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

# For license information, please see license.txt

from __future__ import unicode_literals

import copy
import json

from six import string_types

import frappe
from erpnext.setup.doctype.item_group.item_group import get_child_item_groups
from erpnext.stock.doctype.warehouse.warehouse import get_child_warehouses
from erpnext.stock.get_item_details import get_conversion_factor
from frappe import _, throw
from frappe.utils import cint, flt, get_datetime, get_link_to_form, getdate, today


class MultiplePricingRuleConflict(frappe.ValidationError): pass

apply_on_table = {
    'Item Code': 'items',
    'Item Group': 'item_groups',
    'Brand': 'brands'
}

def get_pricing_rules(args, doc=None):
	pricing_rules = []
	values =  {}

	for apply_on in ['Item Code', 'Item Group', 'Brand']:
		pricing_rules.extend(_get_pricing_rules(apply_on, args, values))
		if pricing_rules and not apply_multiple_pricing_rules(pricing_rules):
			break

	rules = []

	if not pricing_rules: return []

	if apply_multiple_pricing_rules(pricing_rules):
		for pricing_rule in pricing_rules:
			pricing_rule = filter_pricing_rules(args, pricing_rule, doc)
			if pricing_rule:
				rules.append(pricing_rule)
	else:
		pricing_rule = filter_pricing_rules(args, pricing_rules, doc)
		if pricing_rule:
			rules.append(pricing_rule)

	return rules

def _get_pricing_rules(apply_on, args, values):
	apply_on_field = frappe.scrub(apply_on)

	if not args.get(apply_on_field): return []

	child_doc = '`tabPricing Rule {0}`'.format(apply_on)

	conditions = item_variant_condition = item_conditions = ""
	values[apply_on_field] = args.get(apply_on_field)
	if apply_on_field in ['item_code', 'brand']:
		item_conditions = "{child_doc}.{apply_on_field}= %({apply_on_field})s".format(child_doc=child_doc,
			apply_on_field = apply_on_field)

		if apply_on_field == 'item_code':
			if "variant_of" not in args:
				args.variant_of = frappe.get_cached_value("Item", args.item_code, "variant_of")

			if args.variant_of:
				item_variant_condition = ' or {child_doc}.item_code=%(variant_of)s '.format(child_doc=child_doc)
				values['variant_of'] = args.variant_of
	elif apply_on_field == 'item_group':
		item_conditions = _get_tree_conditions(args, "Item Group", child_doc, False)

	conditions += get_other_conditions(conditions, values, args)
	warehouse_conditions = _get_tree_conditions(args, "Warehouse", '`tabPricing Rule`')
	if warehouse_conditions:
		warehouse_conditions = " and {0}".format(warehouse_conditions)

	if not args.price_list: args.price_list = None

	conditions += " and ifnull(`tabPricing Rule`.for_price_list, '') in (%(price_list)s, '')"
	values["price_list"] = args.get("price_list")

	pricing_rules = frappe.db.sql("""select `tabPricing Rule`.*,
			{child_doc}.{apply_on_field}, {child_doc}.uom
		from `tabPricing Rule`, {child_doc}
		where ({item_conditions} or (`tabPricing Rule`.apply_rule_on_other is not null
			and `tabPricing Rule`.{apply_on_other_field}=%({apply_on_field})s) {item_variant_condition})
			and {child_doc}.parent = `tabPricing Rule`.name
			and `tabPricing Rule`.disable = 0 and
			`tabPricing Rule`.{transaction_type} = 1 {warehouse_cond} {conditions}
		order by `tabPricing Rule`.priority desc,
			`tabPricing Rule`.name desc""".format(
			child_doc = child_doc,
			apply_on_field = apply_on_field,
			item_conditions = item_conditions,
			item_variant_condition = item_variant_condition,
			transaction_type = args.transaction_type,
			warehouse_cond = warehouse_conditions,
			apply_on_other_field = "other_{0}".format(apply_on_field),
			conditions = conditions), values, as_dict=1) or []

	return pricing_rules

def apply_multiple_pricing_rules(pricing_rules):
	apply_multiple_rule = [d.apply_multiple_pricing_rules
		for d in pricing_rules if d.apply_multiple_pricing_rules]

	if not apply_multiple_rule: return False

	if (apply_multiple_rule
		and len(apply_multiple_rule) == len(pricing_rules)):
		return True

