# -*- coding: utf-8 -*-
# Copyright (c) 2020, Frappe Technologies Pvt. Ltd. and contributors
# For license information, please see license.txt

from __future__ import unicode_literals

import base64
import io
import json
import os
import re
import sys
import traceback

import frappe
import jwt
import six
from frappe import _, bold
from frappe.core.page.background_jobs.background_jobs import get_info
from frappe.integrations.utils import make_get_request, make_post_request
from frappe.utils.background_jobs import enqueue
from frappe.utils.data import (
	add_to_date,
	cint,
	cstr,
	flt,
	format_date,
	get_link_to_form,
	getdate,
	now_datetime,
	time_diff_in_hours,
	time_diff_in_seconds,
)
from frappe.utils.scheduler import is_scheduler_inactive
from pyqrcode import create as qrcreate

from erpnext.regional.india.utils import get_gst_accounts, get_place_of_supply


@frappe.whitelist()
def validate_eligibility(doc):
	if isinstance(doc, six.string_types):
		doc = json.loads(doc)

	invalid_doctype = doc.get('doctype') != 'Sales Invoice'
	if invalid_doctype:
		return False

	einvoicing_enabled = cint(frappe.db.get_single_value('E Invoice Settings', 'enable'))
	if not einvoicing_enabled:
		return False

	einvoicing_eligible_from = frappe.db.get_single_value('E Invoice Settings', 'applicable_from') or '2021-04-01'
	if getdate(doc.get('posting_date')) < getdate(einvoicing_eligible_from):
		return False

	invalid_company = not frappe.db.get_value('E Invoice User', { 'company': doc.get('company') })
	invalid_supply_type = doc.get('gst_category') not in ['Registered Regular', 'SEZ', 'Overseas', 'Deemed Export']
	company_transaction = doc.get('billing_address_gstin') == doc.get('company_gstin')

	# if export invoice, then taxes can be empty
	# invoice can only be ineligible if no taxes applied and is not an export invoice
	no_taxes_applied = not doc.get('taxes') and not doc.get('gst_category') == 'Overseas'
	has_non_gst_item = any(d for d in doc.get('items', []) if d.get('is_non_gst'))

	if invalid_company or invalid_supply_type or company_transaction or no_taxes_applied or has_non_gst_item:
		return False

	return True

def validate_einvoice_fields(doc):
	invoice_eligible = validate_eligibility(doc)

	if not invoice_eligible:
		return

	if doc.docstatus == 0 and doc._action == 'save':
		if doc.irn:
			frappe.throw(_('You cannot edit the invoice after generating IRN'), title=_('Edit Not Allowed'))
		if len(doc.name) > 16:
			raise_document_name_too_long_error()

		doc.einvoice_status = 'Pending'

	elif doc.docstatus == 1 and doc._action == 'submit' and not doc.irn:
		frappe.throw(_('You must generate IRN before submitting the document.'), title=_('Missing IRN'))

	elif doc.irn and doc.docstatus == 2 and doc._action == 'cancel' and not doc.irn_cancelled:
		frappe.throw(_('You must cancel IRN before cancelling the document.'), title=_('Cancel Not Allowed'))

def raise_document_name_too_long_error():
	title = _('Document ID Too Long')
	msg = _('As you have E-Invoicing enabled, to be able to generate IRN for this invoice')
	msg += ', '
	msg += _('document id {} exceed 16 letters.').format(bold(_('should not')))
	msg += '<br><br>'
	msg += _('You must {} your {} in order to have document id of {} length 16.').format(
		bold(_('modify')), bold(_('naming series')), bold(_('maximum'))
	)
	msg += _('Please account for ammended documents too.')
	frappe.throw(msg, title=title)

def read_json(name):
	file_path = os.path.join(os.path.dirname(__file__), '{name}.json'.format(name=name))
	with open(file_path, 'r') as f:
		return cstr(f.read())

def get_transaction_details(invoice):
	supply_type = ''
	if invoice.gst_category == 'Registered Regular': supply_type = 'B2B'
	elif invoice.gst_category == 'SEZ': supply_type = 'SEZWOP'
	elif invoice.gst_category == 'Overseas': supply_type = 'EXPWOP'
	elif invoice.gst_category == 'Deemed Export': supply_type = 'DEXP'

	if not supply_type:
		rr, sez, overseas, export = bold('Registered Regular'), bold('SEZ'), bold('Overseas'), bold('Deemed Export')
		frappe.throw(_('GST category should be one of {}, {}, {}, {}').format(rr, sez, overseas, export),
			title=_('Invalid Supply Type'))

	return frappe._dict(dict(
		tax_scheme='GST',
		supply_type=supply_type,
		reverse_charge=invoice.reverse_charge
	))

def get_doc_details(invoice):
	if getdate(invoice.posting_date) < getdate('2021-01-01'):
		frappe.throw(_('IRN generation is not allowed for invoices dated before 1st Jan 2021'), title=_('Not Allowed'))

	invoice_type = 'CRN' if invoice.is_return else 'INV'

	invoice_name = invoice.name
	invoice_date = format_date(invoice.posting_date, 'dd/mm/yyyy')

	return frappe._dict(dict(
		invoice_type=invoice_type,
		invoice_name=invoice_name,
		invoice_date=invoice_date
	))

def validate_address_fields(address, skip_gstin_validation):
	if ((not address.gstin and not skip_gstin_validation)
		or not address.city
		or not address.pincode
		or not address.address_title
		or not address.address_line1
		or not address.gst_state_number):

