feat: show expected withholding tax on Sales Invoice

Custom fields Tax Withholding Category (fetched from Customer),
Withholding Tax and Net Payable After Withholding Tax on Sales Invoice;
computed in the Thai set_tax_withholding override from the category
rate and single threshold, informational only (totals/GL unchanged),
printed under Rounded Total by the standard layout. Payment Entry now
prefers each invoice's category over the customer's.

default_thai_company/fixtures/custom_field.json

@@ -0,0 +1,50 @@
+[
+ {
+  "docstatus": 0,
+  "doctype": "Custom Field",
+  "dt": "Sales Invoice",
+  "fetch_from": "customer.tax_withholding_category",
+  "fetch_if_empty": 1,
+  "fieldname": "tax_withholding_category",
+  "fieldtype": "Link",
+  "insert_after": "taxes_and_charges",
+  "label": "Tax Withholding Category",
+  "modified": "2026-09-11 18:00:00.000000",
+  "name": "Sales Invoice-tax_withholding_category",
+  "options": "Tax Withholding Category",
+  "print_hide": 1
+ },
+ {
+  "depends_on": "eval:doc.tax_withholding_category",
+  "docstatus": 0,
+  "doctype": "Custom Field",
+  "dt": "Sales Invoice",
+  "fieldname": "withholding_tax_amount",
+  "fieldtype": "Currency",
+  "insert_after": "rounded_total",
+  "label": "Withholding Tax",
+  "modified": "2026-09-11 18:00:00.000000",
+  "name": "Sales Invoice-withholding_tax_amount",
+  "no_copy": 1,
+  "options": "currency",
+  "print_hide_if_no_value": 1,
+  "read_only": 1
+ },
+ {
+  "bold": 1,
+  "depends_on": "eval:doc.tax_withholding_category",
+  "docstatus": 0,
+  "doctype": "Custom Field",
+  "dt": "Sales Invoice",
+  "fieldname": "amount_after_withholding",
+  "fieldtype": "Currency",
+  "insert_after": "withholding_tax_amount",
+  "label": "Net Payable After Withholding Tax",
+  "modified": "2026-09-11 18:00:00.000000",
+  "name": "Sales Invoice-amount_after_withholding",
+  "no_copy": 1,
+  "options": "currency",
+  "print_hide_if_no_value": 1,
+  "read_only": 1
+ }
+]

default_thai_company/fixtures/property_setter.json

@@ -14,5 +14,21 @@
   "property_type": "Data",
   "row_name": null,
   "value": "Default Standard Sales Invoice"
+ },
+ {
+  "default_value": null,
+  "doc_type": "Payment Entry",
+  "docstatus": 0,
+  "doctype": "Property Setter",
+  "doctype_or_field": "DocField",
+  "field_name": "apply_tax_withholding_amount",
+  "is_system_generated": 0,
+  "modified": "2026-09-11 12:00:00.000000",
+  "module": null,
+  "name": "Payment Entry-apply_tax_withholding_amount-depends_on",
+  "property": "depends_on",
+  "property_type": "Data",
+  "row_name": null,
+  "value": "eval:doc.party_type == 'Supplier' || (doc.party_type == 'Customer' && doc.payment_type == 'Receive')"
  }
 ]

