{ stdenv, fetchurl, buildPackages, perl, coreutils
, withCryptodev ? false, cryptodevHeaders
, enableSSL2 ? false
, static ? false
}:

with stdenv.lib;

let
  common = args@{ version, sha256, patches ? [] }: stdenv.mkDerivation rec {
    name = "openssl-${version}";

    src = fetchurl {
      url = "https://www.openssl.org/source/${name}.tar.gz";
      inherit sha256;
    };

    inherit patches;

    postPatch = ''
      patchShebangs Configure
    '' + optionalString (versionOlder version "1.1.0") ''
      patchShebangs test/*
      for a in test/t* ; do
        substituteInPlace "$a" \
          --replace /bin/rm rm
      done
    '' + optionalString (versionAtLeast version "1.1.1") ''
      substituteInPlace config --replace '/usr/bin/env' '${coreutils}/bin/env'
    '' + optionalString (versionAtLeast version "1.1.0" && stdenv.hostPlatform.isMusl) ''
      substituteInPlace crypto/async/arch/async_posix.h \
        --replace '!defined(__ANDROID__) && !defined(__OpenBSD__)' \
                  '!defined(__ANDROID__) && !defined(__OpenBSD__) && 0'
    '';

    outputs = [ "bin" "dev" "out" "man" ];
    setOutputFlags = false;
    separateDebugInfo = stdenv.hostPlatform.isLinux;

    nativeBuildInputs = [ perl ];
    buildInputs = stdenv.lib.optional withCryptodev cryptodevHeaders;

    # TODO(@Ericson2314): Improve with mass rebuild
    configurePlatforms = [];
    configureScript = {
        "x86_64-darwin"  = "./Configure darwin64-x86_64-cc";
        "x86_64-solaris" = "./Configure solaris64-x86_64-gcc";
        "armv6l-linux" = "./Configure linux-armv4 -march=armv6";
        "armv7l-linux" = "./Configure linux-armv4 -march=armv7-a";
      }.${stdenv.hostPlatform.system} or (
        if stdenv.hostPlatform == stdenv.buildPlatform
          then "./config"
        else if stdenv.hostPlatform.isMinGW
          then "./Configure mingw${optionalString
                                     (stdenv.hostPlatform.parsed.cpu.bits != 32)
                                     (toString stdenv.hostPlatform.parsed.cpu.bits)}"
        else if stdenv.hostPlatform.isLinux
          then "./Configure linux-generic${toString stdenv.hostPlatform.parsed.cpu.bits}"
        else if stdenv.hostPlatform.isiOS
          then "./Configure ios${toString stdenv.hostPlatform.parsed.cpu.bits}-cross"
        else
          throw "Not sure what configuration to use for ${stdenv.hostPlatform.config}"
      );

    configureFlags = [
      "shared" # "shared" builds both shared and static libraries
      "--libdir=lib"
      "--openssldir=etc/ssl"
    ] ++ stdenv.lib.optionals withCryptodev [
      "-DHAVE_CRYPTODEV"
      "-DUSE_CRYPTODEV_DIGESTS"
    ] ++ stdenv.lib.optional enableSSL2 "enable-ssl2"
      ++ stdenv.lib.optional (versionAtLeast version "1.1.0" && stdenv.hostPlatform.isAarch64) "no-afalgeng";

    makeFlags = [ "MANDIR=$(man)/share/man" ];

    enableParallelBuilding = true;

    postInstall =
    stdenv.lib.optionalString (!static) ''
      # If we're building dynamic libraries, then don't install static
      # libraries.
      if [ -n "$(echo $out/lib/*.so $out/lib/*.dylib $out/lib/*.dll)" ]; then
          rm "$out/lib/"*.a
      fi

    '' +
    ''
      mkdir -p $bin
      mv $out/bin $bin/

      mkdir $dev
      mv $out/include $dev/

      # remove dependency on Perl at runtime
      rm -r $out/etc/ssl/misc

      rmdir $out/etc/ssl/{certs,private}
    '';

    postFixup = ''
      # Check to make sure the main output doesn't depend on perl
      if grep -r '${buildPackages.perl}' $out; then
        echo "Found an erroneous dependency on perl ^^^" >&2
        exit 1
      fi
    '';

    meta = with stdenv.lib; {
      homepage = https://www.openssl.org/;
      description = "A cryptographic library that implements the SSL and TLS protocols";
      license = licenses.openssl;
      platforms = platforms.all;
      maintainers = [ maintainers.peti ];
      priority = 10; # resolves collision with ‘man-pages’
    };
  };

in {

  openssl_1_0_2 = common {
    version = "1.0.2q";
    sha256 = "115nisqy7kazbg6br2wrcra9nphyph1l4dgp563b9cf2rv5wyi2p";
    patches = [
      ./1.0.2/nix-ssl-cert-file.patch

      (if stdenv.hostPlatform.isDarwin
       then ./1.0.2/use-etc-ssl-certs-darwin.patch
       else ./1.0.2/use-etc-ssl-certs.patch)
    ];
  };

  openssl_1_1 = common {
    version = "1.1.1a";
    sha256 = "0hcz7znzznbibpy3iyyhvlqrq44y88plxwdj32wjzgbwic7i687w";
    patches = [ ./1.1/nix-ssl-cert-file.patch ];
  };

}