diff --git a/controllers/tax_controller.py b/controllers/tax_controller.py
new file mode 100644
index 0000000..6df17f5
--- /dev/null
+++ b/controllers/tax_controller.py
@@ -0,0 +1,433 @@
+# ERPNext - web based ERP (http://erpnext.com)
+# Copyright (C) 2012 Web Notes Technologies Pvt Ltd
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License 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
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import unicode_literals
+import webnotes
+import webnotes.model
+from webnotes import _, msgprint
+from webnotes.utils import cint, flt
+from webnotes.model.utils import round_doc
+import json
+
+from controllers.transaction_controller import TransactionController
+
+class TaxController(TransactionController):
+	def append_taxes(self):
+		"""append taxes as per tax master link field"""
+		# clear tax table
+		self.doclist = self.doclist.get({"parentfield": ["!=",
+			self.fmap.taxes_and_charges]})
+		
+		tax_master_doctype = self.meta.get_options(self.fmap.taxes_and_charges_master)
+		master_tax_list = webnotes.get_doclist(tax_master_doctype,
+			self.doc.fields.get(self.fmap.taxes_and_charges_master)).get(
+			{"parentfield": self.fmap.taxes_and_charges})
+			
+		for base_tax in master_tax_list:
+			tax = DictObj([[field, base_tax.fields.get(field)]
+				for field in base_tax.fields
+				if field not in webnotes.model.default_fields])
+			tax.update({
+				"doctype": self.meta.get_options(self.fmap.taxes_and_charges),
+				"parentfield": self.fmap.taxes_and_charges,
+				"rate": flt(tax.rate, self.precision.tax.rate),
+			})
+			self.doclist.append(tax)
+	
+	def calculate_taxes_and_totals(self):
+		"""
+			Calculates:
+				* amount for each item
+				* valuation_tax_amount for each item, 
+				* tax amount and tax total for each tax
+				* net total
+				* total taxes
+				* grand total
+		"""
+		self.doc.fields[self.fmap.exchange_rate] = \
+			flt(self.doc.fields.get(self.fmap.exchange_rate),
+			self.precision.main[self.fmap.exchange_rate])
+		
+		self.calculate_item_values()
+		
+		self.initialize_taxes()
+		if self.meta.get_field("included_in_print_rate",
+				parentfield=self.fmap.taxes_and_charges):
+			self.determine_exclusive_rate()
+		
+		self.calculate_net_total()
+		self.calculate_taxes()
+		self.calculate_totals()
+		self.set_amount_in_words()
+		
+	def calculate_item_values(self):
+		def _set_base(item, print_field, base_field):
+			"""set values in base currency"""
+			item.fields[base_field] = flt((flt(item.fields[print_field],
+				self.precision.item[print_field]) * \
+				self.doc.fields.get(self.fmap.exchange_rate)),
+				self.precision.item[base_field])
+		
+		for item in self.item_doclist:
+			round_doc(item, self.precision.item)
+			
+			if item.fields.get(self.fmap.discount) == 100:
+				if not item.fields.get(self.fmap.print_ref_rate):
+					item.fields[self.fmap.print_ref_rate] = \
+						item.fields.get(self.fmap.print_rate)
+				item.fields[self.fmap.print_rate] = 0
+			else:
+				if item.fields.get(self.fmap.print_ref_rate):
+					item.fields[self.fmap.print_rate] = \
+						flt(item.fields.get(self.fmap.print_ref_rate) *
+						(1.0 - (item.fields.get(self.fmap.discount) / 100.0)),
+						self.precision.item[self.fmap.print_rate])
+				else:
+					# assume that print rate and discount are specified
+					item.fields[self.fmap.print_ref_rate] = \
+						flt(item.fields.get(self.fmap.print_rate) / 
+						(1.0 - (item.fields.get(self.fmap.discount) / 100.0)),
+						self.precision.item[self.fmap.print_ref_rate])
