{ lib, pkgs, cfg, models, backgroundEntries }:

pkgs.linkFarm "voip-tftp-root" (
  lib.concatLists (lib.mapAttrsToList (key: phone:
    let m = models.${phone.model}; in
    lib.optional m.hasProvisioning (
      let
        upperKey = lib.toUpper key;
        ext      = cfg.extensions.${phone.extension};
        xml      = m.template ({
          mac            = key;
          inherit (phone) label password;
          displayName    = ext.displayName;
          serverAddress  = cfg.serverAddress;
          ntpServer      = cfg.ntpServer;
          sipPort        = cfg.sipPort;
          directoryPort  = cfg.directoryPort;
        } // lib.optionalAttrs (cfg.intercomPrefix != null) {
          intercomEnabled  = true;
          intercomPassword = phone.password;
        });
      in {
        name = "SEP${upperKey}.cnf.xml";
        path = pkgs.writeText "SEP${upperKey}.cnf.xml" xml;
      }
    )
  ) cfg.phones)
  ++ backgroundEntries
)