{
  config,
  lib,
  ...
}:
with lib; let
  cfg = config.flock.docker;
in {
  options = {
    flock.docker = {
      enable = mkEnableOption "Enable Docker";
      dockerMount = mkEnableOption "Mount disk as Docker directory";
    };
  };

  config =
    mkIf cfg.enable
    {
      # Add user to docker group.
      users.users.fern = {
        extraGroups = ["docker"];
      };

      # Enable docker.
      virtualisation.docker = {
        enable = true;
        autoPrune.enable = true;
        liveRestore = true;
        daemon.settings = {
          data-root = "/home/fern/docker/daemon";
          default-address-pools = [
            {
              base = "172.20.0.0/12";
              size = 24;
            }
          ];
        };
      };

      # Docker data directory
      fileSystems."/home/fern/docker" = mkIf (cfg.dockerMount) {
        device = "/dev/disk/by-label/docker";
        fsType = "ext4";
      };
    };
}