package host

import (
	"github.com/weaveworks/scope/report"
)

// Tagger tags each node in each topology of a report with the origin host
// node ID of this (probe) host. Effectively, a foreign key linking every node
// in every topology to an origin host node in the host topology.
type Tagger struct{ hostNodeID string }

// NewTagger tags each node with a foreign key linking it to its origin host
// in the host topology.
func NewTagger(hostID string) Tagger {
	return Tagger{hostNodeID: report.MakeHostNodeID(hostID)}
}

// Tag implements Tagger.
func (t Tagger) Tag(r report.Report) (report.Report, error) {
	md := report.MakeNodeMetadataWith(map[string]string{report.HostNodeID: t.hostNodeID})
	for _, topology := range r.Topologies() {
		for nodeID := range topology.NodeMetadatas {
			topology.NodeMetadatas[nodeID].Merge(md)
		}
	}
	return r, nil
}