+						
+			item.fields[self.fmap.print_amount] = \
+				flt(item.fields.get(self.fmap.print_rate) * \
+				item.fields.get(self.fmap.qty),
+				self.precision.item[self.fmap.print_amount])
+				
+			_set_base(item, self.fmap.print_ref_rate, self.fmap.ref_rate)
+			_set_base(item, self.fmap.print_rate, self.fmap.rate)
+			_set_base(item, self.fmap.print_amount, self.fmap.amount)
+			
+	def initialize_taxes(self):
+		for tax in self.tax_doclist:
+			# initialize totals to 0
+			tax.tax_amount = tax.total = tax.total_print = 0
+			tax.grand_total_for_current_item = tax.tax_amount_for_current_item = 0
+			
+			# for actual type, user can mention actual tax amount in tax.tax_amount_print
+			if tax.charge_type != "Actual" or tax.rate:
+				tax.tax_amount_print = 0
+			
+			self.validate_on_previous_row(tax)
+			self.validate_included_tax(tax)
+			
+			# round relevant values
+			round_doc(tax, self.precision.tax)
+			
+	def calculate_net_total(self):
+		self.doc.net_total = 0
+		self.doc.fields[self.fmap.net_total_print] = 0
+		
+		for item in self.item_doclist:
+			self.doc.net_total += item.amount
+			self.doc.fields[self.fmap.net_total_print] += \
+				item.fields.get(self.fmap.print_amount)
+
+		self.doc.net_total = flt(self.doc.net_total, self.precision.main.net_total)
+		self.doc.fields[self.fmap.net_total_print] = \
+			flt(self.doc.fields.get(self.fmap.net_total_print),
+			self.precision.main[self.fmap.net_total_print])
+			
+	def calculate_taxes(self):
+		for item in self.item_doclist:
+			item_tax_map = self._load_item_tax_rate(item.item_tax_rate)
+			item.fields[self.fmap.valuation_tax_amount] = 0
+			
+			for i, tax in enumerate(self.tax_doclist):
+				# tax_amount represents the amount of tax for the current step
+				current_tax_amount = self.get_current_tax_amount(item, tax, item_tax_map)
+				
+				if hasattr(self, "set_valuation_tax_amount"):
+					self.set_valuation_tax_amount(item, tax, current_tax_amount)
+				
+				# case when net total is 0 but there is an actual type charge
+				# in this case add the actual amount to tax.tax_amount
+				# and tax.grand_total_for_current_item for the first such iteration
+				if not (current_tax_amount or self.doc.net_total or tax.tax_amount) and \
+						tax.charge_type=="Actual":
+					zero_net_total_adjustment = flt((tax.tax_amount_print * 
+						self.doc.fields.get(self.fmap.exchange_rate)) or tax.rate, 
+						self.precision.tax.tax_amount)
+					current_tax_amount += zero_net_total_adjustment
+				
+				# store tax_amount for current item as it will be used for
+				# charge type = 'On Previous Row Amount'
+				tax.tax_amount_for_current_item = current_tax_amount
+				
+				# accumulate tax amount into tax.tax_amount
+				tax.tax_amount += tax.tax_amount_for_current_item
+				
+				# accumulate tax_amount_print only if tax is not included
+				# and if tax amount of actual type is entered in 'rate' field
+				if not cint(tax.included_in_print_rate) and (tax.charge_type != "Actual"
+						or tax.rate):
+					tax.tax_amount_print += flt((tax.tax_amount_for_current_item /
+						self.doc.fields.get(self.fmap.exchange_rate)),
+						self.precision.tax.tax_amount_print)
+				
+				if tax.category == "Valuation":
+					# if just for valuation, do not add the tax amount in total
+					# hence, setting it as 0 for further steps
+					current_tax_amount = 0
+				
+				# Calculate tax.total viz. grand total till that step
+				# note: grand_total_for_current_item contains the contribution of 
+				# item's amount, previously applied tax and the current tax on that item
+				if i==0:
+					tax.grand_total_for_current_item = flt(item.amount +
+						current_tax_amount, self.precision.tax.total)
+					
+					# if inclusive pricing, current_tax_amount should not be considered
+					if cint(tax.included_in_print_rate):
+						current_tax_amount = 0
+						
+					tax.grand_total_print_for_current_item = \
+						flt(item.fields.get(self.fmap.print_amount) +
+						(current_tax_amount / self.doc.fields.get(
+							self.fmap.exchange_rate)),
+						self.precision.tax.total_print)
+				else:
+					tax.grand_total_for_current_item = \
+						flt(self.tax_doclist[i-1].grand_total_for_current_item +
+							current_tax_amount, self.precision.tax.total)
+					
+					# if inclusive pricing, current_tax_amount should not be considered
+					if cint(tax.included_in_print_rate):
+						current_tax_amount = 0
+					
+					tax.grand_total_print_for_current_item = \
+						flt(self.tax_doclist[i-1].grand_total_print_for_current_item +
+							(current_tax_amount / self.doc.fields.get(
+								self.fmap.exchange_rate)),
+							self.precision.tax.total_print)
+
+				# in tax.total, accumulate grand total of each item
+				tax.total += tax.grand_total_for_current_item
+				tax.total_print += tax.grand_total_print_for_current_item
+				
+				# TODO store tax_breakup for each item
+				
+	def get_current_tax_amount(self, item, tax, item_tax_map):
+		tax_rate = self._get_tax_rate(tax, item_tax_map)
+
+		if tax.charge_type == "Actual":
+			# distribute the tax amount proportionally to each item row
+			actual = flt(tax.rate or (tax.tax_amount_print * \
+				self.doc.fields.get(self.fmap.exchange_rate)),
+				self.precision.tax.tax_amount)
+			current_tax_amount = (self.doc.net_total
+				and ((item.amount / self.doc.net_total) * actual)
+				or 0)
+		elif tax.charge_type == "On Net Total":
+			current_tax_amount = (tax_rate / 100.0) * item.amount
+		elif tax.charge_type == "On Previous Row Amount":
+			current_tax_amount = (tax_rate / 100.0) * \
+				self.tax_doclist[cint(tax.row_id) - 1].tax_amount_for_current_item
+		elif tax.charge_type == "On Previous Row Total":
+			current_tax_amount = (tax_rate / 100.0) * \
+				self.tax_doclist[cint(tax.row_id) - 1].grand_total_for_current_item
+
+		return flt(current_tax_amount, self.precision.tax.tax_amount)
+		
+	def calculate_totals(self):
+		if self.tax_doclist:
+			self.doc.grand_total = flt(self.tax_doclist[-1].total,
+				self.precision.main.grand_total)
+			self.doc.fields[self.fmap.grand_total_print] = \
+				flt(self.tax_doclist[-1].total_print,
+				self.precision.main[self.fmap.grand_total_print])
+		else:
+			self.doc.grand_total = flt(self.doc.net_total,
+				self.precision.main.grand_total)
+			self.doc.fields[self.fmap.grand_total_print] = \
+				flt(self.doc.fields.get(self.fmap.net_total_print),
+				self.precision.main[self.fmap.grand_total_print])
+		
+		self.doc.fields[self.fmap.taxes_and_charges_total] = \
+			flt(self.doc.grand_total - self.doc.net_total,
+			self.precision.main[self.fmap.taxes_and_charges_total])
+			
+		self.doc.taxes_and_charges_total_print = \
+			flt(self.doc.fields.get(self.fmap.grand_total_print) - \
+			self.doc.fields.get(self.fmap.net_total_print),
+			self.precision.main.taxes_and_charges_total_print)
+		
+		self.doc.rounded_total = round(self.doc.grand_total)
+		self.doc.fields[self.fmap.rounded_total_print] = \
+			round(self.doc.fields.get(self.fmap.grand_total_print))
+		
+	def set_amount_in_words(self):
