{ lib, entities, ... }:

with lib;
let
  getHostSite = hostname:
    let site-name = entities.hosts."${hostname}".site;
    in entities.sites."${site-name}";
  getHostDomain = hostname:
    let domain-name = entities.hosts."${hostname}".domain;
    in entities.domains."${domain-name}";
  getHostRealm = hostname: (getHostDomain hostname).gssapi-realm;
  getHostFqdn = hostname:
    let hostDomain = entities.hosts."${hostname}".domain;
    in "${hostname}.${hostDomain}";

  getHostNetworkSettings = hostname:
    let
      hostDomain = entities.hosts."${hostname}".domain;
      hostNetwork = entities.zones."${hostDomain}";
    in hostNetwork.hosts."${hostname}";

  getIfAttr = as: a: if hasAttr as a then getAttr as a else null;

  getHostIpv4 = hostname:
    getIfAttr "ipv4-address" (getHostNetworkSettings hostname);
  getHostIpv6 = hostname:
    getIfAttr "ipv6-address" (getHostNetworkSettings hostname);
  getHostIps = hostname:
    filter (o: o != null) [ (getHostIpv4 hostname) (getHostIpv6 hostname) ];

  getDomainPostgresqlServer = domain:
    getHostFqdn entities.domains."${domain}".postgresql-server;

in {
  inherit getHostSite getHostDomain getHostRealm getHostFqdn getHostIpv4
    getHostIpv6 getHostIps getDomainPostgresqlServer;
}