{
  config,
  lib,
  pkgs,
  ...
}: let
  homelab = config.homelab or {};

  # Build a list of { name, unit } for all non-null motd entries
  motdServices = lib.pipe homelab [
    lib.attrNames
    (map (name: {
      inherit name;
      unit = homelab.${name}.motd or null;
    }))
    (lib.filter (s: s.unit != null))
  ];
in {
  options.homelab.motd = {
    enable = lib.mkEnableOption "enable custom homelab motd";
  };

  config = lib.mkIf config.homelab.motd.enable {
    # write into /etc/profile.d so shells source it at login
    environment.etc."profile.d/homelab-motd.sh".text = ''
      #!/usr/bin/env bash
      # Homelab MOTD — pretty status display
      # Generated by NixOS
      
      # ────────────────────────────────────────────────────────────────────────
      # Colors
      blue="\033[34m"
      red="\033[31m"
      cyan="\033[36m"
      magenta="\033[35m"
      bold="\033[1m"
      reset="\033[0m"
      
      # ────────────────────────────────────────────────────────────────────────
      # System info
      hostname=$(hostname)
      nixos_ver=$(nixos-version 2>/dev/null || echo "unknown")
      kernel_ver=$(uname -r)
      
      read iface ipv4 <<< "$(ip route get 1.1.1.1 2>/dev/null | awk '/dev/ {for (i=1;i<=NF;i++) if ($i=="dev") iface=$(i+1); if ($1=="src") ip=$2;} END {print iface, ip}')"
      
      # CPU usage (avg over 1s)
      read cpu_a idle_a < <(awk '/^cpu /{print $2+$4,$5}' /proc/stat)
      sleep 0.5
      read cpu_b idle_b < <(awk '/^cpu /{print $2+$4,$5}' /proc/stat)
      cpu_usage=$(( (100 * (cpu_b - cpu_a - (idle_b - idle_a))) / (cpu_b - cpu_a) ))
      
      # Memory usage
      read total used <<< "$(free -m | awk '/Mem:/ {print $2, $3}')"
      mem_pct=$((100 * used / total))
      
      # Uptime
      uptime_fmt=$(awk '{d=int($1/86400);h=int(($1%86400)/3600);m=int(($1%3600)/60);printf("%dd %dh %dm",d,h,m)}' /proc/uptime)
      
      # ────────────────────────────────────────────────────────────────────────
      # Display system info
      printf "\\n${bold}${cyan}System Info${reset}\\n"
      printf "  %-15s %s\\n" "Hostname:" "$hostname"
      printf "  %-15s %s\\n" "Interface:" "${iface:-N/A}"
      printf "  %-15s %s\\n" "IPv4 Address:" "${ipv4:-N/A}"
      printf "  %-15s %s\\n" "NixOS Version:" "$nixos_ver"
      printf "  %-15s %s\\n" "Kernel:" "$kernel_ver"
      
      printf "\\n${bold}${magenta}Performance${reset}\\n"
      printf "  %-15s %s%%\\n" "CPU Usage:" "$cpu_usage"
      printf "  %-15s %s%% of %s MB\\n" "Memory Usage:" "$mem_pct" "$total"
      printf "  %-15s %s\\n" "Uptime:" "$uptime_fmt"
      
      printf "\\n${bold}${blue}Service Status${reset}\\n"
      
      # ────────────────────────────────────────────────────────────────────────
      # Loop through Nix-provided list of services
      ${lib.concatStringsSep "\n" (map (s: ''
        status=$(systemctl is-active ${lib.escapeShellArg s.unit} 2>/dev/null)
        if [ "$status" = "active" ]; then
          printf "  ${blue}%-25s${reset} %s\\n" "${s.name}" "running"
        else
          printf "  ${red}%-25s${reset} %s\\n" "${s.name}" "FAILED ($status)"
        fi
      '') motdServices)}
      
      echo ""
    '';

    # make sure it is executable
    environment.etc."profile.d/homelab-motd.sh".mode = "0755";
  };
}