]);
+                               }
+                       }
+                       // convert document into child and prepare qtys for entry
+                       if ($prepare_child)
+                               $this->prepare_child($prepare_child);
+
+               } else { // new document
+                       $this->trans_type = $type;
+                       $this->trans_no = 0;
+                       $this->customer_currency = get_company_currency();
+                       // set new sales document defaults here
+                       if (get_global_customer() != ALL_TEXT)
+                         $this->customer_id = get_global_customer();
+                       else
+                         $this->customer_id = '';
+                       $this->document_date = new_doc_date();
+                       if (!is_date_in_fiscalyear($this->document_date))
+                               $this->document_date = end_fiscalyear();
+                       $this->reference = $Refs->get_next($this->trans_type, null, array('date' => Today(),
+                               'customer' => $this->customer_id));
+                       if ($type != ST_SALESORDER && $type != ST_SALESQUOTE) // Added 2.1 Joe Hunt 2008-11-12
+                       {
+                               $dim = get_company_pref('use_dimension');
+                               if ($dim > 0)
+                               {
+                                       if ($this->customer_id == '')
+                                               $this->dimension_id = 0;
+                                       else
+                                       {
+                                               $cust = get_customer($this->customer_id);
+                                               $this->dimension_id = $cust['dimension_id'];
+                                       }       
+                                       if ($dim > 1)
+                                       {
+                                               if ($this->customer_id == '')
+                                                       $this->dimension2_id = 0;
+                                               else
+                                                       $this->dimension2_id = $cust['dimension2_id'];
+                                       }               
+                               }               
+                       }       
+                       if ($type == ST_SALESINVOICE) {
+                               $this->due_date =
+                                       get_invoice_duedate($this->payment, $this->document_date);
+                       } else
+                               $this->due_date =
+                                       add_days($this->document_date, $SysPrefs->default_delivery_required_by());
+               }
+               $this->credit = get_current_cust_credit($this->customer_id);
+       }
+
+       //-------------------------------------------------------------------------
+       // Writing new/modified sales document to database.
+       // Makes parent documents for direct delivery/invoice by recurent call.
+       // $policy - 0 or 1:  writeoff/return for IV, back order/cancel for DN
+       function write($policy=0) {
+               
+               global $SysPrefs, $Refs;
+               
+               begin_transaction(); // prevents partial database changes in case of direct delivery/invoice
+               if ($this->reference != 'auto' && $this->trans_no == 0 && !is_new_reference($this->reference, $this->trans_type))
                {
-                       $this->line_items[$line_no]->quantity = $qty;
+                       if (!empty($SysPrefs->prefs['ref_no_auto_increase']))
+                               $this->reference = $Refs->get_next($this->trans_type, null, array('date' => Today()));
+                       if (!is_new_reference($this->reference, $this->trans_type))     
+                       {
+                               commit_transaction();
+                               return -1;
+                       }       
+               }
+               if (count($this->src_docs) == 0 && ($this->trans_type == ST_SALESINVOICE || $this->trans_type == ST_CUSTDELIVERY) && !$this->is_prepaid()) {
+                       // this is direct document - first add parent
+                       $ref = $this->reference;
+                       $date = $this->document_date;
+                       $due_date = $this->due_date;
+                       $dimension_id = $this->dimension_id;
+                       $dimension2_id = $this->dimension2_id;
+                       $this->trans_type = get_parent_type($this->trans_type);
+
+                       $this->reference = 'auto'; 
+                       $trans_no = $this->write(1); 
+
+                       // re-read parent document converting it to child
