austax: Implement tax offsets

austax/__init__.py

@@ -38,6 +38,7 @@ def plugin_init():
 	drcr.plugins.account_kinds.append(('austax.d4', 'Work-related self-education expenses (D4)'))
 	drcr.plugins.account_kinds.append(('austax.d5', 'Other work-related expenses (D5)'))
 	drcr.plugins.account_kinds.append(('austax.d9', 'Gifts or donations (D9)'))
+	drcr.plugins.account_kinds.append(('austax.offset', 'Tax offset'))
 	drcr.plugins.account_kinds.append(('austax.paygw', 'PAYG withheld amounts'))
 	drcr.plugins.account_kinds.append(('austax.cgtasset', 'CGT asset'))
 	drcr.plugins.account_kinds.append(('austax.rfb', 'Reportable fringe benefit'))

austax/reports.py

@@ -36,6 +36,18 @@ def base_income_tax(year, taxable_income):
 			lower_limit = base_tax[year][i - 1][0]
 			return Amount(flat_amount * (10**AMOUNT_DPS) + marginal_rate * (taxable_income.quantity - lower_limit * (10**AMOUNT_DPS)), '$')
 
+def lito(taxable_income):
+	"""Get the amount of low income tax offset"""
+	
+	if taxable_income.quantity <= 3750000:
+		return Amount(70000, '$')
+	if taxable_income.quantity <= 4500000:
+		return Amount(70000 - 0.05 * (taxable_income.quantity - 3750000), '$')
+	if taxable_income.quantity <= 6666700:
+		return Amount(32500 - int(0.015 * (taxable_income.quantity - 4500000)), '$')
+	
+	return Amount(0, '$')
+
 def medicare_levy(taxable_income):
 	if taxable_income.quantity < 2920700:
 		raise NotImplementedError('Medicare levy reduction is not implemented')
@@ -153,6 +165,14 @@ def tax_summary_report():
 					]
 				),
 				Spacer(),
+				Section(
+					title='Tax offsets',
+					entries=entries_for_kind(account_configurations, accounts, 'austax.offset', neg=True) + [
+						Calculated('Low income tax offset', lambda _: lito(report.by_id('taxable').amount)),
+						Subtotal('Total tax offsets', id='offsets')
+					]
+				),
+				Spacer(),
 				Section(
 					entries=[
 						Calculated(
@@ -181,7 +201,7 @@ def tax_summary_report():
 				Spacer(),
 				Calculated(
 					'ATO liability payable (refundable)',
-					lambda _: report.by_id('total_tax').amount - report.by_id('paygw').amount + report.by_id('loan_repayment').amount,
+					lambda _: report.by_id('total_tax').amount - report.by_id('offsets').amount - report.by_id('paygw').amount + report.by_id('loan_repayment').amount,
 					heading=True,
 					bordered=True
 				)