addons/point_of_sale/static/src/js/models.js

   1 function openerp_pos_models(instance, module){ //module is instance.point_of_sale
   2     var QWeb = instance.web.qweb;
   3         var _t = instance.web._t;
   4
   5     var round_di = instance.web.round_decimals;
   6     var round_pr = instance.web.round_precision
   7
   8     // The PosModel contains the Point Of Sale's representation of the backend.
   9     // Since the PoS must work in standalone ( Without connection to the server )
  10     // it must contains a representation of the server's PoS backend.
  11     // (taxes, product list, configuration options, etc.)  this representation
  12     // is fetched and stored by the PosModel at the initialisation.
  13     // this is done asynchronously, a ready deferred alows the GUI to wait interactively
  14     // for the loading to be completed
  15     // There is a single instance of the PosModel for each Front-End instance, it is usually called
  16     // 'pos' and is available to all widgets extending PosWidget.
  17
  18     module.PosModel = Backbone.Model.extend({
  19         initialize: function(session, attributes) {
  20             Backbone.Model.prototype.initialize.call(this, attributes);
  21             var  self = this;
  22             this.session = session;
  23             this.flush_mutex = new $.Mutex();                   // used to make sure the orders are sent to the server once at time
  24             this.pos_widget = attributes.pos_widget;
  25
  26             this.proxy = new module.ProxyDevice(this);              // used to communicate to the hardware devices via a local proxy
  27             this.barcode_reader = new module.BarcodeReader({'pos': this, proxy:this.proxy, patterns: {}});  // used to read barcodes
  28             this.proxy_queue = new module.JobQueue();           // used to prevent parallels communications to the proxy
  29             this.db = new module.PosDB();                       // a local database used to search trough products and categories & store pending orders
  30             this.debug = jQuery.deparam(jQuery.param.querystring()).debug !== undefined;    //debug mode
  31
  32             // Business data; loaded from the server at launch
  33             this.accounting_precision = 2; //TODO
  34             this.company_logo = null;
  35             this.company_logo_base64 = '';
  36             this.currency = null;
  37             this.shop = null;
  38             this.company = null;
  39             this.user = null;
  40             this.users = [];
  41             this.partners = [];
  42             this.cashier = null;
  43             this.cashregisters = [];
  44             this.bankstatements = [];
  45             this.taxes = [];
  46             this.pos_session = null;
  47             this.config = null;
  48             this.units = [];
  49             this.units_by_id = {};
  50             this.pricelist = null;
  51             this.order_sequence = 1;
  52             window.posmodel = this;
  53
  54             // these dynamic attributes can be watched for change by other models or widgets
  55             this.set({
  56                 'synch':            { state:'connected', pending:0 },
  57                 'orders':           new module.OrderCollection(),
  58                 'selectedOrder':    null,
  59             });
  60
  61             this.bind('change:synch',function(pos,synch){
  62                 clearTimeout(self.synch_timeout);
  63                 self.synch_timeout = setTimeout(function(){
  64                     if(synch.state !== 'disconnected' && synch.pending > 0){
  65                         self.set('synch',{state:'disconnected', pending:synch.pending});
  66                     }
  67                 },3000);
  68             });
  69
  70             this.get('orders').bind('remove', function(order,_unused_,options){
  71                 self.on_removed_order(order,options.index,options.reason);
  72             });
  73
  74             // We fetch the backend data on the server asynchronously. this is done only when the pos user interface is launched,
  75             // Any change on this data made on the server is thus not reflected on the point of sale until it is relaunched.
  76             // when all the data has loaded, we compute some stuff, and declare the Pos ready to be used.
  77             this.ready = this.load_server_data()
  78                 .then(function(){
  79                     if(self.config.use_proxy){
  80                         return self.connect_to_proxy();
  81                     }
  82                 });
  83
  84         },
  85
  86         // releases ressources holds by the model at the end of life of the posmodel
  87         destroy: function(){
  88             // FIXME, should wait for flushing, return a deferred to indicate successfull destruction
  89             // this.flush();
  90             this.proxy.close();
  91             this.barcode_reader.disconnect();
  92             this.barcode_reader.disconnect_from_proxy();
  93         },
  94         connect_to_proxy: function(){
  95             var self = this;
  96             var  done = new $.Deferred();
  97             this.barcode_reader.disconnect_from_proxy();
  98             this.pos_widget.loading_message(_t('Connecting to the PosBox'),0);
  99             this.pos_widget.loading_skip(function(){
 100                     self.proxy.stop_searching();
 101                 });
 102             this.proxy.autoconnect({
 103                     force_ip: self.config.proxy_ip || undefined,
 104                     progress: function(prog){
 105                         self.pos_widget.loading_progress(prog);
 106                     },
 107                 }).then(function(){
 108                     if(self.config.iface_scan_via_proxy){
 109                         self.barcode_reader.connect_to_proxy();
 110                     }
 111                 }).always(function(){
 112                     done.resolve();
 113                 });
 114             return done;
 115         },
 116
 117         // helper function to load data from the server. Obsolete use the models loader below.
 118         fetch: function(model, fields, domain, ctx){
 119             this._load_progress = (this._load_progress || 0) + 0.05;
 120             this.pos_widget.loading_message(_t('Loading')+' '+model,this._load_progress);
 121             return new instance.web.Model(model).query(fields).filter(domain).context(ctx).all()
 122         },
 123
 124         // Server side model loaders. This is the list of the models that need to be loaded from
 125         // the server. The models are loaded one by one by this list's order. The 'loaded' callback
 126         // is used to store the data in the appropriate place once it has been loaded. This callback
 127         // can return a deferred that will pause the loading of the next module.
 128         // a shared temporary dictionary is available for loaders to communicate private variables
 129         // used during loading such as object ids, etc.
