package envelope

import "strings"

// NormalizeSourceEndpointKey returns the stable, low-cardinality source key used
// by identity lookup and statistics source tracking.
func NormalizeSourceEndpointKey(endpoint string) string {
	endpoint = strings.TrimSpace(endpoint)
	if endpoint == "" {
		return ""
	}
	if strings.HasPrefix(strings.ToLower(endpoint), "mqtt://") {
		return "mqtt"
	}
	if host, _, ok := strings.Cut(endpoint, ":"); ok {
		return strings.TrimSpace(host)
	}
	return endpoint
}