		frappe.throw(
			msg=_('Address Lines, City, Pincode, GSTIN are mandatory for address {}. Please set them and try again.').format(address.name),
			title=_('Missing Address Fields')
		)

	if address.address_line2 and len(address.address_line2) < 2:
		# to prevent "The field Address 2 must be a string with a minimum length of 3 and a maximum length of 100"
		address.address_line2 = ""

def get_party_details(address_name, skip_gstin_validation=False):
	addr = frappe.get_doc('Address', address_name)

	validate_address_fields(addr, skip_gstin_validation)

	if addr.gst_state_number == 97:
		# according to einvoice standard
		addr.pincode = 999999

	party_address_details = frappe._dict(dict(
		legal_name=sanitize_for_json(addr.address_title),
		location=sanitize_for_json(addr.city),
		pincode=addr.pincode, gstin=addr.gstin,
		state_code=addr.gst_state_number,
		address_line1=sanitize_for_json(addr.address_line1),
		address_line2=sanitize_for_json(addr.address_line2)
	))

	return party_address_details

def get_overseas_address_details(address_name):
	address_title, address_line1, address_line2, city = frappe.db.get_value(
		'Address', address_name, ['address_title', 'address_line1', 'address_line2', 'city']
	)

	if not address_title or not address_line1 or not city:
		frappe.throw(
			msg=_('Address lines and city is mandatory for address {}. Please set them and try again.').format(
				get_link_to_form('Address', address_name)
			),
			title=_('Missing Address Fields')
		)

	return frappe._dict(dict(
		gstin='URP',
		legal_name=sanitize_for_json(address_title),
		location=city,
		address_line1=sanitize_for_json(address_line1),
		address_line2=sanitize_for_json(address_line2),
		pincode=999999, state_code=96, place_of_supply=96
	))

def get_item_list(invoice):
	item_list = []

	for d in invoice.items:
		einvoice_item_schema = read_json('einv_item_template')
		item = frappe._dict({})
		item.update(d.as_dict())

		item.sr_no = d.idx
		item.description = sanitize_for_json(d.item_name)

		item.qty = abs(item.qty)
		if flt(item.qty) != 0.0:
			item.unit_rate = abs(item.taxable_value / item.qty)
		else:
			item.unit_rate = abs(item.taxable_value)
		item.gross_amount = abs(item.taxable_value)
		item.taxable_value = abs(item.taxable_value)
		item.discount_amount = 0

		item.batch_expiry_date = frappe.db.get_value('Batch', d.batch_no, 'expiry_date') if d.batch_no else None
		item.batch_expiry_date = format_date(item.batch_expiry_date, 'dd/mm/yyyy') if item.batch_expiry_date else None
		item.is_service_item = 'Y' if item.gst_hsn_code and item.gst_hsn_code[:2] == "99" else 'N'
		item.serial_no = ""

		item = update_item_taxes(invoice, item)

		item.total_value = abs(
			item.taxable_value + item.igst_amount + item.sgst_amount +
			item.cgst_amount + item.cess_amount + item.cess_nadv_amount + item.other_charges
		)
		einv_item = einvoice_item_schema.format(item=item)
		item_list.append(einv_item)

	return ', '.join(item_list)

def update_item_taxes(invoice, item):
	gst_accounts = get_gst_accounts(invoice.company)
	gst_accounts_list = [d for accounts in gst_accounts.values() for d in accounts if d]

	for attr in [
		'tax_rate', 'cess_rate', 'cess_nadv_amount',
		'cgst_amount',  'sgst_amount', 'igst_amount',
		'cess_amount', 'cess_nadv_amount', 'other_charges'
		]:
		item[attr] = 0

	for t in invoice.taxes:
		is_applicable = t.tax_amount and t.account_head in gst_accounts_list
		if is_applicable:
			# this contains item wise tax rate & tax amount (incl. discount)
			item_tax_detail = json.loads(t.item_wise_tax_detail).get(item.item_code or item.item_name)

			item_tax_rate = item_tax_detail[0]
			# item tax amount excluding discount amount
			item_tax_amount = (item_tax_rate / 100) * item.taxable_value

			if t.account_head in gst_accounts.cess_account:
				item_tax_amount_after_discount = item_tax_detail[1]
				if t.charge_type == 'On Item Quantity':
					item.cess_nadv_amount += abs(item_tax_amount_after_discount)
				else:
					item.cess_rate += item_tax_rate
					item.cess_amount += abs(item_tax_amount_after_discount)

			for tax_type in ['igst', 'cgst', 'sgst']:
				if t.account_head in gst_accounts[f'{tax_type}_account']:
					item.tax_rate += item_tax_rate
					item[f'{tax_type}_amount'] += abs(item_tax_amount)
		else:
			# TODO: other charges per item
			pass

	return item

def get_invoice_value_details(invoice):
	invoice_value_details = frappe._dict(dict())
	invoice_value_details.base_total = abs(sum([i.taxable_value for i in invoice.get('items')]))
	invoice_value_details.invoice_discount_amt = 0

	invoice_value_details.round_off = invoice.base_rounding_adjustment
	invoice_value_details.base_grand_total = abs(invoice.base_rounded_total) or abs(invoice.base_grand_total)
	invoice_value_details.grand_total = abs(invoice.rounded_total) or abs(invoice.grand_total)

	invoice_value_details = update_invoice_taxes(invoice, invoice_value_details)

	return invoice_value_details

def update_invoice_taxes(invoice, invoice_value_details):
	gst_accounts = get_gst_accounts(invoice.company)
	gst_accounts_list = [d for accounts in gst_accounts.values() for d in accounts if d]

