feat: Thai VAT schemes as Sales/Purchase Taxes and Charges Templates

Per Thai company: Thailand VAT 7%, Thailand VAT 7% (Included) for
VAT-inclusive pricing, Thailand VAT 0% for zero-rated supplies. Sales
schemes post to Output VAT, purchase schemes to Input VAT (category
Total, so recoverable VAT stays out of valuation). The 7% scheme is the
default when the company has none. Created on Company save, after
install, and by a patch for existing companies.

default_thai_company/hooks.py

@@ -103,7 +103,8 @@ fixtures = [
 # ------------
 
 # before_install = "default_thai_company.install.before_install"
-# after_install = "default_thai_company.install.after_install"
+# Fixtures are synced before this runs; VAT schemes for companies that already exist.
+after_install = "default_thai_company.vat.setup_companies"
 
 # Uninstallation
 # ------------
@@ -167,7 +168,10 @@ doc_events = {
 		"before_import": "default_thai_company.tax_withholding.prepare_fixture_accounts",
 	},
 	"Company": {
-		"on_update": "default_thai_company.tax_withholding.setup_company",
+		"on_update": [
+			"default_thai_company.tax_withholding.setup_company",
+			"default_thai_company.vat.setup_company",
+		],
 	},
 	"Payment Entry": {
 		"validate": "default_thai_company.tax_withholding.set_customer_withholding",

default_thai_company/patches.txt

@@ -4,3 +4,5 @@
 
 [post_model_sync]
 # Patches added in this section will be executed after doctypes are migrated
+default_thai_company.patches.create_vat_accounts
+default_thai_company.patches.create_vat_templates

default_thai_company/patches/create_vat_accounts.py

@@ -0,0 +1,8 @@
+from default_thai_company.tax_withholding import ensure_company_accounts, thai_companies
+
+
+def execute():
+	"""Output VAT / Input VAT were added to COMPANY_ACCOUNTS; Company.on_update
+	only runs on save, so give existing Thai companies the pair."""
+	for company in thai_companies():
+		ensure_company_accounts(company)

default_thai_company/patches/create_vat_templates.py

@@ -0,0 +1,5 @@
+from default_thai_company.vat import setup_companies
+
+
+def execute():
+	setup_companies()

default_thai_company/tax_withholding.py

@@ -12,10 +12,23 @@ from frappe.utils import cint, flt
 
 from default_thai_company.utils import money_in_words
 
-# Liability: tax we withhold from suppliers and remit on P.N.D.3/53 (linked on every category).
-# Asset: tax customers withhold from us, creditable against corporate income tax.
+# Tax accounts every Thai company gets (Company.on_update, fixture import, and the
+# create_vat_accounts patch for companies that predate the VAT pair).
+# Withholding: liability = tax we withhold from suppliers, remitted on P.N.D.3/53
+# (linked on every category); asset = tax customers withhold from us, creditable
+# against corporate income tax.
+# VAT: output (ภาษีขาย) collected on sales is payable, input (ภาษีซื้อ) paid on
+# purchases is recoverable; the P.P.30 return nets the two, so they are kept apart.
 LIABILITY_ACCOUNT = "Withholding Tax Payable"
 ASSET_ACCOUNT = "Withholding Tax Receivable"
+OUTPUT_VAT_ACCOUNT = "Output VAT"
+INPUT_VAT_ACCOUNT = "Input VAT"
+COMPANY_ACCOUNTS = (
+	(LIABILITY_ACCOUNT, "Liability"),
+	(ASSET_ACCOUNT, "Asset"),
+	(OUTPUT_VAT_ACCOUNT, "Liability"),
+	(INPUT_VAT_ACCOUNT, "Asset"),
+)
 
 # Preferred parent groups by root type; first match wins, else the root account.
 PARENT_GROUPS = {
@@ -67,9 +80,10 @@ def find_parent_group(company, root_type):
 
 
 def ensure_company_accounts(company):
-	"""Create both withholding accounts for `company`; return the liability account name."""
-	get_or_create_account(company, ASSET_ACCOUNT, "Asset")
-	return get_or_create_account(company, LIABILITY_ACCOUNT, "Liability")
+	"""Create every account in COMPANY_ACCOUNTS for `company`; return the
+	withholding liability account name (the one Tax Withholding Categories link)."""
+	accounts = {name: get_or_create_account(company, name, root_type) for name, root_type in COMPANY_ACCOUNTS}
+	return accounts[LIABILITY_ACCOUNT]
 
 
 def link_company(category, company, account):
@@ -104,9 +118,14 @@ def prepare_fixture_accounts(doc, method=None):
 			link_company(doc, company, ensure_company_accounts(company))
 