 130         models: [
 131         {
 132             model:  'res.users',
 133             fields: ['name','company_id'],
 134             ids:    function(self){ return [self.session.uid]; },
 135             loaded: function(self,users){ self.user = users[0]; },
 136         },{
 137             model:  'res.company',
 138             fields: [ 'currency_id', 'email', 'website', 'company_registry', 'vat', 'name', 'phone', 'partner_id' , 'country_id'],
 139             ids:    function(self){ return [self.user.company_id[0]] },
 140             loaded: function(self,companies){ self.company = companies[0]; },
 141         },{
 142             model:  'decimal.precision',
 143             fields: ['name','digits'],
 144             loaded: function(self,dps){
 145                 self.dp  = {};
 146                 for (var i = 0; i < dps.length; i++) {
 147                     self.dp[dps[i].name] = dps[i].digits;
 148                 }
 149             },
 150         },{
 151             model:  'product.uom',
 152             fields: [],
 153             domain: null,
 154             loaded: function(self,units){
 155                 self.units = units;
 156                 var units_by_id = {};
 157                 for(var i = 0, len = units.length; i < len; i++){
 158                     units_by_id[units[i].id] = units[i];
 159                     units[i].groupable = ( units[i].category_id[0] === 1 );
 160                     units[i].is_unit   = ( units[i].id === 1 );
 161                 }
 162                 self.units_by_id = units_by_id;
 163             }
 164         },{
 165             model:  'res.users',
 166             fields: ['name','ean13'],
 167             domain: null,
 168             loaded: function(self,users){ self.users = users; },
 169         },{
 170             model:  'res.partner',
 171             fields: ['name','street','city','state_id','country_id','vat','phone','zip','mobile','email','ean13','write_date'],
 172             domain: [['customer','=',true]],
 173             loaded: function(self,partners){
 174                 self.partners = partners;
 175                 self.db.add_partners(partners);
 176             },
 177         },{
 178             model:  'res.country',
 179             fields: ['name'],
 180             loaded: function(self,countries){
 181                 self.countries = countries;
 182                 self.company.country = null;
 183                 for (var i = 0; i < countries.length; i++) {
 184                     if (countries[i].id === self.company.country_id[0]){
 185                         self.company.country = countries[i];
 186                     }
 187                 }
 188             },
 189         },{
 190             model:  'account.tax',
 191             fields: ['name','amount', 'price_include', 'type'],
 192             domain: null,
 193             loaded: function(self,taxes){ self.taxes = taxes; },
 194         },{
 195             model:  'pos.session',
 196             fields: ['id', 'journal_ids','name','user_id','config_id','start_at','stop_at','sequence_number','login_number'],
 197             domain: function(self){ return [['state','=','opened'],['user_id','=',self.session.uid]]; },
 198             loaded: function(self,pos_sessions){
 199                 self.pos_session = pos_sessions[0];
 200
 201                 var orders = self.db.get_orders();
 202                 for (var i = 0; i < orders.length; i++) {
 203                     self.pos_session.sequence_number = Math.max(self.pos_session.sequence_number, orders[i].data.sequence_number+1);
 204                 }
 205             },
 206         },{
 207             model: 'pos.config',
 208             fields: [],
 209             domain: function(self){ return [['id','=', self.pos_session.config_id[0]]]; },
 210             loaded: function(self,configs){
 211                 self.config = configs[0];
 212                 self.config.use_proxy = self.config.iface_payment_terminal ||
 213                                         self.config.iface_electronic_scale ||
 214                                         self.config.iface_print_via_proxy  ||
 215                                         self.config.iface_scan_via_proxy   ||
 216                                         self.config.iface_cashdrawer;
 217
 218                 self.barcode_reader.add_barcode_patterns({
 219                     'product':  self.config.barcode_product,
 220                     'cashier':  self.config.barcode_cashier,
 221                     'client':   self.config.barcode_customer,
 222                     'weight':   self.config.barcode_weight,
 223                     'discount': self.config.barcode_discount,
 224                     'price':    self.config.barcode_price,
 225                 });
 226
 227                 if (self.config.company_id[0] !== self.user.company_id[0]) {
 228                     throw new Error(_t("Error: The Point of Sale User must belong to the same company as the Point of Sale. You are probably trying to load the point of sale as an administrator in a multi-company setup, with the administrator account set to the wrong company."));
 229                 }
 230             },
 231         },{
 232             model: 'stock.location',
 233             fields: [],
 234             ids:    function(self){ return [self.config.stock_location_id[0]]; },
 235             loaded: function(self, locations){ self.shop = locations[0]; },
 236         },{
 237             model:  'product.pricelist',
 238             fields: ['currency_id'],
 239             ids:    function(self){ return [self.config.pricelist_id[0]]; },
 240             loaded: function(self, pricelists){ self.pricelist = pricelists[0]; },
 241         },{
 242             model: 'res.currency',
 243             fields: ['symbol','position','rounding','accuracy'],
 244             ids:    function(self){ return [self.pricelist.currency_id[0]]; },
 245             loaded: function(self, currencies){
 246                 self.currency = currencies[0];
 247                 if (self.currency.rounding > 0) {
 248                     self.currency.decimals = Math.ceil(Math.log(1.0 / self.currency.rounding) / Math.log(10));
 249                 } else {
 250                     self.currency.decimals = 0;
 251                 }
 252
 253             },
 254         },{
 255             model: 'product.packaging',
 256             fields: ['ean','product_tmpl_id'],
 257             domain: null,
 258             loaded: function(self, packagings){
 259                 self.db.add_packagings(packagings);
 260             },
 261         },{
 262             model:  'pos.category',
 263             fields: ['id','name','parent_id','child_id','image'],
 264             domain: null,
 265             loaded: function(self, categories){
 266                 self.db.add_categories(categories);
 267             },
 268         },{
 269             model:  'product.product',
 270             fields: ['display_name', 'list_price','price','pos_categ_id', 'taxes_id', 'ean13', 'default_code',
 271                      'to_weight', 'uom_id', 'uos_id', 'uos_coeff', 'mes_type', 'description_sale', 'description',
 272                      'product_tmpl_id'],
 273             domain: [['sale_ok','=',true],['available_in_pos','=',true]],
 274             context: function(self){ return { pricelist: self.pricelist.id, display_default_code: false }; },
 275             loaded: function(self, products){
 276                 self.db.add_products(products);
 277             },
 278         },{
 279             model:  'account.bank.statement',
 280             fields: ['account_id','currency','journal_id','state','name','user_id','pos_session_id'],
 281             domain: function(self){ return [['state', '=', 'open'],['pos_session_id', '=', self.pos_session.id]]; },
 282             loaded: function(self, bankstatements, tmp){
 283                 self.bankstatements = bankstatements;
 284
 285                 tmp.journals = [];
 286                 _.each(bankstatements,function(statement){
 287                     tmp.journals.push(statement.journal_id[0]);
 288                 });
 289             },
 290         },{
 291             model:  'account.journal',
 292             fields: [],
 293             domain: function(self,tmp){ return [['id','in',tmp.journals]]; },
 294             loaded: function(self, journals){
 295                 self.journals = journals;
 296
 297                 // associate the bank statements with their journals.
 298                 var bankstatements = self.bankstatements;
 299                 for(var i = 0, ilen = bankstatements.length; i < ilen; i++){
 300                     for(var j = 0, jlen = journals.length; j < jlen; j++){
 301                         if(bankstatements[i].journal_id[0] === journals[j].id){
 302                             bankstatements[i].journal = journals[j];
 303                         }
 304                     }
 305                 }
 306                 self.cashregisters = bankstatements;
 307             },
 308         },{
 309             label: 'fonts',
 310             loaded: function(self){
 311                 var fonts_loaded = new $.Deferred();
 312                 // Waiting for fonts to be loaded to prevent receipt printing
 313                 // from printing empty receipt while loading Inconsolata
 314                 // ( The font used for the receipt )
 315                 waitForWebfonts(['Lato','Inconsolata'], function(){
 316                     fonts_loaded.resolve();
 317                 });
 318                 // The JS used to detect font loading is not 100% robust, so
 319                 // do not wait more than 5sec
 320                 setTimeout(function(){
 321                     fonts_loaded.resolve();
 322                 },5000);
 323
 324                 return fonts_loaded;
 325             },
 326         },{
 327             label: 'pictures',
 328             loaded: function(self){
 329                 self.company_logo = new Image();
 330                 var  logo_loaded = new $.Deferred();
 331                 self.company_logo.onload = function(){
 332                     var img = self.company_logo;
 333                     var ratio = 1;
 334                     var targetwidth = 300;
 335                     var maxheight = 150;
 336                     if( img.width !== targetwidth ){
 337                         ratio = targetwidth / img.width;
 338                     }
 339                     if( img.height * ratio > maxheight ){
 340                         ratio = maxheight / img.height;
 341                     }
 342                     var width  = Math.floor(img.width * ratio);
 343                     var height = Math.floor(img.height * ratio);
 344                     var c = document.createElement('canvas');
 345                         c.width  = width;
 346                         c.height = height
 347                     var ctx = c.getContext('2d');
 348                         ctx.drawImage(self.company_logo,0,0, width, height);
 349
 350                     self.company_logo_base64 = c.toDataURL();
 351                     logo_loaded.resolve();
 352                 };
 353                 self.company_logo.onerror = function(){
 354                     logo_loaded.reject();
 355                 };
 356                     self.company_logo.crossOrigin = "anonymous";
 357                 self.company_logo.src = '/web/binary/company_logo' +'?_'+Math.random();
 358
 359                 return logo_loaded;
 360             },
 361         },
 362         ],
 363
 364         // loads all the needed data on the sever. returns a deferred indicating when all the data has loaded.
 365         load_server_data: function(){
 366             var self = this;
 367             var loaded = new $.Deferred();
 368             var progress = 0;
 369             var progress_step = 1.0 / self.models.length;
 370             var tmp = {}; // this is used to share a temporary state between models loaders
 371
 372             function load_model(index){
 373                 if(index >= self.models.length){
 374                     loaded.resolve();
 375                 }else{
 376                     var model = self.models[index];
 377                     self.pos_widget.loading_message(_t('Loading')+' '+(model.label || model.model || ''), progress);
 378                     var fields =  typeof model.fields === 'function'  ? model.fields(self,tmp)  : model.fields;
 379                     var domain =  typeof model.domain === 'function'  ? model.domain(self,tmp)  : model.domain;
 380                     var context = typeof model.context === 'function' ? model.context(self,tmp) : model.context;
 381                     var ids     = typeof model.ids === 'function'     ? model.ids(self,tmp) : model.ids;
 382                     progress += progress_step;
 383
 384
 385                     if( model.model ){
 386                         if (model.ids) {
 387                             var records = new instance.web.Model(model.model).call('read',[ids,fields],context);
 388                         } else {
 389                             var records = new instance.web.Model(model.model).query(fields).filter(domain).context(context).all()
 390                         }
 391                         records.then(function(result){
 392                                 try{    // catching exceptions in model.loaded(...)
 393                                     $.when(model.loaded(self,result,tmp))
 394                                         .then(function(){ load_model(index + 1); },
 395                                               function(err){ loaded.reject(err); });
 396                                 }catch(err){
 397                                     loaded.reject(err);
 398                                 }
 399                             },function(err){
 400                                 loaded.reject(err);
 401                             });
 402                     }else if( model.loaded ){
 403                         try{    // catching exceptions in model.loaded(...)
 404                             $.when(model.loaded(self,tmp))
 405                                 .then(  function(){ load_model(index +1); },
 406                                         function(err){ loaded.reject(err); });
 407                         }catch(err){
 408                             loaded.reject(err);
 409                         }
 410                     }else{
 411                         load_model(index + 1);
 412                     }
 413                 }
 414             }
 415
 416             try{
 417                 load_model(0);
 418             }catch(err){
 419                 loaded.reject(err);
 420             }
 421
 422             return loaded;
 423         },
 424
 425         // reload the list of partner, returns as a deferred that resolves if there were
 426         // updated partners, and fails if not
 427         load_new_partners: function(){
 428             var self = this;
 429             var def  = new $.Deferred();
 430             var fields = _.find(this.models,function(model){ return model.model === 'res.partner'; }).fields;
 431             new instance.web.Model('res.partner')
 432                 .query(fields)
 433                 .filter([['write_date','>',this.db.get_partner_write_date()]])
 434                 .all({'timeout':3000, 'shadow': true})
 435                 .then(function(partners){
 436                     if (self.db.add_partners(partners)) {   // check if the partners we got were real updates
 437                         def.resolve();
 438                     } else {
 439                         def.reject();
 440                     }
 441                 }, function(err,event){ event.preventDefault(); def.reject(); });
 442             return def;
 443         },
 444
 445         // this is called when an order is removed from the order collection. It ensures that there is always an existing
 446         // order and a valid selected order
 447         on_removed_order: function(removed_order,index,reason){
 448             if( (reason === 'abandon' || removed_order.temporary) && this.get('orders').size() > 0){
 449                 // when we intentionally remove an unfinished order, and there is another existing one
 450                 this.set({'selectedOrder' : this.get('orders').at(index) || this.get('orders').last()});
 451             }else{
 452                 // when the order was automatically removed after completion,
 453                 // or when we intentionally delete the only concurrent order
 454                 this.add_new_order();
 455             }
 456         },
 457
 458         //creates a new empty order and sets it as the current order
 459         add_new_order: function(){
 460             var order = new module.Order({pos:this});
 461             this.get('orders').add(order);
 462             this.set('selectedOrder', order);
 463         },
 464
 465         get_order: function(){
 466             return this.get('selectedOrder');
 467         },
 468
 469         //removes the current order
 470         delete_current_order: function(){
 471             this.get('selectedOrder').destroy({'reason':'abandon'});
 472         },
 473
 474         // saves the order locally and try to send it to the backend.
 475         // it returns a deferred that succeeds after having tried to send the order and all the other pending orders.
