@startuml
title Indexer — Heartbeat double (Pair A + Pair B → Indexer partagé)

participant "Node A" as NodeA
participant "Node B" as NodeB
participant "IndexerService (partagé)" as Indexer

note over NodeA,NodeB: Chaque pair tick toutes les 20s

par Pair A heartbeat
    NodeA -> Indexer: NewStream /opencloud/heartbeat/1.0
    NodeA -> Indexer: json.Encode(Heartbeat A {Name, DID_A, PeerID_A, IndexersBinded})

    Indexer -> Indexer: CheckHeartbeat(host, stream, streams, mu, maxNodes)
    note over Indexer: len(peers) < maxNodes ?

    Indexer -> Indexer: getBandwidthChallenge(512-2048 bytes, stream)
    Indexer -> NodeA: Write(random payload)
    NodeA -> Indexer: Echo(same payload)
    Indexer -> Indexer: Mesure round-trip → Mbps A

    Indexer -> Indexer: getDiversityRate(host, IndexersBinded_A)
    note over Indexer: /24 subnet diversity des indexeurs liés

    Indexer -> Indexer: ComputeIndexerScore(uptimeA%, MbpsA%, diversityA%)
    note over Indexer: Score = 0.4×uptime + 0.4×bpms + 0.2×diversity

    alt Score A < 75
        Indexer -> NodeA: (close stream)
    else Score A >= 75
        Indexer -> Indexer: StreamRecord[PeerID_A] = {DID_A, Heartbeat, UptimeTracker}
    end
else Pair B heartbeat
    NodeB -> Indexer: NewStream /opencloud/heartbeat/1.0
    NodeB -> Indexer: json.Encode(Heartbeat B {Name, DID_B, PeerID_B, IndexersBinded})

    Indexer -> Indexer: CheckHeartbeat → getBandwidthChallenge
    Indexer -> NodeB: Write(random payload)
    NodeB -> Indexer: Echo(same payload)
    Indexer -> Indexer: ComputeIndexerScore(uptimeB%, MbpsB%, diversityB%)

    alt Score B >= 75
        Indexer -> Indexer: StreamRecord[PeerID_B] = {DID_B, Heartbeat, UptimeTracker}
    end
end par

note over Indexer: Les deux pairs sont désormais\nenregistrés avec leurs streams actifs

@enduml