{ stdenv, lib, fetchFromGitHub
, cmake, pkg-config, qttools
, libxcb, libXau, pam, qtbase, wrapQtAppsHook, qtdeclarative
, qtquickcontrols2 ? null, systemd, xkeyboardconfig
}:
let
  isQt6 = lib.versions.major qtbase.version == "6";
in stdenv.mkDerivation {
  pname = "sddm";
  version = "0.20.0-unstable-2023-12-29";

  src = fetchFromGitHub {
    owner = "sddm";
    repo = "sddm";
    rev = "501129294be1487f753482c29949fc1c19ef340e";
    hash = "sha256-mLm987Ah0X9s0tBK2a45iERwYoh5JzWb3TFlSoxi8CA=";
  };

  patches = [
    ./sddm-ignore-config-mtime.patch
    ./sddm-default-session.patch
  ];

  postPatch = ''
    substituteInPlace src/greeter/waylandkeyboardbackend.cpp \
      --replace "/usr/share/X11/xkb/rules/evdev.xml" "${xkeyboardconfig}/share/X11/xkb/rules/evdev.xml"
  '';

  nativeBuildInputs = [ wrapQtAppsHook cmake pkg-config qttools ];

  buildInputs = [
    libxcb
    libXau
    pam
    qtbase
    qtdeclarative
    qtquickcontrols2
    systemd
  ];

  cmakeFlags = [
    (lib.cmakeBool "BUILD_WITH_QT6" isQt6)
    "-DCONFIG_FILE=/etc/sddm.conf"
    "-DCONFIG_DIR=/etc/sddm.conf.d"

    # Set UID_MIN and UID_MAX so that the build script won't try
    # to read them from /etc/login.defs (fails in chroot).
    # The values come from NixOS; they may not be appropriate
    # for running SDDM outside NixOS, but that configuration is
    # not supported anyway.
    "-DUID_MIN=1000"
    "-DUID_MAX=29999"

    # we still want to run the DM on VT 7 for the time being, as 1-6 are
    # occupied by getties by default
    "-DSDDM_INITIAL_VT=7"

    "-DQT_IMPORTS_DIR=${placeholder "out"}/${qtbase.qtQmlPrefix}"
    "-DCMAKE_INSTALL_SYSCONFDIR=${placeholder "out"}/etc"
    "-DSYSTEMD_SYSTEM_UNIT_DIR=${placeholder "out"}/lib/systemd/system"
    "-DSYSTEMD_SYSUSERS_DIR=${placeholder "out"}/lib/sysusers.d"
    "-DSYSTEMD_TMPFILES_DIR=${placeholder "out"}/lib/tmpfiles.d"
    "-DDBUS_CONFIG_DIR=${placeholder "out"}/share/dbus-1/system.d"
  ];

  postInstall = ''
    # remove empty scripts
    rm "$out/share/sddm/scripts/Xsetup" "$out/share/sddm/scripts/Xstop"
    for f in $out/share/sddm/themes/**/theme.conf ; do
      substituteInPlace $f \
        --replace 'background=' "background=$(dirname $f)/"
    done
  '';

  meta = with lib; {
    description = "QML based X11 display manager";
    homepage    = "https://github.com/sddm/sddm";
    maintainers = with maintainers; [ abbradar ttuegel ];
    platforms   = platforms.linux;
    license     = licenses.gpl2Plus;
  };
}