{ config, pkgs, ... }:

let
  pkgsUnstable = import (fetchTarball
    "https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz")
    { };
  localConfiguration = pkgs.callPackage /etc/nixos/local-configuration.nix { };
in {
  imports = [ # Include the results of the hardware scan.
    /etc/nixos/hardware-configuration.nix
  ];

  # Use the systemd-boot EFI boot loader.
  boot = {
    loader = {
      systemd-boot.enable = true;
      efi.canTouchEfiVariables = true;
    };
    initrd = {
      luks.devices = [{
        name = "root";
        device = localConfiguration.luksDevice;
        preLVM = true;
      }];
    };
  };

  hardware = {
    bluetooth.enable = true;
    pulseaudio = {
      package = pkgs.pulseaudioFull;
      enable = true;
    };
  };

  networking.hostName = localConfiguration.hostName;
  networking.networkmanager.enable = true;

  # Auto-upgrade channel
  # https://nixos.org/nixos/manual/index.html#idm140737316795120
  system.autoUpgrade.enable = true;

  nix.gc = {
    automatic = false;
    dates = "03:15"; # change to hour?
  };

  # Select internationalisation properties.
  i18n = {
    consoleFont = "Lat2-Terminus16";
    consoleKeyMap = "br-abnt2";
    defaultLocale = "en_US.UTF-8";
  };

  # Set your time zone.
  time.timeZone = "America/Sao_Paulo";

  virtualisation.docker.enable = true;
  virtualisation.virtualbox.host.enable = true;

  fonts.fonts = with pkgs; [
    source-code-pro
    fira-code
    fira-mono
    fira-code-symbols
    freefont_ttf
  ];

  environment.systemPackages = let
    timidityWithEvenMoreFormats = pkgs.timidity.overrideAttrs (oldAttrs: {
      configureFlags = oldAttrs.configureFlags
        ++ [ "--enable-audio=vorbis,flac" ];
      buildInputs = oldAttrs.buildInputs
        ++ [ pkgs.libogg pkgs.libvorbis pkgs.flac ];
    });

    # See https://github.com/NixOS/nixpkgs/issues/53938#issuecomment-454158967
    untested-quodlibet-full = pkgs.quodlibet-full.overrideAttrs (oldAttrs: {
      doInstallCheck = false;
      doCheck = false;
    });

    # Should be removed during fresh OS installation:
    # https://github.com/NixOS/nix/issues/2497
    nixfmt = import
      (fetchTarball "https://github.com/serokell/nixfmt/archive/master.tar.gz")
      { };

    # https://github.com/nixos/nixpkgs/blob/0d202221f98e500f1df79112dc464d013eefcdae/pkgs/development/web/nodejs/v10.nix#L4
  in with pkgs;
  [
    nixfmt

    ## Personal data tools

    gitAndTools.git-open
    gitAndTools.gitFull
    gitAndTools.diff-so-fancy
    gitAndTools.git-annex
    gitAndTools.gitRemoteGcrypt
    gitAndTools.git-dit
    gitAndTools.git-secrets
    git-crypt
    git-lfs
    pkgsUnstable.gnupg
    mr
    pkgsUnstable.nextcloud-client
    borgbackup
    git-sizer

