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

let
  network = import ./network.nix;
  isVM = config.ptw.system.isVM;
  wireless = config.ptw.system.wireless;
  primaryInterface = lib.attrByPath [ "ptw" "system" "primaryInterface" ] "" config;
in {
  time.timeZone = "Europe/Berlin";
  ostylk.nftables = {
    enable = true;

    tables.firewall = {
      family = "inet";
      chains = {
        non-libvirt.extraConfig = let
          deviceIPString = lib.concatStringsSep "," (with network; [
            miku nishimiya tamaki mashu # ayame
          ]);
        in ''
            # Accept traffic from my devices
            ip saddr != { ${deviceIPString} } drop
          '';
        input.extraConfig = ''
            type filter hook input priority 0

            ct state { established, related } accept
            iif lo accept
            iif ${primaryInterface} goto non-libvirt
          '';
      };
    };
  };
  networking = {
    useDHCP = false; # Done by the network manager
    networkmanager.enable = true;

    #interfaces.*.useDHCP = false;
    
    hostName = config.ptw.system.hostName;
    hosts = lib.mkIf (!isVM) {
      "${network.miku}" = [ "miku.local" ];
      "${network.nishimiya}" = [ "nishimiya.local" ];
      #"${network.ayame}" = [ "ayame.local" ];
      "${network.tamaki}" = [ "tamaki.local" ];
      "${network.mashu}" = [ "mashu.local" ];
    };
  };

  i18n.defaultLocale = "en_GB.UTF-8";
  console = {
    font = "Lat2-Terminus16";
    keyMap = "de";
  };

  users = {
    mutableUsers = false;

    extraUsers = {
      root = {
	      # Disable root login
	      hashedPassword = "*";
      };
    };
  };

  documentation.nixos.enable = false;
  
  environment = {
    systemPackages = with pkgs; [
      htop
      vim
      git # Otherwise we cannot install home-manager
      git-crypt
      gnupg
      python3
      
      # RT scheduling
      rtkit
    ] ++ lib.optionals (!isVM) (with pkgs; [ gopass ]);

    sessionVariables = {
      # Prevent us from having to always type it out
      NIXOS_CONFIG = "/home/${config.ptw.system.singleUser}/Development/Personal/nixos-config/hosts/${config.networking.hostName}.nix";
    };
  };

  fonts.fonts = with pkgs; [
    # CJK fonts
    source-han-sans source-han-serif
    # Coding fonts
    source-code-pro
    # Icon fonts
    nerdfonts
  ];

  # We don't tolerate non-free software, except for Steam and Linux firmware
  nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
    "firmwareLinuxNonfree" "microcodeAmd" "microcodeIntel"
    "steam" "steam-original" "steam-runtime"
    "discord"
  ];

  services = {
    # TODO: Is this correct? Maybe run once
    timesyncd.enable = false;

    # Everyone needs sound
    pipewire = {
      enable = true;
      pulse.enable = true;
      jack.enable = true;
      alsa.enable = true;
      alsa.support32Bit = true;
    };

    # On desktop: Monitor keyboards, mice, ...
    # On portable devices: Monitor their battery
    upower.enable = true;

    # What generated entropy?
    haveged.enable = true;
    
    printing.enable = lib.mkDefault false;
    avahi.enable = false;

    # For debugging.
    # TODO: Lock to known IPs and keys
    sshd.enable = true;

    # Prevent unexpected OOM situations with heavy swapping
    earlyoom = {
      enable = true;
      enableNotifications = true;
    };
  };

  # Don't wait for a network connection
  systemd.services.NetworkManager-wait-online.enable = false;
  
  security.sudo.extraConfig = ''
      Defaults env_keep += "NIXOS_CONFIG"
    '';

  hardware = {
    enableRedistributableFirmware = true;
    # This is a Pipewire household!
    pulseaudio.enable = false;

    opengl = {
      enable = true;
      driSupport32Bit = true;
      driSupport = true;
      extraPackages = with pkgs; [ vaapiVdpau libvdpau-va-gl ];
    };

    # Only a subset of my devices have bluetooth
    bluetooth = lib.mkIf wireless {
      enable = true;
    };
  };

  nix = {
    package = pkgs.nixUnstable;
    extraOptions = ''
      experimental-features = nix-command flakes ca-references
    '';
    registry = {
      nixpkgs.flake = inputs.nixpkgs;
    };
  };
  
  boot = {
    loader =  {
      systemd-boot.enable = true;
      efi.canTouchEfiVariables = true;
    };
  };

  system.stateVersion = "21.05";
}