Some basic TUI widgets ported to Go

tools/tui/progress-bar.go

@@ -0,0 +1,61 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package tui
+
+import (
+	"fmt"
+	"kitty/tools/cli/markup"
+	"strings"
+)
+
+var _ = fmt.Print
+
+func RepeatChar(char string, count int) string {
+	if count <= 5 {
+		return strings.Repeat(char, count)
+	}
+	return fmt.Sprintf("%s\x1b[%db", char, count-1)
+}
+
+func RenderProgressBar(frac float64, width int) string {
+	fc := markup.New(true)
+	if frac >= 1 {
+		return fc.Green(RepeatChar("🬋", width))
+	}
+	if frac <= 0 {
+		return fc.Dim(RepeatChar("🬋", width))
+	}
+	w := frac * float64(width)
+	fl := int(w)
+	overhang := w - float64(fl)
+	filled := RepeatChar("🬋", fl)
+	needs_break := false
+	if overhang < 0.2 {
+		needs_break = true
+	} else if overhang < 0.8 {
+		filled += "🬃"
+		fl += 1
+	} else {
+		if fl < width-1 {
+			filled += "🬋"
+			fl += 1
+			needs_break = true
+		} else {
+			filled += "🬃"
+			fl += 1
+		}
+	}
+	ans := fc.Blue(filled)
+	unfilled := ""
+	if width > fl && needs_break {
+		unfilled = "🬇"
+	}
+	filler := width - fl - len(unfilled)
+	if filler > 0 {
+		unfilled += RepeatChar("🬋", filler)
+	}
+	if unfilled != "" {
+		ans += fc.Dim(unfilled)
+	}
+	return ans
+}

tools/tui/spinners.go

@@ -0,0 +1,27 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package tui
+
+import (
+	"fmt"
+	"time"
+)
+
+var _ = fmt.Print
+
+type Spinner struct {
+	Name           string
+	interval       time.Duration
+	frames         []string
+	current_frame  int
+	last_change_at time.Time
+}
+
+func (self *Spinner) Tick() string {
+	now := time.Now()
+	if now.Sub(self.last_change_at) >= self.interval {
+		self.last_change_at = now
+		self.current_frame = (self.current_frame + 1) % len(self.frames)
+	}
+	return self.frames[self.current_frame]
+}