+		from webnotes.utils import money_in_words
+		base_currency = webnotes.conn.get_value("Company", self.doc.currency,
+			"default_currency")
+		
+		self.doc.fields[self.fmap.grand_total_in_words] = \
+			money_in_words(self.doc.grand_total, base_currency)
+		self.doc.fields[self.fmap.rounded_total_in_words] = \
+			money_in_words(self.doc.rounded_total, base_currency)
+		
+		self.doc.fields[self.fmap.grand_total_in_words_print] = \
+			money_in_words(self.doc.fields.get(self.fmap.grand_total_print),
+			self.doc.currency)
+		self.doc.fields[self.fmap.rounded_total_in_words_print] = \
+			money_in_words(self.doc.fields.get(self.fmap.rounded_total_print),
+			self.doc.currency)
+			
+	def validate_on_previous_row(self, tax):
+		"""
+			validate if a valid row id is mentioned in case of
+			On Previous Row Amount and On Previous Row Total
+		"""
+		if tax.charge_type in ["On Previous Row Amount", "On Previous Row Total"] and \
+				(not tax.row_id or cint(tax.row_id) >= tax.idx):
+			msgprint((_("Row") + " # %(idx)s [%(taxes_doctype)s]: " + \
+				_("Please specify a valid") + " %(row_id_label)s") % {
+					"idx": tax.idx,
+					"taxes_doctype": tax.parenttype,
+					"row_id_label": self.meta.get_label("row_id",
+						parentfield=self.fmap.taxes_and_charges)
+				}, raise_exception=True)
+	
+	def validate_included_tax(self, tax):
+		"""
+			validate conditions related to "Is this Tax Included in Rate?"
+		"""
+		def _on_previous_row_error(tax, row_range):
+			msgprint((_("Row") + " # %(idx)s [%(taxes_doctype)s]: " + \
+				_("If") + " '%(inclusive_label)s' " + _("is checked for") + \
+				" '%(charge_type_label)s' = '%(charge_type)s', " + _("then") + " " + \
+				_("Row") + " # %(row_range)s " + _("should also have") + \
+				" '%(inclusive_label)s' = " + _("checked")) % {
+					"idx": tax.idx,
+					"taxes_doctype": tax.doctype,
+					"inclusive_label": self.meta.get_label("included_in_print_rate",
+						parentfield=self.fmap.taxes_and_charges),
+					"charge_type_label": self.meta.get_label("charge_type",
+						parentfield=self.fmap.taxes_and_charges),
+					"charge_type": tax.charge_type,
+					"row_range": row_range,
+				}, raise_exception=True)
+		
+		if cint(tax.included_in_print_rate):
+			if tax.charge_type == "Actual":
+				# now inclusive rate for type 'Actual'
+				msgprint((_("Row") + " # %(idx)s [%(taxes_doctype)s]: " + \
+					"'%(charge_type_label)s' = '%(charge_type)s' " + \
+					_("cannot be included in item's rate")) % {
+						"idx": tax.idx,
+						"taxes_doctype": self.meta.get_options(
+							self.fmap.taxes_and_charges),
+						"charge_type_label": self.meta.get_label("charge_type",
+							parentfield=self.fmap.taxes_and_charges),
+						"charge_type": tax.charge_type,
+					}, raise_exception=True)
+					
+			elif tax.charge_type == "On Previous Row Amount" and \
+					not cint(self.tax_doclist[cint(tax.row_id) - 1]\
+						.included_in_print_rate):
+				# for an inclusive tax of type "On Previous Row Amount",
+				# dependent row should also be inclusive
+				_on_previous_row_error(tax, tax.row_id)
+				
+			elif tax.charge_type == "On Previous Row Total" and \
+					not all([cint(t.included_in_print_rate) \
+						for t in self.tax_doclist[:tax.idx - 1]]):
+				# for an inclusive tax of type "On Previous Row Total", 
+				# all rows above it should also be inclusive
+				_on_previous_row_error(tax, "1 - %d" % (tax.idx - 1))
+		
+	def determine_exclusive_rate(self):
+		if not any((cint(tax.included_in_print_rate) for tax in self.tax_doclist)):