    ## CLI tools

    bash
    bash-completion
    nix-bash-completions
    youtube-dl
    wget
    vim
    thefuck
    tmux
    tmuxinator
    sox # =play=
    gettext # =envsubst=
    ag
    gnugrep
    ack
    htop
    rlwrap
    awscli
    jq
    openvpn
    xclip
    bc # binary calculator used in nucli
    sassc
    watchman
    ipfs
    gnumake
    gcc
    psmisc # =killall=
    xorg.xkill
    bfg-repo-cleaner
    pwgen
    gksu # =gksudo=
    gnome2.GConf # https://github.com/NixOS/nixpkgs/issues/15978
    lsof
    pciutils
    python27Packages.pywatchman # =watchman-wait=
    libressl
    tree
    i2p
    libxml2 # =xmllint=
    unzip # used by extract bash function and Clojure go-to-source
    odt2txt # used to diff odf files
    feh # simplistic image viewer
    nixUnstable # =nix=
    zip
    zlib
    redis
    alsaUtils # for xmonad volume commands
    multimarkdown # =markdown=
    pup # command-line HTML parsing https://github.com/ericchiang/pup
    binutils-unwrapped # =ar= command for cargo build
    nssTools # =pk12util=
    gitAndTools.hub # GitHub helper
    insomnia
    bind # =dig=
    file
    gitlab-runner
    sshpass
    zathura # for viewing Emacs PDF files
    nvi
    cacert
    gtypist
    pandoc
    inotify-tools
    fzf
    ncdu
    fd
    nnn
    python36Packages.python-slugify
    moreutils # =vipe=
    bazel
    graphviz # =dot= and others
    graph-easy # ASCII drawings for GraphViz output
    mkpasswd
    direnv
    recutils
    sqlite
    sqlitebrowser
    trash-cli
    qrencode

    diffoscope
    poppler_utils # used by diffoscope for comparing PDF files
    pdftk

    gnome3.libgnome-keyring
    gnome3.gnome-keyring

    ## Mail

    pkgsUnstable.notmuch
    isync
    procmail # includes =formail=

    ## Spell checking

    (aspellWithDicts (ps: with ps; [ en eo fr pt_BR ]))
    languagetool

    ## NixOS

    pypi2nix
    bundix

    ## Music

    texlive.combined.scheme-full
    lilypond
    python36Packages.python-ly
    lame
    frescobaldi
    timidityWithEvenMoreFormats
    untested-quodlibet-full

    ## Programming tools

    sbcl
    stack
    leiningen
    python3
    python
    yarn
    elixir
    openjdk
    solc
    bundler
    rustup
    cargo
    clojure # =clj=
    visualvm # JVM profiling tool
    ant
    maven
    go_bootstrap
    bats
    ledger
    newsboat
    perl
    dhall
    dhall-json
    nodePackages.node2nix
    shellcheck
    # (haskell.lib.justStaticExecutables haskellPackages.github-backup)
    rustracer
    xsel
    nodejs-10_x
    swift
    gocode

    ## Containers and VMs

    packer
    docker_compose
    docker-machine
    vagrant
    kubernetes
    ansible
    qemu
    gnome3.gtk-vnc
    nixops
    terraform-full

    ## xmonad

    xorg.xmodmap
    xorg.xmessage
    trayer
    dmenu
    escrotum
    xorg.xbacklight
    networkmanagerapplet
    playerctl
    lightdm
    fvwm # =xpmroot=
    haskellPackages.xmobar
    haskellPackages.yeganesh
    arandr

    ## GUI programs

    inkscape
    calibre
    pkgsUnstable.cozy
    gpodder
    firefox
    emacs
    tdesktop
    vlc
    pkgsUnstable.keepassxc
    yubioath-desktop
    # tor-browser-bundle-bin
    libreoffice
    android-studio
    # androidsdk_extras
    # androidndk
    patchwork-classic
    # gnome3.gpaste

    ## Cryptocururencies

    electrum
    zbar # for on-screen QR Code scanning
    monero

  ] ++ localConfiguration.packages;

  nixpkgs.config = {
    android_sdk.accept_license = true;
    allowUnfree = localConfiguration.allowUnfree;
  };

  # Look at
  # https://www.vivaolinux.com.br/topico/Off-Code-Cafe/Me-apresente-sua-distro

  programs = {
    bash.enableCompletion = true;
    autojump.enable = true;
  };

  services = {
    cron.enable = true;
    # We can see the actual generated crontab at /etc/crontab
    cron.systemCronJobs = localConfiguration.cronJobs;

    xserver = {
      enable = true;
      layout = "br";
      xkbOptions = "caps:swapescape";

      config = ''
        Section "Device"
          Identifier  "Intel Graphics"
          Driver      "intel01"
          Option      "Backlight"  "intel_backlight"
        EndSection
      '';

      windowManager.default = "xmonad";
      windowManager.xmonad = {
        enable = true;
        enableContribAndExtras = true;
      };
      desktopManager = {
        default = "none";
        xterm.enable = false;
        gnome3.enable = true;
      };
      displayManager = {
        lightdm.enable = true;