+                       $this->read($this->trans_type, $trans_no, true); 
+                       $this->document_date = $date;
+                       $this->reference = $ref;
+                       $this->due_date = $due_date;
+                       $this->dimension_id = $dimension_id;
+                       $this->dimension2_id = $dimension2_id;
+               }
+               $this->reference = @html_entity_decode($this->reference, ENT_QUOTES);
+               $this->Comments = @html_entity_decode($this->Comments, ENT_QUOTES);
+               foreach($this->line_items as $lineno => $line) {
+                       $this->line_items[$lineno]->stock_id = @html_entity_decode($line->stock_id, ENT_QUOTES);
+                       $this->line_items[$lineno]->item_description = @html_entity_decode($line->item_description, ENT_QUOTES);
                }
+               switch($this->trans_type) {
+                       case ST_SALESINVOICE:
+                               $ret = write_sales_invoice($this); break;
+                       case ST_CUSTCREDIT:
+                               $ret = write_credit_note($this, $policy); break;
+                       case ST_CUSTDELIVERY:
+                               $ret = write_sales_delivery($this, $policy); break;
+                       case ST_SALESORDER:
+                       case ST_SALESQUOTE:
+                               if ($this->trans_no==0) // new document
+                                       $ret = add_sales_order($this);
+                               else
+                                       $ret = update_sales_order($this);
+               }
+
+               commit_transaction();
+
+               return $ret;
+       }
+
+       function set_customer($customer_id, $customer_name, $currency, $discount, $payment, $cdiscount=0)
+       {
+               $this->customer_name = $customer_name;
+               $this->customer_id = $customer_id;
+               $this->default_discount = $discount;
+               $this->customer_currency = $currency;
+               $this->payment = $payment;
+               $this->payment_terms = get_payment_terms($payment);
+               $this->cash_discount = $cdiscount;
+
+               if ($this->payment_terms['cash_sale']) {
+                       $this->Location = $this->pos['pos_location'];
+                       $this->location_name = $this->pos['location_name'];
+               }
+               $this->credit = get_current_cust_credit($customer_id);
+       }
+
+       function set_branch($branch_id, $tax_group_id, $tax_group_name, $phone='', $email='')
+       {
+               $this->Branch = $branch_id;
+               $this->phone = $phone;
+               $this->email = $email;
+               $this->tax_group_id = $tax_group_id;
+               $this->tax_group_array = get_tax_group_items_as_array($tax_group_id);
+       }
+
+       function set_sales_type($sales_type, $sales_name, $tax_included=0, $factor=0)
+       {
+           $this->sales_type = $sales_type;
+           $this->sales_type_name = $sales_name;
+           $this->tax_included = $tax_included;
+           $this->price_factor = $factor;
+       }
+
+       function set_location($id, $name)
+       {
+               $this->Location = $id;
+               $this->location_name = $name;
+       }
+
+       function set_delivery($shipper, $destination, $address, $freight_cost=null)
+       {
+               $this->ship_via = $shipper;
+               $this->deliver_to = $destination;
+               $this->delivery_address = $address;
+               if (isset($freight_cost))
+                       $this->freight_cost = $freight_cost;
+       }
+
+       function add_to_cart($line_no, $stock_id, $qty, $price, $disc, $qty_done=0, $standard_cost=0, $description=null, $id=0, $src_no=0,
+               $src_id=0)
+       {
+               $line = new line_details($stock_id, $qty, $price, $disc,
+                       $qty_done,  $standard_cost, $description, $id, $src_no, $src_id);
+
+               if ($line->valid) {
+                       $this->line_items[$line_no] = $line;
+                       return 1;
+               } else
+                       display_error(_("You have to enter valid stock code or nonempty description"));
+               return 0;
+       }
+
+       function update_cart_item($line_no, $qty, $price, $disc, $description="")
+       {
+               if ($description != "")
+                       $this->line_items[$line_no]->item_description = $description;
+               $this->line_items[$line_no]->quantity = $qty;
+               $this->line_items[$line_no]->qty_dispatched = $qty;
                $this->line_items[$line_no]->price = $price;
                $this->line_items[$line_no]->discount_percent = $disc;
        }
+
        function update_add_cart_item_qty($line_no, $qty)
        {
                $this->line_items[$line_no]->quantity += $qty;
@@ -90,78 +425,66 @@ class cart
 
        function remove_from_cart($line_no)
        {
-                       unset($this->line_items[$line_no]);
+               array_splice($this->line_items, $line_no, 1);
        }
 
        function clear_items()
        {
-       unset($this->line_items);
+               unset($this->line_items);
                $this->line_items = array();
-               $this->default_sales_type = "";
+               $this->sales_type = "";
                $this->trans_no = 0;
                $this->customer_id = $this->order_no = 0;
        }
 
        function count_items()
        {
-         $counter=0;
-         foreach($this->line_items as $line) {
-               if($line->quantity>$line->qty_done) $counter++;
-         }
+               $counter=0;
+               foreach ($this->line_items as $line) {
+                       if ($line->quantity!=$line->qty_done) $counter++;
+               }
                return $counter;
        }
 
-       function get_items_total_dispatch($tax_group_id=null)
+       function get_items_total()
        {
                $total = 0;
 
-               // preload the taxgroup !
-               if ($tax_group_id != null)
-                       $tax_group_array = get_tax_group_items_as_array($tax_group_id);
-               else
-                       $tax_group_array = null;
-
-               foreach ($this->line_items as $ln_itm)
-               {
-                       $total += ($ln_itm->qty_dispatched * $ln_itm->taxfree_price($tax_group_id, $tax_group_array) * (1 - $ln_itm->discount_percent));
+               foreach ($this->line_items as $ln_itm) {
+                       $price = $ln_itm->line_price();
+                       $total += round($ln_itm->quantity * $price * (1 - $ln_itm->discount_percent), 
+                          user_price_dec());
                }
                return $total;
        }
 
-       function has_items_dispatch()
+       function get_items_total_dispatch()
        {
-               foreach ($this->line_items as $ln_itm)
-               {
-                       if ($ln_itm->qty_dispatched > 0)
-                               return true;
+               $total = 0;
+
+               foreach ($this->line_items as $ln_itm) {
+                       $price = $ln_itm->line_price();
+                       $total += round(($ln_itm->qty_dispatched * $price * (1 - $ln_itm->discount_percent)), 
+                          user_price_dec());
                }
-               return false;
+               return $total;
        }
 
-       function get_items_total($tax_group_id=null)
+       function has_items_dispatch()
        {
-               $total = 0;
-
-               // preload the taxgroup !
-               if ($tax_group_id != null)
-                       $tax_group_array = get_tax_group_items_as_array($tax_group_id);
-               else
-                       $tax_group_array = null;
-
                foreach ($this->line_items as $ln_itm) {
-                       $total += ($ln_itm->quantity * $ln_itm->taxfree_price($tax_group_id, $tax_group_array) * (1 - $ln_itm->discount_percent));
+                       if ($ln_itm->qty_dispatched > 0)
+                               return true;
                }
-               return $total;
+               return false;
        }
 
        function any_already_delivered()
        {
-               /* Checks if there have been deliveries of line items */
+               /* Checks if there have been any line item processed */
 
-               foreach ($this->line_items as $stock_item)
-               {
-                       if ($stock_item->qty_done !=0)
-                       {
+               foreach ($this->line_items as $stock_item) {
+                       if ($stock_item->qty_done !=0) {
                                return 1;
                        }
                }
@@ -173,42 +496,167 @@ class cart
        function some_already_delivered($line_no)
        {
                /* Checks if there have been deliveries of a specific line item */
-               if (isset($this->line_items[$line_no]) && 
-                       $this->line_items[$line_no]->qty_done != 0)
-               {
+               if (isset($this->line_items[$line_no]) &&
+                       $this->line_items[$line_no]->qty_done != 0) {
                        return 1;
                }
                return 0;
        }
 
-    function get_taxes($tax_group_id=null, $shipping_cost=0)
-    {
-       $items = array();
-       $prices = array();
+       function get_taxes($shipping_cost=null)
+       {
+               $items = array();
+               $prices = array();
+               if($shipping_cost==null)
+                       $shipping_cost = $this->freight_cost;
+
+               foreach ($this->line_items as $ln_itm) {
+                       $items[] = $ln_itm->stock_id;
+                       $prices[] = round(((
+                               $this->trans_type==ST_SALESORDER ?      $ln_itm->quantity : $ln_itm->qty_dispatched) *
+                               $ln_itm->line_price()* (1 - $ln_itm->discount_percent)),  user_price_dec());
+               }
+
+               $taxes = get_tax_for_items($items, $prices, $shipping_cost,
+                       $this->tax_group_id, $this->tax_included,  $this->tax_group_array);
+
+    // Adjustment for swiss franken, we always have 5 rappen = 1/20 franken
+    if ($this->customer_currency == 'CHF') {
+                       $val = $taxes['1']['Value'];
+                       $val1 = (floatval((intval(round(($val*20),0)))/20));
+                       $taxes['1']['Value'] = $val1;
+               } 
+               return $taxes;
+       }
+
+
+       function get_tax_free_shipping()
+       {
+
+               if ($this->tax_included==0)
+                       return $this->freight_cost;
+               else
+                       return ($this->freight_cost - $this->get_shipping_tax());
+       }
+
+       function get_shipping_tax()
+       {
 
