Basic implementation of tax estimation

drcr/config.py.example

@@ -20,3 +20,8 @@ INCOME_STATEMENT_MAPPING = {
 	'Income': ['Sales'],
 	'Expenses': ['Operating costs', 'Purchases']
 }
+
+TAX_MAPPING = {
+	'Assessable income': [],
+	'Deductions': []
+}

drcr/reports/views.py

@@ -1,5 +1,5 @@
 #   DrCr: Web-based double-entry bookkeeping framework
-#   Copyright (C) 2022  Lee Yingtong Li (RunasSudo)
+#   Copyright (C) 2022–2023  Lee Yingtong Li (RunasSudo)
 #
 #   This program is free software: you can redistribute it and/or modify
 #   it under the terms of the GNU Affero General Public License as published by
@@ -29,8 +29,6 @@ def get_trial_balance():
 	for source_account, destination_account in COA_MAPPING.items():
 		balancer.transfer_balance(source_account, destination_account)
 	
-	return balancer
-	
 	# Validate COA
 	for account in balancer.accounts:
 		if account in BALANCE_SHEET_MAPPING['Current assets']:
@@ -47,6 +45,8 @@ def get_trial_balance():
 			continue
 		if account == 'Accumulated surplus (deficit)':
 			continue
+		if account == 'Income tax':
+			continue
 		
 		raise Exception('Account "{}" is not mapped to a report'.format(account))
 	
@@ -66,7 +66,7 @@ def balance_sheet():
 	balancer = get_trial_balance()
 	
 	# Transfer surplus to balance sheet
-	for account in INCOME_STATEMENT_MAPPING['Income'] + INCOME_STATEMENT_MAPPING['Expenses']:
+	for account in INCOME_STATEMENT_MAPPING['Income'] + INCOME_STATEMENT_MAPPING['Expenses'] + ['Income tax']:
 		balancer.transfer_balance(account, 'Current year surplus (deficit)')
 	
 	return render_template('reports/balance_sheet.html', accounts=balancer.accounts, running_total=Amount(0, '$'), BALANCE_SHEET_MAPPING=BALANCE_SHEET_MAPPING)

drcr/tax/aus_tax.py

@@ -0,0 +1,59 @@
+#   DrCr: Web-based double-entry bookkeeping framework
+#   Copyright (C) 2022–2023  Lee Yingtong Li (RunasSudo)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from ..config import TAX_MAPPING
+from ..models import Amount, Posting, Transaction, TrialBalancer
+
+from datetime import datetime
+
+def taxable_income():
+	balancer = TrialBalancer()
+	balancer.apply_transactions(Transaction.query.all())
+	
+	result = Amount(0, '$')
+	for account in TAX_MAPPING['Assessable income']:
+		result.quantity += balancer.accounts[account].quantity
+	return result
+
+def calculate_tax(taxable_income):
+	taxable_income = -taxable_income.as_cost().quantity
+	
+	if taxable_income <= 1820000:
+		return Amount(0, '$')
+	if taxable_income <= 4500000:
+		return Amount(int((taxable_income - 1820000) * 0.19), '$')
+	if taxable_income <= 12000000:
+		return Amount(int(509200 + (taxable_income - 4500000) * 0.325), '$')
+	if taxable_income <= 18000000:
+		return Amount(int(2946700 + (taxable_income - 12000000) * 0.37), '$')
+	return Amount(int(5166700 + (taxable_income - 18000000) * 0.45), '$')
+
+def tax_transaction(taxable_income):
+	tax = calculate_tax(taxable_income)
+	
+	# Get EOFY date
+	dt = datetime.now().replace(month=6, day=30)
+	if dt < datetime.now():
+		dt = dt.replace(year=dt.year + 1)
+	
+	return Transaction(
+		dt=dt,
+		description='Estimated tax payable',
+		postings=[
+			Posting(account='Income Tax', quantity=tax.quantity, commodity='$'),
+			Posting(account='Income Tax Control', quantity=-tax.quantity, commodity='$')
+		]
+	)

drcr/tax/views.py

@@ -0,0 +1,36 @@
+#   DrCr: Web-based double-entry bookkeeping framework
+#   Copyright (C) 2022–2023  Lee Yingtong Li (RunasSudo)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from flask import render_template
+
+from ..config import TAX_MAPPING
+from ..models import Amount, TrialBalancer
+from ..webapp import all_transactions, app
+from .aus_tax import calculate_tax
+
+@app.route('/tax/summary')
+def tax_summary():
+	# Get trial balance and validate COA
+	balancer = TrialBalancer()
+	balancer.apply_transactions(all_transactions())
+	
+	return render_template(
+		'tax/summary.html',
+		accounts=balancer.accounts,
+		calculate_tax=calculate_tax,
+		running_total=Amount(0, '$'),
+		TAX_MAPPING=TAX_MAPPING
+	)

drcr/templates/index.html

@@ -36,5 +36,6 @@
 	<ul>
 		<li><a href="/reports/balance-sheet">Balance sheet</a></li>
 		<li><a href="/reports/income-statement">Income statement</a></li>
+		<li><a href="/tax/summary">Tax summary</a></li>
 	</ul>
 {% endblock %}

drcr/templates/journal/journal.html

@@ -22,7 +22,7 @@
 	<h1 class="h2 my-4">Journal</h1>
 	
 	<div class="mb-2">
-		{#<a href="/journal/new-transaction" class="btn btn-primary"><i class="bi bi-plus-lg"></i> New transaction</a>#}
+		<a href="/journal/new-transaction" class="btn btn-primary"><i class="bi bi-plus-lg"></i> New transaction</a>
 		{% if commodity_detail %}
 			<a href="?commodity-detail=0" class="btn btn-outline-secondary">Hide commodity detail</a>
 		{% else %}

drcr/templates/reports/income_statement.html

@@ -1,5 +1,5 @@
 {#  DrCr: Web-based double-entry bookkeeping framework
-    Copyright (C) 2022  Lee Yingtong Li (RunasSudo)
+    Copyright (C) 2022–2023  Lee Yingtong Li (RunasSudo)
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU Affero General Public License as published by
@@ -76,8 +76,18 @@
 			