 476         push_order: function(order) {
 477             var self = this;
 478
 479             if(order){
 480                 this.proxy.log('push_order',order.export_as_JSON());
 481                 this.db.add_order(order.export_as_JSON());
 482             }
 483
 484             var pushed = new $.Deferred();
 485
 486             this.flush_mutex.exec(function(){
 487                 var flushed = self._flush_orders(self.db.get_orders());
 488
 489                 flushed.always(function(ids){
 490                     pushed.resolve();
 491                 });
 492             });
 493             return pushed;
 494         },
 495
 496         // saves the order locally and try to send it to the backend and make an invoice
 497         // returns a deferred that succeeds when the order has been posted and successfully generated
 498         // an invoice. This method can fail in various ways:
 499         // error-no-client: the order must have an associated partner_id. You can retry to make an invoice once
 500         //     this error is solved
 501         // error-transfer: there was a connection error during the transfer. You can retry to make the invoice once
 502         //     the network connection is up
 503
 504         push_and_invoice_order: function(order){
 505             var self = this;
 506             var invoiced = new $.Deferred();
 507
 508             if(!order.get_client()){
 509                 invoiced.reject('error-no-client');
 510                 return invoiced;
 511             }
 512
 513             var order_id = this.db.add_order(order.export_as_JSON());
 514
 515             this.flush_mutex.exec(function(){
 516                 var done = new $.Deferred(); // holds the mutex
 517
 518                 // send the order to the server
 519                 // we have a 30 seconds timeout on this push.
 520                 // FIXME: if the server takes more than 30 seconds to accept the order,
 521                 // the client will believe it wasn't successfully sent, and very bad
 522                 // things will happen as a duplicate will be sent next time
 523                 // so we must make sure the server detects and ignores duplicated orders
 524
 525                 var transfer = self._flush_orders([self.db.get_order(order_id)], {timeout:30000, to_invoice:true});
 526
 527                 transfer.fail(function(){
 528                     invoiced.reject('error-transfer');
 529                     done.reject();
 530                 });
 531
 532                 // on success, get the order id generated by the server
 533                 transfer.pipe(function(order_server_id){
 534
 535                     // generate the pdf and download it
 536                     self.pos_widget.do_action('point_of_sale.pos_invoice_report',{additional_context:{
 537                         active_ids:order_server_id,
 538                     }});
 539
 540                     invoiced.resolve();
 541                     done.resolve();
 542                 });
 543
 544                 return done;
 545
 546             });
 547
 548             return invoiced;
 549         },
 550
 551         // wrapper around the _save_to_server that updates the synch status widget
 552         _flush_orders: function(orders, options) {
 553             var self = this;
 554             this.set('synch',{ state: 'connecting', pending: orders.length});
 555
 556             return self._save_to_server(orders, options).done(function (server_ids) {
 557                 var pending = self.db.get_orders().length;
 558
 559                 self.set('synch', {
 560                     state: pending ? 'connecting' : 'connected',
 561                     pending: pending
 562                 });
 563
 564                 return server_ids;
 565             });
 566         },
 567
 568         // send an array of orders to the server
 569         // available options:
 570         // - timeout: timeout for the rpc call in ms
 571         // returns a deferred that resolves with the list of
 572         // server generated ids for the sent orders
 573         _save_to_server: function (orders, options) {
 574             if (!orders || !orders.length) {
 575                 var result = $.Deferred();
 576                 result.resolve([]);
 577                 return result;
 578             }
 579
 580             options = options || {};
 581
 582             var self = this;
 583             var timeout = typeof options.timeout === 'number' ? options.timeout : 7500 * orders.length;
 584
 585             // we try to send the order. shadow prevents a spinner if it takes too long. (unless we are sending an invoice,
 586             // then we want to notify the user that we are waiting on something )
 587             var posOrderModel = new instance.web.Model('pos.order');
 588             return posOrderModel.call('create_from_ui',
 589                 [_.map(orders, function (order) {
 590                     order.to_invoice = options.to_invoice || false;
 591                     return order;
 592                 })],
 593                 undefined,
 594                 {
 595                     shadow: !options.to_invoice,
 596                     timeout: timeout
 597                 }
 598             ).then(function (server_ids) {
 599                 _.each(orders, function (order) {
 600                     self.db.remove_order(order.id);
 601                 });
 602                 return server_ids;
 603             }).fail(function (error, event){
 604                 if(error.code === 200 ){    // Business Logic Error, not a connection problem
 605                     //if warning do not need to dispaly traceback!!
 606                     if(error.data.exception_type == 'warning'){
 607                         delete error.data.debug;
 608                     }
 609                     self.pos_widget.screen_selector.show_popup('error-traceback',{
 610                         message: error.data.message,
 611                         comment: error.data.debug
 612                     });
 613                 }
 614                 // prevent an error popup creation by the rpc failure
 615                 // we want the failure to be silent as we send the orders in the background
 616                 event.preventDefault();
 617                 console.error('Failed to send orders:', orders);
 618             });
 619         },
 620
 621         scan_product: function(parsed_code){
 622             var self = this;
 623             var selectedOrder = this.get('selectedOrder');
 624             if(parsed_code.encoding === 'ean13'){
 625                 var product = this.db.get_product_by_ean13(parsed_code.base_code);
 626             }else if(parsed_code.encoding === 'reference'){
 627                 var product = this.db.get_product_by_reference(parsed_code.code);
 628             }
 629
 630             if(!product){
 631                 return false;
 632             }
 633
 634             if(parsed_code.type === 'price'){
 635                 selectedOrder.addProduct(product, {price:parsed_code.value});
 636             }else if(parsed_code.type === 'weight'){
 637                 selectedOrder.addProduct(product, {quantity:parsed_code.value, merge:false});
 638             }else if(parsed_code.type === 'discount'){
 639                 selectedOrder.addProduct(product, {discount:parsed_code.value, merge:false});
 640             }else{
 641                 selectedOrder.addProduct(product);
 642             }
 643             return true;
 644         },
 645     });
 646
 647     var orderline_id = 1;
 648
 649     // An orderline represent one element of the content of a client's shopping cart.
 650     // An orderline contains a product, its quantity, its price, discount. etc.
 651     // An Order contains zero or more Orderlines.
