nixpkgs/pkgs/misc/vscode-extensions/updateSettings.nix

# Updates the vscode setting file base on a nix expression
# should run from the workspace root.
{ writeShellScriptBin
, lib
, jq
}:
##User Input
{ settings      ? {}
# if marked as true will create an empty json file if does not exists
, createIfDoesNotExists ? true
, vscodeSettingsFile ? ".vscode/settings.json"
, userSettingsFolder ? ""
, symlinkFromUserSetting ? false
}:
let

  updateVSCodeSettingsCmd = ''
  (
    echo 'updateSettings.nix: Updating ${vscodeSettingsFile}...' 
    oldSettings=$(cat ${vscodeSettingsFile})
    echo $oldSettings' ${builtins.toJSON settings}' | ${jq}/bin/jq -s add > ${vscodeSettingsFile}
  )'';

  createEmptySettingsCmd = ''mkdir -p .vscode && echo "{}" > ${vscodeSettingsFile}'';
  fileName = builtins.baseNameOf vscodeSettingsFile;
  symlinkFromUserSettingCmd = lib.optionalString symlinkFromUserSetting
    '' && mkdir -p "${userSettingsFolder}" && ln -sfv "$(pwd)/${vscodeSettingsFile}" "${userSettingsFolder}/" '';
in 

  writeShellScriptBin ''vscodeNixUpdate-${lib.removeSuffix ".json" (fileName)}''
  (lib.optionalString (settings != {}) 
    (if createIfDoesNotExists then ''
      [ ! -f "${vscodeSettingsFile}" ] && ${createEmptySettingsCmd}
      ${updateVSCodeSettingsCmd} ${symlinkFromUserSettingCmd}
    ''
    else ''[ -f "${vscodeSettingsFile}" ] && ${updateVSCodeSettingsCmd} ${symlinkFromUserSettingCmd}
    ''
    )
  )