add indexation index data for taxable debt fund gains computation

Author: codereverser

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## 0.4.9 - WIP
+## 0.5.0 - 2021-07-02
 - Support for calculating capital gains from detailed CAS statements
 
 

casparser/analysis/gains.py

@@ -13,7 +13,7 @@
 from casparser.exceptions import IncompleteCASError
 from casparser.enums import FundType, GainType, TransactionType
 from casparser.types import CASParserDataType, TransactionDataType
-from .utils import nav_search
+from .utils import CII, get_fin_year, nav_search
 
 
 @dataclass
@@ -35,18 +35,9 @@ class Fund:
     isin: str
     type: str
 
-    def __le__(self, other: "Fund"):
-        return self.name <= other.name
-
-    def __ge__(self, other: "Fund"):
-        return self.name >= other.name
-
     def __lt__(self, other: "Fund"):
         return self.name < other.name
 
-    def __gt__(self, other: "Fund"):
-        return self.name > other.name
-
 
 @dataclass
 class GainEntry:
@@ -94,8 +85,16 @@ def fmv(self) -> Decimal:
             return self.buy_price
         return self._cached_nav * self.units
 
+    @property
+    def index_ratio(self) -> Decimal:
+        return Decimal(
+            round(CII[get_fin_year(self.sell_date)] / CII[get_fin_year(self.buy_date)], 2)
+        )
+
     @property
     def coa(self) -> Decimal:
+        if self.fund.type == FundType.DEBT.name:
+            return Decimal(round(self.buy_price * self.index_ratio, 2))
         if self.buy_date < self.__cutoff_date:
             if self.sell_date < self.__sell_cutoff_date:
                 return self.sell_price
@@ -108,6 +107,12 @@ def ltcg_taxable(self) -> Decimal:
             return Decimal(round(self.sell_price - self.coa, 2))
         return Decimal(0.0)
 
+    @property
+    def stcg_taxable(self) -> Decimal:
+        if self.gain_type == GainType.STCG:
+            return Decimal(round(self.sell_price - self.coa, 2))
+        return Decimal(0.0)
+
     @property
     def ltcg(self) -> Decimal:
         if self.gain_type == GainType.LTCG:
@@ -194,19 +199,6 @@ def merge_transactions(self):
                 merged_transactions[dt].amount += txn["amount"]
         return merged_transactions
 
-    @staticmethod
-    def get_fin_year(dt: date):
-        """Get financial year representation."""
-        if dt.month > 3:
-            year1, year2 = dt.year, dt.year + 1
-        else:
-            year1, year2 = dt.year - 1, dt.year
-
-        if year1 % 100 != 99:
-            year2 %= 100
-
-        return f"FY{year1}-{year2}"
-
     def process(self):
         self.gains = []
         for dt in sorted(self._merged_transactions.keys()):
@@ -221,7 +213,7 @@ def buy(self, txn_date: date, quantity: Decimal, nav: Decimal, tax: Decimal):
         self.transactions.append((txn_date, quantity, nav, tax))
 
     def sell(self, sell_date: date, quantity: Decimal, nav: Decimal, tax: Decimal):
-        fin_year = self.get_fin_year(sell_date)
+        fin_year = get_fin_year(sell_date)
         original_quantity = abs(quantity)
         pending_units = original_quantity
         while pending_units > 0:
@@ -291,17 +283,20 @@ def get_summary(self):
         """Calculate capital gains summary"""
         summary = []
         for (fy, fund), txns in itertools.groupby(self.gains, key=lambda x: (x.fy, x.fund)):
-            ltcg = stcg = ltcg_taxable = Decimal(0.0)
+            ltcg = stcg = ltcg_taxable = stcg_taxable = Decimal(0.0)
             for txn in txns:
                 ltcg += txn.ltcg
                 stcg += txn.stcg
                 ltcg_taxable += txn.ltcg_taxable
-            summary.append([fy, fund.name, fund.isin, fund.type, ltcg, ltcg_taxable, stcg])
+                stcg_taxable += txn.stcg_taxable
+            summary.append(
+                [fy, fund.name, fund.isin, fund.type, ltcg, ltcg_taxable, stcg, stcg_taxable]
+            )
         return summary
 
     def get_summary_csv_data(self) -> str:
         """Return summary data as a csv string."""
-        headers = ["FY", "Fund", "ISIN", "Type", "LTCG", "LTCG(Taxable)", "STCG"]
+        headers = ["FY", "Fund", "ISIN", "Type", "LTCG", "LTCG(Taxable)", "STCG", "STCG(Taxable)"]
         with io.StringIO() as csv_fp:
             writer = csv.writer(csv_fp)
             writer.writerow(headers)
@@ -329,6 +324,7 @@ def get_gains_csv_data(self) -> str:
             "LTCG",
             "LTCG Taxable",
             "STCG",
+            "STCG Taxable",
         ]
         with io.StringIO() as csv_fp:
             writer = csv.writer(csv_fp)
@@ -351,6 +347,7 @@ def get_gains_csv_data(self) -> str:
                         gain.ltcg,
                         gain.ltcg_taxable,
                         gain.stcg,
+                        gain.stcg_taxable,
                     ]
                 )
             csv_fp.seek(0)

