# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# License: GNU General Public License v3. See license.txt

from __future__ import unicode_literals

import json
from math import ceil

import frappe
from frappe import _
from frappe.utils import add_days, cint, flt, nowdate

import erpnext


def reorder_item():
	""" Reorder item if stock reaches reorder level"""
	# if initial setup not completed, return
	if not (frappe.db.a_row_exists("Company") and frappe.db.a_row_exists("Fiscal Year")):
		return

	if cint(frappe.db.get_value('Stock Settings', None, 'auto_indent')):
		return _reorder_item()

def _reorder_item():
	material_requests = {"Purchase": {}, "Transfer": {}, "Material Issue": {}, "Manufacture": {}}
	warehouse_company = frappe._dict(frappe.db.sql("""select name, company from `tabWarehouse`
		where disabled=0"""))
	default_company = (erpnext.get_default_company() or
		frappe.db.sql("""select name from tabCompany limit 1""")[0][0])

	items_to_consider = frappe.db.sql_list("""select name from `tabItem` item
		where is_stock_item=1 and has_variants=0
			and disabled=0
			and (end_of_life is null or end_of_life='0000-00-00' or end_of_life > %(today)s)
			and (exists (select name from `tabItem Reorder` ir where ir.parent=item.name)
				or (variant_of is not null and variant_of != ''
				and exists (select name from `tabItem Reorder` ir where ir.parent=item.variant_of))
			)""",
		{"today": nowdate()})

	if not items_to_consider:
		return

	item_warehouse_projected_qty = get_item_warehouse_projected_qty(items_to_consider)

	def add_to_material_request(item_code, warehouse, reorder_level, reorder_qty, material_request_type, warehouse_group=None):
		if warehouse not in warehouse_company:
			# a disabled warehouse
			return

		reorder_level = flt(reorder_level)
		reorder_qty = flt(reorder_qty)

		# projected_qty will be 0 if Bin does not exist
		if warehouse_group:
			projected_qty = flt(item_warehouse_projected_qty.get(item_code, {}).get(warehouse_group))
		else:
			projected_qty = flt(item_warehouse_projected_qty.get(item_code, {}).get(warehouse))

		if (reorder_level or reorder_qty) and projected_qty < reorder_level:
			deficiency = reorder_level - projected_qty
			if deficiency > reorder_qty:
				reorder_qty = deficiency

			company = warehouse_company.get(warehouse) or default_company

			material_requests[material_request_type].setdefault(company, []).append({
				"item_code": item_code,
				"warehouse": warehouse,
				"reorder_qty": reorder_qty
			})

	for item_code in items_to_consider:
		item = frappe.get_doc("Item", item_code)

		if item.variant_of and not item.get("reorder_levels"):
			item.update_template_tables()

		if item.get("reorder_levels"):
			for d in item.get("reorder_levels"):
				add_to_material_request(item_code, d.warehouse, d.warehouse_reorder_level,
					d.warehouse_reorder_qty, d.material_request_type, warehouse_group=d.warehouse_group)

	if material_requests:
		return create_material_request(material_requests)

def get_item_warehouse_projected_qty(items_to_consider):
	item_warehouse_projected_qty = {}

	for item_code, warehouse, projected_qty in frappe.db.sql("""select item_code, warehouse, projected_qty
		from tabBin where item_code in ({0})
			and (warehouse != "" and warehouse is not null)"""\
		.format(", ".join(["%s"] * len(items_to_consider))), items_to_consider):

		if item_code not in item_warehouse_projected_qty:
			item_warehouse_projected_qty.setdefault(item_code, {})

		if warehouse not in item_warehouse_projected_qty.get(item_code):
			item_warehouse_projected_qty[item_code][warehouse] = flt(projected_qty)

		warehouse_doc = frappe.get_doc("Warehouse", warehouse)

