# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# MIT License. See license.txt

from __future__ import unicode_literals
from six import iteritems, string_types

import frappe
import datetime
from frappe import _
from frappe.model import default_fields, table_fields
from frappe.model.naming import set_new_name
from frappe.model.utils.link_count import notify_link_count
from frappe.modules import load_doctype_module
from frappe.model import display_fieldtypes, data_fieldtypes
from frappe.utils.password import get_decrypted_password, set_encrypted_password
from frappe.utils import (cint, flt, now, cstr, strip_html, getdate, get_datetime, to_timedelta,
	sanitize_html, sanitize_email, cast_fieldtype)

max_positive_value = {
	'smallint': 2 ** 15,
	'int': 2 ** 31,
	'bigint': 2 ** 63
}

_classes = {}

def get_controller(doctype):
	"""Returns the **class** object of the given DocType.
	For `custom` type, returns `frappe.model.document.Document`.

	:param doctype: DocType name as string."""
	from frappe.model.document import Document
	from frappe.utils.nestedset import NestedSet
	global _classes

	if not doctype in _classes:
		module_name, custom = frappe.db.get_value("DocType", doctype, ("module", "custom"), cache=True) \
			or ["Core", False]

		if custom:
			if frappe.db.field_exists("DocType", "is_tree"):
				is_tree = frappe.db.get_value("DocType", doctype, "is_tree", cache=True)
			else:
				is_tree = False
			_class = NestedSet if is_tree else Document
		else:
			module = load_doctype_module(doctype, module_name)
			classname = doctype.replace(" ", "").replace("-", "")
			if hasattr(module, classname):
				_class = getattr(module, classname)
				if issubclass(_class, BaseDocument):
					_class = getattr(module, classname)
				else:
					raise ImportError(doctype)
			else:
				raise ImportError(doctype)
		_classes[doctype] = _class

	return _classes[doctype]

class BaseDocument(object):
	ignore_in_getter = ("doctype", "_meta", "meta", "_table_fields", "_valid_columns")

	def __init__(self, d):
		self.update(d)
		self.dont_update_if_missing = []

		if hasattr(self, "__setup__"):
			self.__setup__()

	@property
	def meta(self):
		if not hasattr(self, "_meta"):
			self._meta = frappe.get_meta(self.doctype)

		return self._meta

	def update(self, d):
		if "doctype" in d:
			self.set("doctype", d.get("doctype"))

		# first set default field values of base document
		for key in default_fields:
			if key in d:
				self.set(key, d.get(key))

		for key, value in iteritems(d):
			self.set(key, value)

		return self

	def update_if_missing(self, d):
		if isinstance(d, BaseDocument):
			d = d.get_valid_dict()

		if "doctype" in d:
			self.set("doctype", d.get("doctype"))
		for key, value in iteritems(d):
			# dont_update_if_missing is a list of fieldnames, for which, you don't want to set default value
			if (self.get(key) is None) and (value is not None) and (key not in self.dont_update_if_missing):
				self.set(key, value)

	def get_db_value(self, key):
		return frappe.db.get_value(self.doctype, self.name, key)

	def get(self, key=None, filters=None, limit=None, default=None):
		if key:
			if isinstance(key, dict):
				return _filter(self.get_all_children(), key, limit=limit)
			if filters:
				if isinstance(filters, dict):
					value = _filter(self.__dict__.get(key, []), filters, limit=limit)
				else:
					default = filters
					filters = None
					value = self.__dict__.get(key, default)
			else:
				value = self.__dict__.get(key, default)

			if value is None and key not in self.ignore_in_getter \
				and key in (d.fieldname for d in self.meta.get_table_fields()):
				self.set(key, [])
				value = self.__dict__.get(key)

			return value
		else:
			return self.__dict__

	def getone(self, key, filters=None):
		return self.get(key, filters=filters, limit=1)[0]

	def set(self, key, value, as_value=False):
		if isinstance(value, list) and not as_value:
			self.__dict__[key] = []
			self.extend(key, value)
		else:
			self.__dict__[key] = value

	def delete_key(self, key):
		if key in self.__dict__:
			del self.__dict__[key]

	def append(self, key, value=None):
		if value==None:
			value={}
		if isinstance(value, (dict, BaseDocument)):
			if not self.__dict__.get(key):
				self.__dict__[key] = []
			value = self._init_child(value, key)
			self.__dict__[key].append(value)

