{
  stdenv,
  lib,
  fetchFromGitHub,
  cmake,
  ninja,
  python3,
  withGodef ? true,
  godef,
  withGopls ? true,
  gopls,
  withRustAnalyzer ? true,
  rust-analyzer,
  withTypescript ? true,
  typescript,
  abseil-cpp,
  boost,
  llvmPackages,
  fixDarwinDylibNames,
}:

stdenv.mkDerivation {
  pname = "ycmd";
  version = "0-unstable-2025-10-24";

  # required for third_party directory creation
  src = fetchFromGitHub {
    owner = "ycm-core";
    repo = "ycmd";
    rev = "7895484ad55e0cbd0686e882891d59661f183476";
    hash = "sha256-MSzYX1vXuhd4TNxUfHWaRu7O0r89az1XjZBIZ6B3gBk=";
    fetchSubmodules = true;
  };

  nativeBuildInputs = [
    cmake
    ninja
  ]
  ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames;
  buildInputs =
    with python3.pkgs;
    with llvmPackages;
    [
      abseil-cpp
      boost
      libllvm.all
      libclang.all
      legacy-cgi
    ]
    ++ [
      jedi
      jedi-language-server
    ];

  buildPhase = ''
    export EXTRA_CMAKE_ARGS="-DPATH_TO_LLVM_ROOT=${llvmPackages.libllvm} -DUSE_SYSTEM_ABSEIL=true"
    ${python3.pythonOnBuildForHost.interpreter} build.py --system-libclang --clang-completer --ninja
  '';

  dontConfigure = true;

  # remove the tests
  #
  # make __main__.py executable and add shebang
  #
  # copy over third-party libs
  # note: if we switch to using our packaged libs, we'll need to symlink them
  # into the same spots, as YouCompleteMe (the vim plugin) expects those paths
  # to be available
  #
  # symlink completion backends where ycmd expects them
  installPhase = ''
    rm -rf ycmd/tests
    find third_party -type d -name "test" -exec rm -rf {} +

    chmod +x ycmd/__main__.py
    sed -i "1i #!${python3.interpreter}\
    " ycmd/__main__.py

    mkdir -p $out/lib/ycmd
    cp -r ycmd/ CORE_VERSION *.so* *.dylib* $out/lib/ycmd/

    mkdir -p $out/bin
    ln -s $out/lib/ycmd/ycmd/__main__.py $out/bin/ycmd

    ## Work-around CMake/Nix naming of `.so` output
    ln -s $out/lib/ycmd/ycm_core.cpython-[[:digit:]-][^[:space:]]*-gnu${stdenv.hostPlatform.extensions.sharedLibrary} $out/lib/ycmd/ycm_core.so

    # Copy everything: the structure of third_party has been known to change.
    # When linking our own libraries below, do so with '-f'
    # to clobber anything we may have copied here.
    mkdir -p $out/lib/ycmd/third_party
    cp -r third_party/* $out/lib/ycmd/third_party/

  ''
  + lib.optionalString withGodef ''
    TARGET=$out/lib/ycmd/third_party/godef
    mkdir -p $TARGET
    ln -sf ${godef}/bin/godef $TARGET
  ''
  + lib.optionalString withGopls ''
    TARGET=$out/lib/ycmd/third_party/go/bin
    mkdir -p $TARGET
    ln -sf ${gopls}/bin/gopls $TARGET
  ''
  + lib.optionalString withRustAnalyzer ''
    TARGET=$out/lib/ycmd/third_party/rust-analyzer
    mkdir -p $TARGET
    ln -sf ${rust-analyzer} $TARGET
  ''
  + lib.optionalString withTypescript ''
    TARGET=$out/lib/ycmd/third_party/tsserver
    ln -sf ${typescript} $TARGET
  '';

  # fixup the argv[0] and replace __file__ with the corresponding path so
  # python won't be thrown off by argv[0]
  postFixup = ''
    substituteInPlace $out/lib/ycmd/ycmd/__main__.py \
      --replace __file__ "'$out/lib/ycmd/ycmd/__main__.py'"
  '';

  meta = {
    description = "Code-completion and comprehension server";
    longDescription = ''
      Note if YouCompleteMe Vim plugin complains with;

      > ImportError: Python version mismatch: module was compiled for Python 3.13, but the interpreter version is incompatible: 3.10.18

      ...  then set something similar to following in `programs.vim.extraConfig`;

          let g:ycm_server_python_interpreter = "''${python3.interpreter}"
    '';
    mainProgram = "ycmd";
    homepage = "https://github.com/ycm-core/ycmd";
    license = lib.licenses.gpl3;
    maintainers = with lib.maintainers; [
      lnl7
      mel
      S0AndS0
    ];
    platforms = lib.platforms.all;
  };
}