	invoice_value_details.total_cgst_amt = 0
	invoice_value_details.total_sgst_amt = 0
	invoice_value_details.total_igst_amt = 0
	invoice_value_details.total_cess_amt = 0
	invoice_value_details.total_other_charges = 0
	considered_rows = []

	for t in invoice.taxes:
		tax_amount = t.base_tax_amount_after_discount_amount
		if t.account_head in gst_accounts_list:
			if t.account_head in gst_accounts.cess_account:
				# using after discount amt since item also uses after discount amt for cess calc
				invoice_value_details.total_cess_amt += abs(t.base_tax_amount_after_discount_amount)

			for tax_type in ['igst', 'cgst', 'sgst']:
				if t.account_head in gst_accounts[f'{tax_type}_account']:

					invoice_value_details[f'total_{tax_type}_amt'] += abs(tax_amount)
				update_other_charges(t, invoice_value_details, gst_accounts_list, invoice, considered_rows)
		else:
			invoice_value_details.total_other_charges += abs(tax_amount)

	return invoice_value_details

def update_other_charges(tax_row, invoice_value_details, gst_accounts_list, invoice, considered_rows):
	prev_row_id = cint(tax_row.row_id) - 1
	if tax_row.account_head in gst_accounts_list and prev_row_id not in considered_rows:
		if tax_row.charge_type == 'On Previous Row Amount':
			amount = invoice.get('taxes')[prev_row_id].tax_amount_after_discount_amount
			invoice_value_details.total_other_charges -= abs(amount)
			considered_rows.append(prev_row_id)
		if tax_row.charge_type == 'On Previous Row Total':
			amount = invoice.get('taxes')[prev_row_id].base_total - invoice.base_net_total
			invoice_value_details.total_other_charges -= abs(amount)
			considered_rows.append(prev_row_id)

def get_payment_details(invoice):
	payee_name = invoice.company
	mode_of_payment = ', '.join([d.mode_of_payment for d in invoice.payments])
	paid_amount = invoice.base_paid_amount
	outstanding_amount = invoice.outstanding_amount

	return frappe._dict(dict(
		payee_name=payee_name, mode_of_payment=mode_of_payment,
		paid_amount=paid_amount, outstanding_amount=outstanding_amount
	))

def get_return_doc_reference(invoice):
	invoice_date = frappe.db.get_value('Sales Invoice', invoice.return_against, 'posting_date')
	return frappe._dict(dict(
		invoice_name=invoice.return_against, invoice_date=format_date(invoice_date, 'dd/mm/yyyy')
	))

def get_eway_bill_details(invoice):
	if invoice.is_return:
		frappe.throw(_('E-Way Bill cannot be generated for Credit Notes & Debit Notes. Please clear fields in the Transporter Section of the invoice.'),
			title=_('Invalid Fields'))


	mode_of_transport = { '': '', 'Road': '1', 'Air': '2', 'Rail': '3', 'Ship': '4' }
	vehicle_type = { 'Regular': 'R', 'Over Dimensional Cargo (ODC)': 'O' }

	return frappe._dict(dict(
		gstin=invoice.gst_transporter_id,
		name=invoice.transporter_name,
		mode_of_transport=mode_of_transport[invoice.mode_of_transport],
		distance=invoice.distance or 0,
		document_name=invoice.lr_no,
		document_date=format_date(invoice.lr_date, 'dd/mm/yyyy'),
		vehicle_no=invoice.vehicle_no,
		vehicle_type=vehicle_type[invoice.gst_vehicle_type]
	))

def validate_mandatory_fields(invoice):
	if not invoice.company_address:
		frappe.throw(
			_('Company Address is mandatory to fetch company GSTIN details. Please set Company Address and try again.'),
			title=_('Missing Fields')
		)
	if not invoice.customer_address:
		frappe.throw(
			_('Customer Address is mandatory to fetch customer GSTIN details. Please set Company Address and try again.'),
			title=_('Missing Fields')
		)
	if not frappe.db.get_value('Address', invoice.company_address, 'gstin'):
		frappe.throw(
			_('GSTIN is mandatory to fetch company GSTIN details. Please enter GSTIN in selected company address.'),
			title=_('Missing Fields')
		)
	if invoice.gst_category != 'Overseas' and not frappe.db.get_value('Address', invoice.customer_address, 'gstin'):
		frappe.throw(
			_('GSTIN is mandatory to fetch customer GSTIN details. Please enter GSTIN in selected customer address.'),
			title=_('Missing Fields')
		)

def validate_totals(einvoice):
	item_list = einvoice['ItemList']
	value_details = einvoice['ValDtls']

	total_item_ass_value = 0
	total_item_cgst_value = 0
	total_item_sgst_value = 0
	total_item_igst_value = 0
	total_item_value = 0
	for item in item_list:
		total_item_ass_value += flt(item['AssAmt'])
		total_item_cgst_value += flt(item['CgstAmt'])
		total_item_sgst_value += flt(item['SgstAmt'])
		total_item_igst_value += flt(item['IgstAmt'])
		total_item_value += flt(item['TotItemVal'])

		if abs(flt(item['AssAmt']) * flt(item['GstRt']) / 100) - (flt(item['CgstAmt']) + flt(item['SgstAmt']) + flt(item['IgstAmt'])) > 1:
			frappe.throw(_('Row #{}: GST rate is invalid. Please remove tax rows with zero tax amount from taxes table.').format(item.idx))

	if abs(flt(value_details['AssVal']) - total_item_ass_value) > 1:
		frappe.throw(_('Total Taxable Value of the items is not equal to the Invoice Net Total. Please check item taxes / discounts for any correction.'))