			# reference parent document
			value.parent_doc = self

			return value
		else:

			# metaclasses may have arbitrary lists
			# which we can ignore
			if (getattr(self, '_metaclass', None)
				or self.__class__.__name__ in ('Meta', 'FormMeta', 'DocField')):
				return value

			raise ValueError(
				'Document for field "{0}" attached to child table of "{1}" must be a dict or BaseDocument, not {2} ({3})'.format(key,
					self.name, str(type(value))[1:-1], value)
			)

	def extend(self, key, value):
		if isinstance(value, list):
			for v in value:
				self.append(key, v)
		else:
			raise ValueError

	def remove(self, doc):
		self.get(doc.parentfield).remove(doc)

	def _init_child(self, value, key):
		if not self.doctype:
			return value
		if not isinstance(value, BaseDocument):
			if "doctype" not in value or value['doctype'] is None:
				value["doctype"] = self.get_table_field_doctype(key)
				if not value["doctype"]:
					raise AttributeError(key)

			value = get_controller(value["doctype"])(value)
			value.init_valid_columns()

		value.parent = self.name
		value.parenttype = self.doctype
		value.parentfield = key

		if value.docstatus is None:
			value.docstatus = 0

		if not getattr(value, "idx", None):
			value.idx = len(self.get(key) or []) + 1

		if not getattr(value, "name", None):
			value.__dict__['__islocal'] = 1

		return value

	def get_valid_dict(self, sanitize=True, convert_dates_to_str=False, ignore_nulls = False):
		d = frappe._dict()
		for fieldname in self.meta.get_valid_columns():
			d[fieldname] = self.get(fieldname)

			# if no need for sanitization and value is None, continue
			if not sanitize and d[fieldname] is None:
				continue

			df = self.meta.get_field(fieldname)
			if df:
				if df.fieldtype=="Check":
					d[fieldname] = 1 if cint(d[fieldname]) else 0

				elif df.fieldtype=="Int" and not isinstance(d[fieldname], int):
					d[fieldname] = cint(d[fieldname])

				elif df.fieldtype in ("Currency", "Float", "Percent") and not isinstance(d[fieldname], float):
					d[fieldname] = flt(d[fieldname])

				elif df.fieldtype in ("Datetime", "Date", "Time") and d[fieldname]=="":
					d[fieldname] = None

				elif df.get("unique") and cstr(d[fieldname]).strip()=="":
					# unique empty field should be set to None
					d[fieldname] = None

				if isinstance(d[fieldname], list) and df.fieldtype not in table_fields:
					frappe.throw(_('Value for {0} cannot be a list').format(_(df.label)))

			if convert_dates_to_str and isinstance(d[fieldname], (datetime.datetime, datetime.time, datetime.timedelta)):
				d[fieldname] = str(d[fieldname])

			if d[fieldname] == None and ignore_nulls:
				del d[fieldname]

		return d

	def init_valid_columns(self):
		for key in default_fields:
			if key not in self.__dict__:
				self.__dict__[key] = None

			if key in ("idx", "docstatus") and self.__dict__[key] is None:
				self.__dict__[key] = 0

		for key in self.get_valid_columns():
			if key not in self.__dict__:
				self.__dict__[key] = None

	def get_valid_columns(self):
		if self.doctype not in frappe.local.valid_columns:
			if self.doctype in ("DocField", "DocPerm") and self.parent in ("DocType", "DocField", "DocPerm"):
				from frappe.model.meta import get_table_columns
				valid = get_table_columns(self.doctype)
			else:
				valid = self.meta.get_valid_columns()

