add multi-line scrolling support, timestamps to error view

widgets/error.go

@@ -2,37 +2,59 @@ package widgets
 
 import (
 	"fmt"
+	"strings"
+	"time"
+
 	ui "github.com/gizak/termui"
 )
 
 type ErrorView struct {
 	*ui.Par
+	lines []string
 }
 
 func NewErrorView() *ErrorView {
+	const yPad = 1
+	const xPad = 2
+
 	p := ui.NewPar("")
+	p.X = xPad
+	p.Y = yPad
 	p.Border = true
 	p.Height = 10
 	p.Width = 20
-	p.PaddingTop = 1
-	p.PaddingBottom = 1
-	p.PaddingLeft = 2
-	p.PaddingRight = 2
+	p.PaddingTop = yPad
+	p.PaddingBottom = yPad
+	p.PaddingLeft = xPad
+	p.PaddingRight = xPad
+	p.BorderLabel = " ctop - error "
 	p.Bg = ui.ThemeAttr("bg")
 	p.TextFgColor = ui.ThemeAttr("status.warn")
 	p.TextBgColor = ui.ThemeAttr("menu.text.bg")
 	p.BorderFg = ui.ThemeAttr("status.warn")
 	p.BorderLabelFg = ui.ThemeAttr("status.warn")
-	return &ErrorView{p}
+	return &ErrorView{p, make([]string, 0, 50)}
+}
+
+func (w *ErrorView) Append(s string) {
+	if len(w.lines)+2 >= cap(w.lines) {
+		w.lines = append(w.lines[:0], w.lines[2:]...)
+	}
+	ts := time.Now().Local().Format("15:04:05 MST")
+	w.lines = append(w.lines, fmt.Sprintf("[%s] %s", ts, s))
+	w.lines = append(w.lines, "")
 }
 
 func (w *ErrorView) Buffer() ui.Buffer {
-	w.BorderLabel = fmt.Sprintf(" %s ", timeStr())
+	offset := len(w.lines) - w.InnerHeight()
+	if offset < 0 {
+		offset = 0
+	}
+	w.Text = strings.Join(w.lines[offset:len(w.lines)], "\n")
 	return w.Par.Buffer()
 }
 
 func (w *ErrorView) Resize() {
-	w.SetX(ui.TermWidth() / 12)
-	w.SetY(ui.TermHeight() / 3)
-	w.SetWidth(w.X * 10)
+	w.Height = ui.TermHeight() - (w.PaddingTop + w.PaddingBottom)
+	w.SetWidth(ui.TermWidth() - (w.PaddingLeft + w.PaddingRight))
 }