default_thai_company/fixtures/tax_withholding_category.json

@@ -0,0 +1,574 @@
+[
+ {
+  "accounts": [],
+  "category_name": "Commission, brokerage, agency fees - Sec. 40(2), juristic payee (P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Commission",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Commission",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Royalties, goodwill, copyright, other rights - Sec. 40(3), juristic payee (P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Royalty",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Royalty",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Interest - Sec. 40(4)(a), juristic payee excl. banks/finance companies (P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Interest (Company)",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Interest (Company)",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Interest - Sec. 40(4)(a), individual payee, Sec. 50(2) (P.N.D.2)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 15% - Interest (Individual)",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 15% - Interest (Individual)",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 15.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Dividends, share of profits - Sec. 40(4)(b) (P.N.D.2 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 10% - Dividend",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 10% - Dividend",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 10.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Rent of property, hire-purchase of movable property - Sec. 40(5) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 5% - Rent",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 5% - Rent",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 5.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Rent of ships under the Merchant Marine Promotion Act - Sec. 40(5) (P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Ship Rental",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Ship Rental",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Law, medicine, engineering, architecture, accounting, fine arts - Sec. 40(6) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Professional Fee",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Professional Fee",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Contract work, contractor supplies essential materials - Sec. 40(7) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Contract Work",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Contract Work",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Hire of work, service fees - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Service",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Service",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Rewards, discounts, sales promotion benefits - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 3% - Sales Promotion",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 3% - Sales Promotion",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 3.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Advertising fees - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 2% - Advertising",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 2% - Advertising",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 2.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Transport of goods or passengers, excl. public transport - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Transportation",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Transportation",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Non-life insurance premiums - Sec. 40(8) (P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Non-Life Insurance",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Non-Life Insurance",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Prizes from contests, competitions, lucky draws - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 5% - Prize",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 5% - Prize",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 5.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Public entertainers resident in Thailand - Sec. 40(8) (P.N.D.3)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 5% - Public Entertainer",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 5% - Public Entertainer",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 5.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Rubber, cassava, jute, rice, maize, sugarcane, coffee beans, oil palm - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 0.75% - Agricultural Produce",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 0.75% - Agricultural Produce",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 0.75,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Aquatic animals bought from non-registered sellers - Sec. 40(8) (P.N.D.3 / P.N.D.53)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Aquatic Animals",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Aquatic Animals",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1000.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Sale of immovable property, juristic seller - Sec. 69 Ter (remitted at the Land Office)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 1% - Immovable Property (Company)",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 1% - Immovable Property (Company)",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 1.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Sec. 40(2)-(6) income paid to non-resident individuals - Sec. 50(2) (P.N.D.3)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 15% - Non-Resident Individual",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 15% - Non-Resident Individual",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 15.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Sec. 40(2)-(6) income excl. dividends to foreign companies not doing business in Thailand - Sec. 70, pre-DTA (P.N.D.54)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 15% - Foreign Company",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 15% - Foreign Company",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 15.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ },
+ {
+  "accounts": [],
+  "category_name": "Dividends to foreign companies not doing business in Thailand - Sec. 70, pre-DTA (P.N.D.54)",
+  "consider_party_ledger_amount": 0,
+  "docstatus": 0,
+  "doctype": "Tax Withholding Category",
+  "modified": "2026-09-11 09:00:00.000000",
+  "name": "WHT 10% - Foreign Company Dividend",
+  "rates": [
+   {
+    "cumulative_threshold": 0.0,
+    "docstatus": 0,
+    "doctype": "Tax Withholding Rate",
+    "from_date": "2024-01-01",
+    "idx": 1,
+    "parent": "WHT 10% - Foreign Company Dividend",
+    "parentfield": "rates",
+    "parenttype": "Tax Withholding Category",
+    "single_threshold": 1.0,
+    "tax_withholding_rate": 10.0,
+    "to_date": "2099-12-31"
+   }
+  ],
+  "round_off_tax_amount": 0,
+  "tax_on_excess_amount": 0
+ }
+]

default_thai_company/hooks.py

@@ -43,7 +43,7 @@ required_apps = ["erpnext"]
 # page_js = {"page" : "public/js/file.js"}
 
