# This module contains the basic configuration for building a NixOS
# installation CD.

{ config, pkgs, ... }:

with pkgs.lib;

let

  options = {

    system.nixosVersion = mkOption {
      default = "${builtins.readFile ../../../VERSION}";
      description = ''
        NixOS version number.
      '';
    };

    installer.configModule = mkOption {
      example = "./nixos/modules/installer/cd-dvd/installation-cd.nix";
      description = ''
        Filename of the configuration module that builds the CD
        configuration.  Must be specified to support reconfiguration
        in live CDs.
      '';
    };
  };


  # We need a copy of the Nix expressions for Nixpkgs and NixOS on the
  # CD.  We put them in a tarball because accessing that many small
  # files from a slow device like a CD-ROM takes too long.  !!! Once
  # we use squashfs, maybe we won't need this anymore.
  makeTarball = tarName: input: pkgs.runCommand "tarball" {inherit tarName;}
    ''
      ensureDir $out
      (cd ${input} && tar cvfj $out/${tarName} . \
        --exclude '*~' --exclude 'result')
    '';

  # Put the current directory in a tarball.
  nixosTarball = makeTarball "nixos.tar.bz2" (cleanSource ../../..);

  # Put Nixpkgs in a tarball.
  nixpkgsTarball = makeTarball "nixpkgs.tar.bz2" (cleanSource pkgs.path);

  includeSources = true;


  # A dummy /etc/nixos/configuration.nix in the booted CD that
  # rebuilds the CD's configuration (and allows the configuration to
  # be modified, of course, providing a true live CD).  Problem is
  # that we don't really know how the CD was built - the Nix
  # expression language doesn't allow us to query the expression being
  # evaluated.  So we'll just hope for the best.
  dummyConfiguration = pkgs.writeText "configuration.nix"
    ''
      {config, pkgs, ...}:

      {
        require = [${config.installer.configModule}];

        # Add your own options below and run "nixos-rebuild switch".
        # E.g.,
        #   services.openssh.enable = true;
      }
    '';
  
  
in

{
  require =
    [ options
      ./memtest.nix
      ./iso-image.nix
      ../../hardware/network/intel-3945abg.nix
      ../../hardware/network/rt73.nix
      ../../profiles/base.nix
    ];

  # ISO naming.
  isoImage.isoName = "nixos-${config.system.nixosVersion}-${pkgs.stdenv.system}.iso";
    
  isoImage.volumeID = "NIXOS_INSTALL_CD_${config.system.nixosVersion}";
  
  # Show the manual.
  services.nixosManual.showManual = true;

  # Let the user play Rogue on TTY 8 during the installation.
  services.rogue.enable = true;

  # Disable some other stuff we don't need.
  security.sudo.enable = false;

  # Include only the en_US locale.  This saves 75 MiB or so compared to
  # the full glibcLocales package.
  i18n.supportedLocales = ["en_US.UTF-8/UTF-8" "en_US/ISO-8859-1"];

  # nixos-install will do a pull from this channel to speed up the
  # installation.
  installer.nixpkgsURL = http://nixos.org/releases/nixpkgs/channels/nixpkgs-unstable;

  boot.postBootCommands =
    ''
      export PATH=${pkgs.gnutar}/bin:${pkgs.bzip2}/bin:$PATH

      # Provide a mount point for nixos-install.
      mkdir -p /mnt

      # Provide the NixOS/Nixpkgs sources in /etc/nixos.  This is required
      # for nixos-install.
      ${optionalString includeSources ''
        echo "unpacking the NixOS/Nixpkgs sources..."
        mkdir -p /etc/nixos/nixos
        tar xjf ${nixosTarball}/nixos.tar.bz2 -C /etc/nixos/nixos
        mkdir -p /etc/nixos/nixpkgs
        tar xjf ${nixpkgsTarball}/nixpkgs.tar.bz2 -C /etc/nixos/nixpkgs
        chown -R root.root /etc/nixos
     ''}

      # Provide a configuration for the CD/DVD itself, to allow users
      # to run nixos-rebuild to change the configuration of the
      # running system on the CD/DVD.
      cp ${dummyConfiguration} /etc/nixos/configuration.nix
    '';

  # Some more help text.
  services.mingetty.helpLine =
    ''
        
      Log in as "root" with an empty password.  ${
        if config.services.xserver.enable then
          "Type `start xserver' to start\nthe graphical user interface."
        else ""
      }
    '';

  # Include the firmware for various wireless cards.
  networking.enableRT73Firmware = true;
  networking.enableIntel2200BGFirmware = true;
  networking.enableIntel3945ABGFirmware = true;

  # To speed up installation a little bit, include the complete stdenv
  # in the Nix store on the CD.
  isoImage.storeContents = [ pkgs.stdenv pkgs.klibc pkgs.klibcShrunk ];

  # Allow sshd to be started manually through "start sshd".  It should
  # not be started by default on the installation CD because the
  # default root password is empty.
  services.openssh.enable = true;
  jobs.sshd.startOn = pkgs.lib.mkOverrideTemplate 50 {} "";

  # Enable wpa_supplicant, but don't start it by default.
  networking.enableWLAN = true;
  jobs.wpa_supplicant.startOn = pkgs.lib.mkOverrideTemplate 50 {} "";
}