			frappe.local.valid_columns[self.doctype] = valid

		return frappe.local.valid_columns[self.doctype]

	def is_new(self):
		return self.get("__islocal")

	def as_dict(self, no_nulls=False, no_default_fields=False, convert_dates_to_str=False):
		doc = self.get_valid_dict(convert_dates_to_str=convert_dates_to_str)
		doc["doctype"] = self.doctype
		for df in self.meta.get_table_fields():
			children = self.get(df.fieldname) or []
			doc[df.fieldname] = [d.as_dict(no_nulls=no_nulls) for d in children]

		if no_nulls:
			for k in list(doc):
				if doc[k] is None:
					del doc[k]

		if no_default_fields:
			for k in list(doc):
				if k in default_fields:
					del doc[k]

		for key in ("_user_tags", "__islocal", "__onload", "_liked_by", "__run_link_triggers"):
			if self.get(key):
				doc[key] = self.get(key)

		return doc

	def as_json(self):
		return frappe.as_json(self.as_dict())

	def get_table_field_doctype(self, fieldname):
		return self.meta.get_field(fieldname).options

	def get_parentfield_of_doctype(self, doctype):
		fieldname = [df.fieldname for df in self.meta.get_table_fields() if df.options==doctype]
		return fieldname[0] if fieldname else None

	def db_insert(self):
		"""INSERT the document (with valid columns) in the database."""
		if not self.name:
			# name will be set by document class in most cases
			set_new_name(self)

		if not self.creation:
			self.creation = self.modified = now()
			self.created_by = self.modified_by = frappe.session.user

		# if doctype is "DocType", don't insert null values as we don't know who is valid yet
		d = self.get_valid_dict(convert_dates_to_str=True, ignore_nulls = self.doctype in ('DocType', 'DocField', 'DocPerm'))

		columns = list(d)
		try:
			frappe.db.sql("""INSERT INTO `tab{doctype}` ({columns})
					VALUES ({values})""".format(
					doctype = self.doctype,
					columns = ", ".join(["`"+c+"`" for c in columns]),
					values = ", ".join(["%s"] * len(columns))
				), list(d.values()))
		except Exception as e:
			if frappe.db.is_primary_key_violation(e):
				if self.meta.autoname=="hash":
					# hash collision? try again
					self.name = None
					self.db_insert()
					return

				frappe.msgprint(_("Duplicate name {0} {1}").format(self.doctype, self.name))
				raise frappe.DuplicateEntryError(self.doctype, self.name, e)

			elif frappe.db.is_unique_key_violation(e):
				# unique constraint
				self.show_unique_validation_message(e)

			else:
				raise

		self.set("__islocal", False)

	def db_update(self):
		if self.get("__islocal") or not self.name:
			self.db_insert()
			return

		d = self.get_valid_dict(convert_dates_to_str=True, ignore_nulls = self.doctype in ('DocType', 'DocField', 'DocPerm'))

		# don't update name, as case might've been changed
		name = d['name']
		del d['name']

		columns = list(d)

		try:
			frappe.db.sql("""UPDATE `tab{doctype}`
				SET {values} WHERE `name`=%s""".format(
					doctype = self.doctype,
					values = ", ".join(["`"+c+"`=%s" for c in columns])
				), list(d.values()) + [name])
		except Exception as e:
			if frappe.db.is_unique_key_violation(e):
				self.show_unique_validation_message(e)
			else:
				raise

	def show_unique_validation_message(self, e):
		# TODO: Find a better way to extract fieldname
		if frappe.db.db_type != 'postgres':
			fieldname = str(e).split("'")[-2]
			label = None

			# unique_first_fieldname_second_fieldname is the constraint name
			# created using frappe.db.add_unique
			if "unique_" in fieldname:
				fieldname = fieldname.split("_", 1)[1]

			df = self.meta.get_field(fieldname)
			if df:
				label = df.label

			frappe.msgprint(_("{0} must be unique".format(label or fieldname)))

