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

# ==============================================================================
# CUSTOM NETBOOT CONFIGURATION EXAMPLE
# ==============================================================================
# This example demonstrates how to create a custom netboot configuration with:
# - Custom kernel version and modules
# - Additional packages for specialized use cases
# - Hardware-specific drivers
# - Custom network configuration
# - Debugging tools
#
# Usage:
#   1. Copy this file to nix/images/netboot-custom.nix
#   2. Add to flake.nix:
#      nixosConfigurations.netboot-custom = nixpkgs.lib.nixosSystem {
#        system = "x86_64-linux";
#        modules = [ ./nix/images/netboot-custom.nix ];
#      };
#   3. Build: ./build-images.sh --profile custom
# ==============================================================================

{
  imports = [
    ../netboot-base.nix  # Adjust path as needed
    ../../modules        # PlasmaCloud service modules
  ];

  # ============================================================================
  # CUSTOM KERNEL CONFIGURATION
  # ============================================================================

  # Use specific kernel version instead of latest
  boot.kernelPackages = pkgs.linuxPackages_6_6;  # LTS kernel

  # Add custom kernel modules for specialized hardware
  boot.kernelModules = [
    # Infiniband/RDMA support
    "ib_core"
    "ib_uverbs"
    "mlx5_core"
    "mlx5_ib"

    # GPU support (for GPU compute nodes)
    "nvidia"
    "nvidia_uvm"

    # Custom storage controller
    "megaraid_sas"
    "mpt3sas"
  ];

  # Custom kernel parameters
  boot.kernelParams = [
    # Default console configuration
    "console=ttyS0,115200"
    "console=tty0"
    "loglevel=4"

    # Custom parameters
    "intel_iommu=on"           # Enable IOMMU for PCI passthrough
    "iommu=pt"                 # Passthrough mode
    "hugepagesz=2M"            # 2MB hugepages
    "hugepages=1024"           # Allocate 1024 hugepages (2GB)
    "isolcpus=2-7"             # CPU isolation for real-time workloads
  ];

  # Blacklist problematic modules
  boot.blacklistedKernelModules = [
    "nouveau"     # Disable nouveau if using proprietary NVIDIA
    "i915"        # Disable Intel GPU if not needed
  ];

  # ============================================================================
  # ADDITIONAL PACKAGES
  # ============================================================================

  environment.systemPackages = with pkgs; [
    # Networking diagnostics
    iperf3           # Network performance testing
    mtr              # Network diagnostic tool
    nmap             # Network scanner
    wireshark-cli    # Packet analyzer

    # Storage tools
    nvme-cli         # NVMe management
    smartmontools    # SMART monitoring
    fio              # I/O performance testing
    sg3_utils        # SCSI utilities

    # Hardware diagnostics
    pciutils         # lspci
    usbutils         # lsusb
    dmidecode        # Hardware information
    lshw             # Hardware lister
    hwinfo           # Hardware info tool

    # Debugging tools
    strace           # System call tracer
    ltrace           # Library call tracer
    gdb              # GNU debugger
    valgrind         # Memory debugger

    # Performance tools
    perf             # Linux perf tool
    bpftrace         # eBPF tracing
    sysstat          # System statistics (sar, iostat)

    # Container/virtualization tools
    qemu_full        # Full QEMU with all features
    libvirt          # Virtualization management
    virt-manager     # VM management (CLI)
    docker           # Container runtime
    podman           # Alternative container runtime

    # Development tools (for on-site debugging)
    python3Full      # Python with all modules
    python3Packages.pip
    nodejs           # Node.js runtime
    git              # Version control
    gcc              # C compiler
    rustc            # Rust compiler
    cargo            # Rust package manager

    # Custom tools
    # Add your organization's custom packages here
  ];

  # ============================================================================
  # CUSTOM NETWORK CONFIGURATION
  # ============================================================================

  # Static IP instead of DHCP (example)
  networking.useDHCP = lib.mkForce false;

  networking.interfaces.eth0 = {
    useDHCP = false;
    ipv4.addresses = [{
      address = "10.0.1.100";
      prefixLength = 24;
    }];
  };

  networking.defaultGateway = "10.0.1.1";
  networking.nameservers = [ "10.0.1.1" "8.8.8.8" ];

  # Custom DNS domain
  networking.domain = "custom.example.com";

  # Enable jumbo frames
  networking.interfaces.eth0.mtu = 9000;

  # ============================================================================
  # CUSTOM SSH CONFIGURATION
  # ============================================================================

  # Multiple SSH keys for different operators
  users.users.root.openssh.authorizedKeys.keys = [
    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOperator1Key operator1@example.com"
    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOperator2Key operator2@example.com"
    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOperator3Key operator3@example.com"
  ];

  # Custom SSH port (for security through obscurity - not recommended for production)
  # services.openssh.ports = [ 2222 ];

  # ============================================================================
  # CUSTOM SERVICES
  # ============================================================================

  # Enable only specific PlasmaCloud services
  services.plasmavmc = {
    enable = lib.mkDefault false;
    port = 8081;
  };

  services.novanet = {
    enable = lib.mkDefault false;
    port = 8082;
  };

  # ============================================================================
  # DEBUGGING AND LOGGING
  # ============================================================================

  # Enable verbose boot logging
  boot.kernelParams = lib.mkAfter [ "loglevel=7" "debug" ];

  # Enable systemd debug logging
  systemd.services."serial-getty@ttyS0".environment = {
    SYSTEMD_LOG_LEVEL = "debug";
  };

  # Enable additional logging
  services.journald.extraConfig = ''
    Storage=persistent
    MaxRetentionSec=7day
    SystemMaxUse=1G
  '';

  # ============================================================================
  # PERFORMANCE TUNING
  # ============================================================================

  # Custom sysctl settings for high-performance networking
  boot.kernel.sysctl = {
    # Network buffer sizes
    "net.core.rmem_max" = 268435456;      # 256 MB
    "net.core.wmem_max" = 268435456;      # 256 MB
    "net.core.rmem_default" = 67108864;   # 64 MB
    "net.core.wmem_default" = 67108864;   # 64 MB

    # TCP tuning
    "net.ipv4.tcp_rmem" = "4096 87380 134217728";
    "net.ipv4.tcp_wmem" = "4096 65536 134217728";
    "net.ipv4.tcp_congestion_control" = "bbr";

    # Connection tracking
    "net.netfilter.nf_conntrack_max" = 1048576;

    # File descriptor limits
    "fs.file-max" = 2097152;

    # Virtual memory
    "vm.swappiness" = 1;
    "vm.vfs_cache_pressure" = 50;
    "vm.dirty_ratio" = 10;
    "vm.dirty_background_ratio" = 5;

    # Kernel
    "kernel.pid_max" = 4194304;
  };

  # Increase systemd limits
  systemd.extraConfig = ''
    DefaultLimitNOFILE=1048576
    DefaultLimitNPROC=1048576
  '';

  # ============================================================================
  # HARDWARE-SPECIFIC CONFIGURATION
  # ============================================================================

  # Enable CPU microcode updates
  hardware.cpu.intel.updateMicrocode = true;
  hardware.cpu.amd.updateMicrocode = true;

  # Enable firmware updates
  hardware.enableRedistributableFirmware = true;

  # GPU support (example for NVIDIA)
  # Uncomment if using NVIDIA GPUs
  # hardware.nvidia.modesetting.enable = true;
  # services.xserver.videoDrivers = [ "nvidia" ];

  # ============================================================================
  # CUSTOM INITIALIZATION
  # ============================================================================

  # Run custom script on boot
  systemd.services.custom-init = {
    description = "Custom initialization script";
    wantedBy = [ "multi-user.target" ];
    after = [ "network-online.target" ];
    wants = [ "network-online.target" ];

    serviceConfig = {
      Type = "oneshot";
      RemainAfterExit = true;
    };

    script = ''
      echo "Running custom initialization..."

      # Example: Configure network interfaces
      ${pkgs.iproute2}/bin/ip link set dev eth1 up

      # Example: Load custom kernel modules
      ${pkgs.kmod}/bin/modprobe custom_driver || true

      # Example: Call home to provisioning server
      ${pkgs.curl}/bin/curl -X POST http://provisioning.example.com/api/register \
        -d "hostname=$(hostname)" \
        -d "ip=$(${pkgs.iproute2}/bin/ip -4 addr show eth0 | grep -oP '(?<=inet\s)\d+(\.\d+){3}')" \
        || true

      echo "Custom initialization complete"
    '';
  };

  # ============================================================================
  # FIREWALL CONFIGURATION
  # ============================================================================

  # Custom firewall rules (disabled by default in netboot, but example provided)
  networking.firewall = {
    enable = lib.mkDefault false;  # Disabled during provisioning

    # When enabled, allow these ports
    allowedTCPPorts = [
      22    # SSH
      8081  # PlasmaVMC
      8082  # NovaNET
    ];

    # Custom iptables rules
    extraCommands = ''
      # Allow ICMP
      iptables -A INPUT -p icmp -j ACCEPT

      # Rate limit SSH connections
      iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --set
      iptables -A INPUT -p tcp --dport 22 -m state --state NEW -m recent --update --seconds 60 --hitcount 4 -j DROP
    '';
  };

  # ============================================================================
  # NIX CONFIGURATION
  # ============================================================================

  # Custom binary caches
  nix.settings = {
    substituters = [
      "https://cache.nixos.org"
      "https://custom-cache.example.com"  # Your organization's cache
    ];

    trusted-public-keys = [
      "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
      "custom-cache.example.com:YourPublicKeyHere"
    ];

    # Build settings
    max-jobs = "auto";
    cores = 0;  # Use all available cores

    # Experimental features
    experimental-features = [ "nix-command" "flakes" "repl-flake" ];
  };

  # ============================================================================
  # TIMEZONE AND LOCALE
  # ============================================================================

  # Custom timezone (instead of UTC)
  time.timeZone = lib.mkForce "America/New_York";

  # Additional locale support
  i18n.supportedLocales = [
    "en_US.UTF-8/UTF-8"
    "ja_JP.UTF-8/UTF-8"  # Japanese support
  ];

  i18n.defaultLocale = "en_US.UTF-8";

  # ============================================================================
  # SYSTEM STATE VERSION
  # ============================================================================

  system.stateVersion = "24.11";
}