# `checks.module-eval-swarm-services-switch` — see ./lib.nix for the shared
# rationale (why this suite exists, naming convention, "evaluates
# not executes").
{
  pkgs,
  lib,
  self,
  nixosSystem,
}:
let
  inherit
    (import ./lib.nix {
      inherit
        pkgs
        lib
        self
        nixosSystem
        ;
    })
    hive
    runGroup
    bridgePortsOrNone
    swarmServiceEnables
    ;

  # The swarm-services toggle with the central one off, so the only thing
  # that can enable the gateway/resolver/bridge here is that toggle's own
  # module — every other module that asserts them is behind `enable`.
  swarmServicesOnly = hive {
    enable = false;
    deploy.allSwarmServices = true;
  };

  # Ports asked for on such a host. The request is the whole condition: the
  # firewall hole exists because an operator named a port, not because the
  # hive is running, and an agent reaching a host service is a claim about
  # the host's own listeners either way.
  exposedPortsNoHive = hive {
    enable = false;
    network.exposeHostPorts = [ 5432 ];
  };

  # The swarm UI where its own toggle is on — the control the absence arm
  # needs, since nothing else in this suite renders this vhost and an arm
  # saying "it is not there" would hold just as well if it were never there.
  # Package stubbed per this file's header: the vhost roots at it.
  swarmUiHere = hive {
    deploy.swarm-ui.enable = true;
    deploy.swarm-ui.package = pkgs.emptyDirectory;
  };

  # The swarm's shared services hosted HERE without the all-local mode — a
  # services box with hives elsewhere, the shape ./host-modules/
  # swarm-required-services.nix documents the switch for.
  swarmServicesHere = hive { deploy.allSwarmServices = true; };

  # Same, with one of those services placed on another host. Every derivation
  # in that module is `mkDefault` so this stays expressible.
  swarmServicesBaoElsewhere = hive {
    deploy.allSwarmServices = true;
    deploy.bao.enable = false;
  };
  cases = [
    {
      # `lib.all` over an empty set holds vacuously, so the roster is counted
      # before it is read: a helper that lost a member would otherwise turn
      # this case green by measuring nothing.
      name = "hosting the swarm's shared services turns on every service that switch owns";
      ok =
        let
          es = swarmServiceEnables swarmServicesHere;
        in
        lib.length (lib.attrNames es) == 9 && lib.all lib.id (lib.attrValues es);
    }
    {
      # The switch fills in for an operator who has not spoken and yields to
      # one who has — that is what keeps a shared service placeable on a host
      # of its own. A plain assignment or `mkForce` would satisfy both cases
      # above and break this one. `nats` is the control: without it the case
      # also passes on a fixture where nothing came on at all.
      name = "placing one shared service elsewhere survives the switch that would enable it";
      ok =
        let
          es = swarmServiceEnables swarmServicesBaoElsewhere;
        in
        !es.bao && es.nats;
    }
    {
      # The controller sits on the OTHER tier: `singleHostSwarm` places it
      # (./host-modules/local-defaults.nix) and swarm-ui follows the
      # controller. Pinned so that moving a service between tiers is a
      # decision someone makes rather than a merge nobody reads.
      name = "hosting the swarm's shared services does not make a hive the swarm's control plane";
      ok =
        !swarmServicesHere.services.hyperhive.deploy.swarm-controller.enable
        && !swarmServicesHere.services.hyperhive.deploy.swarm-ui.enable;
    }
    {
      # Control for the arm above, and the one place this slice is not inert:
      # the ports are opened because they were named, on a host that never
      # turned the hive on. The bridge firewall is the host's own, so there is
      # nothing here for the hive toggle to have been protecting.
      name = "a named exposeHostPorts opens its bridge port on the host's own say-so";
      ok = builtins.elem 5432 (bridgePortsOrNone exposedPortsNoHive);
    }
    {
      name = "the swarm UI claims the swarm apex where this host serves it";
      ok = swarmUiHere.services.nginx.virtualHosts ? "t.local";
    }
    {
      # The swarm-services toggle enables them explicitly, from its own
      # module rather than from any of their defaults.
      name = "the swarm-services toggle turns on the gateway, resolver and bridge by itself";
      ok =
        swarmServicesOnly.services.hyperhive.gateway.enable
        && swarmServicesOnly.services.hyperhive.gateway.dns.enable
        && swarmServicesOnly.services.hyperhive.network.enable;
    }
    {
      # An operator's explicit `false` beats every `mkDefault` assertion,
      # which is what keeps "asserted by whoever needs it" from being a
      # setting the operator cannot turn off.
      name = "an explicit gateway.enable = false wins over the modules asserting it";
      ok = !(hive { gateway.enable = false; }).services.nginx.enable;
    }
  ];
in
runGroup "swarm-services-switch" cases