take cost inflation index when calculating tax

cmd/init.go

@@ -73,16 +73,17 @@ commodities:
     type: mutualfund
     code: 120716
     harvest: 365
-    grandfather: 2018-01-31
+    tax_category: equity
   - name: NIFTY_JR
     type: mutualfund
     code: 120684
     harvest: 365
-    grandfather: 2018-01-31
+    tax_category: equity
   - name: ABCBF
     type: mutualfund
     code: 119533
     harvest: 1095
+    tax_category: debt
   - name: NPS_HDFC_E
     type: nps
     code: SM008001

cmd/update.go

@@ -30,6 +30,10 @@ var updateCmd = &cobra.Command{
 		if syncAll || updateCommodities {
 			model.SyncCommodities(db)
 		}
+
+		if syncAll {
+			model.SyncCII(db)
+		}
 	},
 }
 

internal/model/cii/cii.go

@@ -0,0 +1,42 @@
+package cii
+
+import (
+	log "github.com/sirupsen/logrus"
+	"gorm.io/gorm"
+)
+
+type CII struct {
+	ID                 uint   `gorm:"primaryKey" json:"id"`
+	FinancialYear      string `json:"financial_year"`
+	CostInflationIndex uint   `json:"cost_inflation_index"`
+}
+
+func UpsertAll(db *gorm.DB, ciis []*CII) {
+	err := db.Transaction(func(tx *gorm.DB) error {
+		err := tx.Exec("DELETE FROM ciis").Error
+		if err != nil {
+			return err
+		}
+		for _, cii := range ciis {
+			err := tx.Create(cii).Error
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func GetIndex(db *gorm.DB, financialYear string) uint {
+	var cii CII
+	result := db.Where("financial_year = ?", financialYear).First(&cii)
+	if result.Error != nil {
+		log.Fatal(result.Error)
+	}
+	return cii.CostInflationIndex
+}

internal/model/model.go

@@ -2,9 +2,11 @@ package model
 
 import (
 	"github.com/ananthakumaran/paisa/internal/ledger"
+	"github.com/ananthakumaran/paisa/internal/model/cii"
 	"github.com/ananthakumaran/paisa/internal/model/commodity"
 	"github.com/ananthakumaran/paisa/internal/model/posting"
 	"github.com/ananthakumaran/paisa/internal/model/price"
+	"github.com/ananthakumaran/paisa/internal/scraper/india"
 	"github.com/ananthakumaran/paisa/internal/scraper/mutualfund"
 	"github.com/ananthakumaran/paisa/internal/scraper/nps"
 	"github.com/logrusorgru/aurora"
@@ -48,3 +50,13 @@ func SyncCommodities(db *gorm.DB) {
 		price.UpsertAll(db, commodity.Type, schemeCode, prices)
 	}
 }
+
+func SyncCII(db *gorm.DB) {
+	db.AutoMigrate(&cii.CII{})
+	log.Info("Fetching taxation related info")
+	ciis, err := india.GetCostInflationIndex()
+	if err != nil {
+		log.Fatal(err)
+	}
+	cii.UpsertAll(db, ciis)
+}

internal/model/mutualfund/scheme/scheme.go

@@ -58,7 +58,7 @@ func FindScheme(db *gorm.DB, amc string, NAVName string) Scheme {
 	var scheme Scheme
 	result := db.Where("amc = ? and nav_name = ?", amc, NAVName).First(&scheme)
 	if result.Error != nil {
-		log.Fatal(result)
+		log.Fatal(result.Error)
 	}
 	return scheme
 }

internal/model/nps/scheme/scheme.go

@@ -59,7 +59,7 @@ func FindScheme(db *gorm.DB, pfm string, schemeName string) Scheme {
 	var scheme Scheme
 	result := db.Where("pfm_name = ? and scheme_name = ?", pfm, schemeName).First(&scheme)
 	if result.Error != nil {
-		log.Fatal(result)
+		log.Fatal(result.Error)
 	}
 	return scheme
 }