		# this is used to preserve traceback
		raise frappe.UniqueValidationError(self.doctype, self.name, e)

	def update_modified(self):
		'''Update modified timestamp'''
		self.set("modified", now())
		frappe.db.set_value(self.doctype, self.name, 'modified', self.modified, update_modified=False)

	def _fix_numeric_types(self):
		for df in self.meta.get("fields"):
			if df.fieldtype == "Check":
				self.set(df.fieldname, cint(self.get(df.fieldname)))

			elif self.get(df.fieldname) is not None:
				if df.fieldtype == "Int":
					self.set(df.fieldname, cint(self.get(df.fieldname)))

				elif df.fieldtype in ("Float", "Currency", "Percent"):
					self.set(df.fieldname, flt(self.get(df.fieldname)))

		if self.docstatus is not None:
			self.docstatus = cint(self.docstatus)

	def _get_missing_mandatory_fields(self):
		"""Get mandatory fields that do not have any values"""
		def get_msg(df):
			if df.fieldtype in table_fields:
				return "{}: {}: {}".format(_("Error"), _("Data missing in table"), _(df.label))

			elif self.parentfield:
				return "{}: {} {} #{}: {}: {}".format(_("Error"), frappe.bold(_(self.doctype)),
					_("Row"), self.idx, _("Value missing for"), _(df.label))

			else:
				return _("Error: Value missing for {0}: {1}").format(_(df.parent), _(df.label))

		missing = []

		for df in self.meta.get("fields", {"reqd": ('=', 1)}):
			if self.get(df.fieldname) in (None, []) or not strip_html(cstr(self.get(df.fieldname))).strip():
				missing.append((df.fieldname, get_msg(df)))

		# check for missing parent and parenttype
		if self.meta.istable:
			for fieldname in ("parent", "parenttype"):
				if not self.get(fieldname):
					missing.append((fieldname, get_msg(frappe._dict(label=fieldname))))

		return missing

	def get_invalid_links(self, is_submittable=False):
		'''Returns list of invalid links and also updates fetch values if not set'''
		def get_msg(df, docname):
			if self.parentfield:
				return "{} #{}: {}: {}".format(_("Row"), self.idx, _(df.label), docname)
			else:
				return "{}: {}".format(_(df.label), docname)

		invalid_links = []
		cancelled_links = []

		for df in (self.meta.get_link_fields()
				+ self.meta.get("fields", {"fieldtype": ('=', "Dynamic Link")})):
			docname = self.get(df.fieldname)

			if docname:
				if df.fieldtype=="Link":
					doctype = df.options
					if not doctype:
						frappe.throw(_("Options not set for link field {0}").format(df.fieldname))
				else:
					doctype = self.get(df.options)
					if not doctype:
						frappe.throw(_("{0} must be set first").format(self.meta.get_label(df.options)))

				# MySQL is case insensitive. Preserve case of the original docname in the Link Field.

				# get a map of values ot fetch along with this link query
				# that are mapped as link_fieldname.source_fieldname in Options of
				# Readonly or Data or Text type fields

				fields_to_fetch = [
					_df for _df in self.meta.get_fields_to_fetch(df.fieldname)
					if
						not _df.get('fetch_if_empty')
						or (_df.get('fetch_if_empty') and not self.get(_df.fieldname))
				]

				if not fields_to_fetch:
					# cache a single value type
					values = frappe._dict(name=frappe.db.get_value(doctype, docname,
						'name', cache=True))
				else:
					values_to_fetch = ['name'] + [_df.fetch_from.split('.')[-1]
						for _df in fields_to_fetch]

