Improve handling of alerts when no active alerts are present

internal/briefing/package.go

@@ -35,6 +35,7 @@ type Metadata struct {
 	SourceLocation   string                   `json:"sourceLocation,omitempty"`
 	Sources          []SourceMetadata         `json:"sources,omitempty"`
 	SourceWarnings   []forecast.SourceWarning `json:"sourceWarnings,omitempty"`
+	Alerts           *AlertStatus             `json:"alerts,omitempty"`
 }
 
 type SourceMetadata struct {
@@ -48,6 +49,13 @@ type SourceMetadata struct {
 	Warnings   []forecast.SourceWarning `json:"warnings,omitempty"`
 }
 
+type AlertStatus struct {
+	Checked       bool `json:"checked"`
+	ActiveCount   int  `json:"activeCount"`
+	RelevantCount int  `json:"relevantCount"`
+	Missing       bool `json:"missing,omitempty"`
+}
+
 type BuildContext struct {
 	Resolved report.Resolved
 	Bundle   *forecast.Bundle
@@ -72,6 +80,7 @@ func BuildMetadata(ctx BuildContext) Metadata {
 		SourceLocation:   sourceLocation,
 		Sources:          sourceMetadata(ctx.Bundle),
 		SourceWarnings:   sourceWarnings(ctx.Bundle),
+		Alerts:           alertStatus(ctx.Bundle),
 	}
 }
 
@@ -124,6 +133,37 @@ func sourceWarnings(bundle *forecast.Bundle) []forecast.SourceWarning {
 	return bundle.Warnings
 }
 
+func alertStatus(bundle *forecast.Bundle) *AlertStatus {
+	if bundle == nil {
+		return nil
+	}
+	status := &AlertStatus{}
+	if bundle.Alerts != nil {
+		status.Checked = true
+		status.ActiveCount = len(bundle.Alerts.Alerts)
+	}
+	for _, source := range bundle.Sources {
+		if source.Name == "alerts" && source.Missing {
+			status.Missing = true
+			break
+		}
+	}
+	if !status.Checked && !status.Missing {
+		return nil
+	}
+	return status
+}
+
+func setRelevantAlertCount(metadata *Metadata, count int) {
+	if metadata.Alerts == nil {
+		if count == 0 {
+			return
+		}
+		metadata.Alerts = &AlertStatus{}
+	}
+	metadata.Alerts.RelevantCount = count
+}
+
 func variantForReport(id report.ID) string {
 	switch id {
 	case report.DailyToday: