nixos-config/nixos/modules/services/castget.nix

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

with lib;

let

  cfg = config.custom.services.castget;

in
{

  options.custom.services.castget = {
    enable = mkEnableOption "enable custom.services.castget";
    feeds = mkOption {
      type = with types;
        attrsOf (submodule {
          options = {
            url = mkOption {
              type = with types; str;
              description = ''
                url to the rss feed
              '';
            };
            spool = mkOption {
              type = with types; path;
              description = ''
                download enclosures to this directory.
              '';
            };
          };
        });
      description = ''
        configurations for the cast
      '';
    };
    user = mkOption {
      type = with types; string;
      description = ''
        user to run the systemd service as
      '';
    };
    timerConfig = mkOption {
      type = with types; attrsOf str;
      default = { OnCalendar = "daily"; };
      example = {
        OnCalendar = "00:05";
        RandomizedDelaySec = "5h";
      };
      description = ''
        When to run the polling script. See man systemd.timer for details.
      '';
    };
    serviceName = mkOption {
      type = with types; string;
      default = "castget";
      description = ''
        the name of the castget systemd service
      '';
    };
  };

  config = mkIf cfg.enable {

    systemd.services."${cfg.serviceName}" = {
      description = "castget polling service";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];
      restartIfChanged = false;
      serviceConfig.User = cfg.user;

      preStart =
        let
          mkSpools =
            mapAttrsToList (ignore: value: "mkdir -p ${value.spool}") cfg.feeds;
        in
        concatStringsSep "\n" mkSpools;
      script =
        let
          channels = mapAttrsToList (key: ignore: key) cfg.feeds;
          castget = "${pkgs.castget}/bin/castget";

          configurationFile =
            let
              configurations = mapAttrsToList
                (key: value: ''
                  [${key}]
                  url=${value.url}
                  spool=${value.spool}
                '')
                cfg.feeds;
            in
            (pkgs.writeText "castget-configuration"
              (concatStringsSep "" configurations));
        in
        (concatMapStringsSep "\n"
          (channel: "${castget} --rcfile ${configurationFile} ${channel}")
          channels);
    };

    systemd.timers."${cfg.serviceName}" = {
      wantedBy = [ "timers.target" ];
      timerConfig = cfg.timerConfig;
    };

  };
}