	if abs(flt(value_details['CgstVal']) + flt(value_details['SgstVal']) - total_item_cgst_value - total_item_sgst_value) > 1:
		frappe.throw(_('CGST + SGST value of the items is not equal to total CGST + SGST value. Please review taxes for any correction.'))

	if abs(flt(value_details['IgstVal']) - total_item_igst_value) > 1:
		frappe.throw(_('IGST value of all items is not equal to total IGST value. Please review taxes for any correction.'))

	if abs(
		flt(value_details['TotInvVal']) + flt(value_details['Discount']) -
		flt(value_details['OthChrg']) - flt(value_details['RndOffAmt']) -
		total_item_value
	) > 1:
		frappe.throw(_('Total Value of the items is not equal to the Invoice Grand Total. Please check item taxes / discounts for any correction.'))

	calculated_invoice_value = \
			flt(value_details['AssVal']) + flt(value_details['CgstVal']) \
			+ flt(value_details['SgstVal']) + flt(value_details['IgstVal']) \
			+ flt(value_details['OthChrg']) + flt(value_details['RndOffAmt']) - flt(value_details['Discount'])

	if abs(flt(value_details['TotInvVal']) - calculated_invoice_value) > 1:
		frappe.throw(_('Total Item Value + Taxes - Discount is not equal to the Invoice Grand Total. Please check taxes / discounts for any correction.'))

def make_einvoice(invoice):
	validate_mandatory_fields(invoice)

	schema = read_json('einv_template')

	transaction_details = get_transaction_details(invoice)
	item_list = get_item_list(invoice)
	doc_details = get_doc_details(invoice)
	invoice_value_details = get_invoice_value_details(invoice)
	seller_details = get_party_details(invoice.company_address)

	if invoice.gst_category == 'Overseas':
		buyer_details = get_overseas_address_details(invoice.customer_address)
	else:
		buyer_details = get_party_details(invoice.customer_address)
		place_of_supply = get_place_of_supply(invoice, invoice.doctype)
		if place_of_supply:
			place_of_supply = place_of_supply.split('-')[0]
		else:
			place_of_supply = sanitize_for_json(invoice.billing_address_gstin)[:2]
		buyer_details.update(dict(place_of_supply=place_of_supply))

	seller_details.update(dict(legal_name=invoice.company))
	buyer_details.update(dict(legal_name=invoice.customer_name or invoice.customer))

	shipping_details = payment_details = prev_doc_details = eway_bill_details = frappe._dict({})
	if invoice.shipping_address_name and invoice.customer_address != invoice.shipping_address_name:
		if invoice.gst_category == 'Overseas':
			shipping_details = get_overseas_address_details(invoice.shipping_address_name)
		else:
			shipping_details = get_party_details(invoice.shipping_address_name, skip_gstin_validation=True)

	dispatch_details = frappe._dict({})
	if invoice.dispatch_address_name:
		dispatch_details = get_party_details(invoice.dispatch_address_name, skip_gstin_validation=True)

	if invoice.is_pos and invoice.base_paid_amount:
		payment_details = get_payment_details(invoice)

	if invoice.is_return and invoice.return_against:
		prev_doc_details = get_return_doc_reference(invoice)

	if invoice.transporter and not invoice.is_return:
		eway_bill_details = get_eway_bill_details(invoice)

	# not yet implemented
	period_details = export_details = frappe._dict({})

	einvoice = schema.format(
		transaction_details=transaction_details, doc_details=doc_details, dispatch_details=dispatch_details,
		seller_details=seller_details, buyer_details=buyer_details, shipping_details=shipping_details,
		item_list=item_list, invoice_value_details=invoice_value_details, payment_details=payment_details,
		period_details=period_details, prev_doc_details=prev_doc_details,
		export_details=export_details, eway_bill_details=eway_bill_details
	)

	try:
		einvoice = safe_json_load(einvoice)
		einvoice = santize_einvoice_fields(einvoice)
	except Exception:
		show_link_to_error_log(invoice, einvoice)

	try:
		validate_totals(einvoice)
	except Exception:
		log_error(einvoice)
		raise

	return einvoice

def show_link_to_error_log(invoice, einvoice):
	err_log = log_error(einvoice)
	link_to_error_log = get_link_to_form('Error Log', err_log.name, 'Error Log')
	frappe.throw(
		_('An error occurred while creating e-invoice for {}. Please check {} for more information.').format(
			invoice.name, link_to_error_log),
		title=_('E Invoice Creation Failed')
	)

def log_error(data=None):
	if isinstance(data, six.string_types):
		data = json.loads(data)

	seperator = "--" * 50
	err_tb = traceback.format_exc()
	err_msg = str(sys.exc_info()[1])
	data = json.dumps(data, indent=4)

	message = "\n".join([
		"Error", err_msg, seperator,
		"Data:", data, seperator,
		"Exception:", err_tb
	])
	return frappe.log_error(title=_('E Invoice Request Failed'), message=message)

