{ session_key ? "/etc/etherpad-lite/SESSIONKEY.txt"
, api_key ? "/etc/etherpad-lite/APIKEY.txt"
, stdenv, mylibs, cacert, nodejs, python, fetchurl }:
let
  jquery = fetchurl {
    url = https://code.jquery.com/jquery-1.9.1.js;
    sha256 = "0h4dk67yc9d0kadqxb6b33585f3x3559p6qmp70l00qwq030vn3v";
  };
  withModules = modules: package.overrideAttrs(old: {
    buildPhase = old.buildPhase +
      builtins.concatStringsSep "\n"
        (map (n: "npm install ${n}; touch node_modules/${n}/.ep_initialized") modules);
    # FIXME: ln -s don’t seem to work, etherpad seems
    # unable to "touch" them after initialization
    passthru = old.passthru // {
      inherit modules;
      withModules = moreModules: old.withModules (moreModules ++ modules);
    };
  });
  package = stdenv.mkDerivation (mylibs.fetchedGithub ./etherpad-lite.json // rec {
    __noChroot = true;
    patches = [ ./libreoffice_patch.diff ];
    buildPhase = ''
      export GIT_SSL_CAINFO=${cacert}/etc/ssl/certs/ca-bundle.crt
      export SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt
      export HOME=$PWD

      touch src/.ep_initialized
      cp -v src/static/custom/js.template src/static/custom/index.js
      cp -v src/static/custom/js.template src/static/custom/pad.js
      cp -v src/static/custom/js.template src/static/custom/timeslider.js
      cp -v src/static/custom/css.template src/static/custom/index.css
      cp -v src/static/custom/css.template src/static/custom/pad.css
      cp -v src/static/custom/css.template src/static/custom/timeslider.css

      sed -i 's/var\/dirty.db/\/var\/lib\/etherpad-lite\/dirty.db/g' \
        settings.json.template

      mkdir -v node_modules
      ln -s ../src node_modules/ep_etherpad-lite

      node bin/doc/generate doc/index.md --format=html \
        --template=doc/template.html > documentation.html

      cd src
      npm install
      cd ..
      '';
    installPhase = ''
      mkdir -p $out
      install -t $out/src/ -vDm 644 src/.ep_initialized
      cp -a node_modules $out/
      cp -a src/* $out/src/
      ln -sf ${session_key} $out/SESSIONKEY.txt
      ln -sf ${api_key} $out/APIKEY.txt
      cp ${jquery} $out/src/static/js/jquery.js

      mkdir $out/doc
      install -t "$out/doc/" \
        -vDm 644 {CHANGELOG,CONTRIBUTING,README}.md \
        -vDm 644 documentation.html
    '';
    buildInputs = [ nodejs python ];
    passthru = {
      modules = [];
      inherit withModules;
    };
  });
in package