def _get_tree_conditions(args, parenttype, table, allow_blank=True):
	field = frappe.scrub(parenttype)
	condition = ""
	if args.get(field):
		if not frappe.flags.tree_conditions:
			frappe.flags.tree_conditions = {}
		key = (parenttype, args.get(field))
		if key in frappe.flags.tree_conditions:
			return frappe.flags.tree_conditions[key]

		try:
			lft, rgt = frappe.db.get_value(parenttype, args.get(field), ["lft", "rgt"])
		except TypeError:
			frappe.throw(_("Invalid {0}").format(args.get(field)))

		parent_groups = frappe.db.sql_list("""select name from `tab%s`
			where lft<=%s and rgt>=%s""" % (parenttype, '%s', '%s'), (lft, rgt))

		if parent_groups:
			if allow_blank: parent_groups.append('')
			condition = "ifnull({table}.{field}, '') in ({parent_groups})".format(
				table=table,
				field=field,
				parent_groups=", ".join([frappe.db.escape(d) for d in parent_groups])
			)

			frappe.flags.tree_conditions[key] = condition
	return condition

def get_other_conditions(conditions, values, args):
	for field in ["company", "customer", "supplier", "campaign", "sales_partner"]:
		if args.get(field):
			conditions += " and ifnull(`tabPricing Rule`.{0}, '') in (%({1})s, '')".format(field, field)
			values[field] = args.get(field)
		else:
			conditions += " and ifnull(`tabPricing Rule`.{0}, '') = ''".format(field)

	for parenttype in ["Customer Group", "Territory", "Supplier Group"]:
		group_condition = _get_tree_conditions(args, parenttype, '`tabPricing Rule`')
		if group_condition:
			conditions += " and " + group_condition

	if args.get("transaction_date"):
		conditions += """ and %(transaction_date)s between ifnull(`tabPricing Rule`.valid_from, '2000-01-01')
			and ifnull(`tabPricing Rule`.valid_upto, '2500-12-31')"""
		values['transaction_date'] = args.get('transaction_date')

	return conditions

def filter_pricing_rules(args, pricing_rules, doc=None):
	if not isinstance(pricing_rules, list):
		pricing_rules = [pricing_rules]

	original_pricing_rule = copy.copy(pricing_rules)

	# filter for qty
	if pricing_rules:
		stock_qty = flt(args.get('stock_qty'))
		amount = flt(args.get('price_list_rate')) * flt(args.get('qty'))

		if pricing_rules[0].apply_rule_on_other:
			field = frappe.scrub(pricing_rules[0].apply_rule_on_other)

			if (field and pricing_rules[0].get('other_' + field) != args.get(field)): return

		pr_doc = frappe.get_cached_doc('Pricing Rule', pricing_rules[0].name)

		if pricing_rules[0].mixed_conditions and doc:
			stock_qty, amount, items = get_qty_and_rate_for_mixed_conditions(doc, pr_doc, args)
			for pricing_rule_args in pricing_rules:
				pricing_rule_args.apply_rule_on_other_items = items

		elif pricing_rules[0].is_cumulative:
			items = [args.get(frappe.scrub(pr_doc.get('apply_on')))]
			data = get_qty_amount_data_for_cumulative(pr_doc, args, items)

			if data:
				stock_qty += data[0]
				amount += data[1]

		if pricing_rules[0].apply_rule_on_other and not pricing_rules[0].mixed_conditions and doc:
			pricing_rules = get_qty_and_rate_for_other_item(doc, pr_doc, pricing_rules) or []
		else:
			pricing_rules = filter_pricing_rules_for_qty_amount(stock_qty, amount, pricing_rules, args)

		if not pricing_rules:
			for d in original_pricing_rule:
				if not d.threshold_percentage: continue

				msg = validate_quantity_and_amount_for_suggestion(d, stock_qty,
					amount, args.get('item_code'), args.get('transaction_type'))

				if msg:
					return {'suggestion': msg, 'item_code': args.get('item_code')}

		# add variant_of property in pricing rule
		for p in pricing_rules:
			if p.item_code and args.variant_of:
				p.variant_of = args.variant_of
			else:
				p.variant_of = None

	# find pricing rule with highest priority
	if pricing_rules:
		max_priority = max([cint(p.priority) for p in pricing_rules])
		if max_priority:
			pricing_rules = list(filter(lambda x: cint(x.priority)==max_priority, pricing_rules))

