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

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

    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
    and 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

    Note over Indexer: Les deux pairs sont désormais<br/>enregistrés avec leurs streams actifs