Bugfix: Fix wrong date calculation for day of the week

main.go

@@ -107,28 +107,29 @@ func convertToDay(input string) (time.Time, error) {
 		return todayStart.Add(-24 * time.Hour), nil
 	}
 
-	var day time.Weekday
+	var weekdayWant time.Weekday
 	switch input {
 	case "monday":
-		day = time.Monday
+		weekdayWant = time.Monday
 	case "tuesday":
-		day = time.Tuesday
+		weekdayWant = time.Tuesday
 	case "wednesday":
-		day = time.Wednesday
+		weekdayWant = time.Wednesday
 	case "thursday":
-		day = time.Thursday
+		weekdayWant = time.Thursday
 	case "friday":
-		day = time.Friday
+		weekdayWant = time.Friday
 	case "saturday":
-		day = time.Saturday
+		weekdayWant = time.Saturday
 	case "sunday":
-		day = time.Sunday
+		weekdayWant = time.Weekday(7) // week ends with sunday
 	default:
-		day = -1 // NoneDay
+		weekdayWant = -1 // NoneDay
 	}
 
-	if day != -1 {
-		return todayStart.Add(time.Duration(time.Now().Weekday()-day) * 24 * time.Hour), nil
+	if weekdayWant != -1 {
+		weekdayNow := time.Now().Weekday()
+		return todayStart.Add(time.Duration(weekdayWant-weekdayNow) * 24 * time.Hour), nil
 	}
 
 	if d, err := strconv.Atoi(input); err == nil {

main_test.go

@@ -46,6 +46,12 @@ func Test_convertToDay(t *testing.T) {
 		{name: "today", input: "today", want: time.Now()},
 		{name: "yesterday", input: "yesterday", want: time.Now().Add(-24 * time.Hour)},
 		{name: "monday", input: "monday", want: time.Now().Add(daysDiff(time.Monday, time.Now().Weekday()))},
+		{name: "tuesday", input: "tuesday", want: time.Now().Add(daysDiff(time.Tuesday, time.Now().Weekday()))},
+		{name: "wednesday", input: "wednesday", want: time.Now().Add(daysDiff(time.Wednesday, time.Now().Weekday()))},
+		{name: "thursday", input: "thursday", want: time.Now().Add(daysDiff(time.Thursday, time.Now().Weekday()))},
+		{name: "friday", input: "friday", want: time.Now().Add(daysDiff(time.Friday, time.Now().Weekday()))},
+		{name: "saturday", input: "saturday", want: time.Now().Add(daysDiff(time.Saturday, time.Now().Weekday()))},
+		{name: "sunday", input: "sunday", want: time.Now().Add(daysDiff(time.Weekday(7), time.Now().Weekday()))},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {