{ ... }:
{
  _class = "clan.service";
  manifest.name = "asterisk";
  manifest.description = "Asterisk PBX server";
  manifest.categories = [ "System" ];

  roles.default = {
    perInstance.nixosModule =
      {
        lib,
        ...
      }:
      {
        services.asterisk = {
          enable = lib.mkDefault true;
          confFiles = {
            # Dial plan config
            "extensions.conf" = ''
              exten => 1001,1,Dial(PJSIP/user1,20)
              exten => 1002,1,Dial(PJSIP/user2,20)

              exten => 100,1,Answer()
              same  =>     n,Wait(1)
              same  =>     n,Playback(hello-world)
              same  =>     n,Hangup()
            '';

            "pjsip.conf" = ''
              [transport-udp]
              type=transport
              protocol=udp
              bind=0.0.0.0,[::]

              [endpoint_internal](!)
              type=endpoint
              context=from-internal
              disallow=all
              allow=ulaw

              [auth_userpass](!)
              type=auth
              auth_type=userpass

              [aor_dynamic](!)
              type=aor
              max_contacts=1

              [user1](endpoint_internal)
              auth=user1
              aors=user1
              [user1](auth_userpass)
              password=user1
              username=user1
              [user1](aor_dynamic)

              [user2](endpoint_internal)
              auth=user2
              aors=user2
              [user2](auth_userpass)
              password=user2
              username=user2
              [user2](aor_dynamic)
            '';
          };
        };
      };
  };
}