 			<tr><td colspan="2">&nbsp;</td></tr>
 			
+			<tr>
+				<th>Net surplus (deficit) before income tax</th>
+				{% set _ = running_total.__setattr__('quantity', surplus) %}
+				<th class="text-end">{{ fmtbal(running_total, -1) }}</th>
+			</tr>
+			<tr>
+				<td>Income tax expense</td>
+				<td class="text-end">{{ fmtbal(accounts['Income tax']) }}</td>
+				{% set surplus = surplus + accounts['Income tax'].quantity %}
+			</tr>
 			<tr style="border-width:1px 0">
-				<th>Net surplus (deficit)</th>
+				<th>Net surplus (deficit) after income tax</th>
 				{% set _ = running_total.__setattr__('quantity', surplus) %}
 				<th class="text-end">{{ fmtbal(running_total, -1) }}</th>
 			</tr>

drcr/templates/tax/summary.html

@@ -0,0 +1,90 @@
+{#  DrCr: Web-based double-entry bookkeeping framework
+    Copyright (C) 2022–2023  Lee Yingtong Li (RunasSudo)
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#}
+
+{% extends 'base.html' %}
+{% block title %}Tax summary{% endblock %}
+
+{% macro fmtbal(amount, mul=1) %}
+	{# FIXME: Honour AMOUNT_DPS #}
+	{% if amount.quantity * mul >= 0 %}
+		{{ '{:,.2f}'.format(amount.quantity|abs / 100) }}&nbsp;
+	{% else %}
+		({{ '{:,.2f}'.format(amount.quantity|abs / 100) }})
+	{% endif %}
+{% endmacro %}
+
+{% macro acctrow(name, mul=1) %}
+	<tr>
+		<td>{{ name }}</td>
+		<td class="text-end">{{ fmtbal(accounts[name], mul) }}</td>
+	</tr>
+	{% set _ = running_total.__setattr__('quantity', running_total.quantity + accounts[name].quantity) %}
+{% endmacro %}
+
+{% block content %}
+	<h1 class="h2 mt-4">Tax summary</h1>
+	
+	<table class="table table-borderless">
+		<thead>
+			<tr style="border-width:0 0 1px 0">
+				<th></th>
+				<th class="text-end">$&nbsp;</th>
+			</tr>
+		</thead>
+		<tbody>
+			<tr>
+				<th colspan="2">Assessable income</th>
+			</tr>
+			{% set _ = running_total.__setattr__('quantity', 0) %}
+			{% for account in TAX_MAPPING['Assessable income'] if account in accounts %}
+				{{ acctrow(account, -1) }}
+			{% endfor %}
+			<tr style="border-width:1px 0">
+				<th>Total assessable income</th>
+				<th class="text-end">{{ fmtbal(running_total, -1) }}</th>
+			</tr>
+			{% set taxable_income = running_total.quantity %}
+			
+			<tr><td colspan="2">&nbsp;</td></tr>
+			
+			<tr>
+				<th colspan="2">Deductions</th>
+			</tr>
+			{% set _ = running_total.__setattr__('quantity', 0) %}
+			{% for account in TAX_MAPPING['Deductions'] if account in accounts %}
+				{{ acctrow(account) }}
+			{% endfor %}
+			<tr style="border-width:1px 0">
+				<th>Total deductions</th>
+				<th class="text-end">{{ fmtbal(running_total) }}</th>
+			</tr>
+			{% set taxable_income = taxable_income + running_total.quantity %}
+			
+			<tr><td colspan="2">&nbsp;</td></tr>
+			
+			{% set _ = running_total.__setattr__('quantity', taxable_income) %}
+			<tr style="border-width:1px 0">
+				<th>Taxable income</th>
+				<th class="text-end">{{ fmtbal(running_total, -1) }}</th>
+			</tr>
+			<tr>
+				<td>Tax on taxable income</td>
+				<td class="text-end">{{ fmtbal(calculate_tax(running_total)) }}</td>
+			</tr>
+		</tbody>
+	</table>
+{% endblock %}

drcr/webapp.py

@@ -20,6 +20,7 @@ from flask_sqlalchemy.record_queries import get_recorded_queries
 from .database import db
 from .models import Transaction
 from .statements.models import StatementLine
+from .tax import aus_tax
 
 import time
 
@@ -32,13 +33,15 @@ db.init_app(app)
 def all_transactions():
 	return (
 		Transaction.query.all() +
-		[line.into_transaction() for line in StatementLine.query.filter(StatementLine.reconciliation == None)]
+		[line.into_transaction() for line in StatementLine.query.filter(StatementLine.reconciliation == None)] +
+		[aus_tax.tax_transaction(aus_tax.taxable_income())]
 	)
 
 from . import views
 from .journal import views
 from .reports import views
 from .statements import views
+from .tax import views
 
 @app.cli.command('initdb')
 def initdb():