 # include js in doctype views
-# doctype_js = {"doctype" : "public/js/doctype.js"}
+doctype_js = {"Payment Entry": "public/js/payment_entry.js"}
 # doctype_list_js = {"doctype" : "public/js/doctype_list.js"}
 # doctype_tree_js = {"doctype" : "public/js/doctype_tree.js"}
 # doctype_calendar_js = {"doctype" : "public/js/doctype_calendar.js"}
@@ -90,7 +90,31 @@ fixtures = [
 	{"doctype": "Print Format", "filters": [["name", "in", ["Default Standard Sales Invoice"]]]},
 	{
 		"doctype": "Property Setter",
-		"filters": [["name", "in", ["Sales Invoice-main-default_print_format"]]],
+		"filters": [
+			[
+				"name",
+				"in",
+				[
+					"Sales Invoice-main-default_print_format",
+					"Payment Entry-apply_tax_withholding_amount-depends_on",
+				],
+			]
+		],
+	},
+	{"doctype": "Tax Withholding Category", "filters": [["name", "like", "WHT %"]]},
+	{
+		"doctype": "Custom Field",
+		"filters": [
+			[
+				"name",
+				"in",
+				[
+					"Sales Invoice-tax_withholding_category",
+					"Sales Invoice-withholding_tax_amount",
+					"Sales Invoice-amount_after_withholding",
+				],
+			]
+		],
 	},
 ]
 
@@ -144,9 +168,9 @@ fixtures = [
 # ---------------
 # Override standard doctype classes
 
-# override_doctype_class = {
+override_doctype_class = {
-# 	"ToDo": "custom_app.overrides.CustomToDo"
+	"Sales Invoice": "default_thai_company.tax_withholding.ThaiSalesInvoice",
-# }
+}
 
 # Document Events
 # ---------------
@@ -156,7 +180,16 @@ doc_events = {
 	"Letter Head": {
 		"before_import": "default_thai_company.utils.stash_letter_head_source",
 		"before_insert": "default_thai_company.utils.restore_letter_head_source",
-	}
+	},
+	"Tax Withholding Category": {
+		"before_import": "default_thai_company.tax_withholding.prepare_fixture_accounts",
+	},
+	"Company": {
+		"on_update": "default_thai_company.tax_withholding.setup_company",
+	},
+	"Payment Entry": {
+		"validate": "default_thai_company.tax_withholding.set_customer_withholding",
+	},
 }
 
 # Scheduled Tasks

default_thai_company/public/js/payment_entry.js

@@ -0,0 +1,10 @@
+frappe.ui.form.on("Payment Entry", {
+	apply_tax_withholding_amount(frm) {
+		if (frm.doc.party_type !== "Customer" || !frm.doc.apply_tax_withholding_amount) return;
+		// ERPNext's handler looks the category up on Supplier and clears it for a
+		// Customer; wait for that request to settle, then set the Customer's value.
+		frappe.db.get_value("Customer", frm.doc.party, "tax_withholding_category").then(({ message }) => {
+			frappe.after_ajax(() => frm.set_value("tax_withholding_category", message.tax_withholding_category));
+		});
+	},
+});