	# apply internal priority
	all_fields = ["item_code", "item_group", "brand", "customer", "customer_group", "territory",
		"supplier", "supplier_group", "campaign", "sales_partner", "variant_of"]

	if len(pricing_rules) > 1:
		for field_set in [["item_code", "variant_of", "item_group", "brand"],
			["customer", "customer_group", "territory"], ["supplier", "supplier_group"]]:
				remaining_fields = list(set(all_fields) - set(field_set))
				if if_all_rules_same(pricing_rules, remaining_fields):
					pricing_rules = apply_internal_priority(pricing_rules, field_set, args)
					break

	if pricing_rules and not isinstance(pricing_rules, list):
		pricing_rules = list(pricing_rules)

	if len(pricing_rules) > 1:
		rate_or_discount = list(set([d.rate_or_discount for d in pricing_rules]))
		if len(rate_or_discount) == 1 and rate_or_discount[0] == "Discount Percentage":
			pricing_rules = list(filter(lambda x: x.for_price_list==args.price_list, pricing_rules)) \
				or pricing_rules

	if len(pricing_rules) > 1 and not args.for_shopping_cart:
		frappe.throw(_("Multiple Price Rules exists with same criteria, please resolve conflict by assigning priority. Price Rules: {0}")
			.format("\n".join([d.name for d in pricing_rules])), MultiplePricingRuleConflict)
	elif pricing_rules:
		return pricing_rules[0]

def validate_quantity_and_amount_for_suggestion(args, qty, amount, item_code, transaction_type):
	fieldname, msg = '', ''
	type_of_transaction = 'purchase' if transaction_type == 'buying' else 'sale'

	for field, value in {'min_qty': qty, 'min_amt': amount}.items():
		if (args.get(field) and value < args.get(field)
			and (args.get(field) - cint(args.get(field) * args.threshold_percentage * 0.01)) <= value):
			fieldname = field

	for field, value in {'max_qty': qty, 'max_amt': amount}.items():
		if (args.get(field) and value > args.get(field)
			and (args.get(field) + cint(args.get(field) * args.threshold_percentage * 0.01)) >= value):
			fieldname = field

	if fieldname:
		msg = _("""If you {0} {1} quantities of the item <b>{2}</b>, the scheme <b>{3}</b>
			will be applied on the item.""").format(type_of_transaction, args.get(fieldname), item_code, args.rule_description)

		if fieldname in ['min_amt', 'max_amt']:
			msg = _("""If you {0} {1} worth item <b>{2}</b>, the scheme <b>{3}</b> will be applied on the item.
				""").format(frappe.fmt_money(type_of_transaction, args.get(fieldname)), item_code, args.rule_description)

		frappe.msgprint(msg)

	return msg

def filter_pricing_rules_for_qty_amount(qty, rate, pricing_rules, args=None):
	rules = []

	for rule in pricing_rules:
		status = False
		conversion_factor = 1

		if rule.get("uom"):
			conversion_factor = get_conversion_factor(rule.item_code, rule.uom).get("conversion_factor", 1)

		if (flt(qty) >= (flt(rule.min_qty) * conversion_factor)
			and (flt(qty)<= (rule.max_qty * conversion_factor) if rule.max_qty else True)):
			status = True

		# if user has created item price against the transaction UOM
		if args and rule.get("uom") == args.get("uom"):
			conversion_factor = 1.0

		if status and (flt(rate) >= (flt(rule.min_amt) * conversion_factor)
			and (flt(rate)<= (rule.max_amt * conversion_factor) if rule.max_amt else True)):
			status = True
		else:
			status = False

		if status:
			rules.append(rule)

	return rules

def if_all_rules_same(pricing_rules, fields):
	all_rules_same = True
	val = [pricing_rules[0].get(k) for k in fields]
	for p in pricing_rules[1:]:
		if val != [p.get(k) for k in fields]:
			all_rules_same = False
			break

	return all_rules_same

def apply_internal_priority(pricing_rules, field_set, args):
	filtered_rules = []
	for field in field_set:
		if args.get(field):
			# filter function always returns a filter object even if empty
			# list conversion is necessary to check for an empty result
			filtered_rules = list(filter(lambda x: x.get(field)==args.get(field), pricing_rules))
			if filtered_rules: break