def santize_einvoice_fields(einvoice):
	int_fields = ["Pin","Distance","CrDay"]
	float_fields = ["Qty","FreeQty","UnitPrice","TotAmt","Discount","PreTaxVal","AssAmt","GstRt","IgstAmt","CgstAmt","SgstAmt","CesRt","CesAmt","CesNonAdvlAmt","StateCesRt","StateCesAmt","StateCesNonAdvlAmt","OthChrg","TotItemVal","AssVal","CgstVal","SgstVal","IgstVal","CesVal","StCesVal","Discount","OthChrg","RndOffAmt","TotInvVal","TotInvValFc","PaidAmt","PaymtDue","ExpDuty",]
	copy = einvoice.copy()
	for key, value in copy.items():
		if isinstance(value, list):
			for idx, d in enumerate(value):
				santized_dict = santize_einvoice_fields(d)
				if santized_dict:
					einvoice[key][idx] = santized_dict
				else:
					einvoice[key].pop(idx)

			if not einvoice[key]:
				einvoice.pop(key, None)

		elif isinstance(value, dict):
			santized_dict = santize_einvoice_fields(value)
			if santized_dict:
				einvoice[key] = santized_dict
			else:
				einvoice.pop(key, None)

		elif not value or value == "None":
			einvoice.pop(key, None)

		elif key in float_fields:
			einvoice[key] = flt(value, 2)

		elif key in int_fields:
			einvoice[key] = cint(value)

	return einvoice

def safe_json_load(json_string):
	try:
		return json.loads(json_string)
	except json.JSONDecodeError as e:
		# print a snippet of 40 characters around the location where error occured
		pos = e.pos
		start, end = max(0, pos-20), min(len(json_string)-1, pos+20)
		snippet = json_string[start:end]
		frappe.throw(_("Error in input data. Please check for any special characters near following input: <br> {}").format(snippet))

class RequestFailed(Exception):
	pass
class CancellationNotAllowed(Exception):
	pass

class GSPConnector():
	def __init__(self, doctype=None, docname=None):
		self.doctype = doctype
		self.docname = docname

		self.set_invoice()
		self.set_credentials()

		# authenticate url is same for sandbox & live
		self.authenticate_url = 'https://gsp.adaequare.com/gsp/authenticate?grant_type=token'
		self.base_url = 'https://gsp.adaequare.com' if not self.e_invoice_settings.sandbox_mode else 'https://gsp.adaequare.com/test'

		self.cancel_irn_url = self.base_url + '/enriched/ei/api/invoice/cancel'
		self.irn_details_url = self.base_url + '/enriched/ei/api/invoice/irn'
		self.generate_irn_url = self.base_url + '/enriched/ei/api/invoice'
		self.gstin_details_url = self.base_url + '/enriched/ei/api/master/gstin'
		self.cancel_ewaybill_url = self.base_url + '/enriched/ewb/ewayapi?action=CANEWB'
		self.generate_ewaybill_url = self.base_url + '/enriched/ei/api/ewaybill'

	def set_invoice(self):
		self.invoice = None
		if self.doctype and self.docname:
			self.invoice = frappe.get_cached_doc(self.doctype, self.docname)

	def set_credentials(self):
		self.e_invoice_settings = frappe.get_cached_doc('E Invoice Settings')

		if not self.e_invoice_settings.enable:
			frappe.throw(_("E-Invoicing is disabled. Please enable it from {} to generate e-invoices.").format(get_link_to_form("E Invoice Settings", "E Invoice Settings")))

		if self.invoice:
			gstin = self.get_seller_gstin()
			credentials_for_gstin = [d for d in self.e_invoice_settings.credentials if d.gstin == gstin]
			if credentials_for_gstin:
				self.credentials = credentials_for_gstin[0]
			else:
				frappe.throw(_('Cannot find e-invoicing credentials for selected Company GSTIN. Please check E-Invoice Settings'))
		else:
			self.credentials = self.e_invoice_settings.credentials[0] if self.e_invoice_settings.credentials else None

	def get_seller_gstin(self):
		gstin = frappe.db.get_value('Address', self.invoice.company_address, 'gstin')
		if not gstin:
			frappe.throw(_('Cannot retrieve Company GSTIN. Please select company address with valid GSTIN.'))
		return gstin

	def get_auth_token(self):
		if time_diff_in_seconds(self.e_invoice_settings.token_expiry, now_datetime()) < 150.0:
			self.fetch_auth_token()

		return self.e_invoice_settings.auth_token

	def make_request(self, request_type, url, headers=None, data=None):
		if request_type == 'post':
			res = make_post_request(url, headers=headers, data=data)
		else:
			res = make_get_request(url, headers=headers, data=data)

		self.log_request(url, headers, data, res)
		return res

	def log_request(self, url, headers, data, res):
		headers.update({ 'password': self.credentials.password })
		request_log = frappe.get_doc({
			"doctype": "E Invoice Request Log",
			"user": frappe.session.user,
			"reference_invoice": self.invoice.name if self.invoice else None,
			"url": url,
			"headers": json.dumps(headers, indent=4) if headers else None,
			"data": json.dumps(data, indent=4) if isinstance(data, dict) else data,
			"response": json.dumps(res, indent=4) if res else None
		})
		request_log.save(ignore_permissions=True)
		frappe.db.commit()

	def fetch_auth_token(self):
		client_id = self.e_invoice_settings.client_id or frappe.conf.einvoice_client_id
		client_secret = self.e_invoice_settings.get_password('client_secret') or frappe.conf.einvoice_client_secret
		headers = {
			'gspappid': client_id,
			'gspappsecret': client_secret
		}
		res = {}
		try:
			res = self.make_request('post', self.authenticate_url, headers)
			self.e_invoice_settings.auth_token = "{} {}".format(res.get('token_type'), res.get('access_token'))
			self.e_invoice_settings.token_expiry = add_to_date(None, seconds=res.get('expires_in'))
			self.e_invoice_settings.save(ignore_permissions=True)
			self.e_invoice_settings.reload()