default_thai_company/tax_withholding.py

@@ -0,0 +1,244 @@
+import erpnext
+import frappe
+from erpnext.accounts.doctype.sales_invoice.sales_invoice import SalesInvoice
+from erpnext.accounts.doctype.tax_withholding_category.tax_withholding_category import (
+	get_tax_withholding_details,
+	normal_round,
+)
+from frappe import _
+from frappe.utils import cint, flt
+
+# 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.
+LIABILITY_ACCOUNT = "Withholding Tax Payable"
+ASSET_ACCOUNT = "Withholding Tax Receivable"
+
+# Preferred parent groups by root type; first match wins, else the root account.
+PARENT_GROUPS = {
+	"Liability": ("Duties and Taxes", "Current Liabilities"),
+	"Asset": ("Tax Assets", "Current Assets"),
+}
+
+CATEGORY_FILTERS = {"name": ("like", "WHT %")}
+
+
+def thai_companies():
+	return frappe.get_all("Company", filters={"country": "Thailand"}, pluck="name")
+
+
+def get_or_create_account(company, account_name, root_type):
+	name = frappe.db.get_value(
+		"Account", {"company": company, "account_name": account_name, "is_group": 0, "root_type": root_type}
+	)
+	if name:
+		return name
+
+	account = frappe.get_doc(
+		{
+			"doctype": "Account",
+			"company": company,
+			"account_name": account_name,
+			"parent_account": find_parent_group(company, root_type),
+			"root_type": root_type,
+			"account_type": "Tax",
+			"is_group": 0,
+		}
+	).insert(ignore_permissions=True)
+	return account.name
+
+
+def find_parent_group(company, root_type):
+	for account_name in PARENT_GROUPS[root_type]:
+		parent = frappe.db.get_value(
+			"Account",
+			{"company": company, "account_name": account_name, "is_group": 1, "root_type": root_type},
+		)
+		if parent:
+			return parent
+
+	return frappe.db.get_value(
+		"Account",
+		{"company": company, "root_type": root_type, "is_group": 1, "parent_account": ("is", "not set")},
+	)
+
+
+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")
+
+
+def link_company(category, company, account):
+	"""Append `account` for `company` to the category's accounts table if missing."""
+	if any(row.company == company for row in category.accounts):
+		return False
+	category.append("accounts", {"company": company, "account": account})
+	return True
+
+
+def prepare_fixture_accounts(doc, method=None):
+	"""Tax Withholding Category fixtures ship without `accounts` (company-specific).
+
+	Fixture import re-inserts the doc on every migrate, so: carry over the rows
+	already configured on this site, then link every Thai company, creating the
+	withholding accounts on first use. Mandatory is relaxed for sites without a
+	Thai company yet (setup wizard not run); `setup_company` links them later.
+	"""
+	doc.flags.ignore_mandatory = True
+
+	if not doc.accounts and frappe.db.exists(doc.doctype, doc.name):
+		for row in frappe.get_all(
+			"Tax Withholding Account",
+			filters={"parent": doc.name, "parenttype": doc.doctype},
+			fields=["company", "account"],
+			order_by="idx",
+		):
+			doc.append("accounts", row)
+
+	for company in thai_companies():
+		if not any(row.company == company for row in doc.accounts):
+			link_company(doc, company, ensure_company_accounts(company))
+
+
+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}):
+		return
+
+	account = ensure_company_accounts(doc.name)
+	for name in frappe.get_all("Tax Withholding Category", filters=CATEGORY_FILTERS, pluck="name"):
+		category = frappe.get_doc("Tax Withholding Category", name)
+		if link_company(category, doc.name, account):
+			category.save(ignore_permissions=True)
+
+
+def is_thai_company(company):
+	return frappe.get_cached_value("Company", company, "country") == "Thailand"
+
+
+def get_withholding_details(category, posting_date, company):
+	details = get_tax_withholding_details(category, posting_date, company)
+	if not details:
+		frappe.throw(
+			_("Tax Withholding Category {0} has no account for Company {1}").format(category, company)
+		)
+	return details
+
+
+def withholding_on(details, taxable, base_taxable, precision):
+	"""Withholding for a taxable amount; the single threshold is checked in company currency."""
+	if details.threshold and flt(base_taxable) < flt(details.threshold):
+		return 0.0
+	amount = flt(taxable) * flt(details.rate) / 100
+	return normal_round(amount) if cint(details.round_off_tax_amount) else flt(amount, precision)
