{ config, pkgs, name, lib, pkgs-no-overlay, secrets, ... }:
{
  # ssh-keyscan dilion | nix-shell -p ssh-to-age --run ssh-to-age
  secrets.ageKeys = [ "age1x49n6qa0arkdpq8530s7umgm0gqkq90exv4jep97q30rfnzknpaqate06a" ];
  boot = {
    loader = {
      grub = {
        devices = [ "/dev/sda" "/dev/sdb" "/dev/sdc" "/dev/sdd" ];
      };
      timeout = 1;
    };
    blacklistedKernelModules = [ "nvidiafb" ];
    supportedFilesystems = [ "zfs" ];
    kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;
    kernelModules = [ "kvm-intel" ];
    initrd.availableKernelModules = [ "ahci" "sd_mod" ];
    initrd.secrets = {
      "/boot/pass.key" = "/boot/pass.key";
    };
    kernel.sysctl."vm.nr_hugepages" = 256; # for xmr-stak
    # available in nixos-20.09
    #zfs.requestEncryptionCredentials = [ "zpool/root" ];
  };
  powerManagement.cpuFreqGovernor = "powersave";
  hardware.enableRedistributableFirmware = true;

  swapDevices = [ { label = "swap"; } ];
  fileSystems = {
    "/"           = { fsType = "zfs"; device = "zpool/root"; };
    "/boot"       = { fsType = "ext4"; device = "/dev/disk/by-uuid/fd1c511e-2bc0-49d5-b8bb-95e7e8c8c816"; };
    "/etc"        = { fsType = "zfs"; device = "zpool/root/etc"; };
    "/home"       = { fsType = "zfs"; device = "zpool/root/home"; };
    "/tmp"        = { fsType = "zfs"; device = "zpool/root/tmp"; };
    "/var"        = { fsType = "zfs"; device = "zpool/root/var"; };
    "/data"       = { fsType = "ext4"; label = "data"; };
    "/nix"        = { fsType = "ext4"; label = "nix"; };
  };

  services.udev.extraRules = ''
    ACTION=="add", SUBSYSTEM=="net", ATTR{address}=="10:bf:48:7f:e6:3b", NAME="eth0"
  '';

  nixpkgs.config.permittedInsecurePackages = [
    "python-2.7.18.6" # for nagios-cli
  ];

  networking = {
    hostId = "27c3048d"; # generated with head -c4 /dev/urandom | od -A none -t x4
    firewall.enable = false;
    interfaces."eth0".ipv4.addresses =
      [ { address = lib.head config.hostEnv.ips.main.ip4; prefixLength = 27; } ]
      ++ pkgs.lib.flatten (pkgs.lib.attrsets.mapAttrsToList
        (n: ips: map (ip: { address = ip; prefixLength = 32; }) (ips.ip4 or []))
        (pkgs.lib.attrsets.filterAttrs (n: v: n != "main") config.hostEnv.ips));
    interfaces."eth0".ipv6.addresses =
      [ { address = "2a01:4f8:141:53e7::"; prefixLength = 64; } ]
      ++ pkgs.lib.flatten (pkgs.lib.attrsets.mapAttrsToList
        (n: ips: map (ip: { address = ip; prefixLength = (if n == "main" && ip == pkgs.lib.head ips.ip6 then 64 else 128); }) (ips.ip6 or []))
        config.hostEnv.ips);
    defaultGateway = { address = "176.9.10.225"; interface = "eth0"; };
    defaultGateway6 = { address = "fe80::1"; interface = "eth0"; };
    nameservers = [
      "213.133.98.98"
      "213.133.99.99"
      "213.133.100.100"
      "2a01:4f8:0:a0a1::add:1010"
      "2a01:4f8:0:a102::add:9999"
      "2a01:4f8:0:a111::add:9898"
    ];
  };

  imports = [
    secrets.nixosModules.users-config-dilion
    ./monitoring.nix
    ./vms.nix
  ];

  myServices.vms.libvirt-guests = {
    buildbot = {
      pool = "zfspool";
      network = "immae";
      cpus = 1;
      memory = 3;
      diskSize = 10;
      destroyVolumeOnExit = true;
    };
  };
  myServices.vms.libvirt-images = {
    nixos = ./vms/base_configuration.nix;
    buildbot = ./vms/buildbot_configuration.nix;
  };
  myServices.vms.libvirt-networks.immae = {
    bridgeNumber = 1;
    ipRange = "192.168.100";
  };
  myServices.vms.libvirt-pools = {
    niximages = {
      type = "dir";
      target = "/etc/libvirtd/base-images";
    };
    buildbot-disks = rec {
      type = "dir";
      target = "/var/lib/libvirt/images/buildbot-disks";
      preStart = ''
        mkdir -p ${target}
      '';
    };
    zfspool = {
      # pool-define-as --name zfspool --source-name zpool/libvirt --type zfs
      type = "zfs";
      xml = ''
        <source>
          <name>zpool/libvirt</name>
        </source>
      '';
    };
  };

  system.nssModules = [ pkgs.libvirt ];
  system.nssDatabases.hosts = lib.mkForce [ "files" "libvirt_guest" "mymachines" "dns" "myhostname" ];
  programs.zsh.enable = true;

  users.users.libvirt = {
    hashedPassword = "!";
    shell = pkgs.bashInteractive;
    isSystemUser = true;
    group = "libvirtd";
    packages = [ pkgs.libressl.nc ];
    openssh.authorizedKeys.keys = [
      config.myEnv.buildbot.ssh_key.public
      config.myEnv.sshd.rootKeys.ismael_flony
    ];
  };

