// Span is ES database representation of the domain span.
type Span struct {
	TraceID       TraceID     `json:"traceID"`
	SpanID        SpanID      `json:"spanID"`
	ParentSpanID  SpanID      `json:"parentSpanID,omitempty"` // deprecated
	Flags         uint32      `json:"flags,omitempty"`
	OperationName string      `json:"operationName"`
	References    []Reference `json:"references"`
	StartTime     uint64      `json:"startTime"` // microseconds since Unix epoch
	// ElasticSearch does not support a UNIX Epoch timestamp in microseconds,
	// so Jaeger maps StartTime to a 'long' type. This extra StartTimeMillis field
	// works around this issue, enabling timerange queries.
	StartTimeMillis uint64     `json:"startTimeMillis"`
	Duration        uint64     `json:"duration"` // microseconds
	Tags            []KeyValue `json:"tags"`
	// Alternative representation of tags for better kibana support
	Tag     map[string]interface{} `json:"tag,omitempty"`
	Logs    []Log                  `json:"logs"`
	Process Process                `json:"process,omitempty"`
}

func (fd FromDomain) convertSpanInternal(span *model.Span) Span {
	tags, tagsMap := fd.convertKeyValuesString(span.Tags)
	return Span{
		TraceID:         TraceID(span.TraceID.String()),
		SpanID:          SpanID(span.SpanID.String()),
		Flags:           uint32(span.Flags),
		OperationName:   span.OperationName,
		StartTime:       model.TimeAsEpochMicroseconds(span.StartTime),
		StartTimeMillis: model.TimeAsEpochMicroseconds(span.StartTime) / 1000,
		Duration:        model.DurationAsMicroseconds(span.Duration),
		Tags:            tags,
		Tag:             tagsMap,
		Logs:            fd.convertLogs(span.Logs),
	}
}


// DurationAsMicroseconds converts time.Duration to microseconds,
// which is the format the Duration field is stored in the Span.
func DurationAsMicroseconds(d time.Duration) uint64 {
	return uint64(d.Nanoseconds() / 1000)
}