+
+
+class ThaiSalesInvoice(SalesInvoice):
+	def set_tax_withholding(self):
+		"""Thai customers withhold at payment (see `set_customer_withholding`);
+		ERPNext's customer-side handling is Indian TCS, which adds tax on top of
+		the invoice. For Thai companies only show the expected withholding and
+		the net payable; totals and GL are untouched."""
+		if not is_thai_company(self.company):
+			return super().set_tax_withholding()
+
+		self.withholding_tax_amount = self.amount_after_withholding = 0
+		if not self.tax_withholding_category:
+			return
+
+		details = get_withholding_details(self.tax_withholding_category, self.posting_date, self.company)
+		self.withholding_tax_amount = withholding_on(
+			details, self.net_total, self.base_net_total, self.precision("withholding_tax_amount")
+		)
+		if self.withholding_tax_amount:
+			self.amount_after_withholding = flt(
+				(self.rounded_total or self.grand_total) - self.withholding_tax_amount,
+				self.precision("amount_after_withholding"),
+			)
+
+
+def set_customer_withholding(doc, method=None):
+	"""Payment Entry.validate: tax withheld by the customer on a Receive entry
+	becomes a deduction to the company's withholding receivable account.
+
+	Withholding is rate x pre-VAT amount of each allocated reference, prorated
+	by the allocation. `paid_amount` is the cash actually received, so the
+	deduction closes the difference against the gross allocation. Runs after
+	the controller's validate (exchange rates and allocations are final), then
+	re-derives the two amounts that depend on deductions.
+	"""
+	if doc.party_type != "Customer" or doc.payment_type != "Receive" or not doc.apply_tax_withholding_amount:
+		return
+
+	if not doc.tax_withholding_category:
+		doc.tax_withholding_category = frappe.db.get_value("Customer", doc.party, "tax_withholding_category")
+
+	account = frappe.db.get_value(
+		"Account",
+		{"company": doc.company, "account_name": ASSET_ACCOUNT, "root_type": "Asset", "is_group": 0},
+	)
+	if not account:
+		frappe.throw(_("Account {0} not found for Company {1}").format(ASSET_ACCOUNT, doc.company))
+
+	amount, description = get_customer_withholding(doc)
+	row = next((d for d in doc.deductions if d.account == account), None)
+
+	if not amount:
+		if row:
+			doc.remove(row)
+	else:
+		if not row:
+			row = doc.append("deductions", {"account": account})
+		row.amount = amount
+		row.description = description
+		row.cost_center = doc.cost_center or erpnext.get_default_cost_center(doc.company)
+
+	doc.set_unallocated_amount()
+	doc.set_difference_amount()
+
+
+def get_customer_withholding(doc):
+	"""Total withheld across allocated references, in company currency.
+
+	A Sales Invoice's own category wins over the Payment Entry's; Sales Orders
+	use the Payment Entry's. Withholding is prorated by allocated / grand total
+	on the pre-VAT amount, per reference.
+	"""
+	total = 0.0
+	details_by_category = {}
+	precision = doc.precision("difference_amount")
+
+	for ref in doc.references:
+		if ref.reference_doctype not in ("Sales Invoice", "Sales Order") or not ref.allocated_amount:
+			continue
+
+		fields = ["net_total", "grand_total"]
+		if ref.reference_doctype == "Sales Invoice":
+			fields.append("tax_withholding_category")
+		values = frappe.db.get_value(ref.reference_doctype, ref.reference_name, fields, as_dict=True)
+		if not values.grand_total:
+			continue
+
+		category = values.get("tax_withholding_category") or doc.tax_withholding_category
+		if not category:
+			frappe.throw(
+				_("Please set Tax Withholding Category on {0} {1} or on this Payment Entry").format(
+					_(ref.reference_doctype), ref.reference_name
+				)
+			)
+		if category not in details_by_category:
+			details_by_category[category] = get_withholding_details(category, doc.posting_date, doc.company)
+
+		base_taxable = (
+			flt(ref.allocated_amount)
+			* flt(values.net_total)
+			/ flt(values.grand_total)
+			* flt(doc.source_exchange_rate)
+		)
+		total += withholding_on(details_by_category[category], base_taxable, base_taxable, precision)
+
+	if len(details_by_category) == 1:
+		description = next(iter(details_by_category.values())).description
+	else:
+		description = _("Withholding tax deducted by customer")
+	return flt(total, precision), description

