dotfiles/modules/nixos/hardware/monitors.nix

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

  config =
    lib.mkIf (config.gui.enable && config.physical && pkgs.stdenv.isLinux) {

      environment.systemPackages = with pkgs;
        [
          ddcutil # Monitor brightness control
        ];

      # Reduce blue light at night
      services.redshift = {
        enable = true;
        brightness = {
          day = "1.0";
          night = "1.0";
        };
      };

      # Detect monitors (brightness) for ddcutil
      hardware.i2c.enable = true;

      # Grant main user access to external monitors
      users.users.${config.user}.extraGroups = [ "i2c" ];

      services.xserver.displayManager = {

        # Put the login screen on the left monitor
        lightdm.greeters.gtk.extraConfig = ''
          active-monitor=0
        '';

        # Set up screen position and rotation
        setupCommands = ''
          ${pkgs.xorg.xrandr}/bin/xrandr --output DisplayPort-1 \
                                              --mode 1920x1200 \
                                              --pos 1920x0 \
                                              --rotate left \
                                          --output HDMI-A-0 \
                                              --primary \
                                              --mode 1920x1080 \
                                              --pos 0x560 \
                                              --rotate normal \
                                          --output DVI-0 --off \
                                          --output DVI-1 --off \
        '';
      };

    };

}