internal/scraper/india/cii.go

@@ -0,0 +1,47 @@
+package india
+
+import (
+	"net/http"
+
+	"encoding/json"
+	"io/ioutil"
+
+	"github.com/ananthakumaran/paisa/internal/model/cii"
+	log "github.com/sirupsen/logrus"
+)
+
+func GetCostInflationIndex() ([]*cii.CII, error) {
+	log.Info("Fetching Cost Inflation Index from Purified Bytes")
+	resp, err := http.Get("https://india.purifiedbytes.com/api/cii/v2.json")
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	respBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	type CII struct {
+		FinancialYear      string `json:"financial_year"`
+		CostInflationIndex uint   `json:"cost_inflation_index"`
+	}
+	type Result struct {
+		Data []CII
+	}
+
+	var result Result
+	err = json.Unmarshal(respBytes, &result)
+	if err != nil {
+		return nil, err
+	}
+
+	var ciis []*cii.CII
+	for _, s := range result.Data {
+		c := cii.CII{FinancialYear: s.FinancialYear, CostInflationIndex: s.CostInflationIndex}
+		ciis = append(ciis, &c)
+
+	}
+	return ciis, nil
+}

internal/scraper/mutualfund/nav.go

@@ -3,16 +3,17 @@ package mutualfund
 import (
 	"encoding/json"
 	"fmt"
+	log "github.com/sirupsen/logrus"
 	"io/ioutil"
+	"net/http"
 	"strconv"
 	"time"
 
-	"net/http"
-
 	"github.com/ananthakumaran/paisa/internal/model/price"
 )
 
 func GetNav(schemeCode string, commodityName string) ([]*price.Price, error) {
+	log.Info("Fetching Mutual Fund nav from mfapi.in")
 	url := fmt.Sprintf("https://api.mfapi.in/mf/%s", schemeCode)
 	resp, err := http.Get(url)
 	if err != nil {

internal/scraper/nps/nav.go

@@ -3,15 +3,16 @@ package nps
 import (
 	"encoding/json"
 	"fmt"
+	log "github.com/sirupsen/logrus"
 	"io/ioutil"
-	"time"
-
 	"net/http"
+	"time"
 
 	"github.com/ananthakumaran/paisa/internal/model/price"
 )
 
 func GetNav(schemeCode string, commodityName string) ([]*price.Price, error) {
+	log.Info("Fetching NPS Fund nav from Purified Bytes")
 	url := fmt.Sprintf("https://nps.purifiedbytes.com/api/schemes/%s/nav.json", schemeCode)
 	resp, err := http.Get(url)
 	if err != nil {

internal/server/harvest.go

@@ -3,6 +3,7 @@ package server
 import (
 	"time"
 
+	"github.com/ananthakumaran/paisa/internal/model/cii"
 	c "github.com/ananthakumaran/paisa/internal/model/commodity"
 	"github.com/ananthakumaran/paisa/internal/model/posting"
 	"github.com/ananthakumaran/paisa/internal/query"
@@ -48,7 +49,8 @@ type CapitalGain struct {
 	Harvestable Harvestable              `json:"harvestable"`
 }
 
-var EQUITY_GRANDFATHER_DATE, _ = time.Parse("2006-01-02", "2018-01-31")
+var EQUITY_GRANDFATHER_DATE, _ = time.Parse("2006-01-02", "2018-02-01")
+var CII_START_DATE, _ = time.Parse("2006-01-02", "2001-03-31")
 
 func GetHarvest(db *gorm.DB) gin.H {
 	commodities := lo.Filter(c.All(), func(c c.Commodity, _ int) bool {
@@ -118,6 +120,10 @@ func computeCapitalGains(db *gorm.DB, account string, commodity c.Commodity, pos
 			if grandfather && p.Date.Before(EQUITY_GRANDFATHER_DATE) {
 				taxableGain = grandfatherUnitPrice*p.Quantity - p.Amount
 			}
+
+			if commodity.TaxCategory == c.Debt && p.Date.After(CII_START_DATE) {
+				taxableGain = currentPrice.Value*p.Quantity - (p.Amount*float64(cii.GetIndex(db, utils.FY(today))))/float64(cii.GetIndex(db, utils.FY(p.Date)))
+			}
 			harvestable.HarvestableUnits += p.Quantity
 			harvestable.UnrealizedGain += gain
 			harvestable.TaxableUnrealizedGain += taxableGain

internal/utils/utils.go

@@ -19,7 +19,7 @@ func BTreeDescendFirstLessOrEqual[I btree.Item](tree *btree.BTree, item I) I {
 
 func FY(date time.Time) string {
 	if date.Month() < time.April {
-		return fmt.Sprintf("%d-%d", date.Year()+1, date.Year()%100)
+		return fmt.Sprintf("%d-%d", date.Year()-1, date.Year()%100)
 	} else {
 		return fmt.Sprintf("%d-%d", date.Year(), (date.Year()+1)%100)
 	}