From 809d361ca79c059b307a7373c7f251f2db4ecc00 Mon Sep 17 00:00:00 2001
From: sqshq <sqshq@sqshq.com>
Date: Thu, 9 May 2019 23:59:38 -0400
Subject: [PATCH] added radix chars printing and trailing zeros trim

---
 component/barchart/barchart.go | 26 ++--------------
 component/gauge/gauge.go       | 14 +--------
 component/util/format.go       | 56 ++++++++++++++++++++++++++++++++--
 3 files changed, 56 insertions(+), 40 deletions(-)

diff --git a/component/barchart/barchart.go b/component/barchart/barchart.go
index 12d9080..5803ae6 100644
--- a/component/barchart/barchart.go
+++ b/component/barchart/barchart.go
@@ -11,7 +11,6 @@ import (
 	"github.com/sqshq/sampler/data"
 	"image"
 	"math"
-	"strconv"
 )
 
 const (
@@ -149,9 +148,9 @@ func (b *BarChart) Draw(buffer *ui.Buffer) {
 			image.Pt(labelXCoordinate, b.Inner.Max.Y-1))
 
 		// draw value & delta
-		value := formatValue(bar.value, b.scale)
+		value := util.FormatValue(bar.value, b.scale)
 		if bar.delta != 0 {
-			value = fmt.Sprintf("%s / %s", value, formatValueWithSign(bar.delta, b.scale))
+			value = fmt.Sprintf("%s / %s", value, util.FormatValueWithSign(bar.delta, b.scale))
 		}
 		valueXCoordinate := barXCoordinate +
 			int(float64(barWidth)/2) -
@@ -166,24 +165,3 @@ func (b *BarChart) Draw(buffer *ui.Buffer) {
 
 	component.RenderAlert(b.alert, b.Rectangle, buffer)
 }
-
-// TODO extract to utils
-func formatValue(value float64, scale int) string {
-	if math.Abs(value) == math.MaxFloat64 {
-		return "Inf"
-	} else {
-		format := "%." + strconv.Itoa(scale) + "f"
-		return fmt.Sprintf(format, value)
-	}
-}
-
-// TODO extract to utils
-func formatValueWithSign(value float64, scale int) string {
-	if value == 0 {
-		return " 0"
-	} else if value > 0 {
-		return "+" + formatValue(value, scale)
-	} else {
-		return formatValue(value, scale)
-	}
-}
diff --git a/component/gauge/gauge.go b/component/gauge/gauge.go
index 110fc30..afddf28 100644
--- a/component/gauge/gauge.go
+++ b/component/gauge/gauge.go
@@ -9,8 +9,6 @@ import (
 	"github.com/sqshq/sampler/console"
 	"github.com/sqshq/sampler/data"
 	"image"
-	"math"
-	"strconv"
 )
 
 const (
@@ -89,7 +87,7 @@ func (g *Gauge) Draw(buffer *ui.Buffer) {
 		percent = (100 * g.curValue) / (g.maxValue - g.minValue)
 	}
 
-	label := fmt.Sprintf("%v%% (%v)", formatValue(percent, g.scale), g.curValue)
+	label := fmt.Sprintf("%v%% (%v)", util.FormatValue(percent, g.scale), g.curValue)
 
 	// draw bar
 	barWidth := int((percent / 100) * float64(g.Inner.Dx()))
@@ -118,13 +116,3 @@ func (g *Gauge) Draw(buffer *ui.Buffer) {
 
 	component.RenderAlert(g.alert, g.Rectangle, buffer)
 }
-
-// TODO extract to utils
-func formatValue(value float64, scale int) string {
-	if math.Abs(value) == math.MaxFloat64 {
-		return "Inf"
-	} else {
-		format := "%." + strconv.Itoa(scale) + "f"
-		return fmt.Sprintf(format, value)
-	}
-}
diff --git a/component/util/format.go b/component/util/format.go
index fa692e3..22aca80 100644
--- a/component/util/format.go
+++ b/component/util/format.go
@@ -1,17 +1,17 @@
 package util
 
 import (
-	"fmt"
+	"bytes"
 	"math"
 	"strconv"
+	"strings"
 )
 
 func FormatValue(value float64, scale int) string {
 	if math.Abs(value) == math.MaxFloat64 {
 		return "Inf"
 	} else {
-		format := "%." + strconv.Itoa(scale) + "f"
-		return fmt.Sprintf(format, value)
+		return formatTrailingDigits(addRadixChars(value), scale)
 	}
 }
 
@@ -24,3 +24,53 @@ func FormatValueWithSign(value float64, scale int) string {
 		return FormatValue(value, scale)
 	}
 }
+
+func addRadixChars(value float64) string {
+	buf := &bytes.Buffer{}
+	if value < 0 {
+		buf.Write([]byte{'-'})
+		value = 0 - value
+	}
+
+	radix := []byte{','}
+
+	parts := strings.Split(strconv.FormatFloat(value, 'f', -1, 64), ".")
+	pos := 0
+	if len(parts[0])%3 != 0 {
+		pos += len(parts[0]) % 3
+		buf.WriteString(parts[0][:pos])
+		buf.Write(radix)
+	}
+	for ; pos < len(parts[0]); pos += 3 {
+		buf.WriteString(parts[0][pos : pos+3])
+		buf.Write(radix)
+	}
+	buf.Truncate(buf.Len() - 1)
+
+	if len(parts) > 1 {
+		buf.Write([]byte{'.'})
+		buf.WriteString(parts[1])
+	}
+	return buf.String()
+}
+
+func formatTrailingDigits(value string, scale int) string {
+
+	if i := strings.Index(value, "."); i >= 0 {
+
+		formatted := value
+
+		if scale <= 0 {
+			formatted = value[:i]
+		}
+
+		i++
+		if i+scale < len(value) {
+			formatted = value[:i+scale]
+		}
+
+		return strings.TrimRight(formatted, "0.")
+	}
+
+	return value
+}