{ hostName, flake, config, pkgs, lib, ... }:
{
  imports = with flake.nixosModules.systemProfiles; [
    ./zfs.nix ./dsl.nix
    initrd-all-crypto-modules default-locale openssh rebuild-machines
    build-server
    initrd-ssh
  ];

  config = {
    nixpkgs = {
      system = "x86_64-linux";
    };

    networking.hostId = "1e7ddd78";
    environment.etc."machine-id".text = "1e7ddd784c525bba2a03d7c160c5da4e";

    boot = {
      loader.grub = {
        enable = true;
        version = 2;
        device = "/dev/disk/by-id/ata-SuperMicro_SSD_SMC0515D95019BDF4083";
      };

      kernelPackages = pkgs.linuxPackages_latest;
      kernelModules = [ "kvm-intel" ];

      kernelParams = [
        "ip=10.141.0.1:::255.255.255.0::eno1:static"
      ];

      tmpOnTmpfs = true;

      initrd = {
        supportedFilesystems = [ "zfs" ];
        availableKernelModules = [ "ehci_pci" "ahci" "nvme" "isci" "xhci_pci" "usb_storage" "usbhid" "sd_mod" "sr_mod" "drbg" "rtsx_pci_sdmmc" "libsas" "scsi_transport_sas" "e1000e" ];
        kernelModules = [ "dm-raid" "dm-integrity" "dm-snapshot" "dm-thin-pool" ];

        luks.devices = {
          nvm0.device = "/dev/disk/by-label/${hostName}-nvm0";
          nvm1.device = "/dev/disk/by-label/${hostName}-nvm1";
          
          hdd0.device = "/dev/disk/by-label/${hostName}-hdd0";
          hdd1.device = "/dev/disk/by-label/${hostName}-hdd1";
          hdd2.device = "/dev/disk/by-label/${hostName}-hdd2";
          hdd3.device = "/dev/disk/by-label/${hostName}-hdd3";
          hdd4.device = "/dev/disk/by-label/${hostName}-hdd4";
          hdd5.device = "/dev/disk/by-label/${hostName}-hdd5";
        };

        network.flushBeforeStage2 = false;
      };
      
      supportedFilesystems = [ "zfs" ];
      zfs = {
        enableUnstable = true;
      };
    };

    fileSystems = {
      "/" = {
        fsType = "tmpfs";
        options = [ "mode=0755" ];
      };
    };

    networking = {
      hostName = "vidhar";
      domain = "yggdrasil";
      search = [ "yggdrasil" ];

      useDHCP = false;
      useNetworkd = true;

      interfaces."eno1" = {
        ipv4.addresses = [
          { address = "10.141.0.1"; prefixLength = 24; }
        ];
      };

      firewall.enable = false;
      nftables = {
        enable = true;
        rulesetFile = ./ruleset.nft;
      };
    };

    services.resolved = {
      llmnr = "false";
    };

    services.dhcpd4 = {
      enable = true;
      interfaces = [ "eno1" ];
      extraConfig = ''
        subnet 10.141.0.0 netmask 255.255.255.0 {
          range 10.141.0.128 10.141.0.254;
          option domain-name-servers 10.141.0.1;
          option broadcast-address 10.141.0.255;
          option routers 10.141.0.1;
          option domain-name "yggdrasil";
        }
      '';
      machines = [
        {
          ethernetAddress = "50:d4:f7:f3:0f:7e";
          hostName = "gauss-ap01";
          ipAddress = "10.141.0.64";
        }
        {
          ethernetAddress = "60:a4:b7:53:94:b5";
          hostName = "switch01";
          ipAddress = "10.141.0.65";
        }
      ];
    };
    services.corerad = {
      enable = true;
      settings = {
        interfaces = [
          { name = config.networking.pppInterface;
            monitor = true;
            verbose = true;
          }
          { name = "eno1";
            advertise = true;
            verbose = true;
            prefix = [{ prefix = "::/64"; }];
            route = [{ prefix = "::/0"; }];
            rdnss = [{ servers = ["::"]; }];
            dnssl = [{ domain_names = ["yggdrasil"]; }];
          }
        ];
      };
    };
    services.ndppd = {
      enable = true;
      proxies = {
        ${config.networking.pppInterface} = {
          router = true;
          rules.lan = {
            method = "iface";
            interface = "eno1";
            network = "::/0";
          };
        };
      };
    };
    boot.kernel.sysctl = {
      "net.ipv6.conf.all.forwarding" = true;
      "net.ipv6.conf.default.forwarding" = true;
      "net.ipv4.conf.all.forwarding" = true;
      "net.ipv4.conf.default.forwarding" = true;

