The Throbber

internal/app/app.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
+	"time"
 
 	"gitea.westgate.pw/ShadowsOverWestgate/sow-tools/internal/pipeline"
 	"gitea.westgate.pw/ShadowsOverWestgate/sow-tools/internal/project"
@@ -27,6 +29,48 @@ type context struct {
 	args   []string
 }
 
+type spinner struct {
+	mu   sync.Mutex
+	on   bool
+	text string
+	msg  []string
+}
+
+var spin = &spinner{
+	msg: []string{"-", "\\", "|", "/"},
+}
+
+func (s *spinner) start(text string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.on = true
+	s.text = text
+	go s.run(text)
+}
+
+func (s *spinner) stop() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.on = false
+}
+
+func (s *spinner) run(text string) {
+	i := 0
+	for {
+		s.mu.Lock()
+		if !s.on {
+			s.mu.Unlock()
+			fmt.Fprintf(os.Stderr, "\r")
+			return
+		}
+		msg := s.msg[i%len(s.msg)]
+		fmt.Fprintf(os.Stderr, "\r[%s] %s", msg, text)
+		s.mu.Unlock()
+		i++
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
 var commands = []command{
 	{
 		name:        "build",
@@ -118,9 +162,12 @@ func Run(args []string) (int, error) {
 	default:
 		for _, cmd := range commands {
 			if cmd.name == args[0] {
+				spin.start("running " + cmd.name)
 				if err := cmd.run(ctx); err != nil {
+					spin.stop()
 					return 1, err
 				}
+				spin.stop()
 				return 0, nil
 			}
 		}