+			# if no tax is marked as included in print rate, no need to proceed further
+			return
+		
+		for item in self.item_doclist:
+			item_tax_map = self._load_item_tax_rate(item.item_tax_rate)
+			
+			cumulated_tax_fraction = 0
+			
+			for i, tax in enumerate(self.tax_doclist):
+				if cint(tax.included_in_print_rate):
+					tax.tax_fraction_for_current_item = \
+						self.get_current_tax_fraction(tax, item_tax_map)
+				else:
+					tax.tax_fraction_for_current_item = 0
+				
+				if i==0:
+					tax.grand_total_fraction_for_current_item = 1 + \
+						tax.tax_fraction_for_current_item
+				else:
+					tax.grand_total_fraction_for_current_item = \
+						self.tax_doclist[i-1].grand_total_fraction_for_current_item \
+						+ tax.tax_fraction_for_current_item
+						
+				cumulated_tax_fraction += tax.tax_fraction_for_current_item
+			
+			if cumulated_tax_fraction:
+				item.fields[self.fmap.rate] = \
+					flt((item.fields.get(self.fmap.print_rate) * \
+					self.doc.fields.get(self.fmap.exchange_rate)) / 
+					(1 + cumulated_tax_fraction), self.precision.item[self.fmap.rate])
+				
+				item.amount = flt(item.fields.get(self.fmap.rate) * item.qty,
+					self.precision.item.amount)
+				
+				item.fields[self.fmap.ref_rate] = \
+					flt(item.fields.get(self.fmap.rate) / (1 - \
+					(item.fields.get(self.fmap.discount) / 100.0)),
+					self.precision.item[self.fmap.ref_rate])
+		
+				# print item.print_rate, 1+cumulated_tax_fraction, item.rate, item.amount
+				# print "-"*10
+
+	def get_current_tax_fraction(self, tax, item_tax_map):
+		"""
+			Get tax fraction for calculating tax exclusive amount
+			from tax inclusive amount
+		"""
+		current_tax_fraction = 0
+		
+		if cint(tax.included_in_print_rate):
+			tax_rate = self._get_tax_rate(tax, item_tax_map)
+			
+			if tax.charge_type == "On Net Total":
+				current_tax_fraction = tax_rate / 100.0
+			
+			elif tax.charge_type == "On Previous Row Amount":
+				current_tax_fraction = (tax_rate / 100.0) * \
+					self.tax_doclist[cint(tax.row_id) - 1]\
+						.tax_fraction_for_current_item
+			
+			elif tax.charge_type == "On Previous Row Total":
+				current_tax_fraction = (tax_rate / 100.0) * \
+					self.tax_doclist[cint(tax.row_id) - 1]\
+						.grand_total_fraction_for_current_item
+						
+			# print tax.account_head, tax_rate, current_tax_fraction
+
+		return current_tax_fraction
+	
+	def _load_item_tax_rate(self, item_tax_rate):
+		if not item_tax_rate:
+			return {}
+
+		return json.loads(item_tax_rate)
+		
+	def _get_tax_rate(self, tax, item_tax_map):
+		if item_tax_map.has_key(tax.account_head):
+			return flt(item_tax_map.get(tax.account_head), self.precision.tax.rate)
+		else:
+			return tax.rate
diff --git a/controllers/transaction_controller.py b/controllers/transaction_controller.py
new file mode 100644
index 0000000..39a7376
--- /dev/null
+++ b/controllers/transaction_controller.py
@@ -0,0 +1,121 @@
+# ERPNext - web based ERP (http://erpnext.com)
+# Copyright (C) 2012 Web Notes Technologies Pvt Ltd
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License 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
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import unicode_literals
+import webnotes
+import webnotes.model
+from webnotes import _, msgprint, DictObj
+from webnotes.utils import cint, formatdate, cstr, flt
+from webnotes.model.code import get_obj
+from webnotes.model.doc import make_autoname, Document
+import json
+
+import stock.utils
+
+from webnotes.model.controller import DocListController
+
