add ParseDuration() util

internal/util/util.go

@@ -287,3 +287,27 @@ func Milliseconds(d time.Duration) int {
 func MillisecondsSince(t time.Time) int {
 	return int(time.Since(t) / time.Millisecond)
 }
+
+// ParseDuration string with day and month approximation support.
+func ParseDuration(s string) (d time.Duration, err error) {
+	r := strings.NewReader(s)
+
+	switch {
+	case strings.HasSuffix(s, "d"):
+		var v float64
+		_, err = fmt.Fscanf(r, "%fd", &v)
+		d = time.Duration(v * float64(24*time.Hour))
+	case strings.HasSuffix(s, "mo"):
+		var v float64
+		_, err = fmt.Fscanf(r, "%fmo", &v)
+		d = time.Duration(v * float64(30*24*time.Hour))
+	case strings.HasSuffix(s, "M"):
+		var v float64
+		_, err = fmt.Fscanf(r, "%fM", &v)
+		d = time.Duration(v * float64(30*24*time.Hour))
+	default:
+		d, err = time.ParseDuration(s)
+	}
+
+	return
+}

internal/util/util_test.go

@@ -3,6 +3,7 @@ package util
 import (
 	"os/exec"
 	"testing"
+	"time"
 
 	"github.com/tj/assert"
 )
@@ -26,3 +27,39 @@ func TestExitStatus(t *testing.T) {
 		assert.Equal(t, "5", code)
 	})
 }
+
+func TestParseDuration(t *testing.T) {
+	t.Run("day", func(t *testing.T) {
+		v, err := ParseDuration("1d")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, time.Hour*24, v)
+	})
+
+	t.Run("day with faction", func(t *testing.T) {
+		v, err := ParseDuration("1.5d")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, time.Duration(float64(time.Hour*24)*1.5), v)
+	})
+
+	t.Run("month", func(t *testing.T) {
+		v, err := ParseDuration("1mo")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, time.Hour*24*30, v)
+
+		v, err = ParseDuration("1M")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, time.Hour*24*30, v)
+	})
+
+	t.Run("month with faction", func(t *testing.T) {
+		v, err := ParseDuration("1.5mo")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, time.Duration(float64(time.Hour*24*30)*1.5), v)
+	})
+
+	t.Run("default", func(t *testing.T) {
+		v, err := ParseDuration("15m")
+		assert.NoError(t, err, "parsing")
+		assert.Equal(t, 15*time.Minute, v)
+	})
+}