 652     module.Orderline = Backbone.Model.extend({
 653         initialize: function(attr,options){
 654             this.pos = options.pos;
 655             this.order = options.order;
 656             this.product = options.product;
 657             this.price   = options.product.price;
 658             this.quantity = 1;
 659             this.quantityStr = '1';
 660             this.discount = 0;
 661             this.discountStr = '0';
 662             this.type = 'unit';
 663             this.selected = false;
 664             this.id       = orderline_id++;
 665         },
 666         clone: function(){
 667             var orderline = new module.Orderline({},{
 668                 pos: this.pos,
 669                 order: null,
 670                 product: this.product,
 671                 price: this.price,
 672             });
 673             orderline.quantity = this.quantity;
 674             orderline.quantityStr = this.quantityStr;
 675             orderline.discount = this.discount;
 676             orderline.type = this.type;
 677             orderline.selected = false;
 678             return orderline;
 679         },
 680         // sets a discount [0,100]%
 681         set_discount: function(discount){
 682             var disc = Math.min(Math.max(parseFloat(discount) || 0, 0),100);
 683             this.discount = disc;
 684             this.discountStr = '' + disc;
 685             this.trigger('change',this);
 686         },
 687         // returns the discount [0,100]%
 688         get_discount: function(){
 689             return this.discount;
 690         },
 691         get_discount_str: function(){
 692             return this.discountStr;
 693         },
 694         get_product_type: function(){
 695             return this.type;
 696         },
 697         // sets the quantity of the product. The quantity will be rounded according to the
 698         // product's unity of measure properties. Quantities greater than zero will not get
 699         // rounded to zero
 700         set_quantity: function(quantity){
 701             if(quantity === 'remove'){
 702                 this.order.removeOrderline(this);
 703                 return;
 704             }else{
 705                 var quant = parseFloat(quantity) || 0;
 706                 var unit = this.get_unit();
 707                 if(unit){
 708                     if (unit.rounding) {
 709                         this.quantity    = round_pr(quant, unit.rounding);
 710                         this.quantityStr = this.quantity.toFixed(Math.ceil(Math.log(1.0 / unit.rounding) / Math.log(10)));
 711                     } else {
 712                         this.quantity    = round_pr(quant, 1);
 713                         this.quantityStr = this.quantity.toFixed(0);
 714                     }
 715                 }else{
 716                     this.quantity    = quant;
 717                     this.quantityStr = '' + this.quantity;
 718                 }
 719             }
 720             this.trigger('change',this);
 721         },
 722         // return the quantity of product
 723         get_quantity: function(){
 724             return this.quantity;
 725         },
 726         get_quantity_str: function(){
 727             return this.quantityStr;
 728         },
 729         get_quantity_str_with_unit: function(){
 730             var unit = this.get_unit();
 731             if(unit && !unit.is_unit){
 732                 return this.quantityStr + ' ' + unit.name;
 733             }else{
 734                 return this.quantityStr;
 735             }
 736         },
 737         // return the unit of measure of the product
 738         get_unit: function(){
 739             var unit_id = this.product.uom_id;
 740             if(!unit_id){
 741                 return undefined;
 742             }
 743             unit_id = unit_id[0];
 744             if(!this.pos){
 745                 return undefined;
 746             }
 747             return this.pos.units_by_id[unit_id];
 748         },
 749         // return the product of this orderline
 750         get_product: function(){
 751             return this.product;
 752         },
 753         // selects or deselects this orderline
 754         set_selected: function(selected){
 755             this.selected = selected;
 756             this.trigger('change',this);
 757         },
 758         // returns true if this orderline is selected
 759         is_selected: function(){
 760             return this.selected;
 761         },
 762         // when we add an new orderline we want to merge it with the last line to see reduce the number of items
 763         // in the orderline. This returns true if it makes sense to merge the two
 764         can_be_merged_with: function(orderline){
 765             if( this.get_product().id !== orderline.get_product().id){    //only orderline of the same product can be merged
 766                 return false;
 767             }else if(!this.get_unit() || !this.get_unit().groupable){
 768                 return false;
 769             }else if(this.get_product_type() !== orderline.get_product_type()){
 770                 return false;
 771             }else if(this.get_discount() > 0){             // we don't merge discounted orderlines
 772                 return false;
 773             }else if(this.price !== orderline.price){
 774                 return false;
 775             }else{
 776                 return true;
 777             }
 778         },
 779         merge: function(orderline){
 780             this.set_quantity(this.get_quantity() + orderline.get_quantity());
 781         },
 782         export_as_JSON: function() {
 783             return {
 784                 qty: this.get_quantity(),
 785                 price_unit: this.get_unit_price(),
 786                 discount: this.get_discount(),
 787                 product_id: this.get_product().id,
 788             };
 789         },
 790         //used to create a json of the ticket, to be sent to the printer
 791         export_for_printing: function(){
 792             return {
 793                 quantity:           this.get_quantity(),
 794                 unit_name:          this.get_unit().name,
 795                 price:              this.get_unit_price(),
 796                 discount:           this.get_discount(),
 797                 product_name:       this.get_product().display_name,
 798                 price_display :     this.get_display_price(),
 799                 price_with_tax :    this.get_price_with_tax(),
 800                 price_without_tax:  this.get_price_without_tax(),
 801                 tax:                this.get_tax(),
 802                 product_description:      this.get_product().description,
 803                 product_description_sale: this.get_product().description_sale,
 804             };
 805         },
 806         // changes the base price of the product for this orderline
 807         set_unit_price: function(price){
 808             this.price = round_di(parseFloat(price) || 0, this.pos.dp['Product Price']);
 809             this.trigger('change',this);
 810         },
 811         get_unit_price: function(){
 812             return this.price;
 813         },
 814         get_base_price:    function(){
 815             var rounding = this.pos.currency.rounding;
 816             return  round_pr(round_pr(this.get_unit_price() * this.get_quantity(),rounding) * (1- this.get_discount()/100.0),rounding);
 817         },
 818         get_display_price: function(){
 819             return this.get_base_price();
 820         },
 821         get_price_without_tax: function(){
 822             return this.get_all_prices().priceWithoutTax;
 823         },
 824         get_price_with_tax: function(){
 825             return this.get_all_prices().priceWithTax;
 826         },
 827         get_tax: function(){
 828             return this.get_all_prices().tax;
 829         },
 830         get_tax_details: function(){
 831             return this.get_all_prices().taxDetails;
 832         },
 833         get_all_prices: function(){
 834             var self = this;
 835             var currency_rounding = this.pos.currency.rounding;
 836             var base = this.get_base_price();
 837             var totalTax = base;
 838             var totalNoTax = base;
 839
 840             var product =  this.get_product();
 841             var taxes_ids = product.taxes_id;
 842             var taxes =  self.pos.taxes;
 843             var taxtotal = 0;
 844             var taxdetail = {};
 845             _.each(taxes_ids, function(el) {
 846                 var tax = _.detect(taxes, function(t) {return t.id === el;});
 847                 if (tax.price_include) {
 848                     var tmp;
 849                     if (tax.type === "percent") {
 850                         tmp =  base - round_pr(base / (1 + tax.amount),currency_rounding);
 851                     } else if (tax.type === "fixed") {
 852                         tmp = round_pr(tax.amount * self.get_quantity(),currency_rounding);
 853                     } else {
 854                         throw "This type of tax is not supported by the point of sale: " + tax.type;
 855                     }
 856                     tmp = round_pr(tmp,currency_rounding);
 857                     taxtotal += tmp;
 858                     totalNoTax -= tmp;
 859                     taxdetail[tax.id] = tmp;
 860                 } else {
 861                     var tmp;
 862                     if (tax.type === "percent") {
 863                         tmp = tax.amount * base;
 864                     } else if (tax.type === "fixed") {
 865                         tmp = tax.amount * self.get_quantity();
 866                     } else {
 867                         throw "This type of tax is not supported by the point of sale: " + tax.type;
 868                     }
 869                     tmp = round_pr(tmp,currency_rounding);
 870                     taxtotal += tmp;
 871                     totalTax += tmp;
 872                     taxdetail[tax.id] = tmp;
 873                 }
 874             });
 875             return {
 876                 "priceWithTax": totalTax,
 877                 "priceWithoutTax": totalNoTax,
 878                 "tax": taxtotal,
 879                 "taxDetails": taxdetail,
 880             };
 881         },
 882     });
 883
 884     module.OrderlineCollection = Backbone.Collection.extend({
 885         model: module.Orderline,
 886     });
 887
 888     // Every Paymentline contains a cashregister and an amount of money.