default_thai_company/tests/test_tax_withholding.py

@@ -0,0 +1,220 @@
+import frappe
+from frappe.modules.import_file import import_file_by_path
+from frappe.tests.utils import FrappeTestCase
+from frappe.utils import nowdate
+
+from default_thai_company.tax_withholding import ASSET_ACCOUNT, LIABILITY_ACCOUNT, thai_companies
+
+COMPANY = "_Test WHT Company"
+ABBR = "_TWC"
+CUSTOMER = "_Test WHT Customer"
+ITEM = "_Test WHT Service"
+FIXTURE = frappe.get_app_path("default_thai_company", "fixtures", "tax_withholding_category.json")
+CUSTOM_FIELDS = frappe.get_app_path("default_thai_company", "fixtures", "custom_field.json")
+
+
+class TestTaxWithholding(FrappeTestCase):
+	@classmethod
+	def setUpClass(cls):
+		super().setUpClass()
+		# Fixture categories must exist before the company is created so the
+		# Company hook has something to link; force=True re-imports.
+		import_file_by_path(FIXTURE, force=True, data_import=True)
+		import_file_by_path(CUSTOM_FIELDS, force=True, data_import=True)
+		frappe.clear_cache(doctype="Sales Invoice")
+
+		frappe.get_doc(
+			{
+				"doctype": "Company",
+				"company_name": COMPANY,
+				"abbr": ABBR,
+				"country": "Thailand",
+				"default_currency": "THB",
+				"chart_of_accounts": "Standard",
+			}
+		).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()
+
+		frappe.get_doc(
+			{
+				"doctype": "Customer",
+				"customer_name": CUSTOMER,
+				"customer_type": "Company",
+				"customer_group": frappe.db.get_value("Customer Group", {"is_group": 0}),
+				"territory": frappe.db.get_value("Territory", {"is_group": 0}),
+				"tax_withholding_category": "WHT 3% - Service",
+			}
+		).insert()
+
+		frappe.get_doc(
+			{
+				"doctype": "Item",
+				"item_code": ITEM,
+				"item_group": frappe.db.get_value("Item Group", {"is_group": 0}),
+				"is_stock_item": 0,
+				"stock_uom": "Nos",
+			}
+		).insert()
+
+	def make_invoice(self, rate=10000, category=None):
+		si = frappe.get_doc(
+			{
+				"doctype": "Sales Invoice",
+				"company": COMPANY,
+				"customer": CUSTOMER,
+				"posting_date": nowdate(),
+				"due_date": nowdate(),
+				"tax_withholding_category": category,
+				"items": [{"item_code": ITEM, "qty": 1, "rate": rate}],
+				"taxes": [
+					{
+						"charge_type": "On Net Total",
+						"account_head": self.vat.name,
+						"rate": 7,
+						"description": "VAT 7%",
+					}
+				],
+			}
+		)
+		si.set_missing_values()
+		return si.submit()
+
+	def make_receipt(self, invoice, allocated, paid, apply=1):
+		return frappe.get_doc(
+			{
+				"doctype": "Payment Entry",
+				"company": COMPANY,
+				"payment_type": "Receive",
+				"party_type": "Customer",
+				"party": CUSTOMER,
+				"posting_date": nowdate(),
+				"paid_from": f"Debtors - {ABBR}",
+				"paid_to": f"Cash - {ABBR}",
+				"paid_amount": paid,
+				"received_amount": paid,
+				"apply_tax_withholding_amount": apply,
+				"references": [
+					{
+						"reference_doctype": "Sales Invoice",
+						"reference_name": invoice.name,
+						"allocated_amount": allocated,
+					}
+				],
+			}
+		).insert()
+
+	def category_account(self, category, company=COMPANY):
+		return frappe.db.get_value(
+			"Tax Withholding Account",
+			{"parent": category, "parenttype": "Tax Withholding Category", "company": company},
+			"account",
+		)
+
+	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}"),
+		)
+
+		categories = frappe.get_all(
+			"Tax Withholding Category", filters={"name": ("like", "WHT %")}, pluck="name"
+		)
+		self.assertEqual(len(categories), 22)
+		for name in categories:
+			self.assertEqual(self.category_account(name), self.payable, name)
