{ pkgs, lib, config, inputs, ... }:
let
  builder = {
    systems = [ "x86_64-linux" "i686-linux" ];
    speedFactor = 4;
    supportedFeatures = [ "benchmark" "nixos-test" ];
    sshKey = config.age.secrets.nixBuilderKey.path;
    protocol = "ssh-ng";
  };
  bigBuilder = builder // {
    speedFactor = 16;
    supportedFeatures = builder.supportedFeatures ++ [ "kvm" "big-parallel" ];
  };
in {
  age.secrets.nixBuilderKey = {
    file = ../../secrets/builder_key.age;
    mode = "0400";
  };
  nixpkgs.overlays = [
    (self: super: {
      nixSuper = inputs.nix-super.packages.x86_64-linux.default;
    })
  ];
  nix = {
    package = pkgs.nixSuper;

    settings = {
      trusted-users = [ "root" "@wheel" ];
      auto-optimise-store = true;

      substituters = [
        "https://cache.privatevoid.net"
        "https://reflex.privatevoid.net?priority=20"
      ];

      trusted-public-keys = [
        "cache.privatevoid.net:SErQ8bvNWANeAvtsOESUwVYr2VJynfuc9JRwlzTTkVg="
      ];

    };

    extraOptions = ''
      experimental-features = nix-command flakes repl-flake
      warn-dirty = false
      builders-use-substitutes = true
      flake-registry = https://git.privatevoid.net/private-void/registry/-/raw/master/registry.json
      max-free = ${toString (8 * 1024*1024*1024)}
      min-free = ${toString (4 * 1024*1024*1024)}
    '';

    gc = {
      automatic = true;
      dates = "weekly";
      options = "--delete-older-than 5d --max-freed 16G";
    };

    distributedBuilds = true;

    buildMachines = [
      (builder // {
        sshUser = "nix";
        hostName = "prophet.node.privatevoid.net";
        systems = [ "aarch64-linux" ];
      })
    ] ++
    (lib.optional (config.networking.hostName != "TITAN") (bigBuilder // {
        sshUser = "nix";
        hostName = "titan.hyprspace";
        speedFactor = 12;
        maxJobs = 12;
    }));
  };

  environment.systemPackages = [ pkgs.cachix ];
}