fix: resolve TUI alert duplication and usability issues

- eliminate duplicate system.Status() call via CheckWithStatus()
- unify sparkline/progress bar color thresholds (70/90%)
- preserve docker cache on timeout instead of discarding
- fix truncate to use rune count for unicode support

Author: Higangssh

internal/alerts/alerts.go

@@ -29,7 +29,10 @@ func Check(cfg *config.AlertConfig) (*AlertResult, error) {
 	if err != nil {
 		return nil, err
 	}
+	return CheckWithStatus(cfg, info), nil
+}
 
+func CheckWithStatus(cfg *config.AlertConfig, info *system.StatusInfo) *AlertResult {
 	result := &AlertResult{
 		CPU: AlertItem{
 			Status:    statusFor(info.CPU.UsagePercent, cfg.CPU),
@@ -52,7 +55,7 @@ func Check(cfg *config.AlertConfig) (*AlertResult, error) {
 		})
 	}
 
-	return result, nil
+	return result
 }
 
 func statusFor(current, threshold float64) string {

internal/tui/fetch.go

@@ -69,8 +69,7 @@ func fetchLocal(alertCfg *config.AlertConfig) ServerData {
 	data.Status = status
 	data.Name = status.Hostname
 
-	alertResult, _ := alerts.Check(alertCfg)
-	data.Alerts = alertResult
+	data.Alerts = alerts.CheckWithStatus(alertCfg, status)
 
 	procs, _ := system.TopProcesses(5)
 	data.Processes = procs
@@ -132,10 +131,12 @@ func fetchDocker() ([]docker.Container, string) {
 		dockerCacheMu.Unlock()
 		return containers, status
 	case <-time.After(2 * time.Second):
-		// Goroutine will finish eventually and update cache + release flag
 		dockerCacheMu.Lock()
-		dockerCacheCtr, dockerCacheSt = nil, "unavailable"
+		c, s := dockerCacheCtr, dockerCacheSt
 		dockerCacheMu.Unlock()
+		if s != "" {
+			return c, s
+		}
 		return nil, "unavailable"
 	}
 }

internal/tui/sparkline.go

@@ -42,17 +42,15 @@ func sparkline(data []float64, width int) string {
 	return b.String()
 }
 
-// sparklineColor returns the appropriate style for a sparkline
-// based on the last value: green <50%, yellow 50-80%, red >80%.
 func sparklineColor(data []float64) lipgloss.Style {
 	if len(data) == 0 {
 		return greenStyle
 	}
 	last := data[len(data)-1]
 	switch {
-	case last > 80:
+	case last >= 90:
 		return redStyle
-	case last >= 50:
+	case last >= 70:
 		return yellowStyle
 	default:
 		return greenStyle

internal/tui/sparkline_test.go

@@ -128,11 +128,11 @@ func TestSparklineColor(t *testing.T) {
 	}{
 		{"empty", nil},
 		{"green low", []float64{30}},
-		{"yellow mid", []float64{60}},
-		{"red high", []float64{90}},
-		{"boundary 50", []float64{50}},
-		{"boundary 80", []float64{80}},
-		{"boundary 81", []float64{81}},
+		{"green mid", []float64{60}},
+		{"yellow 70", []float64{70}},
+		{"yellow 89", []float64{89}},
+		{"red 90", []float64{90}},
+		{"red high", []float64{95}},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

internal/tui/styles.go

@@ -87,13 +87,13 @@ func alertStyle(status string) lipgloss.Style {
 	}
 }
 
-// truncate shortens a string to max length with ellipsis.
 func truncate(s string, max int) string {
-	if len(s) <= max {
+	r := []rune(s)
+	if len(r) <= max {
 		return s
 	}
 	if max <= 1 {
-		return s[:max]
+		return string(r[:max])
 	}
-	return s[:max-1] + "~"
+	return string(r[:max-1]) + "~"
 }