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

{
  options = {
    environment.persistence = lib.mkOption {
      type = lib.types.attrsOf (lib.types.submodule {
        options = {
          timezone = lib.mkEnableOption "storing system timezone";
        };
      });
    };
  };

  config = {
    systemd = lib.mkMerge (lib.mapAttrsToList (name: cfg: lib.mkIf cfg.timezone {
      services = {
        "timezone@${utils.escapeSystemdPath name}" = {
          wantedBy = [ "multi-user.target" ];
          serviceConfig = {
            Type = "oneshot";
            RemainAfterExit = true;
            ExecStart = "${pkgs.coreutils}/bin/cp -vP ${utils.escapeSystemdExecArg "${name}/etc/localtime"} /etc/localtime";
            ExecStop = "${pkgs.coreutils}/bin/cp -vP /etc/localtime ${utils.escapeSystemdExecArg "${name}/etc/localtime"}";
          };
        };
        "etc-localtime@${utils.escapeSystemdPath name}" = {
          serviceConfig = {
            Type = "oneshot";
            ExecStart = "${pkgs.coreutils}/bin/cp -vP /etc/localtime ${utils.escapeSystemdExecArg "${name}/etc/localtime"}";
          };
        };
      };
      paths."etc-localtime@${utils.escapeSystemdPath name}" = {
        wantedBy = [ "timezone@${utils.escapeSystemdPath name}.service" ];
        after = [ "timezone@${utils.escapeSystemdPath name}.service" ];

        pathConfig.PathChanged = "/etc/localtime";
      };
    }) config.environment.persistence);
  };
}