  users.groups.backup = {};
  users.users.backup = {
    hashedPassword = "!";
    isSystemUser = true;
    extraGroups = [ "keys" ];
    group = "backup";
    shell = pkgs.bashInteractive;
    openssh.authorizedKeys.keys = let
      zreplConfig = "/etc/zrepl/zrepl.yml";
    in
      ["command=\"${pkgs.zrepl}/bin/zrepl stdinserver --config ${zreplConfig} eldiron\",restrict ${config.myEnv.zrepl_backup.ssh_key.public}"];
  };

  virtualisation.docker.enable = true;
  virtualisation.docker.storageDriver = "zfs";
  virtualisation.libvirtd.enable = true;
  virtualisation.libvirtd.qemu.package = pkgs-no-overlay.qemu;
  systemd.services.libvirtd.path = lib.mkAfter [ config.boot.zfs.package ];
  systemd.services.libvirtd.postStart = ''
    install -m 0770 -g libvirtd -d /var/lib/libvirt/images
  '';

  time.timeZone = "Europe/Paris";
  nix = {
    settings = {
      sandbox = "relaxed";
      max-jobs = 8;
      substituters = [ "https://hydra.iohk.io" "https://cache.nixos.org" ];
      trusted-public-keys = [ "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=" ];
      trusted-users = [ "root" "@wheel"] ;
    };
    extraOptions = ''
      keep-outputs = true
      keep-derivations = true
      allow-unsafe-native-code-during-evaluation = true
      experimental-features = nix-command flakes
      #Assumed in NUR
      allow-import-from-derivation = true
    '';
  };

  security.pki.certificateFiles = [
    (pkgs.fetchurl {
      url = "http://downloads.e.eriomem.net/eriomemca.pem";
      sha256 = "1ixx4c6j3m26j8dp9a3dkvxc80v1nr5aqgmawwgs06bskasqkvvh";
    })
  ];

  myServices.monitoring.enable = true;
  security.acme.certs."${name}-immae" = {
    group = "immae";
    domain = "dilion.immae.eu";
  };
  security.acme.certs."${name}" = {
    group = config.services.nginx.group;
    extraDomainNames = [
      "dilion.immae.dev"
    ];
  };
  systemd.services.nginx.serviceConfig.ProtectHome = "read-only";
  services.nginx = {
    enable = true;
    recommendedOptimisation = true;
    recommendedGzipSettings = true;
    recommendedProxySettings = true;
    virtualHosts = {
      "dilion.immae.dev" = {
        acmeRoot = config.security.acme.defaults.webroot;
        useACMEHost = name;
        forceSSL = true;
        locations."/".root = "/home/immae/www";
      };
    };
  };

  secrets.keys = {
    "zrepl/${name}.key" = {
      permissions = "0400";
      text = config.myEnv.zrepl_backup.certs."${name}".key;
      user = "backup";
      group = "root";
    };
  } // builtins.listToAttrs (map (x: lib.attrsets.nameValuePair "zrepl/certificates/${x}.crt" {
    permissions = "0400";
    text = config.myEnv.zrepl_backup.certs."${x}".certificate;
    user = "backup";
    group = "root";
  }) (builtins.attrNames config.myEnv.zrepl_backup.certs));

  environment.etc."mdadm.conf" = {
    enable = true;
    mode = "0644";
    user = "root";
    text = "MAILADDR ${config.myEnv.monitoring.email}";
  };


  systemd.services.zrepl.serviceConfig.User = "backup";
  systemd.services.zrepl.path = [ pkgs.openssh ];
  # pour eldiron:
  # zfs allow backup create,mount,receive,destroy,rename,snapshot,hold,bookmark,release zpool/backup
  # pour flony:
  # zfs allow backup hold,release,bookmark,snapshot,send zpool
  services.zrepl = {
    enable = true;
    settings = {
      global.control.sockpath = "/run/zrepl/control";
      global.serve.stdinserver.sockdir = "/run/zrepl/stdinserver";
      jobs = [
        {
          type = "sink";
          # must not change
          name = "backup-from-eldiron";
          root_fs = "zpool/backup";
          serve.type = "tls";
          serve.listen = ":19000";
          serve.ca = config.secrets.fullPaths."zrepl/certificates/eldiron.crt";
          serve.cert = config.secrets.fullPaths."zrepl/certificates/dilion.crt";
          serve.key = config.secrets.fullPaths."zrepl/dilion.key";
          serve.client_cns = [ "eldiron" ];
        }
        {
          type = "source";
          # must not change
          name = "backup-to-wd-zpool";
          # not encrypted!
          serve.type = "tls";
          serve.listen = ":19001";
          serve.ca = config.secrets.fullPaths."zrepl/certificates/flony.crt";
          serve.cert = config.secrets.fullPaths."zrepl/certificates/dilion.crt";
          serve.key = config.secrets.fullPaths."zrepl/dilion.key";
          serve.client_cns = [ "flony" ];
          filesystems."zpool/libvirt<" = true;
          filesystems."zpool/root<" = true;
          snapshotting.type = "manual";
        }
        {
          type = "source";
          # must not change
          name = "backup-to-wd-zpool-docker";
          # not encrypted!
          serve.type = "tls";
          serve.listen = ":19002";
          serve.ca = config.secrets.fullPaths."zrepl/certificates/flony.crt";
          serve.cert = config.secrets.fullPaths."zrepl/certificates/dilion.crt";
          serve.key = config.secrets.fullPaths."zrepl/dilion.key";
          serve.client_cns = [ "flony" ];
          filesystems."zpool/docker<" = true;
          snapshotting.type = "manual";
        }
      ];
    };
  };
  # This value determines the NixOS release with which your system is
  # to be compatible, in order to avoid breaking some software such as
  # database servers. You should change this only after NixOS release
  # notes say you should.
  # https://nixos.org/nixos/manual/release-notes.html
  system.stateVersion = "23.05"; # Did you read the comment?
}