 
+def company_ready(doc):
+	"""A Thai company whose chart of accounts exists."""
+	return doc.country == "Thailand" and frappe.db.exists("Account", {"company": doc.name})
+
+
 def setup_company(doc, method=None):
-	"""Company.on_update: create withholding accounts and link every WHT category."""
-	if doc.country != "Thailand" or not frappe.db.exists("Account", {"company": doc.name}):
+	"""Company.on_update: create the tax accounts and link every WHT category."""
+	if not company_ready(doc):
 		return
 
 	account = ensure_company_accounts(doc.name)

default_thai_company/tests/test_tax_withholding.py

@@ -8,7 +8,9 @@ from frappe.utils import nowdate
 
 from default_thai_company.tax_withholding import (
 	ASSET_ACCOUNT,
+	INPUT_VAT_ACCOUNT,
 	LIABILITY_ACCOUNT,
+	OUTPUT_VAT_ACCOUNT,
 	get_payment_entry,
 	thai_companies,
 )
@@ -44,16 +46,7 @@ class TestTaxWithholding(FrappeTestCase):
 		).insert()
 		cls.payable = f"{LIABILITY_ACCOUNT} - {ABBR}"
 		cls.receivable = f"{ASSET_ACCOUNT} - {ABBR}"
-
-		cls.vat = frappe.get_doc(
-			{
-				"doctype": "Account",
-				"company": COMPANY,
-				"account_name": "Output VAT",
-				"parent_account": f"Duties and Taxes - {ABBR}",
-				"account_type": "Tax",
-			}
-		).insert()
+		cls.vat = frappe.get_doc("Account", f"{OUTPUT_VAT_ACCOUNT} - {ABBR}")
 
 		frappe.get_doc(
 			{
@@ -137,14 +130,17 @@ class TestTaxWithholding(FrappeTestCase):
 
 	def test_company_creation_adds_accounts_and_links_categories(self):
 		self.assertIn(COMPANY, thai_companies())
-		self.assertEqual(
-			frappe.db.get_value("Account", self.payable, ["root_type", "parent_account"]),
-			("Liability", f"Duties and Taxes - {ABBR}"),
-		)
-		self.assertEqual(
-			frappe.db.get_value("Account", self.receivable, ["root_type", "parent_account"]),
-			("Asset", f"Tax Assets - {ABBR}"),
-		)
+		for account, expected in (
+			(self.payable, ("Liability", f"Duties and Taxes - {ABBR}", "Tax")),
+			(self.receivable, ("Asset", f"Tax Assets - {ABBR}", "Tax")),
+			(f"{OUTPUT_VAT_ACCOUNT} - {ABBR}", ("Liability", f"Duties and Taxes - {ABBR}", "Tax")),
+			(f"{INPUT_VAT_ACCOUNT} - {ABBR}", ("Asset", f"Tax Assets - {ABBR}", "Tax")),
+		):
+			self.assertEqual(
+				frappe.db.get_value("Account", account, ["root_type", "parent_account", "account_type"]),
+				expected,
+				account,
+			)
 
 		categories = frappe.get_all(
 			"Tax Withholding Category", filters={"name": ("like", "WHT %")}, pluck="name"
@@ -153,6 +149,34 @@ class TestTaxWithholding(FrappeTestCase):
 		for name in categories:
 			self.assertEqual(self.category_account(name), self.payable, name)
 