-        if ($tax_group_id == null)
-               $tax_group_id = $this->tax_group_id;
+               $tax_items = get_shipping_tax_as_array($this->tax_group_id);
+               $tax_rate = 0;
+               if ($tax_items != null) {
+                       foreach ($tax_items as $item_tax) {
+                               $index = $item_tax['tax_type_id'];
+                               if (isset($this->tax_group_array[$index]['rate'])) {
+                                       $tax_rate += $item_tax['rate'];
+                               }
+                       }
+               }
+               if($this->tax_included)
+                       return round($this->freight_cost*$tax_rate/($tax_rate+100),  user_price_dec());
+               else
+                       return round($this->freight_cost*$tax_rate/100,  user_price_dec());
+       }
+       /*
+               Returns transaction value including all taxes
+       */
+       function get_trans_total() {
+               
+               $total = $this->get_items_total() + $this->freight_cost;
+               $dec = user_price_dec();
+               if (!$this->tax_included ) {
+                       $total += $this->get_shipping_tax();
+                       $taxes = $this->get_taxes();
+                       foreach($taxes as $tax)
+                               $total += round($tax['Value'], $dec);
+               }
 
-               // preload the taxgroup !
-               $tax_group_array = get_tax_group_items_as_array($tax_group_id);
+               return $total;
+       }
+
+       /*
+               Checks cart quantities on document_date.
+               Returns array of stock_ids which stock quantities would go negative on some day.
+       */
+       function check_qoh($date=null, $location=null)
+       {
+               $low_stock = array();
+               // check only for customer delivery and direct sales invoice 
+               if (!($this->trans_type == ST_CUSTDELIVERY || ($this->trans_type == ST_SALESINVOICE && $this->trans_no==0)))
+                       return $low_stock;
+
+               // collect quantities by stock_id
+               $qtys = array();
+               foreach ($this->line_items as $line_no => $line_item)
+               {
+                       if (has_stock_holding($line_item->mb_flag))
+                       {
+                               if (!$this->trans_no) // new delivery
+                                       $qtys[$line_item->stock_id]['qty'] = $line_item->qty_dispatched + @$qtys[$line_item->stock_id]['qty'];
+                               else    // DN modification: check change in quantity
+                                       $qtys[$line_item->stock_id]['qty'] = ($line_item->qty_dispatched-$line_item->qty_old) + @$qtys[$line_item->stock_id]['qty'];
+                               $qtys[$line_item->stock_id]['line'] = $line_no;
+                       }
+               }
+
+               foreach($qtys as $stock_id => $sum)
+               {
+                       if (check_negative_stock($stock_id, -$sum['qty'], $location ? $location : $this->Location, $date ? $date : $this->document_date))
+                               $low_stock[] = $stock_id;
+               }
 
-        foreach ($this->line_items as $ln_itm)
-        {
-                       $items[] = $ln_itm->stock_id;
-                       $prices[] = ($ln_itm->qty_dispatched * $ln_itm->taxfree_price($tax_group_id, $tax_group_array) * (1 - $ln_itm->discount_percent));
-        }
+               return $low_stock;
+       }
 
+       /*
+               Returns true for documents issued in prepayment cycle.
+       */
+       function is_prepaid()
+       {
+               return $this->prepaid; 
+       }
+       /*
+               Order is ready for delivery in prepament mode.
+       */
+       function is_released()
+       {
+               return floatcmp($this->sum_paid, $this->prep_amount) >= 0;
+       }
 
-        $taxes = get_tax_for_items($items, $prices, $shipping_cost, $tax_group_id, $tax_group_array);
+       /*
+               Check whether order has been already invoiced/send or not.
+       */
+       function is_started()
+       {
+               if ($this->trans_no==0)
+                       return false;
+               $order_no = array_keys($this->trans_no);
 