					# don't cache if fetching other values too
					values = frappe.db.get_value(doctype, docname,
						values_to_fetch, as_dict=True)

				if frappe.get_meta(doctype).issingle:
					values.name = doctype

				if values:
					setattr(self, df.fieldname, values.name)

					for _df in fields_to_fetch:
						if self.is_new() or self.docstatus != 1 or _df.allow_on_submit:
							setattr(self, _df.fieldname, values[_df.fetch_from.split('.')[-1]])

					notify_link_count(doctype, docname)

					if not values.name:
						invalid_links.append((df.fieldname, docname, get_msg(df, docname)))

					elif (df.fieldname != "amended_from"
						and (is_submittable or self.meta.is_submittable) and frappe.get_meta(doctype).is_submittable
						and cint(frappe.db.get_value(doctype, docname, "docstatus"))==2):

						cancelled_links.append((df.fieldname, docname, get_msg(df, docname)))

		return invalid_links, cancelled_links

	def _validate_selects(self):
		if frappe.flags.in_import:
			return

		for df in self.meta.get_select_fields():
			if df.fieldname=="naming_series" or not (self.get(df.fieldname) and df.options):
				continue

			options = (df.options or "").split("\n")

			# if only empty options
			if not filter(None, options):
				continue

			# strip and set
			self.set(df.fieldname, cstr(self.get(df.fieldname)).strip())
			value = self.get(df.fieldname)

			if value not in options and not (frappe.flags.in_test and value.startswith("_T-")):
				# show an elaborate message
				prefix = _("Row #{0}:").format(self.idx) if self.get("parentfield") else ""
				label = _(self.meta.get_label(df.fieldname))
				comma_options = '", "'.join(_(each) for each in options)

				frappe.throw(_('{0} {1} cannot be "{2}". It should be one of "{3}"').format(prefix, label,
					value, comma_options))

	def _validate_constants(self):
		if frappe.flags.in_import or self.is_new() or self.flags.ignore_validate_constants:
			return

		constants = [d.fieldname for d in self.meta.get("fields", {"set_only_once": ('=',1)})]
		if constants:
			values = frappe.db.get_value(self.doctype, self.name, constants, as_dict=True)

		for fieldname in constants:
			df = self.meta.get_field(fieldname)

			# This conversion to string only when fieldtype is Date
			if df.fieldtype == 'Date' or df.fieldtype == 'Datetime':
				value = str(values.get(fieldname))

			else:
				value  = values.get(fieldname)

			if self.get(fieldname) != value:
				frappe.throw(_("Value cannot be changed for {0}").format(self.meta.get_label(fieldname)),
					frappe.CannotChangeConstantError)

	def _validate_length(self):
		if frappe.flags.in_install:
			return

		if self.meta.issingle:
			# single doctype value type is mediumtext
			return

		type_map = frappe.db.type_map

		for fieldname, value in iteritems(self.get_valid_dict()):
			df = self.meta.get_field(fieldname)

			if not df or df.fieldtype == 'Check':
				# skip standard fields and Check fields
				continue

			column_type = type_map[df.fieldtype][0] or None

			if column_type == 'varchar':
				default_column_max_length = type_map[df.fieldtype][1] or None
				max_length = cint(df.get("length")) or cint(default_column_max_length)

				if len(cstr(value)) > max_length:
					self.throw_length_exceeded_error(df, max_length, value)

			elif column_type in ('int', 'bigint', 'smallint'):
				max_length = max_positive_value[column_type]

				if abs(cint(value)) > max_length:
					self.throw_length_exceeded_error(df, max_length, value)

	def throw_length_exceeded_error(self, df, max_length, value):
		if self.parentfield and self.idx:
			reference = _("{0}, Row {1}").format(_(self.doctype), self.idx)

		else:
			reference = "{0} {1}".format(_(self.doctype), self.name)

		frappe.throw(_("{0}: '{1}' ({3}) will get truncated, as max characters allowed is {2}")\
			.format(reference, _(df.label), max_length, value), frappe.CharacterLengthExceededError, title=_('Value too big'))

	def _validate_update_after_submit(self):
		# get the full doc with children
		db_values = frappe.get_doc(self.doctype, self.name).as_dict()

		for key in self.as_dict():
			df = self.meta.get_field(key)
			db_value = db_values.get(key)

			if df and not df.allow_on_submit and (self.get(key) or db_value):
				if df.fieldtype in table_fields:
					# just check if the table size has changed
					# individual fields will be checked in the loop for children
					self_value = len(self.get(key))
					db_value = len(db_value)

				else:
					self_value = self.get_value(key)

				if self_value != db_value:
					frappe.throw(_("Not allowed to change {0} after submission").format(df.label),
						frappe.UpdateAfterSubmitError)

	def _sanitize_content(self):
		"""Sanitize HTML and Email in field values. Used to prevent XSS.