 889     module.Paymentline = Backbone.Model.extend({
 890         initialize: function(attributes, options) {
 891             this.amount = 0;
 892             this.cashregister = options.cashregister;
 893             this.name = this.cashregister.journal_id[1];
 894             this.selected = false;
 895             this.pos = options.pos;
 896         },
 897         //sets the amount of money on this payment line
 898         set_amount: function(value){
 899             this.amount = round_di(parseFloat(value) || 0, this.pos.currency.decimals);
 900             this.trigger('change:amount',this);
 901         },
 902         // returns the amount of money on this paymentline
 903         get_amount: function(){
 904             return this.amount;
 905         },
 906         get_amount_str: function(){
 907             return this.amount.toFixed(this.pos.currency.decimals);
 908         },
 909         set_selected: function(selected){
 910             if(this.selected !== selected){
 911                 this.selected = selected;
 912                 this.trigger('change:selected',this);
 913             }
 914         },
 915         // returns the associated cashregister
 916         //exports as JSON for server communication
 917         export_as_JSON: function(){
 918             return {
 919                 name: instance.web.datetime_to_str(new Date()),
 920                 statement_id: this.cashregister.id,
 921                 account_id: this.cashregister.account_id[0],
 922                 journal_id: this.cashregister.journal_id[0],
 923                 amount: this.get_amount()
 924             };
 925         },
 926         //exports as JSON for receipt printing
 927         export_for_printing: function(){
 928             return {
 929                 amount: this.get_amount(),
 930                 journal: this.cashregister.journal_id[1],
 931             };
 932         },
 933     });
 934
 935     module.PaymentlineCollection = Backbone.Collection.extend({
 936         model: module.Paymentline,
 937     });
 938
 939
 940     // An order more or less represents the content of a client's shopping cart (the OrderLines)
 941     // plus the associated payment information (the Paymentlines)
 942     // there is always an active ('selected') order in the Pos, a new one is created
 943     // automaticaly once an order is completed and sent to the server.
 944     module.Order = Backbone.Model.extend({
 945         initialize: function(attributes){
 946             Backbone.Model.prototype.initialize.apply(this, arguments);
 947             this.pos = attributes.pos;
 948             this.sequence_number = this.pos.pos_session.sequence_number++;
 949             this.uid =     this.generateUniqueId();
 950             this.set({
 951                 creationDate:   new Date(),
 952                 orderLines:     new module.OrderlineCollection(),
 953                 paymentLines:   new module.PaymentlineCollection(),
 954                 name:           _t("Order ") + this.uid,
 955                 client:         null,
 956             });
 957             this.selected_orderline   = undefined;
 958             this.selected_paymentline = undefined;
 959             this.screen_data = {};  // see ScreenSelector
 960             this.receipt_type = 'receipt';  // 'receipt' || 'invoice'
 961             this.temporary = attributes.temporary || false;
 962             this.to_invoice = false;
 963             return this;
 964         },
 965         is_empty: function(){
 966             return (this.get('orderLines').models.length === 0);
 967         },
 968         // Generates a public identification number for the order.
 969         // The generated number must be unique and sequential. They are made 12 digit long
 970         // to fit into EAN-13 barcodes, should it be needed
 971         generateUniqueId: function() {
 972             function zero_pad(num,size){
 973                 var s = ""+num;
 974                 while (s.length < size) {
 975                     s = "0" + s;
 976                 }
 977                 return s;
 978             }
 979             return zero_pad(this.pos.pos_session.id,5) +'-'+
 980                    zero_pad(this.pos.pos_session.login_number,3) +'-'+
 981                    zero_pad(this.sequence_number,4);
 982         },
 983         addOrderline: function(line){
 984             if(line.order){
 985                 order.removeOrderline(line);
 986             }
 987             line.order = this;
 988             this.get('orderLines').add(line);
 989             this.selectLine(this.getLastOrderline());
 990         },
 991         addProduct: function(product, options){
 992             options = options || {};
 993             var attr = JSON.parse(JSON.stringify(product));
 994             attr.pos = this.pos;
 995             attr.order = this;
 996             var line = new module.Orderline({}, {pos: this.pos, order: this, product: product});
 997
 998             if(options.quantity !== undefined){
 999                 line.set_quantity(options.quantity);
1000             }
1001             if(options.price !== undefined){
1002                 line.set_unit_price(options.price);
1003             }
1004             if(options.discount !== undefined){
1005                 line.set_discount(options.discount);
1006             }
1007
1008             var last_orderline = this.getLastOrderline();
1009             if( last_orderline && last_orderline.can_be_merged_with(line) && options.merge !== false){
1010                 last_orderline.merge(line);
1011             }else{
1012                 this.get('orderLines').add(line);
1013             }
1014             this.selectLine(this.getLastOrderline());
1015         },
1016         removeOrderline: function( line ){
1017             this.get('orderLines').remove(line);
1018             this.selectLine(this.getLastOrderline());
1019         },
1020         getOrderline: function(id){
1021             var orderlines = this.get('orderLines').models;
1022             for(var i = 0; i < orderlines.length; i++){
1023                 if(orderlines[i].id === id){
1024                     return orderlines[i];