	return filtered_rules or pricing_rules

def get_qty_and_rate_for_mixed_conditions(doc, pr_doc, args):
	sum_qty, sum_amt = [0, 0]
	items = get_pricing_rule_items(pr_doc) or []
	apply_on = frappe.scrub(pr_doc.get('apply_on'))

	if items and doc.get("items"):
		for row in doc.get('items'):
			if row.get(apply_on) not in items: continue

			if pr_doc.mixed_conditions:
				amt = args.get('qty') * args.get("price_list_rate")
				if args.get("item_code") != row.get("item_code"):
					amt = flt(row.get('qty')) * flt(row.get("price_list_rate") or args.get("rate"))

				sum_qty += flt(row.get("stock_qty")) or flt(args.get("stock_qty")) or flt(args.get("qty"))
				sum_amt += amt

		if pr_doc.is_cumulative:
			data = get_qty_amount_data_for_cumulative(pr_doc, doc, items)

			if data and data[0]:
				sum_qty += data[0]
				sum_amt += data[1]

	return sum_qty, sum_amt, items

def get_qty_and_rate_for_other_item(doc, pr_doc, pricing_rules):
	items = get_pricing_rule_items(pr_doc)

	for row in doc.items:
		if row.get(frappe.scrub(pr_doc.apply_rule_on_other)) in items:
			pricing_rules = filter_pricing_rules_for_qty_amount(row.get("stock_qty"),
				row.get("amount"), pricing_rules, row)

			if pricing_rules and pricing_rules[0]:
				pricing_rules[0].apply_rule_on_other_items = items
				return pricing_rules

def get_qty_amount_data_for_cumulative(pr_doc, doc, items=[]):
	sum_qty, sum_amt = [0, 0]
	doctype = doc.get('parenttype') or doc.doctype

	date_field = 'transaction_date' if frappe.get_meta(doctype).has_field('transaction_date') else 'posting_date'

	child_doctype = '{0} Item'.format(doctype)
	apply_on = frappe.scrub(pr_doc.get('apply_on'))

	values = [pr_doc.valid_from, pr_doc.valid_upto]
	condition = ""

	if pr_doc.warehouse:
		warehouses = get_child_warehouses(pr_doc.warehouse)

		condition += """ and `tab{child_doc}`.warehouse in ({warehouses})
			""".format(child_doc=child_doctype, warehouses = ','.join(['%s'] * len(warehouses)))

		values.extend(warehouses)

	if items:
		condition = " and `tab{child_doc}`.{apply_on} in ({items})".format(child_doc = child_doctype,
			apply_on = apply_on, items = ','.join(['%s'] * len(items)))

		values.extend(items)

	data_set = frappe.db.sql(""" SELECT `tab{child_doc}`.stock_qty,
			`tab{child_doc}`.amount
		FROM `tab{child_doc}`, `tab{parent_doc}`
		WHERE
			`tab{child_doc}`.parent = `tab{parent_doc}`.name and `tab{parent_doc}`.{date_field}
			between %s and %s and `tab{parent_doc}`.docstatus = 1
			{condition} group by `tab{child_doc}`.name
	""".format(parent_doc = doctype,
		child_doc = child_doctype,
		condition = condition,
		date_field = date_field
	), tuple(values), as_dict=1)

	for data in data_set:
		sum_qty += data.get('stock_qty')
		sum_amt += data.get('amount')

	return [sum_qty, sum_amt]

def apply_pricing_rule_on_transaction(doc):
	conditions = "apply_on = 'Transaction'"

	values = {}
	conditions = get_other_conditions(conditions, values, doc)

	pricing_rules = frappe.db.sql(""" Select `tabPricing Rule`.* from `tabPricing Rule`
		where  {conditions} and `tabPricing Rule`.disable = 0
	""".format(conditions = conditions), values, as_dict=1)

	if pricing_rules:
		pricing_rules = filter_pricing_rules_for_qty_amount(doc.total_qty,
			doc.total, pricing_rules)

		for d in pricing_rules:
			if d.price_or_product_discount == 'Price':
				if d.apply_discount_on:
					doc.set('apply_discount_on', d.apply_discount_on)

				for field in ['additional_discount_percentage', 'discount_amount']:
					pr_field = ('discount_percentage'
						if field == 'additional_discount_percentage' else field)