		except Exception:
			log_error(res)
			self.raise_error(True)

	def get_headers(self):
		return {
			'content-type': 'application/json',
			'user_name': self.credentials.username,
			'password': self.credentials.get_password(),
			'gstin': self.credentials.gstin,
			'authorization': self.get_auth_token(),
			'requestid': str(base64.b64encode(os.urandom(18))),
		}

	def fetch_gstin_details(self, gstin):
		headers = self.get_headers()

		try:
			params = '?gstin={gstin}'.format(gstin=gstin)
			res = self.make_request('get', self.gstin_details_url + params, headers)
			if res.get('success'):
				return res.get('result')
			else:
				log_error(res)
				raise RequestFailed

		except RequestFailed:
			self.raise_error()

		except Exception:
			log_error()
			self.raise_error(True)
	@staticmethod
	def get_gstin_details(gstin):
		'''fetch and cache GSTIN details'''
		if not hasattr(frappe.local, 'gstin_cache'):
			frappe.local.gstin_cache = {}

		key = gstin
		gsp_connector = GSPConnector()
		details = gsp_connector.fetch_gstin_details(gstin)

		frappe.local.gstin_cache[key] = details
		frappe.cache().hset('gstin_cache', key, details)
		return details

	def generate_irn(self):
		data = {}
		try:
			headers = self.get_headers()
			einvoice = make_einvoice(self.invoice)
			data = json.dumps(einvoice, indent=4)
			res = self.make_request('post', self.generate_irn_url, headers, data)

			if res.get('success'):
				self.set_einvoice_data(res.get('result'))

			elif '2150' in res.get('message'):
				# IRN already generated but not updated in invoice
				# Extract the IRN from the response description and fetch irn details
				irn = res.get('result')[0].get('Desc').get('Irn')
				irn_details = self.get_irn_details(irn)
				if irn_details:
					self.set_einvoice_data(irn_details)
				else:
					raise RequestFailed('IRN has already been generated for the invoice but cannot fetch details for the it. \
						Contact ERPNext support to resolve the issue.')

			else:
				raise RequestFailed

		except RequestFailed:
			errors = self.sanitize_error_message(res.get('message'))
			self.set_failed_status(errors=errors)
			self.raise_error(errors=errors)

		except Exception as e:
			self.set_failed_status(errors=str(e))
			log_error(data)
			self.raise_error(True)

	@staticmethod
	def bulk_generate_irn(invoices):
		gsp_connector = GSPConnector()
		gsp_connector.doctype = 'Sales Invoice'

		failed = []

		for invoice in invoices:
			try:
				gsp_connector.docname = invoice
				gsp_connector.set_invoice()
				gsp_connector.set_credentials()
				gsp_connector.generate_irn()

			except Exception as e:
				failed.append({
					'docname': invoice,
					'message': str(e)
				})

		return failed

	def get_irn_details(self, irn):
		headers = self.get_headers()

		try:
			params = '?irn={irn}'.format(irn=irn)
			res = self.make_request('get', self.irn_details_url + params, headers)
			if res.get('success'):
				return res.get('result')
			else:
				raise RequestFailed

		except RequestFailed:
			errors = self.sanitize_error_message(res.get('message'))
			self.raise_error(errors=errors)

		except Exception:
			log_error()
			self.raise_error(True)

	def cancel_irn(self, irn, reason, remark):
		data, res = {}, {}
		try:
			# validate cancellation
			if time_diff_in_hours(now_datetime(), self.invoice.ack_date) > 24:
				frappe.throw(_('E-Invoice cannot be cancelled after 24 hours of IRN generation.'), title=_('Not Allowed'), exc=CancellationNotAllowed)
			if not irn:
				frappe.throw(_('IRN not found. You must generate IRN before cancelling.'), title=_('Not Allowed'), exc=CancellationNotAllowed)

			headers = self.get_headers()
			data = json.dumps({
				'Irn': irn,
				'Cnlrsn': reason,
				'Cnlrem': remark
			}, indent=4)

			res = self.make_request('post', self.cancel_irn_url, headers, data)
			if res.get('success') or '9999' in res.get('message'):
				self.invoice.irn_cancelled = 1
				self.invoice.irn_cancel_date = res.get('result')['CancelDate'] if res.get('result') else ""
				self.invoice.einvoice_status = 'Cancelled'
				self.invoice.flags.updater_reference = {
					'doctype': self.invoice.doctype,
					'docname': self.invoice.name,
					'label': _('IRN Cancelled - {}').format(remark)
				}
				self.update_invoice()

			else:
				raise RequestFailed

		except RequestFailed:
			errors = self.sanitize_error_message(res.get('message'))
			self.set_failed_status(errors=errors)
			self.raise_error(errors=errors)

		except CancellationNotAllowed as e:
			self.set_failed_status(errors=str(e))
			self.raise_error(errors=str(e))

		except Exception as e:
			self.set_failed_status(errors=str(e))
			log_error(data)
			self.raise_error(True)