1025                 }
1026             }
1027             return null;
1028         },
1029         getLastOrderline: function(){
1030             return this.get('orderLines').at(this.get('orderLines').length -1);
1031         },
1032         addPaymentline: function(cashregister) {
1033             var paymentLines = this.get('paymentLines');
1034             var newPaymentline = new module.Paymentline({},{cashregister:cashregister, pos:this.pos});
1035             if(cashregister.journal.type !== 'cash'){
1036                 newPaymentline.set_amount( Math.max(this.getDueLeft(),0) );
1037             }
1038             paymentLines.add(newPaymentline);
1039             this.selectPaymentline(newPaymentline);
1040
1041         },
1042         removePaymentline: function(line){
1043             if(this.selected_paymentline === line){
1044                 this.selectPaymentline(undefined);
1045             }
1046             this.get('paymentLines').remove(line);
1047         },
1048         getName: function() {
1049             return this.get('name');
1050         },
1051         getSubtotal : function(){
1052             return (this.get('orderLines')).reduce((function(sum, orderLine){
1053                 return sum + orderLine.get_display_price();
1054             }), 0);
1055         },
1056         getTotalTaxIncluded: function() {
1057             return (this.get('orderLines')).reduce((function(sum, orderLine) {
1058                 return sum + orderLine.get_price_with_tax();
1059             }), 0);
1060         },
1061         getDiscountTotal: function() {
1062             return (this.get('orderLines')).reduce((function(sum, orderLine) {
1063                 return sum + (orderLine.get_unit_price() * (orderLine.get_discount()/100) * orderLine.get_quantity());
1064             }), 0);
1065         },
1066         getTotalTaxExcluded: function() {
1067             return (this.get('orderLines')).reduce((function(sum, orderLine) {
1068                 return sum + orderLine.get_price_without_tax();
1069             }), 0);
1070         },
1071         getTax: function() {
1072             return (this.get('orderLines')).reduce((function(sum, orderLine) {
1073                 return sum + orderLine.get_tax();
1074             }), 0);
1075         },
1076         getTaxDetails: function(){
1077             var details = {};
1078             var fulldetails = [];
1079             var taxes_by_id = {};
1080
1081             for(var i = 0; i < this.pos.taxes.length; i++){
1082                 taxes_by_id[this.pos.taxes[i].id] = this.pos.taxes[i];
1083             }
1084
1085             this.get('orderLines').each(function(line){
1086                 var ldetails = line.get_tax_details();
1087                 for(var id in ldetails){
1088                     if(ldetails.hasOwnProperty(id)){
1089                         details[id] = (details[id] || 0) + ldetails[id];
1090                     }
1091                 }
1092             });
1093
1094             for(var id in details){
1095                 if(details.hasOwnProperty(id)){
1096                     fulldetails.push({amount: details[id], tax: taxes_by_id[id], name: taxes_by_id[id].name});
1097                 }
1098             }
1099
1100             return fulldetails;
1101         },
1102         getPaidTotal: function() {
1103             return (this.get('paymentLines')).reduce((function(sum, paymentLine) {
1104                 return sum + paymentLine.get_amount();
1105             }), 0);
1106         },
1107         getChange: function(paymentline) {
1108             if (!paymentline) {
1109                 var change = this.getPaidTotal() - this.getTotalTaxIncluded();
1110             } else {
1111                 var change = -this.getTotalTaxIncluded();
1112                 var lines  = this.get('paymentLines').models;
1113                 for (var i = 0; i < lines.length; i++) {
1114                     change += lines[i].get_amount();
1115                     if (lines[i] === paymentline) {
1116                         break;
1117                     }
1118                 }
1119             }
1120             return round_pr(Math.max(0,change), this.pos.currency.rounding);
1121         },
1122         getDueLeft: function(paymentline) {
1123             if (!paymentline) {
1124                 var due = this.getTotalTaxIncluded() - this.getPaidTotal();
1125             } else {
1126                 var due = this.getTotalTaxIncluded();
1127                 var lines = this.get('paymentLines').models;
1128                 for (var i = 0; i < lines.length; i++) {
1129                     if (lines[i] === paymentline) {
1130                         break;
1131                     } else {
1132                         due -= lines[i].get_amount();
1133                     }
1134                 }
1135             }
1136             return round_pr(Math.max(0,due), this.pos.currency.rounding);
1137         },
1138         isPaid: function(){
1139             return this.getDueLeft() === 0;
1140         },
1141         isPaidWithCash: function(){
1142             return !!this.get('paymentLines').find( function(pl){
1143                 return pl.cashregister.journal.type === 'cash';
1144             });
1145         },
1146         finalize: function(){
1147             this.destroy();
1148         },
1149         // sets the type of receipt 'receipt'(default) or 'invoice'
1150         set_receipt_type: function(type){
1151             this.receipt_type = type;
1152         },
1153         get_receipt_type: function(){
1154             return this.receipt_type;
1155         },
1156         // the client related to the current order.
1157         set_client: function(client){
1158             this.set('client',client);
1159         },
1160         get_client: function(){
1161             return this.get('client');
1162         },
1163         get_client_name: function(){
1164             var client = this.get('client');
1165             return client ? client.name : "";
1166         },
1167         // the order also stores the screen status, as the PoS supports
1168         // different active screens per order. This method is used to
1169         // store the screen status.
