{ lib
, stdenv
, fetchurl
, bootstrap_cmds
, byacc # can also use bison, but byacc has fewer dependencies
, darwin
, keyutils
, openssl
, perl
, pkg-config

# for passthru.tests
, bind
, curl
, nixosTests
, openssh
, postgresql
, python3

# Extra Arguments
, withLdap ? false, openldap
, withLibedit ? true, libedit
, withVerto ? false, libverto

# This is called "staticOnly" because krb5 does not support
# builting both static and shared, see below.
, staticOnly ? false
}:

stdenv.mkDerivation rec {
  pname = "krb5";
  version = "1.21.3";

  src = fetchurl {
    url = "https://kerberos.org/dist/krb5/${lib.versions.majorMinor version}/krb5-${version}.tar.gz";
    hash = "sha256-t6TNXq1n+wi5gLIavRUP9yF+heoyDJ7QxtrdMEhArTU=";
  };

  outputs = [ "out" "lib" "dev" ];

  # While "out" acts as the bin output, most packages only care about the lib output.
  # We set prefix such that all the pkg-config configuration stays inside the dev and lib outputs.
  # stdenv will take care of overriding bindir, sbindir, etc. such that "out" contains the binaries.
  prefix = builtins.placeholder "lib";

  env = lib.optionalAttrs stdenv.hostPlatform.isStatic {
    NIX_CFLAGS_COMPILE = "-fcommon";
  };

  configureFlags = [
      "--localstatedir=/var/lib"
      (lib.withFeature withLdap "ldap")
      (lib.withFeature withLibedit "libedit")
      (lib.withFeature withVerto "system-verto")
    ]
    # krb5's ./configure does not allow passing --enable-shared and --enable-static at the same time.
    # See https://bbs.archlinux.org/viewtopic.php?pid=1576737#p1576737
    ++ lib.optionals staticOnly [ "--enable-static" "--disable-shared" ]
    ++ lib.optional stdenv.hostPlatform.isFreeBSD ''WARN_CFLAGS=''
    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform)
       [ "krb5_cv_attr_constructor_destructor=yes,yes"
         "ac_cv_func_regcomp=yes"
         "ac_cv_printf_positional=yes"
       ];

  nativeBuildInputs = [ byacc perl pkg-config ]
    # Provides the mig command used by the build scripts
    ++ lib.optional stdenv.hostPlatform.isDarwin bootstrap_cmds;

  buildInputs = [ openssl ]
    ++ lib.optionals (stdenv.hostPlatform.isLinux && stdenv.hostPlatform.libc != "bionic" && !(stdenv.hostPlatform.useLLVM or false)) [ keyutils ]
    ++ lib.optionals withLdap [ openldap ]
    ++ lib.optionals withLibedit [ libedit ]
    ++ lib.optionals withVerto [ libverto ];

  propagatedBuildInputs = lib.optionals stdenv.hostPlatform.isDarwin (with darwin.apple_sdk; [
    libs.xpc
    frameworks.Kerberos
  ]);

  sourceRoot = "krb5-${version}/src";

  postPatch = ''
    substituteInPlace config/shlib.conf \
      --replace "'ld " "'${stdenv.cc.targetPrefix}ld "
  ''
  # this could be accomplished by updateAutotoolsGnuConfigScriptsHook, but that causes infinite recursion
  # necessary for FreeBSD code path in configure
  + ''
    substituteInPlace ./config/config.guess --replace-fail /usr/bin/uname uname
  '';

  libFolders = [ "util" "include" "lib" "build-tools" ];

  # To avoid cyclic outputs, we can't let lib depend on out in any way. Unfortunately, the configure
  # options don't give us enough granularity to specify that, so we have to override the generated
  # Makefiles manually.
  postConfigure = ''
    find $libFolders -type f -name Makefile -print0 | while IFS= read -rd "" f; do
      substituteInPlace "$f" --replace-fail "$out" "$lib"
    done
  '';

  preInstall = ''
    mkdir -p "$lib"/{bin,sbin,lib/pkgconfig,share/{et,man/man1}}
  '';

  # not via outputBin, due to reference from libkrb5.so
  postInstall = ''
    moveToOutput bin/krb5-config "$dev"
  '';

  # Disable _multioutDocs in stdenv by overriding it to be a no-op.
  # We do this because $lib has its own docs and we don't want to squash them into $out.
  preFixup = ''
    _multioutDocs() {
      echo Skipping multioutDocs
    }
  '';

  enableParallelBuilding = true;
  doCheck = false; # fails with "No suitable file for testing purposes"

  meta = with lib; {
    description = "MIT Kerberos 5";
    homepage = "http://web.mit.edu/kerberos/";
    license = licenses.mit;
    platforms = platforms.unix ++ platforms.windows;
  };

  passthru = {
    implementation = "krb5";
    tests = {
      inherit (nixosTests) kerberos;
      inherit (python3.pkgs) requests-credssp;
      bind = bind.override { enableGSSAPI = true; };
      curl = curl.override { gssSupport = true; };
      openssh = openssh.override { withKerberos = true; };
      postgresql = postgresql.override { gssSupport = true; };
    };
  };
}