      "net.core.rmem_max" = "4194304";
      "net.core.wmem_max" = "4194304";
    };
    systemd.network.networks = {
      "eno2" = {
        matchConfig.Name = "eno2";
        networkConfig.LinkLocalAddressing = "no";
      };
      "telekom" = {
        matchConfig.Name = "telekom";
        networkConfig.LinkLocalAddressing = "no";
      };
    };
    systemd.services."pppd-telekom" = {
      bindsTo = [ "sys-subsystem-net-devices-telekom.device" ];
      after = [ "sys-subsystem-net-devices-telekom.device" ];
    };
    systemd.services."dhcpcd-telekom" = {
      wantedBy = [ "multi-user.target" "network-online.target" ];
      bindsTo = [ "pppd-telekom.service" ];
      after = [ "pppd-telekom.service" ];
      wants = [ "network.target" ];
      before = [ "network-online.target" ];

      path = with pkgs; [ dhcpcd nettools openresolv ];
      unitConfig.ConditionCapability = "CAP_NET_ADMIN";

      stopIfChanged = false;

      serviceConfig = let
        dhcpcdConf = pkgs.writeText "dhcpcd.conf" ''
          duid
          vendorclassid
          ipv6only

          nooption domain_name_servers, domain_name, domain_search
          option classless_static_routes
          option interface_mtu

          option host_name
          option rapid_commit
          require dhcp_server_identifier
          slaac private

          noipv6rs                 # disable routing solicitation
          nohook resolv.conf
          allowinterfaces dsl
          interface dsl
            ipv6ra_autoconf
            iaid 1195061668
            ipv6rs                 # enable routing solicitation for WAN adapter
            ia_pd 1 eno1/0/64/0    # request a PD and assign it to the LAN

          waitip 6
        '';
      in {
        Type = "forking";
        PIDFile = "/run/dhcpcd/pid";
        RuntimeDirectory = "dhcpcd";
        ExecStart = "@${pkgs.dhcpcd}/sbin/dhcpcd dhcpcd -q --config ${dhcpcdConf}";
        ExecReload = "${pkgs.dhcpcd}/sbin/dhcpcd --rebind";
        Restart = "always";
      };
    };
    users.users.dhcpcd = {
      isSystemUser = true;
      group = "dhcpcd";
    };
    users.groups.dhcpcd = {};
    
    services.timesyncd.enable = false;
    services.chrony = {
      enable = true;
      servers = [];
      extraConfig = ''
        pool time.cloudflare.com iburst nts
        pool nts.ntp.se iburst nts
        server nts.sth1.ntp.se iburst nts
        server nts.sth2.ntp.se iburst nts
        server ptbtime1.ptb.de iburst nts
        server ptbtime2.ptb.de iburst nts
        server ptbtime3.ptb.de iburst nts

        leapsectz right/UTC

        makestep 0.1 3

        cmdport 0
      '';
    };

    services.openssh = {
      enable = true;
      passwordAuthentication = false;
      challengeResponseAuthentication = false;
      extraConfig = ''
        AllowGroups ssh
      '';
    };
    users.groups."ssh" = {
      members = ["root"];
    };

    security.sudo.extraConfig = ''
      Defaults lecture = never
    '';

    nix = {
      daemonCPUSchedPolicy = "batch";
      daemonIOSchedClass = "idle";

      gc = {
        automatic = true;
        options = "--delete-older-than 30d";
      };
    };

    powerManagement = {
      enable = true;

      cpuFreqGovernor = "schedutil";
    };

    services.unbound = {
      enable = true;
      resolveLocalQueries = false;
      stateDir = "/var/lib/unbound";
      localControlSocketPath = "/run/unbound/unbound.ctl";
      settings = {
        server = {
          interface = ["127.0.0.1" "10.141.0.1" "::0"];
          access-control = ["0.0.0.0/0 allow" "::/0 allow"];
          root-hints = "${pkgs.dns-root-data}/root.hints";

          num-threads = 12;
          so-reuseport = true;
          msg-cache-slabs = 16;
          rrset-cache-slabs = 16;
          infra-cache-slabs = 16;
          key-cache-slabs = 16;

          rrset-cache-size = "100m";
          msg-cache-size = "50m";
          outgoing-range = 8192;
          num-queries-per-thread = 4096;

          so-rcvbuf = "4m";
          so-sndbuf = "4m";

          serve-expired = true;
          serve-expired-ttl = 86400;
          serve-expired-reply-ttl = 0;

          prefetch = true;
          prefetch-key = true;

          minimal-responses = false;

          extended-statistics = true;

          rrset-roundrobin = true;
          use-caps-for-id = true;
        };
      };
    };
  };
}