	@staticmethod
	def bulk_cancel_irn(invoices, reason, remark):
		gsp_connector = GSPConnector()
		gsp_connector.doctype = 'Sales Invoice'

		failed = []

		for invoice in invoices:
			try:
				gsp_connector.docname = invoice
				gsp_connector.set_invoice()
				gsp_connector.set_credentials()
				irn = gsp_connector.invoice.irn
				gsp_connector.cancel_irn(irn, reason, remark)

			except Exception as e:
				failed.append({
					'docname': invoice,
					'message': str(e)
				})

		return failed

	def generate_eway_bill(self, **kwargs):
		args = frappe._dict(kwargs)

		headers = self.get_headers()
		eway_bill_details = get_eway_bill_details(args)
		data = json.dumps({
			'Irn': args.irn,
			'Distance': cint(eway_bill_details.distance),
			'TransMode': eway_bill_details.mode_of_transport,
			'TransId': eway_bill_details.gstin,
			'TransName': eway_bill_details.transporter,
			'TrnDocDt': eway_bill_details.document_date,
			'TrnDocNo': eway_bill_details.document_name,
			'VehNo': eway_bill_details.vehicle_no,
			'VehType': eway_bill_details.vehicle_type
		}, indent=4)

		try:
			res = self.make_request('post', self.generate_ewaybill_url, headers, data)
			if res.get('success'):
				self.invoice.ewaybill = res.get('result').get('EwbNo')
				self.invoice.eway_bill_validity = res.get('result').get('EwbValidTill')
				self.invoice.eway_bill_cancelled = 0
				self.invoice.update(args)
				self.invoice.flags.updater_reference = {
					'doctype': self.invoice.doctype,
					'docname': self.invoice.name,
					'label': _('E-Way Bill Generated')
				}
				self.update_invoice()

			else:
				raise RequestFailed

		except RequestFailed:
			errors = self.sanitize_error_message(res.get('message'))
			self.raise_error(errors=errors)

		except Exception:
			log_error(data)
			self.raise_error(True)

	def cancel_eway_bill(self, eway_bill, reason, remark):
		headers = self.get_headers()
		data = json.dumps({
			'ewbNo': eway_bill,
			'cancelRsnCode': reason,
			'cancelRmrk': remark
		}, indent=4)
		headers["username"] = headers["user_name"]
		del headers["user_name"]
		try:
			res = self.make_request('post', self.cancel_ewaybill_url, headers, data)
			if res.get('success'):
				self.invoice.ewaybill = ''
				self.invoice.eway_bill_cancelled = 1
				self.invoice.flags.updater_reference = {
					'doctype': self.invoice.doctype,
					'docname': self.invoice.name,
					'label': _('E-Way Bill Cancelled - {}').format(remark)
				}
				self.update_invoice()

			else:
				raise RequestFailed

		except RequestFailed:
			errors = self.sanitize_error_message(res.get('message'))
			self.raise_error(errors=errors)

		except Exception:
			log_error(data)
			self.raise_error(True)

	def sanitize_error_message(self, message):
		'''
			On validation errors, response message looks something like this:
			message = '2174 : For inter-state transaction, CGST and SGST amounts are not applicable; only IGST amount is applicable,
						3095 : Supplier GSTIN is inactive'
			we search for string between ':' to extract the error messages
			errors = [
				': For inter-state transaction, CGST and SGST amounts are not applicable; only IGST amount is applicable, 3095 ',
				': Test'
			]
			then we trim down the message by looping over errors
		'''
		if not message:
			return []

		errors = re.findall(': [^:]+', message)
		for idx, e in enumerate(errors):
			# remove colons
			errors[idx] = errors[idx].replace(':', '').strip()
			# if not last
			if idx != len(errors) - 1:
				# remove last 7 chars eg: ', 3095 '
				errors[idx] = errors[idx][:-6]

		return errors

	def raise_error(self, raise_exception=False, errors=None):
		if errors is None:
			errors = []
		title = _('E Invoice Request Failed')
		if errors:
			frappe.throw(errors, title=title, as_list=1)
		else:
			link_to_error_list = '<a href="/app/error-log" target="_blank">Error Log</a>'
			frappe.msgprint(
				_('An error occurred while making e-invoicing request. Please check {} for more information.').format(link_to_error_list),
				title=title,
				raise_exception=raise_exception,
				indicator='red'
			)

	def set_einvoice_data(self, res):
		enc_signed_invoice = res.get('SignedInvoice')
		dec_signed_invoice = jwt.decode(enc_signed_invoice, options={"verify_signature": False})['data']

		self.invoice.irn = res.get('Irn')
		self.invoice.ewaybill = res.get('EwbNo')
		self.invoice.eway_bill_validity = res.get('EwbValidTill')
		self.invoice.ack_no = res.get('AckNo')
		self.invoice.ack_date = res.get('AckDt')
		self.invoice.signed_einvoice = dec_signed_invoice
		self.invoice.ack_no = res.get('AckNo')
		self.invoice.ack_date = res.get('AckDt')
		self.invoice.signed_qr_code = res.get('SignedQRCode')
		self.invoice.einvoice_status = 'Generated'

		self.attach_qrcode_image()

		self.invoice.flags.updater_reference = {
			'doctype': self.invoice.doctype,
			'docname': self.invoice.name,
			'label': _('IRN Generated')
		}
		self.update_invoice()

	def attach_qrcode_image(self):
		qrcode = self.invoice.signed_qr_code
		doctype = self.invoice.doctype
		docname = self.invoice.name
		filename = 'QRCode_{}.png'.format(docname).replace(os.path.sep, "__")

		qr_image = io.BytesIO()
		url = qrcreate(qrcode, error='L')
		url.png(qr_image, scale=2, quiet_zone=1)
		_file = frappe.get_doc({
			"doctype": "File",
			"file_name": filename,
			"attached_to_doctype": doctype,
			"attached_to_name": docname,
			"attached_to_field": "qrcode_image",
			"is_private": 0,
			"content": qr_image.getvalue()})
		_file.save()
		frappe.db.commit()
		self.invoice.qrcode_image = _file.file_url

	def update_invoice(self):
		self.invoice.flags.ignore_validate_update_after_submit = True
		self.invoice.flags.ignore_validate = True
		self.invoice.save()

	def set_failed_status(self, errors=None):
		frappe.db.rollback()
		self.invoice.einvoice_status = 'Failed'
		self.invoice.failure_description = self.get_failure_message(errors) if errors else ""
		self.update_invoice()
		frappe.db.commit()

	def get_failure_message(self, errors):
		if isinstance(errors, list):
			errors = ', '.join(errors)
		return errors

def sanitize_for_json(string):
	"""Escape JSON specific characters from a string."""

