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

{
  options.homelab.dockerNetworks = lib.mkOption {
    description = "Declarative Docker networks to create before containers start.";
    default = {};
    type = lib.types.attrsOf (lib.types.submodule {
      options = {
        requiredBy = lib.mkOption {
          type = lib.types.listOf lib.types.str;
          default = [];
          description = "List of systemd services that require this network (e.g., docker-containerName.service).";
        };
      };
    });
  };

  config = {
    systemd.services = lib.mapAttrs' (networkName: cfg:
      lib.nameValuePair "docker-${networkName}-create-network" {
        description = "Create Docker network for ${networkName}";
        requiredBy = cfg.requiredBy;
        after = [ "network.target" "docker.service" ];
        requires = [ "docker.service" ];
        wantedBy = [ "multi-user.target" ];
        serviceConfig = {
          Type = "oneshot";
          RemainAfterExit = true;
          ExecStart = pkgs.writeShellScript "create-${networkName}-docker-network" ''
            if ! ${pkgs.docker}/bin/docker network ls | grep -q ${networkName}; then
              ${pkgs.docker}/bin/docker network create ${networkName}
            fi
          '';
        };
      }
    ) config.homelab.dockerNetworks;
  };
}