+class TransactionController(DocListController):
+	def __init__(self, doc, doclist):
+		super(TransactionController, self).__init__(doc, doclist)
+		self.cur_docstatus = cint(webnotes.conn.get_value(self.doc.doctype, 
+			self.doc.name, "docstatus"))
+		
+	@property
+	def precision(self):
+		if not hasattr(self, "_precision"):
+			self._precision = DictObj()
+			self._precision.main = self.meta.get_precision_map()
+			self._precision.item = self.meta.get_precision_map(parentfield = \
+				self.item_table_field)
+			if self.meta.get_field(self.fmap.taxes_and_charges):
+				self._precision.tax = self.meta.get_precision_map(parentfield = \
+					self.fmap.taxes_and_charges)
+		return self._precision
+		
+	@property
+	def item_doclist(self):
+		if not hasattr(self, "_item_doclist"):
+			self._item_doclist = self.doclist.get({"parentfield": self.item_table_field})
+		return self._item_doclist
+
+	@property
+	def tax_doclist(self):
+		if not hasattr(self, "_tax_doclist"):
+			self._tax_doclist = self.doclist.get(
+				{"parentfield": self.fmap.taxes_and_charges})
+		return self._tax_doclist
+	
+	@property
+	def stock_items(self):
+		if not hasattr(self, "_stock_items"):
+			item_codes = list(set(item.item_code for item in self.item_doclist))
+			self._stock_items = [r[0] for r in webnotes.conn.sql("""select name
+				from `tabItem` where name in (%s) and is_stock_item='Yes'""" % \
+				(", ".join((["%s"]*len(item_codes))),), item_codes)]
+
+		return self._stock_items
+	
+	@property
+	def fmap(self):
+		if not hasattr(self, "_fmap"):
+			if self.doc.doctype in ["Lead", "Quotation", "Sales Order", "Sales Invoice",
+					"Delivery Note"]:
+				self._fmap = webnotes.DictObj(	{
+					"exchange_rate": "conversion_rate",
+					"taxes_and_charges": "other_charges",
+					"taxes_and_charges_master": "charge",
+					"taxes_and_charges_total": "other_charges_total",
+					"net_total_print": "net_total_print",
+					"grand_total_print": "grand_total_export",
+					"grand_total_in_words": "grand_total_in_words",
+					"grand_total_in_words_print": "grand_total_in_words_print",
+					"rounded_total_print": "rounded_total_export",
+					"rounded_total_in_words": "in_words",
+					"rounded_total_in_words_print": "in_words_export",
+					"print_ref_rate": "ref_rate",
+					"discount": "adj_rate",
+					"print_rate": "export_rate",
+					"print_amount": "export_amount",
+					"ref_rate": "base_ref_rate",
+					"rate": "basic_rate",
+					
+					"plc_exchange_rate": "plc_conversion_rate",
+					"tax_calculation": "other_charges_calculation",
+				})
+			else:
+				self._fmap = webnotes.DictObj({
+					"exchange_rate": "conversion_rate",
+					"taxes_and_charges": "purchase_tax_details",
+					"taxes_and_charges_master": "purchase_other_charges",
+					"taxes_and_charges_total": "total_tax",
+					"net_total_print": "net_total_import",
+					"grand_total_print": "grand_total_import",
+					"grand_total_in_words": "in_words",
+					"grand_total_in_words_print": "in_words_import",
+					"rounded_total_print": "rounded_total_print",
+					"rounded_total_in_words": "rounded_total_in_words",
+					"rounded_total_in_words_print": "rounded_total_in_words_print",
+					"print_ref_rate": "import_ref_rate",
+					"discount": "discount_rate",
+					"print_rate": "import_rate",
+					"print_amount": "import_amount",
+					"ref_rate": "purchase_ref_rate",
+					"rate": "purchase_rate",
+					
+					"valuation_tax_amount": "item_tax_amount"
+				})
+			
+		return self._fmap or webnotes.DictObj()
\ No newline at end of file