					if not d.get(pr_field): continue

					if d.validate_applied_rule and doc.get(field) < d.get(pr_field):
						frappe.msgprint(_("User has not applied rule on the invoice {0}")
							.format(doc.name))
					else:
						doc.set(field, d.get(pr_field))

				doc.calculate_taxes_and_totals()
			elif d.price_or_product_discount == 'Product':
				item_details = frappe._dict({'parenttype': doc.doctype})
				get_product_discount_rule(d, item_details, doc=doc)
				apply_pricing_rule_for_free_items(doc, item_details.free_item_data)
				doc.set_missing_values()

def get_applied_pricing_rules(pricing_rules):
	if pricing_rules:
		if pricing_rules.startswith('['):
			return json.loads(pricing_rules)
		else:
			return pricing_rules.split(',')

	return []

def get_product_discount_rule(pricing_rule, item_details, args=None, doc=None):
	free_item = pricing_rule.free_item
	if pricing_rule.same_item:
		free_item = item_details.item_code or args.item_code

	if not free_item:
		frappe.throw(_("Free item not set in the pricing rule {0}")
			.format(get_link_to_form("Pricing Rule", pricing_rule.name)))

	item_details.free_item_data = {
		'item_code': free_item,
		'qty': pricing_rule.free_qty or 1,
		'rate': pricing_rule.free_item_rate or 0,
		'price_list_rate': pricing_rule.free_item_rate or 0,
		'is_free_item': 1
	}

	item_data = frappe.get_cached_value('Item', free_item, ['item_name',
		'description', 'stock_uom'], as_dict=1)

	item_details.free_item_data.update(item_data)
	item_details.free_item_data['uom'] = pricing_rule.free_item_uom or item_data.stock_uom
	item_details.free_item_data['conversion_factor'] = get_conversion_factor(free_item,
		item_details.free_item_data['uom']).get("conversion_factor", 1)

	if item_details.get("parenttype") == 'Purchase Order':
		item_details.free_item_data['schedule_date'] = doc.schedule_date if doc else today()

	if item_details.get("parenttype") == 'Sales Order':
		item_details.free_item_data['delivery_date'] = doc.delivery_date if doc else today()

def apply_pricing_rule_for_free_items(doc, pricing_rule_args, set_missing_values=False):
	if pricing_rule_args.get('item_code'):
		items = [d.item_code for d in doc.items
			if d.item_code == (pricing_rule_args.get("item_code")) and d.is_free_item]

		if not items:
			doc.append('items', pricing_rule_args)

def get_pricing_rule_items(pr_doc):
	apply_on_data = []
	apply_on = frappe.scrub(pr_doc.get('apply_on'))

	pricing_rule_apply_on = apply_on_table.get(pr_doc.get('apply_on'))

	for d in pr_doc.get(pricing_rule_apply_on):
		if apply_on == 'item_group':
			apply_on_data.extend(get_child_item_groups(d.get(apply_on)))
		else:
			apply_on_data.append(d.get(apply_on))

	if pr_doc.apply_rule_on_other:
		apply_on = frappe.scrub(pr_doc.apply_rule_on_other)
		apply_on_data.append(pr_doc.get("other_" + apply_on))

	return list(set(apply_on_data))

def validate_coupon_code(coupon_name):
	coupon = frappe.get_doc("Coupon Code", coupon_name)

	if coupon.valid_from:
		if coupon.valid_from > getdate(today()):
			frappe.throw(_("Sorry, this coupon code's validity has not started"))
	elif coupon.valid_upto:
		if coupon.valid_upto < getdate(today()):
			frappe.throw(_("Sorry, this coupon code's validity has expired"))
	elif coupon.used >= coupon.maximum_use:
		frappe.throw(_("Sorry, this coupon code is no longer valid"))

def update_coupon_code_count(coupon_name,transaction_type):
	coupon=frappe.get_doc("Coupon Code",coupon_name)
	if coupon:
		if transaction_type=='used':
			if coupon.used<coupon.maximum_use:
				coupon.used=coupon.used+1
				coupon.save(ignore_permissions=True)
			else:
				frappe.throw(_("{0} Coupon used are {1}. Allowed quantity is exhausted").format(coupon.coupon_code,coupon.used))
		elif transaction_type=='cancelled':
			if coupon.used>0:
				coupon.used=coupon.used-1
				coupon.save(ignore_permissions=True)