+
+	def test_fixture_reimport_keeps_site_account_and_relinks(self):
+		alt = frappe.get_doc(
+			{
+				"doctype": "Account",
+				"company": COMPANY,
+				"account_name": "Alternative WHT Payable",
+				"parent_account": f"Duties and Taxes - {ABBR}",
+				"account_type": "Tax",
+			}
+		).insert()
+		rent = frappe.get_doc("Tax Withholding Category", "WHT 5% - Rent")
+		for row in rent.accounts:
+			if row.company == COMPANY:
+				row.account = alt.name
+		rent.save()
+
+		import_file_by_path(FIXTURE, force=True, data_import=True)
+
+		self.assertEqual(self.category_account("WHT 5% - Rent"), alt.name)
+		self.assertEqual(self.category_account("WHT 3% - Service"), self.payable)
+		rates = frappe.get_doc("Tax Withholding Category", "WHT 5% - Rent").rates
+		self.assertEqual([(r.tax_withholding_rate, r.single_threshold) for r in rates], [(5.0, 1000.0)])
+
+	def test_sales_invoice_shows_withholding_without_grossing_up(self):
+		si = self.make_invoice()
+		self.assertEqual((si.net_total, si.grand_total), (10000.0, 10700.0))
+		self.assertEqual([t.account_head for t in si.taxes], [self.vat.name])
+		self.assertEqual(si.tax_withholding_category, "WHT 3% - Service")  # fetched from Customer
+		self.assertEqual((si.withholding_tax_amount, si.amount_after_withholding), (300.0, 10400.0))
+		self.assertEqual(frappe.db.get_value("Sales Invoice", si.name, "outstanding_amount"), 10700.0)
+
+	def test_sales_invoice_below_threshold_shows_nothing(self):
+		si = self.make_invoice(rate=800)
+		self.assertEqual((si.withholding_tax_amount, si.amount_after_withholding), (0.0, 0.0))
+
+	def test_receipt_uses_invoice_category_over_customer_category(self):
+		si = self.make_invoice(category="WHT 5% - Rent")
+		self.assertEqual(si.withholding_tax_amount, 500.0)
+		pe = self.make_receipt(si, allocated=10700, paid=10200)
+		self.assertEqual([(d.account, d.amount) for d in pe.deductions], [(self.receivable, 500.0)])
+		self.assertEqual(pe.difference_amount, 0)
+
+	def test_receipt_deducts_withholding_and_settles_invoice(self):
+		si = self.make_invoice()
+		pe = self.make_receipt(si, allocated=10700, paid=10400)
+
+		self.assertEqual(pe.tax_withholding_category, "WHT 3% - Service")
+		self.assertEqual([(d.account, d.amount) for d in pe.deductions], [(self.receivable, 300.0)])
+		self.assertEqual(pe.difference_amount, 0)
+
+		pe.submit()
+		gl = {
+			g.account: (g.debit, g.credit)
+			for g in frappe.get_all(
+				"GL Entry", filters={"voucher_no": pe.name}, fields=["account", "debit", "credit"]
+			)
+		}
+		self.assertEqual(gl[f"Cash - {ABBR}"], (10400.0, 0.0))
+		self.assertEqual(gl[self.receivable], (300.0, 0.0))
+		self.assertEqual(gl[f"Debtors - {ABBR}"], (0.0, 10700.0))
+		self.assertEqual(frappe.db.get_value("Sales Invoice", si.name, "outstanding_amount"), 0)
+
+	def test_partial_allocation_prorates_withholding(self):
+		si = self.make_invoice()
+		pe = self.make_receipt(si, allocated=5350, paid=5200)
+		self.assertEqual([(d.account, d.amount) for d in pe.deductions], [(self.receivable, 150.0)])
+		self.assertEqual(pe.difference_amount, 0)
+
+	def test_below_single_threshold_has_no_deduction(self):
+		si = self.make_invoice(rate=800)  # net 800 < 1,000 threshold
+		pe = self.make_receipt(si, allocated=856, paid=856)
+		self.assertEqual(pe.deductions, [])
+		self.assertEqual(pe.difference_amount, 0)
+
+	def test_unchecked_receipt_is_untouched(self):
+		si = self.make_invoice()
+		pe = self.make_receipt(si, allocated=10700, paid=10700, apply=0)
+		self.assertEqual(pe.deductions, [])
+		self.assertEqual(pe.difference_amount, 0)