// arborist/mesh — cryptographic identity stack per peer.
//
// Each peer carries two keypairs and one shared epoch secret.
// Keys are raw 32-byte forms; everything lives in the standard SQLite db.
//
// Render: dot -Tpng docs/diagrams/mesh-identity-stack.dot -o /tmp/x.png

digraph mesh_identity_stack {
    rankdir=TB;
    bgcolor="white";
    node [shape=box, style="rounded,filled", fontname="Helvetica"];
    edge [fontname="Helvetica", fontsize=10];

    subgraph cluster_peer {
        label="One peer (e.g. alice)";
        style="rounded,dashed";
        color="#666666";

        sign_priv  [label="Ed25519 priv\n(sign_priv, 32B)", fillcolor="#ffe8a3"];
        sign_pub   [label="Ed25519 pub\n(sign_pub, 32B)\nshared with group", fillcolor="#fff7d6"];
        dh_priv    [label="X25519 priv\n(dh_priv, 32B)", fillcolor="#a3d8ff"];
        dh_pub     [label="X25519 pub\n(dh_pub, 32B)\nshared with group", fillcolor="#d6ecff"];
        member_id  [label="member_id\n8 hex chars", fillcolor="#eeeeee"];

        sign_priv -> sign_pub [label="public_key()"];
        dh_priv   -> dh_pub   [label="public_key()"];
    }

    subgraph cluster_group {
        label="Per-epoch group state";
        style="rounded,dashed";
        color="#666666";

        roster   [label="mesh_roster\n(epoch, member_id, sign_pub, dh_pub, role)", fillcolor="#e8ffe8"];
        epoch    [label="mesh_epochs\n(epoch_id, secret_envelope, started_event_hash)", fillcolor="#e8ffe8"];
        secret   [label="symmetric epoch secret\n32 random bytes\nnever stored in clear", fillcolor="#ffd6d6"];

        epoch -> secret [label="wrapped per member via ECDH"];
    }

    audit [label="audit_events\n(prev_event_hash, event_hash)\nappend-only Merkle chain", fillcolor="#ffffff", shape=note];

    sign_priv -> audit       [label="signs each\nmembership op", style=dashed];
    sign_pub  -> roster      [label="enrolled at"];
    dh_pub    -> roster      [label="enrolled at"];
    dh_priv   -> secret      [label="ECDH-unwraps\nself's envelope entry", style=dashed, color="#0066cc"];
    member_id -> roster      [label="keys by"];

    {rank=same; sign_priv; dh_priv;}
    {rank=same; sign_pub; dh_pub;}
}