			- Ignore if 'Ignore XSS Filter' is checked or fieldtype is 'Code'
		"""
		if frappe.flags.in_install:
			return

		for fieldname, value in self.get_valid_dict().items():
			if not value or not isinstance(value, string_types):
				continue

			value = frappe.as_unicode(value)

			if (u"<" not in value and u">" not in value):
				# doesn't look like html so no need
				continue

			elif "<!-- markdown -->" in value and not ("<script" in value or "javascript:" in value):
				# should be handled separately via the markdown converter function
				continue

			df = self.meta.get_field(fieldname)
			sanitized_value = value

			if df and df.get("fieldtype") in ("Data", "Code", "Small Text") and df.get("options")=="Email":
				sanitized_value = sanitize_email(value)

			elif df and (df.get("ignore_xss_filter")
						or (df.get("fieldtype")=="Code" and df.get("options")!="Email")
						or df.get("fieldtype") in ("Attach", "Attach Image", "Barcode")

						# cancelled and submit but not update after submit should be ignored
						or self.docstatus==2
						or (self.docstatus==1 and not df.get("allow_on_submit"))):
				continue

			else:
				sanitized_value = sanitize_html(value, linkify=df and df.fieldtype=='Text Editor')

			self.set(fieldname, sanitized_value)

	def _save_passwords(self):
		'''Save password field values in __Auth table'''
		if self.flags.ignore_save_passwords is True:
			return

		for df in self.meta.get('fields', {'fieldtype': ('=', 'Password')}):
			if self.flags.ignore_save_passwords and df.fieldname in self.flags.ignore_save_passwords: continue
			new_password = self.get(df.fieldname)
			if new_password and not self.is_dummy_password(new_password):
				# is not a dummy password like '*****'
				set_encrypted_password(self.doctype, self.name, new_password, df.fieldname)

				# set dummy password like '*****'
				self.set(df.fieldname, '*'*len(new_password))

	def get_password(self, fieldname='password', raise_exception=True):
		if self.get(fieldname) and not self.is_dummy_password(self.get(fieldname)):
			return self.get(fieldname)

		return get_decrypted_password(self.doctype, self.name, fieldname, raise_exception=raise_exception)

	def is_dummy_password(self, pwd):
		return ''.join(set(pwd))=='*'

	def precision(self, fieldname, parentfield=None):
		"""Returns float precision for a particular field (or get global default).

		:param fieldname: Fieldname for which precision is required.
		:param parentfield: If fieldname is in child table."""
		from frappe.model.meta import get_field_precision

		if parentfield and not isinstance(parentfield, string_types):
			parentfield = parentfield.parentfield

		cache_key = parentfield or "main"

		if not hasattr(self, "_precision"):
			self._precision = frappe._dict()

		if cache_key not in self._precision:
			self._precision[cache_key] = frappe._dict()

		if fieldname not in self._precision[cache_key]:
			self._precision[cache_key][fieldname] = None

			doctype = self.meta.get_field(parentfield).options if parentfield else self.doctype
			df = frappe.get_meta(doctype).get_field(fieldname)

			if df.fieldtype in ("Currency", "Float", "Percent"):
				self._precision[cache_key][fieldname] = get_field_precision(df, self)

		return self._precision[cache_key][fieldname]


	def get_formatted(self, fieldname, doc=None, currency=None, absolute_value=False, translated=False):
		from frappe.utils.formatters import format_value

		df = self.meta.get_field(fieldname)
		if not df and fieldname in default_fields:
			from frappe.model.meta import get_default_df
			df = get_default_df(fieldname)

		val = self.get(fieldname)

		if translated:
			val = _(val)

		if absolute_value and isinstance(val, (int, float)):
			val = abs(self.get(fieldname))

		if not doc:
			doc = getattr(self, "parent_doc", None) or self

		return format_value(val, df=df, doc=doc, currency=currency)

	def is_print_hide(self, fieldname, df=None, for_print=True):
		"""Returns true if fieldname is to be hidden for print.

