{ pkgs, lib, ... }:
let
  script = pkgs.writeShellScriptBin "update-roa" ''
    mkdir -p /etc/bird/
    ${pkgs.curl}/bin/curl -sfSLR {-o,-z}/etc/bird/roa_dn42_v6.conf https://dn42.burble.com/roa/dn42_roa_bird2_6.conf
    ${pkgs.curl}/bin/curl -sfSLR {-o,-z}/etc/bird/roa_dn42.conf https://dn42.burble.com/roa/dn42_roa_bird2_4.conf
    ${pkgs.bird2}/bin/birdc c
    ${pkgs.bird2}/bin/birdc reload in all
  '';
  bgp = import ./bgp.nix { };
in
{
  systemd = {
    timers.dn42-roa = {
      description = "Trigger a ROA table update";

      timerConfig = {
        OnBootSec = "5m";
        OnUnitInactiveSec = "1h";
        Unit = "dn42-roa.service";
      };

      wantedBy = [ "timers.target" ];
      before = [ "bird.service" ];
    };
    services = {
      dn42-roa = {
        after = [ "network.target" ];
        description = "DN42 ROA Updated";
        unitConfig = {
          Type = "one-shot";
        };
        serviceConfig = {
          ExecStart = "${script}/bin/update-roa";
        };
      };
    };
  };

  services = {
    bird = {
      enable = true;
      package = pkgs.bird2;
      checkConfig = false;
      config =
        builtins.readFile ./bird.conf
        + lib.concatStrings (
          builtins.map (
            x:
            "\n      protocol bgp ${x.name} from dnpeers {\n        ${
              if x.multihop then "multihop;" else ""
            }\n        ${
              if x.gracefulRestart then "graceful restart on;" else ""
            }\n        neighbor ${x.neigh} as ${x.as};\n        ${
              if x.multi || x.v4 then
                "\n        ipv4 {\n                extended next hop on;\n                import where dn42_import_filter(${x.link},25,34);\n                export where dn42_export_filter(${x.link},25,34);\n                import keep filtered;\n        };\n        "
              else
                ""
            }\n        ${
              if x.multi || x.v6 then
                "\n        ipv6 {\n                extended next hop on;\n                import where dn42_import_filter(${x.link},25,34);\n                export where dn42_export_filter(${x.link},25,34);\n                import keep filtered;\n        };\n        "
              else
                ""
            }\n    }\n        "
          ) bgp.sessions
        )
        + bgp.extraConfig;
    };
  };
  users.users.thehedgehog.extraGroups = [ "bird2" ];
}