casparser/analysis/utils.py

@@ -1,9 +1,68 @@
+from collections import UserDict
+from datetime import date
 from decimal import Decimal
+import re
 from typing import Optional
 
 from casparser_isin import MFISINDb
 
+CII_DATA = {
+    "FY2001-02": 100,
+    "FY2002-03": 105,
+    "FY2003-04": 109,
+    "FY2004-05": 113,
+    "FY2005-06": 117,
+    "FY2006-07": 122,
+    "FY2007-08": 129,
+    "FY2008-09": 137,
+    "FY2009-10": 148,
+    "FY2010-11": 167,
+    "FY2011-12": 184,
+    "FY2012-13": 200,
+    "FY2013-14": 220,
+    "FY2014-15": 240,
+    "FY2015-16": 254,
+    "FY2016-17": 264,
+    "FY2017-18": 272,
+    "FY2018-19": 280,
+    "FY2019-20": 289,
+    "FY2020-21": 301,
+}
+
+
+class _CII(UserDict):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.years = list(sorted(self.data.keys()))
+        self._min_year = self.years[0]
+        self._max_year = self.years[-1]
+
+    def __missing__(self, key):
+        if not re.search(r"FY\d{4}-\d{2}", key):
+            raise ValueError("Invalid FY year format.")
+        elif key <= self._min_year:
+            return self.data[self._min_year]
+        elif key >= self._max_year:
+            return self.data[self._max_year]
+        raise KeyError(key)
+
+
+CII = _CII(CII_DATA)
+
 
 def nav_search(isin: str) -> Optional[Decimal]:
     with MFISINDb() as db:
         return db.nav_lookup(isin)
+
+
+def get_fin_year(dt: date):
+    """Get financial year representation."""
+    if dt.month > 3:
+        year1, year2 = dt.year, dt.year + 1
+    else:
+        year1, year2 = dt.year - 1, dt.year
+
+    if year1 % 100 != 99:
+        year2 %= 100
+
+    return f"FY{year1}-{year2}"

casparser/cli.py

@@ -155,30 +155,35 @@ def print_gains(data, output_file_path=None):
     table.add_column("LTCG")
     table.add_column("LTCG (Taxable)")
     table.add_column("STCG")
+    table.add_column("STCG (Taxable)")
 
     for fy, rows in itertools.groupby(summary, lambda x: x[0]):
         table.add_row(f"[bold]{fy}[/]", "", "", "")
         ltcg_total = Decimal(0.0)
         stcg_total = Decimal(0.0)
         ltcg_taxable_total = Decimal(0.0)
+        stcg_taxable_total = Decimal(0.0)
         for row in rows:
-            _, fund, _, _, ltcg, ltcg_taxable, stcg = row
+            _, fund, _, _, ltcg, ltcg_taxable, stcg, stcg_taxable = row
             ltcg_total += ltcg
             stcg_total += stcg
             ltcg_taxable_total += ltcg_taxable
+            stcg_taxable_total += stcg_taxable
             table.add_row(
                 "",
                 fund,
                 f"₹{round(ltcg, 2)}",
                 f"₹{round(ltcg_taxable, 2)}",
                 f"₹{round(stcg, 2)}",
+                f"₹{round(stcg_taxable, 2)}",
             )
         table.add_row(
             "",
             f"[bold]{fy} - Total Gains[/]",
             f"[bold {get_color(ltcg_total)}]₹{round(ltcg_total, 2)}[/]",
             f"[bold {get_color(ltcg_taxable_total)}]₹{round(ltcg_taxable_total, 2)}[/]",
             f"[bold {get_color(stcg_total)}]₹{round(stcg_total, 2)}[/]",
+            f"[bold {get_color(stcg_taxable_total)}]₹{round(stcg_taxable_total, 2)}[/]",
         )
     console.print(table)
     if isinstance(output_file_path, str):

tests/test_gains.py

@@ -0,0 +1,24 @@
+from datetime import date
+
+import pytest
+
+
+from casparser.analysis.utils import CII, get_fin_year
+
+
+class TestGainsClass:
+    def test_cii(self):
+        # Invalid FY
+        with pytest.raises(ValueError):
+            CII["2000-01"]
+        with pytest.raises(KeyError):
+            CII["FY2001-05"]
+
+        # Tests
+        assert abs(CII["FY2020-21"] / CII["FY2001-02"] - 3.01) <= 1e-3
+
+        # Checks for out-of-range FYs
+        today = date.today()
+        future_date = date(today.year + 3, today.month, today.day)
+        assert CII["FY1990-91"] == 100
+        assert CII[get_fin_year(future_date)] == CII[CII._max_year]