{ config, pkgs, lib, utils, ... }:

with utils;
with lib;

let
  dirConfig = {
    options = {
      path = mkOption {
        type = types.path;
      };

      maxSize = mkOption {
        type = with types; either ints.positive str;
      };

      minSleep = mkOption {
        type = with types; nullOr ints.positive;
        default = 3600; 
      };

      monitorTimeout = mkOption {
        type = with types; nullOr ints.positive;
        default = 3600 * 24;
      };
    };
  };

  dirService = dCfg: nameValuePair ("rolling-directory@" + escapeSystemdPath dCfg.path) {
    wantedBy = [ "multi-user.target" ];

    serviceConfig = {
      ExecStart = let
        extraArgs = optionals (dCfg.monitorTimeout != null) ["-t" (toString dCfg.monitorTimeout)]
                  + optionals (dCfg.minSleep != null) ["-s" (toString dCfg.minSleep)];
      in ''
        ${pkgs.rolling-directory}/bin/rolling-directory %I ${toString dCfg.maxSize} monitor ${escapeShellArgs extraArgs}
      '';
    };
  };
in {
  options = {
    services.rollingDirectories = mkOption {
      type = with types; listOf (submodule dirConfig);
      default = [];
    };
  };

  config = {
    nixpkgs.config.packageOverrides = import ./default.nix;

    systemd.services = listToAttrs (map dirService config.services.rollingDirectories);
  };
}