default.nix

{ pkgs ? import <nixpkgs> {} }:

let

  fpm = pkgs.callPackage ./fpm {};

  nixRelease = (import ./nix/release.nix {});

  nix = nixRelease.build.x86_64-linux.overrideAttrs (old: {
    # FIXME: one test fails
    doInstallCheck = false;
  });

  closureInfo = pkgs.closureInfo { rootPaths = [ nix ]; };

  # Profile script installed to /etc/profile.d
  profileScript = pkgs.writeText "nix.sh" ''
    if [ -e /opt/nix-multiuser/nix/etc/profile.d/nix.sh ]; then
      . /opt/nix-multiuser/nix/etc/profile.d/nix.sh
      export PATH="$PATH:/opt/nix-multiuser/nix/bin"
    else
      # Generally, this should never happen, but be defensive just in case we somehow
      # end up with the package installed without running the post-install script.
      echo "nix-multiuser: warning: couldn't locate a Nix profile script to source." >&2
    fi
  '';

  daemonStartupScript = pkgs.writeScript "start-daemon.sh" ''
    #!/bin/sh

    # FIXME: this is copy-pasted from nix profile.sh.in

    if [ -z "$NIX_SSL_CERT_FILE" ]; then
      if [ -e /etc/ssl/certs/ca-certificates.crt ]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
        export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
      elif [ -e /etc/ssl/ca-bundle.pem ]; then # openSUSE Tumbleweed
        export NIX_SSL_CERT_FILE=/etc/ssl/ca-bundle.pem
      elif [ -e /etc/ssl/certs/ca-bundle.crt ]; then # Old NixOS
        export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt
      elif [ -e /etc/pki/tls/certs/ca-bundle.crt ]; then # Fedora, CentOS
        export NIX_SSL_CERT_FILE=/etc/pki/tls/certs/ca-bundle.crt
      fi
    fi

    exec ${nix}/bin/nix-daemon --daemon
  '';

  buildFor = outputFormat: pkgs.stdenv.mkDerivation {
    name = "nix-fpm-multiuser";

    nativeBuildInputs = with pkgs; [ dpkg fpm rpm ];

    packageDescription = ''
      The Nix software deployment system
      Nix is a purely functional package manager. It allows multiple
      versions of a package to be installed side-by-side, ensures that
      dependency specifications are complete, supports atomic upgrades and
      rollbacks, allows non-root users to install software, and has many
      other features. It is the basis of the NixOS Linux distribution, but
      it can be used equally well under other Unix systems.
    '';

    # Grumble.
    systemdUnitDir = if outputFormat == "pacman"
      then "/usr/lib/systemd/system"
      else "/lib/systemd/system";

    buildCommand = ''
      pathsToCopy=""

      # Make local copies here so that they are not owned by root (fpm doesn't like that).
      ln -s ${nix} nix
      pathsToCopy+=" nix=/opt/nix-multiuser/nix"

      cp ${nix}/lib/systemd/system/nix-daemon.* .
      sed -i nix-daemon.service -e 's|ExecStart=.*|ExecStart=/opt/nix-multiuser/start-daemon.sh|'
      pathsToCopy+=" nix-daemon.service=$systemdUnitDir/nix-daemon.service"
      pathsToCopy+=" nix-daemon.socket=$systemdUnitDir/nix-daemon.socket"

      cp ${closureInfo}/registration reginfo
      pathsToCopy+=" reginfo=/opt/nix-multiuser/reginfo"

      cp ${daemonStartupScript} start-daemon.sh
      pathsToCopy+=" start-daemon.sh=/opt/nix-multiuser/start-daemon.sh"

      cp ${profileScript} nix.sh
      pathsToCopy+=" nix.sh=/etc/profile.d/nix.sh"

      for f in $(cat ${closureInfo}/store-paths); do
        cp -r $f .
        pathsToCopy+=" $(basename $f)=/opt/nix-multiuser/bootstrap-store"
      done

      # --verbose 
      # --debug 
      # --debug-workspace

      # TODO:
      # Make description + summary look sane in both RPM and Deb
      # --config-files /etc/nix - deb backend doesn't like if the directory doesn't exist
      # --directories /nix - rpm backend doesn't like if the directory doesn't exist
      # Vcs-Browser:, Vcs-Git: and equivalents for RPM
      # Make sure that if the distro package is removed no files with nixbld* uids stay in /nix!

      fpm \
        --input-type dir \
        --output-type ${outputFormat} \
        --name nix \
        --version 2.0 \
        --maintainer "Eelco Dolstra <eelco.dolstra@logicblox.com>" \
        --vendor NixOS \
        --url https://nixos.org/nix/ \
        --description "$packageDescription" \
        --license 'LGPLv2+' \
        --deb-no-default-config-files \
        --directories /opt/nix-multiuser \
        --rpm-rpmbuild-define '_build_id_links none' \
        --rpm-defattrdir 555 \
        --before-install ${./before-install-linux.sh} \
        --after-install ${./after-install-linux.sh} \
        --before-remove ${./before-remove-linux.sh} \
        --after-remove ${./after-remove-linux.sh} \
        --debug-workspace \
        $pathsToCopy

      case "${outputFormat}" in
        rpm)
          echo "File list:"
          rpm -qlp *.rpm
          echo
          echo "Package metadata:"
          rpm -qip *.rpm
          ;;
        deb)
          echo "File list:"
          dpkg -c *.deb
          echo
          echo "Package metadata:"
          dpkg -I *.deb
          ;;
        pacman)
          # pacman does provide some commands to list metadata, but they don't work without a pacman database set up :(
          echo "File list:"
          tar tvf *.pkg.tar.*
          echo
          echo "Package metadata:"
          tar xf *.pkg.tar.* .PKGINFO
          cat .PKGINFO
          ;;
        *)
          echo "unknown package type: ${outputFormat}"
          ;;
      esac

      mkdir -p $out
      cp *.deb *.rpm *.pkg.tar.* $out/
    '';
  };

in rec {
  deb = buildFor "deb";
  pacman = buildFor "pacman";
  rpm = buildFor "rpm";
}