		while warehouse_doc.parent_warehouse:
			if not item_warehouse_projected_qty.get(item_code, {}).get(warehouse_doc.parent_warehouse):
				item_warehouse_projected_qty.setdefault(item_code, {})[warehouse_doc.parent_warehouse] = flt(projected_qty)
			else:
				item_warehouse_projected_qty[item_code][warehouse_doc.parent_warehouse] += flt(projected_qty)
			warehouse_doc = frappe.get_doc("Warehouse", warehouse_doc.parent_warehouse)

	return item_warehouse_projected_qty

def create_material_request(material_requests):
	"""	Create indent on reaching reorder level	"""
	mr_list = []
	exceptions_list = []

	def _log_exception():
		if frappe.local.message_log:
			exceptions_list.extend(frappe.local.message_log)
			frappe.local.message_log = []
		else:
			exceptions_list.append(frappe.get_traceback())

		frappe.log_error(frappe.get_traceback())

	for request_type in material_requests:
		for company in material_requests[request_type]:
			try:
				items = material_requests[request_type][company]
				if not items:
					continue

				mr = frappe.new_doc("Material Request")
				mr.update({
					"company": company,
					"transaction_date": nowdate(),
					"material_request_type": "Material Transfer" if request_type=="Transfer" else request_type
				})

				for d in items:
					d = frappe._dict(d)
					item = frappe.get_doc("Item", d.item_code)
					uom = item.stock_uom
					conversion_factor = 1.0

					if request_type == 'Purchase':
						uom = item.purchase_uom or item.stock_uom
						if uom != item.stock_uom:
							conversion_factor = frappe.db.get_value("UOM Conversion Detail",
								{'parent': item.name, 'uom': uom}, 'conversion_factor') or 1.0

					must_be_whole_number = frappe.db.get_value("UOM", uom, "must_be_whole_number", cache=True)
					qty = d.reorder_qty / conversion_factor
					if must_be_whole_number:
						qty = ceil(qty)

					mr.append("items", {
						"doctype": "Material Request Item",
						"item_code": d.item_code,
						"schedule_date": add_days(nowdate(),cint(item.lead_time_days)),
						"qty": qty,
						"uom": uom,
						"stock_uom": item.stock_uom,
						"warehouse": d.warehouse,
						"item_name": item.item_name,
						"description": item.description,
						"item_group": item.item_group,
						"brand": item.brand,
					})

				schedule_dates = [d.schedule_date for d in mr.items]
				mr.schedule_date = max(schedule_dates or [nowdate()])
				mr.flags.ignore_mandatory = True
				mr.insert()
				mr.submit()
				mr_list.append(mr)

			except Exception:
				_log_exception()

	if mr_list:
		if getattr(frappe.local, "reorder_email_notify", None) is None:
			frappe.local.reorder_email_notify = cint(frappe.db.get_value('Stock Settings', None,
				'reorder_email_notify'))

		if(frappe.local.reorder_email_notify):
			send_email_notification(mr_list)

	if exceptions_list:
		notify_errors(exceptions_list)

	return mr_list

def send_email_notification(mr_list):
	""" Notify user about auto creation of indent"""

	email_list = frappe.db.sql_list("""select distinct r.parent
		from `tabHas Role` r, tabUser p
		where p.name = r.parent and p.enabled = 1 and p.docstatus < 2
		and r.role in ('Purchase Manager','Stock Manager')
		and p.name not in ('Administrator', 'All', 'Guest')""")

	msg = frappe.render_template("templates/emails/reorder_item.html", {
		"mr_list": mr_list
	})

	frappe.sendmail(recipients=email_list,
		subject=_('Auto Material Requests Generated'), message = msg)

def notify_errors(exceptions_list):
	subject = _("[Important] [ERPNext] Auto Reorder Errors")
	content = _("Dear System Manager,") + "<br>" + _("An error occured for certain Items while creating Material Requests based on Re-order level. \
		Please rectify these issues :") + "<br>"

	for exception in exceptions_list:
		exception = json.loads(exception)
		error_message = """<div class='small text-muted'>{0}</div><br>""".format(_(exception.get("message")))
		content += error_message

	content += _("Regards,") + "<br>" + _("Administrator")

	from frappe.email import sendmail_to_system_managers
	sendmail_to_system_managers(subject, content)