		Print Hide can be set via the Print Format Builder or in the controller as a list
		of hidden fields. Example

			class MyDoc(Document):
				def __setup__(self):
					self.print_hide = ["field1", "field2"]

		:param fieldname: Fieldname to be checked if hidden.
		"""
		meta_df = self.meta.get_field(fieldname)
		if meta_df and meta_df.get("__print_hide"):
			return True

		print_hide = 0

		if self.get(fieldname)==0 and not self.meta.istable:
			print_hide = ( df and df.print_hide_if_no_value ) or ( meta_df and meta_df.print_hide_if_no_value )

		if not print_hide:
			if df and df.print_hide is not None:
				print_hide = df.print_hide
			elif meta_df:
				print_hide = meta_df.print_hide

		return print_hide

	def in_format_data(self, fieldname):
		"""Returns True if shown via Print Format::`format_data` property.
			Called from within standard print format."""
		doc = getattr(self, "parent_doc", self)

		if hasattr(doc, "format_data_map"):
			return fieldname in doc.format_data_map
		else:
			return True

	def reset_values_if_no_permlevel_access(self, has_access_to, high_permlevel_fields):
		"""If the user does not have permissions at permlevel > 0, then reset the values to original / default"""
		to_reset = []

		for df in high_permlevel_fields:
			if df.permlevel not in has_access_to and df.fieldtype not in display_fieldtypes:
				to_reset.append(df)

		if to_reset:
			if self.is_new():
				# if new, set default value
				ref_doc = frappe.new_doc(self.doctype)
			else:
				# get values from old doc
				if self.get('parent_doc'):
					self.parent_doc.get_latest()
					ref_doc = [d for d in self.parent_doc.get(self.parentfield) if d.name == self.name][0]
				else:
					ref_doc = self.get_latest()

			for df in to_reset:
				self.set(df.fieldname, ref_doc.get(df.fieldname))

	def get_value(self, fieldname):
		df = self.meta.get_field(fieldname)
		val = self.get(fieldname)

		return self.cast(val, df)

	def cast(self, value, df):
		return cast_fieldtype(df.fieldtype, value)

	def _extract_images_from_text_editor(self):
		from frappe.core.doctype.file.file import extract_images_from_doc
		if self.doctype != "DocType":
			for df in self.meta.get("fields", {"fieldtype": ('=', "Text Editor")}):
				extract_images_from_doc(self, df.fieldname)

def _filter(data, filters, limit=None):
	"""pass filters as:
		{"key": "val", "key": ["!=", "val"],
		"key": ["in", "val"], "key": ["not in", "val"], "key": "^val",
		"key" : True (exists), "key": False (does not exist) }"""

	out, _filters = [], {}

	if not data:
		return out

	# setup filters as tuples
	if filters:
		for f in filters:
			fval = filters[f]

			if not isinstance(fval, (tuple, list)):
				if fval is True:
					fval = ("not None", fval)
				elif fval is False:
					fval = ("None", fval)
				elif isinstance(fval, string_types) and fval.startswith("^"):
					fval = ("^", fval[1:])
				else:
					fval = ("=", fval)

			_filters[f] = fval

	for d in data:
		add = True
		for f, fval in iteritems(_filters):
			if not frappe.compare(getattr(d, f, None), fval[0], fval[1]):
				add = False
				break

		if add:
			out.append(d)
			if limit and (len(out)-1)==limit:
				break

	return out