	# json.dumps adds double-quotes to the string. Indexing to remove them.
	return json.dumps(string)[1:-1]

@frappe.whitelist()
def get_einvoice(doctype, docname):
	invoice = frappe.get_doc(doctype, docname)
	return make_einvoice(invoice)

@frappe.whitelist()
def generate_irn(doctype, docname):
	gsp_connector = GSPConnector(doctype, docname)
	gsp_connector.generate_irn()

@frappe.whitelist()
def cancel_irn(doctype, docname, irn, reason, remark):
	gsp_connector = GSPConnector(doctype, docname)
	gsp_connector.cancel_irn(irn, reason, remark)

@frappe.whitelist()
def generate_eway_bill(doctype, docname, **kwargs):
	gsp_connector = GSPConnector(doctype, docname)
	gsp_connector.generate_eway_bill(**kwargs)

@frappe.whitelist()
def cancel_eway_bill(doctype, docname):
	# TODO: uncomment when eway_bill api from Adequare is enabled
	# gsp_connector = GSPConnector(doctype, docname)
	# gsp_connector.cancel_eway_bill(eway_bill, reason, remark)

	frappe.db.set_value(doctype, docname, 'ewaybill', '')
	frappe.db.set_value(doctype, docname, 'eway_bill_cancelled', 1)

@frappe.whitelist()
def generate_einvoices(docnames):
	docnames = json.loads(docnames) or []

	if len(docnames) < 10:
		failures = GSPConnector.bulk_generate_irn(docnames)
		frappe.local.message_log = []

		if failures:
			show_bulk_action_failure_message(failures)

		success = len(docnames) - len(failures)
		frappe.msgprint(
			_('{} e-invoices generated successfully').format(success),
			title=_('Bulk E-Invoice Generation Complete')
		)

	else:
		enqueue_bulk_action(schedule_bulk_generate_irn, docnames=docnames)

def schedule_bulk_generate_irn(docnames):
	failures = GSPConnector.bulk_generate_irn(docnames)
	frappe.local.message_log = []

	frappe.publish_realtime("bulk_einvoice_generation_complete", {
		"user": frappe.session.user,
		"failures": failures,
		"invoices": docnames
	})

def show_bulk_action_failure_message(failures):
	for doc in failures:
		docname = '<a href="sales-invoice/{0}">{0}</a>'.format(doc.get('docname'))
		message = doc.get('message').replace("'", '"')
		if message[0] == '[':
			errors = json.loads(message)
			error_list = ''.join(['<li>{}</li>'.format(err) for err in errors])
			message = '''{} has following errors:<br>
				<ul style="padding-left: 20px; padding-top: 5px">{}</ul>'''.format(docname, error_list)
		else:
			message = '{} - {}'.format(docname, message)

		frappe.msgprint(
			message,
			title=_('Bulk E-Invoice Generation Complete'),
			indicator='red'
		)

@frappe.whitelist()
def cancel_irns(docnames, reason, remark):
	docnames = json.loads(docnames) or []

	if len(docnames) < 10:
		failures = GSPConnector.bulk_cancel_irn(docnames, reason, remark)
		frappe.local.message_log = []

		if failures:
			show_bulk_action_failure_message(failures)

		success = len(docnames) - len(failures)
		frappe.msgprint(
			_('{} e-invoices cancelled successfully').format(success),
			title=_('Bulk E-Invoice Cancellation Complete')
		)
	else:
		enqueue_bulk_action(schedule_bulk_cancel_irn, docnames=docnames, reason=reason, remark=remark)

def schedule_bulk_cancel_irn(docnames, reason, remark):
	failures = GSPConnector.bulk_cancel_irn(docnames, reason, remark)
	frappe.local.message_log = []

	frappe.publish_realtime("bulk_einvoice_cancellation_complete", {
		"user": frappe.session.user,
		"failures": failures,
		"invoices": docnames
	})

def enqueue_bulk_action(job, **kwargs):
	check_scheduler_status()

	enqueue(
		job,
		**kwargs,
		queue="long",
		timeout=10000,
		event="processing_bulk_einvoice_action",
		now=frappe.conf.developer_mode or frappe.flags.in_test,
	)

	if job == schedule_bulk_generate_irn:
		msg = _('E-Invoices will be generated in a background process.')
	else:
		msg = _('E-Invoices will be cancelled in a background process.')

	frappe.msgprint(msg, alert=1)

def check_scheduler_status():
	if is_scheduler_inactive() and not frappe.flags.in_test:
		frappe.throw(_("Scheduler is inactive. Cannot enqueue job."), title=_("Scheduler Inactive"))

def job_already_enqueued(job_name):
	enqueued_jobs = [d.get("job_name") for d in get_info()]
	if job_name in enqueued_jobs:
		return True