        # The config inception was inspired by:
        # http://ubuntuforum-br.org/index.php?topic=13784.0
        # Lambda symbol name taken from:
        # http://wiki.linuxquestions.org/wiki/List_of_Keysyms_Recognised_by_Xmodmap
        # To test a keycode:
        # xmodmap -e 'keycode 118 = bar Greek_lamda'
        sessionCommands = ''
          ${pkgs.fvwm}/bin/xpmroot ~/Nextcloud/Images/emotion.png &
        '';
      };
    };

    gnome3 = {
      gnome-keyring.enable = true;
      seahorse.enable = true;
      gnome-terminal-server.enable = true;
      # gpaste.enable = true;                # clipboard manager
      tracker.enable = true;
      sushi.enable = true; # nautilus previewer
      gnome-online-accounts.enable = true;
      gnome-documents.enable = true;
      evolution-data-server.enable = true;
      gvfs.enable = true;
    };

    pcscd.enable = true; # required by yubioath

    # https://nixos.org/nixos/options.html#ipfs
    ipfs = {
      enable = localConfiguration.enableIPFS;
      enableGC = localConfiguration.enableIPFS;
      autoMount = localConfiguration.enableIPFS;
    };
  };

  security = {
    pam.services.lightdm.enableGnomeKeyring = true;
    sudo.enable = true;
    hideProcessInformation = false;
  };

  users = {
    mutableUsers = false;

    extraUsers = let
      andrehUser = {
        andreh = {
          isNormalUser = true;
          uid = 1000;
          description = "EuAndreh";
          extraGroups = [ "wheel" "networkmanager" "docker" ];
          # Generated with:
          # mkpasswd -m sha-512
          hashedPassword = localConfiguration.hashedPassword;
        };
      };
      # From the Guix manual:
      # https://www.gnu.org/software/guix/manual/en/html_node/Build-Environment-Setup.html#Build-Environment-Setup
      buildUser = (i: {
        "guixbuilder${i}" = { # guixbuilder$i
          group = "guixbuild"; # -g guixbuild
          extraGroups = [ "guixbuild" ]; # -G guixbuild
          home = "/var/empty"; # -d /var/empty
          shell = pkgs.nologin; # -s `which nologin`
          description = "Guix build user ${i}"; # -c "Guix buid user $i"
          isSystemUser = true; # --system
        };
      });
      # merge all users
    in pkgs.lib.fold (str: acc: acc // buildUser str) andrehUser
    # for i in `seq -w 1 10`
    (map (pkgs.lib.fixedWidthNumber 2) (builtins.genList (n: n + 1) 10));

    extraGroups.guixbuild = { name = "guixbuild"; };
  };

  systemd = {
    services = {
      # Derived from Guix guix-daemon.service.in
      # https://git.savannah.gnu.org/cgit/guix.git/tree/etc/guix-daemon.service.in?id=00c86a888488b16ce30634d3a3a9d871ed6734a2
      guix-daemon = {
        enable = true;
        description = "Build daemon for GNU Guix";
        serviceConfig = {
          ExecStart =
            "/var/guix/profiles/per-user/root/current-guix/bin/guix-daemon --build-users-group=guixbuild";
          Environment = "GUIX_LOCPATH=/root/.guix-profile/lib/locale";
          RemainAfterExit = "yes";
          StandardOutput = "syslog";
          StandardError = "syslog";
          TaskMax = "8192";
        };
        wantedBy = [ "multi-user.target" ];
      };
    };
  };

  # 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.
  system.stateVersion = "19.03"; # Did you read the comment?
}