1170         set_screen_data: function(key,value){
1171             if(arguments.length === 2){
1172                 this.screen_data[key] = value;
1173             }else if(arguments.length === 1){
1174                 for(key in arguments[0]){
1175                     this.screen_data[key] = arguments[0][key];
1176                 }
1177             }
1178         },
1179         set_to_invoice: function(to_invoice) {
1180             this.to_invoice = to_invoice;
1181         },
1182         is_to_invoice: function(){
1183             return this.to_invoice;
1184         },
1185         // remove all the paymentlines with zero money in it
1186         clean_empty_paymentlines: function() {
1187             var lines = this.get('paymentLines').models;
1188             var empty = [];
1189             for ( var i = 0; i < lines.length; i++) {
1190                 if (!lines[i].get_amount()) {
1191                     empty.push(lines[i]);
1192                 }
1193             }
1194             for ( var i = 0; i < empty.length; i++) {
1195                 this.removePaymentline(empty[i]);
1196             }
1197         },
1198         //see set_screen_data
1199         get_screen_data: function(key){
1200             return this.screen_data[key];
1201         },
1202         // exports a JSON for receipt printing
1203         export_for_printing: function(){
1204             var orderlines = [];
1205             this.get('orderLines').each(function(orderline){
1206                 orderlines.push(orderline.export_for_printing());
1207             });
1208
1209             var paymentlines = [];
1210             this.get('paymentLines').each(function(paymentline){
1211                 paymentlines.push(paymentline.export_for_printing());
1212             });
1213             var client  = this.get('client');
1214             var cashier = this.pos.cashier || this.pos.user;
1215             var company = this.pos.company;
1216             var shop    = this.pos.shop;
1217             var date = new Date();
1218
1219             return {
1220                 orderlines: orderlines,
1221                 paymentlines: paymentlines,
1222                 subtotal: this.getSubtotal(),
1223                 total_with_tax: this.getTotalTaxIncluded(),
1224                 total_without_tax: this.getTotalTaxExcluded(),
1225                 total_tax: this.getTax(),
1226                 total_paid: this.getPaidTotal(),
1227                 total_discount: this.getDiscountTotal(),
1228                 tax_details: this.getTaxDetails(),
1229                 change: this.getChange(),
1230                 name : this.getName(),
1231                 client: client ? client.name : null ,
1232                 invoice_id: null,   //TODO
1233                 cashier: cashier ? cashier.name : null,
1234                 header: this.pos.config.receipt_header || '',
1235                 footer: this.pos.config.receipt_footer || '',
1236                 precision: {
1237                     price: 2,
1238                     money: 2,
1239                     quantity: 3,
1240                 },
1241                 date: {
1242                     year: date.getFullYear(),
1243                     month: date.getMonth(),
1244                     date: date.getDate(),       // day of the month
1245                     day: date.getDay(),         // day of the week
1246                     hour: date.getHours(),
1247                     minute: date.getMinutes() ,
1248                     isostring: date.toISOString(),
1249                     localestring: date.toLocaleString(),
1250                 },
1251                 company:{
1252                     email: company.email,
1253                     website: company.website,
1254                     company_registry: company.company_registry,
1255                     contact_address: company.partner_id[1],
1256                     vat: company.vat,
1257                     name: company.name,
1258                     phone: company.phone,
1259                     logo:  this.pos.company_logo_base64,
1260                 },
1261                 shop:{
1262                     name: shop.name,
1263                 },
1264                 currency: this.pos.currency,
1265             };
1266         },
1267         export_as_JSON: function() {
1268             var orderLines, paymentLines;
1269             orderLines = [];
1270             (this.get('orderLines')).each(_.bind( function(item) {
1271                 return orderLines.push([0, 0, item.export_as_JSON()]);
1272             }, this));
1273             paymentLines = [];
1274             (this.get('paymentLines')).each(_.bind( function(item) {
1275                 return paymentLines.push([0, 0, item.export_as_JSON()]);
1276             }, this));
1277             return {
1278                 name: this.getName(),
1279                 amount_paid: this.getPaidTotal(),
1280                 amount_total: this.getTotalTaxIncluded(),
1281                 amount_tax: this.getTax(),
1282                 amount_return: this.getChange(),
1283                 lines: orderLines,
1284                 statement_ids: paymentLines,
1285                 pos_session_id: this.pos.pos_session.id,
1286                 partner_id: this.get_client() ? this.get_client().id : false,
1287                 user_id: this.pos.cashier ? this.pos.cashier.id : this.pos.user.id,
1288                 uid: this.uid,
1289                 sequence_number: this.sequence_number,
1290             };
1291         },
1292         getSelectedLine: function(){
1293             return this.selected_orderline;
1294         },
1295         selectLine: function(line){
1296             if(line){
1297                 if(line !== this.selected_orderline){
1298                     if(this.selected_orderline){
1299                         this.selected_orderline.set_selected(false);
1300                     }
1301                     this.selected_orderline = line;
1302                     this.selected_orderline.set_selected(true);
1303                 }
1304             }else{
1305                 this.selected_orderline = undefined;
1306             }
1307         },
1308         deselectLine: function(){
1309             if(this.selected_orderline){
1310                 this.selected_orderline.set_selected(false);
1311                 this.selected_orderline = undefined;
1312             }
1313         },
1314         selectPaymentline: function(line){
1315             if(line !== this.selected_paymentline){
1316                 if(this.selected_paymentline){
1317                     this.selected_paymentline.set_selected(false);
1318                 }
1319                 this.selected_paymentline = line;
1320                 if(this.selected_paymentline){
1321                     this.selected_paymentline.set_selected(true);
1322                 }
1323                 this.trigger('change:selected_paymentline',this.selected_paymentline);
1324             }
1325         },
1326     });
1327
1328     module.OrderCollection = Backbone.Collection.extend({
1329         model: module.Order,
1330     });
1331
1332     /*
1333      The numpad handles both the choice of the property currently being modified
1334      (quantity, price or discount) and the edition of the corresponding numeric value.
1335      */
1336     module.NumpadState = Backbone.Model.extend({
1337         defaults: {
1338             buffer: "0",
1339             mode: "quantity"
1340         },
1341         appendNewChar: function(newChar) {
1342             var oldBuffer;
1343             oldBuffer = this.get('buffer');
1344             if (oldBuffer === '0') {
1345                 this.set({
1346                     buffer: newChar
1347                 });
1348             } else if (oldBuffer === '-0') {
1349                 this.set({
1350                     buffer: "-" + newChar
1351                 });
1352             } else {
1353                 this.set({
1354                     buffer: (this.get('buffer')) + newChar
1355                 });
1356             }
1357             this.trigger('set_value',this.get('buffer'));
1358         },
1359         deleteLastChar: function() {
1360             if(this.get('buffer') === ""){
1361                 if(this.get('mode') === 'quantity'){
1362                     this.trigger('set_value','remove');
1363                 }else{
1364                     this.trigger('set_value',this.get('buffer'));
1365                 }
1366             }else{
1367                 var newBuffer = this.get('buffer').slice(0,-1) || "";
1368                 this.set({ buffer: newBuffer });
1369                 this.trigger('set_value',this.get('buffer'));
1370             }
1371         },
1372         switchSign: function() {
1373             var oldBuffer;
1374             oldBuffer = this.get('buffer');
1375             this.set({
1376                 buffer: oldBuffer[0] === '-' ? oldBuffer.substr(1) : "-" + oldBuffer
1377             });
1378             this.trigger('set_value',this.get('buffer'));
1379         },
1380         changeMode: function(newMode) {
1381             this.set({
1382                 buffer: "0",
1383                 mode: newMode
1384             });
1385         },
1386         reset: function() {
1387             this.set({
1388                 buffer: "0",
1389                 mode: "quantity"
1390             });
1391         },
1392         resetValue: function(){
1393             this.set({buffer:'0'});
1394         },
1395     });
1396 }