{ stdenv
, fetchFromGitLab
, makeWrapper
, workadventure-messages
, yarn2nix-moretea
, lib
, replace
, settings ? {}
, ... }:

let
  # nix is nice enough that we can just convert options written in 
  # camelCase into CAMEL_CASE to make environment vars out of them,
  # which workadventure will use during its build
  toCamelCase = 
    (name: builtins.replaceStrings 
      (map
        (c : "_${c}")
        lib.strings.lowerChars)
      lib.strings.upperChars
      (lib.strings.toLower name));
  
  # helper function for defining optional environment arguments, which
  # may be passed to this package through the `settings` argument
  envVar = 
    (name: lib.optionalAttrs
      (settings ? ${toCamelCase name})
      { ${name} = settings.${toCamelCase name}; });

  # all (currently known) options for workadventure-front. Note that
  # some of them are pseudo-options, which are not actually implemented
  # by workadventure (yet?) and which are instead handled during the
  # patch phase of this derivation.
  envVars = envVar "DEBUG_MODE"
         // envVar "API_URL"
         // envVar "UPLOADER_URL"
         // envVar "ADMIN_URL"
         // envVar "MAPS_URL"
         // envVar "API_HOST"
         // envVar "UPLOADER_HOST"
         // envVar "ADMIN_HOST"
         // envVar "MAPS_HOST"
         // envVar "API_PROTOCOL"
         // envVar "UPLOADER_PROTOCOL"
         // envVar "ADMIN_PROTOCOL"
         // envVar "MAPS_PROTOCOL"
         // envVar "TURN_SERVER"
         // envVar "TURN_USER"
         // envVar "TURN_PASSWORD"
         // envVar "JITSI_URL"
         // envVar "JITSI_PRIVATE_MODE"
         // envVar "DEFAULT_MAP_URL"
         // envVar "STUN_SERVER";
in
  yarn2nix-moretea.mkYarnPackage 
    (rec {
      pname = "workadventurefront";
      version = "unstable";

      # TODO: perhaps move this into its own file, to make it easily
      # replacable across all workadventure packages.
      src = fetchFromGitLab {
        owner = "fediventure";
        repo = "workadventure";
        rev = "1bcf0757fd5203132edd17fc806d81e7699111a7";
        sha256 = "0wwgfrcrpimpxjhk073yxlkcp1p0bn0glxd9wisyq5kv8s7jw1yz";
      } + "/front";

      # NOTE: this is optional and generated dynamically if omitted
      yarnNix = ./yarn.nix;

      nativeBuildInputs = [
        makeWrapper
        # includes `replace-literal` for patching. This command is
        # actually the basis for `substituteInPlace`!
        replace
      ];

      dontStrip = true;

      patchPhase = ''
        # remove google tag manager
        replace-literal -efsw '<script async src="https://www.googletagmanager.com/gtag/js?id=UA-10196481-11"></script>' ' ';
        # remove quill js cdn
        replace-literal -efsr -x .ts 'fileref.setAttribute("href", "https://cdn.quilljs.com/1.3.7/quill.snow.css");' ' ';
        replace-literal -efsr '"@types/quill": "^1.3.7",' ' ';
        replace-literal -efsr '"quill": "^1.3.7",' ' ';
      ''
       + (if envVars ? DEFAULT_MAP_URL then ''replace-literal -efs -r -x .ts "/Floor0/floor0.json" ${lib.escapeShellArg envVars.DEFAULT_MAP_URL};'' else "")
       + (if envVars ? STUN_SERVER then ''replace-literal -efs -r -x .ts "stun:stun.l.google.com:19302" ${lib.escapeShellArg envVars.STUN_SERVER};'' else "");

      buildPhase = ''
        mkdir -p $out
        ln -s ${workadventure-messages.outPath}/generated deps/${pname}/src/Messages/generated
        HOME=$TMPDIR yarn --offline run build
        cp -r deps/${pname}/dist/ $out/
      '';

      distPhase = ":";
      installPhase = ":";
    } // envVars)