+	def test_company_creation_adds_vat_schemes(self):
+		for doctype, account in (
+			("Sales Taxes and Charges Template", f"{OUTPUT_VAT_ACCOUNT} - {ABBR}"),
+			("Purchase Taxes and Charges Template", f"{INPUT_VAT_ACCOUNT} - {ABBR}"),
+		):
+			schemes = {}
+			for name in frappe.get_all(
+				doctype, filters={"company": COMPANY, "title": ("like", "Thailand VAT%")}, pluck="name"
+			):
+				doc = frappe.get_doc(doctype, name)
+				(row,) = doc.taxes
+				schemes[doc.title] = (
+					doc.is_default,
+					row.account_head,
+					row.charge_type,
+					row.rate,
+					row.included_in_print_rate,
+				)
+			self.assertEqual(
+				schemes,
+				{
+					"Thailand VAT 7%": (1, account, "On Net Total", 7.0, 0),
+					"Thailand VAT 7% (Included)": (0, account, "On Net Total", 7.0, 1),
+					"Thailand VAT 0%": (0, account, "On Net Total", 0.0, 0),
+				},
+				doctype,
+			)
+
 	def test_fixture_reimport_keeps_site_account_and_relinks(self):
 		alt = frappe.get_doc(
 			{

default_thai_company/translations/th.csv

@@ -53,3 +53,7 @@ Grand Total,ยอดรวมทั้งสิ้น
 Rounded Total,ยอดรวมปัดเศษ
 Terms and Conditions Details,รายละเอียดข้อตกลงและเงื่อนไข
 Page {0} of {1},หน้า {0} จาก {1}
+Withholding Tax Payable,ภาษีหัก ณ ที่จ่ายค้างจ่าย
+Withholding Tax Receivable,ภาษีถูกหัก ณ ที่จ่าย
+Output VAT,ภาษีขาย
+Input VAT,ภาษีซื้อ

default_thai_company/vat.py

@@ -0,0 +1,78 @@
+import erpnext
+import frappe
+
+from default_thai_company.tax_withholding import (
+	INPUT_VAT_ACCOUNT,
+	OUTPUT_VAT_ACCOUNT,
+	company_ready,
+	get_or_create_account,
+	thai_companies,
+)
+
+RATE = 7.0
+
+# title, rate, included_in_print_rate. Exempt supplies take no template.
+SCHEMES = (
+	("Thailand VAT 7%", RATE, 0),
+	("Thailand VAT 7% (Included)", RATE, 1),  # VAT-inclusive prices, the retail norm
+	("Thailand VAT 0%", 0.0, 0),  # zero-rated: exports, international transport
+)
+DEFAULT_SCHEME = "Thailand VAT 7%"
+
+# doctype, account, root type, extra row fields. Input VAT is recoverable, so on
+# purchases it is "Total" (added to the bill, kept out of item valuation).
+TEMPLATES = (
+	("Sales Taxes and Charges Template", OUTPUT_VAT_ACCOUNT, "Liability", {}),
+	(
+		"Purchase Taxes and Charges Template",
+		INPUT_VAT_ACCOUNT,
+		"Asset",
+		{"category": "Total", "add_deduct_tax": "Add"},
+	),
+)
+
+
+def ensure_vat_templates(company):
+	"""Create the VAT schemes for `company`, skipping titles that exist. The 7%
+	scheme becomes the default when the company has no default template."""
+	cost_center = erpnext.get_default_cost_center(company)
+	for doctype, account_name, root_type, extra in TEMPLATES:
+		account = get_or_create_account(company, account_name, root_type)
+		has_default = frappe.db.exists(doctype, {"company": company, "is_default": 1})
+		for title, rate, included in SCHEMES:
+			if frappe.db.exists(doctype, {"company": company, "title": title}):
+				continue
+			is_default = title == DEFAULT_SCHEME and not has_default
+			frappe.get_doc(
+				{
+					"doctype": doctype,
+					"title": title,
+					"company": company,
+					"is_default": int(is_default),
+					"taxes": [
+						{
+							"charge_type": "On Net Total",
+							"account_head": account,
+							"rate": rate,
+							"description": f"VAT {rate:g}%",
+							"included_in_print_rate": included,
+							"cost_center": cost_center,
+							**extra,
+						}
+					],
+				}
+			).insert(ignore_permissions=True)
+			has_default = has_default or is_default
+
+
+def setup_company(doc, method=None):
+	"""Company.on_update: VAT schemes for a Thai company."""
+	if company_ready(doc):
+		ensure_vat_templates(doc.name)
+
+
+def setup_companies():
+	"""after_install and the create_vat_templates patch: companies that exist
+	before this code did never pass through `setup_company`."""
+	for company in thai_companies():
+		ensure_vat_templates(company)