{ lib, stdenv
, fetchgit, fetchFromGitHub, fetchurl
, writeShellScript, runCommand, which
, rustPlatform, jq, nix-prefetch-git, xe, curl, emscripten
, callPackage
}:

# TODO: move to carnix or https://github.com/kolloch/crate2nix
let
  # to update:
  # 1) change all these hashes
  # 2) nix-build -A tree-sitter.updater.update-all-grammars
  # 3) run the ./result script that is output by that (it updates ./grammars)
  version = "0.16.4";
  sha256 = "1m0zxz7h4w2zny7yhrlxwqvizcf043cizg7ca5dn3h9k16adcxil";
  cargoSha256 = "0hxm73diwiybljm6yy3vmwfdpg33b4rlg0h7afq4xgccq2vkwafs";

  src = fetchFromGitHub {
    owner = "tree-sitter";
    repo = "tree-sitter";
    rev = version;
    inherit sha256;
    fetchSubmodules = true;
  };

  update-all-grammars = import ./update.nix {
    inherit writeShellScript nix-prefetch-git curl jq xe src;
  };

  fetchGrammar = (v: fetchgit {inherit (v) url rev sha256 fetchSubmodules; });

  grammars =
    runCommand "grammars" {} (''
       mkdir $out
     '' + (lib.concatStrings (lib.mapAttrsToList
            (name: grammar: "ln -s ${fetchGrammar grammar} $out/${name}\n")
            (import ./grammars))));

  builtGrammars = let
    change = name: grammar:
      callPackage ./library.nix {
        language = name; inherit version; source = fetchGrammar grammar;
      };
  in
    # typescript doesn't have parser.c in the same place as others
    lib.mapAttrs change (removeAttrs (import ./grammars) ["typescript"]);

in rustPlatform.buildRustPackage {
  pname = "tree-sitter";
  inherit src version cargoSha256;

  nativeBuildInputs = [ emscripten which ];

  postPatch = ''
    # needed for the tests
    rm -rf test/fixtures/grammars
    ln -s ${grammars} test/fixtures/grammars
  '';

  # Compile web assembly with emscripten. The --debug flag prevents us from
  # minifying the JavaScript; passing it allows us to side-step more Node
  # JS dependencies for installation.
  preBuild = ''
    HOME=/tmp
    bash ./script/build-wasm --debug
  '';

  # test result: FAILED. 120 passed; 13 failed; 0 ignored; 0 measured; 0 filtered out
  doCheck = false;

  passthru = {
    updater = {
      inherit update-all-grammars;
    };
    inherit grammars;
    inherit builtGrammars;
  };

  meta = {
    homepage = "https://github.com/tree-sitter/tree-sitter";
    description = "A parser generator tool and an incremental parsing library";
    longDescription = ''
      Tree-sitter is a parser generator tool and an incremental parsing library.
      It can build a concrete syntax tree for a source file and efficiently update the syntax tree as the source file is edited.

      Tree-sitter aims to be:

      * General enough to parse any programming language
      * Fast enough to parse on every keystroke in a text editor
      * Robust enough to provide useful results even in the presence of syntax errors
      * Dependency-free so that the runtime library (which is written in pure C) can be embedded in any application
    '';
    platforms = lib.platforms.all;
    license = lib.licenses.mit;
    maintainers = with lib.maintainers; [ Profpatsch ];
    # Darwin needs some more work with default libraries
    # Aarch has test failures with how tree-sitter compiles the generated C files
    broken = stdenv.isDarwin || stdenv.isAarch64;
  };

}