import io
import os
from base64 import b64encode

import frappe
from frappe import _
from frappe.custom.doctype.custom_field.custom_field import create_custom_fields
from frappe.utils.data import add_to_date, get_time, getdate
from pyqrcode import create as qr_create

from erpnext import get_region


def create_qr_code(doc, method=None):
	region = get_region(doc.company)
	if region not in ['Saudi Arabia']:
		return

	# if QR Code field not present, create it. Invoices without QR are invalid as per law.
	if not hasattr(doc, 'ksa_einv_qr'):
		create_custom_fields({
			doc.doctype: [
				dict(
					fieldname='ksa_einv_qr',
					label='KSA E-Invoicing QR',
					fieldtype='Attach Image',
					read_only=1, no_copy=1, hidden=1
				)
			]
		})

	# Don't create QR Code if it already exists
	qr_code = doc.get("ksa_einv_qr")
	if qr_code and frappe.db.exists({"doctype": "File", "file_url": qr_code}):
		return

	meta = frappe.get_meta(doc.doctype)

	if "ksa_einv_qr" in [d.fieldname for d in meta.get_image_fields()]:
		''' TLV conversion for
		1. Seller's Name
		2. VAT Number
		3. Time Stamp
		4. Invoice Amount
		5. VAT Amount
		'''
		tlv_array = []
		# Sellers Name

		seller_name = frappe.db.get_value(
			'Company',
			doc.company,
			'company_name_in_arabic')

		if not seller_name:
			frappe.throw(_('Arabic name missing for {} in the company document').format(doc.company))

		tag = bytes([1]).hex()
		length = bytes([len(seller_name.encode('utf-8'))]).hex()
		value = seller_name.encode('utf-8').hex()
		tlv_array.append(''.join([tag, length, value]))

		# VAT Number
		tax_id = frappe.db.get_value('Company', doc.company, 'tax_id')
		if not tax_id:
			frappe.throw(_('Tax ID missing for {} in the company document').format(doc.company))

		tag = bytes([2]).hex()
		length = bytes([len(tax_id)]).hex()
		value = tax_id.encode('utf-8').hex()
		tlv_array.append(''.join([tag, length, value]))

		# Time Stamp
		posting_date = getdate(doc.posting_date)
		time = get_time(doc.posting_time)
		seconds = time.hour * 60 * 60 + time.minute * 60 + time.second
		time_stamp = add_to_date(posting_date, seconds=seconds)
		time_stamp = time_stamp.strftime('%Y-%m-%dT%H:%M:%SZ')

		tag = bytes([3]).hex()
		length = bytes([len(time_stamp)]).hex()
		value = time_stamp.encode('utf-8').hex()
		tlv_array.append(''.join([tag, length, value]))

		# Invoice Amount
		invoice_amount = str(doc.grand_total)
		tag = bytes([4]).hex()
		length = bytes([len(invoice_amount)]).hex()
		value = invoice_amount.encode('utf-8').hex()
		tlv_array.append(''.join([tag, length, value]))

		# VAT Amount
		vat_amount = str(get_vat_amount(doc))

		tag = bytes([5]).hex()
		length = bytes([len(vat_amount)]).hex()
		value = vat_amount.encode('utf-8').hex()
		tlv_array.append(''.join([tag, length, value]))

		# Joining bytes into one
		tlv_buff = ''.join(tlv_array)

		# base64 conversion for QR Code
		base64_string = b64encode(bytes.fromhex(tlv_buff)).decode()

		qr_image = io.BytesIO()
		url = qr_create(base64_string, error='L')
		url.png(qr_image, scale=2, quiet_zone=1)

		name = frappe.generate_hash(doc.name, 5)

		# making file
		filename = f"QRCode-{name}.png".replace(os.path.sep, "__")
		_file = frappe.get_doc({
			"doctype": "File",
			"file_name": filename,
			"is_private": 0,
			"content": qr_image.getvalue(),
			"attached_to_doctype": doc.get("doctype"),
			"attached_to_name": doc.get("name"),
			"attached_to_field": "ksa_einv_qr"
		})

		_file.save()

		# assigning to document
		doc.db_set('ksa_einv_qr', _file.file_url)
		doc.notify_update()

def get_vat_amount(doc):
	vat_settings = frappe.db.get_value('KSA VAT Setting', {'company': doc.company})
	vat_accounts = []
	vat_amount = 0

	if vat_settings:
		vat_settings_doc = frappe.get_cached_doc('KSA VAT Setting', vat_settings)

		for row in vat_settings_doc.get('ksa_vat_sales_accounts'):
			vat_accounts.append(row.account)

	for tax in doc.get('taxes'):
		if tax.account_head in vat_accounts:
			vat_amount += tax.tax_amount

	return vat_amount

def delete_qr_code_file(doc, method=None):
	region = get_region(doc.company)
	if region not in ['Saudi Arabia']:
		return

	if hasattr(doc, 'ksa_einv_qr'):
		if doc.get('ksa_einv_qr'):
			file_doc = frappe.get_list('File', {
				'file_url': doc.get('ksa_einv_qr')
			})
			if len(file_doc):
				frappe.delete_doc('File', file_doc[0].name)

def delete_vat_settings_for_company(doc, method=None):
	if doc.country != 'Saudi Arabia':
		return

	if frappe.db.exists('KSA VAT Setting', doc.name):
		frappe.delete_doc('KSA VAT Setting', doc.name)