-        return $taxes;
-    }
+               return  is_sales_order_started(reset($order_no));
+       }
 
+       /*
+               Check payment terms and prepayments selected for this invoice,
+               and updates     partial/final invoice value respectively.
+       */
+       function update_payments()
+       {
+               $remainder = prepaid_invoice_remainder($this->order_no);
+
+               // recalculate prepaid part from payments
+               if ($this->payment_terms['days_before_due'] == -1)
+               {       // this is partial invoice for selected prepayments made.
+                       $paid = 0;
+                       foreach($this->prepayments as $payment)
+                               $paid += $payment['amt'];
+                       $this->prep_amount = $this->trans_no ? $paid : min($remainder, $paid);
+               } else  // this is final invoice
+                       $this->prep_amount = $remainder;
+       }
 } /* end of class defintion */
 
 class line_details
 {
-       var $line_no;
        var $id;
        var $stock_id;
        var $item_description;
@@ -216,54 +664,78 @@ class line_details
        var $mb_flag;
        var $tax_type;
        var $tax_type_name;
-
-       var $quantity;
+       var $src_no;    // number of src doc for this line
+       var $src_id;
        var $price;
        var $discount_percent;
-       var $qty_done;  // quantity processed so far
-       var $qty_dispatched; // quantity selected to process 
+       
        var $standard_cost;
+       var $descr_editable;
+
+       var $valid; // validation in constructor
+       /*
+               Line quantity properties in various cart create modes:
+               
+               view:
+               $quantity - quantity on current document
+               $qty_done - quantity processed on all child documents
+               $qty_dispatched - not used
+               $qty_old - not used
+
+               edit:
+               $quantity - free parent quantity including this doc (= max allowed quantity)
+               $qty_done - qty processed on child documents (= min allowed qty)
+               $qty_dispatched - quantity currently selected to process
+               $qty_old - quantity processed on this document before reedition 
+
+               new child entry (view parent followed by prepare_child() call):
+               $quantity - max allowed quantity (get from parent)
+               $qty_done - qty processed on other child documents
+               $qty_dispatched - quantity currently selected to process
+               $qty_old - 0; not used
+       */
+       var $quantity;
+       var $qty_done;
+       var $qty_dispatched;
+       var $qty_old = 0;
 
-       function line_details ($stock_id, $qty, $prc, $disc_percent,  
-               $qty_done, $standard_cost, $description, $id=0)
+
+       function __construct($stock_id, $qty, $prc, $disc_percent,
+               $qty_done, $standard_cost, $description, $id=0, $src_no=0, $src_id=0)
        {
        /* Constructor function to add a new LineDetail object with passed params */
 
                $this->id = $id;
+               $this->src_no = $src_no;
+               $this->src_id = $src_id;
                $item_row = get_item($stock_id);
 
-               if ($item_row == null)
-                       display_db_error("invalid item added to order : $stock_id", "");
-
+               if (!$item_row) 
+                       return;
+                       
                $this->mb_flag = $item_row["mb_flag"];
                $this->units = $item_row["units"];
-               if ($description == null)
+               $this->descr_editable = $item_row["editable"];
+               if ($description == null || !$this->descr_editable)
                        $this->item_description = $item_row["description"];
                else
                        $this->item_description = $description;
-               //$this->standard_cost = $item_row["material_cost"] + $item_row["labour_cost"] + $item_row["overhead_cost"];
                $this->tax_type = $item_row["tax_type_id"];
                $this->tax_type_name = $item_row["tax_type_name"];
-
                $this->stock_id = $stock_id;
                $this->quantity = $qty;
+               $this->qty_dispatched = $qty;
                $this->price = $prc;
                $this->discount_percent = $disc_percent;
                $this->qty_done = $qty_done;
                $this->standard_cost = $standard_cost;
+               $this->valid = true;
        }
 
-       function full_price()
+       // get unit price as stated on document
+       function line_price()
        {
                return $this->price;
        }
-
-       function taxfree_price($tax_group_id, $tax_group_array=null)
-       {
-               if ($tax_group_id==null)
-                       return $this->price;
-               return get_tax_free_price_for_item($this->stock_id, $this->price, $tax_group_id, $tax_group_array);
-       }
 }
 
-?>