Adding optional start and end dates for extrapolation

main.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/sirupsen/logrus"
+
 	"gopkg.in/yaml.v3"
 )
 
@@ -39,6 +41,8 @@ type Config struct {
 }
 
 type ConfigYaml struct {
+	Start        string
+	End          string
 	Accounts     []Account
 	Credit       []TransactionYaml
 	Transactions []TransactionYaml
@@ -118,7 +122,7 @@ func parseDate(date string) (time.Time, bool) {
 		if date == "first" {
 			formalDate = current
 		} else if date == "last" {
-			formalDate = current.AddDate(0, 1, -current.Day())
+			formalDate = lastOfMonth(current)
 		} else {
 			dateString = fmt.Sprintf("%d-%d-%s",
 				time.Now().Year(), int(time.Now().Month()), date)
@@ -219,6 +223,14 @@ func executeTransaction(transactionLog *TransactionLog, accounts []Account, tran
 	return executed
 }
 
+func firstOfMonth(t time.Time) time.Time {
+	return time.Date(t.Year(), t.Month(), 1, 0, 0, 0, 0, time.UTC)
+}
+
+func lastOfMonth(t time.Time) time.Time {
+	return time.Date(t.Year(), t.Month()+1, 0, 0, 0, 0, 0, time.UTC)
+}
+
 func calculateFrequency(frequency string, startDate time.Time, endDate time.Time, hardDate bool) []time.Time {
 	base := time.Now()
 	current := time.Date(base.Year(),
@@ -237,7 +249,11 @@ func calculateFrequency(frequency string, startDate time.Time, endDate time.Time
 		} else if frequency == "biweekly" {
 			initDate = initDate.AddDate(0, 0, 14)
 		} else if frequency == "monthly" {
-			initDate = initDate.AddDate(0, 1, 0)
+			if initDate == lastOfMonth(initDate) {
+				initDate = lastOfMonth(firstOfMonth(initDate).AddDate(0, 1, 0))
+			} else {
+				initDate = initDate.AddDate(0, 1, 0)
+			}
 		} else {
 			break
 		}
@@ -260,7 +276,7 @@ func printOutput(date time.Time, initialBalances []Account, executedCharges []Tr
 	divider2 := delim2 + "|"
 
 	fmt.Println(divider)
-	output := fmt.Sprintf(date.Format("Jan 02 2006"))
+	output := fmt.Sprint(date.Format("Jan 02 2006"))
 	rear_spacer := strings.Repeat(" ", 65-len(output))
 	fmt.Printf("%s%s |\n", output, rear_spacer)
 	for _, v := range initialBalances {
@@ -325,6 +341,21 @@ func main() {
 	config := parseConfig(&configYaml)
 	preFetchDates(config.Credit, &transactionLog)
 	preFetchDates(config.Transactions, &transactionLog)
+
+	if configYaml.Start != "" {
+		transactionLog.StartDate, err = time.Parse("2006-1-2", configYaml.Start)
+		if err != nil {
+			logrus.Error(err)
+		}
+	}
+
+	if configYaml.End != "" {
+		transactionLog.EndDate, err = time.Parse("2006-1-2", configYaml.End)
+		if err != nil {
+			logrus.Error(err)
+		}
+	}
+
 	collectTransactions(config.Credit, &transactionLog)
 	collectTransactions(config.Transactions, &transactionLog)