PlainTranslator

// SPDX-FileCopyrightText: © 2025 Alexander Kromm <mmaulwurff@gmail.com>
// SPDX-License-Identifier: BSD-3-Clause

// PlainTranslator module version: 1.1.0
// PlainTranslator is a part of DoomToolbox: https://github.com/mmaulwurff/doom-toolbox/
//
// In GZDoom, you have two options for putting text in your menu items:
//
// 1. Plain text:
//   - in `menudef`: `StaticText "Hello, world!"`
//
// 2. String id:
//   - in `menudef`: `StaticText "$HELLO_WORLD"`,
//   - in `language`, for each desired language: `HELLO_WORLD = "Hello, world!`;"
//
// The first option is more readable, but such item labels aren't translated.
// PlainTranslator makes the first option translatable too. It creates string
// ids for plain strings automatically.
//
// How to use:
//
// 1. Write label for your menu items in plain text: `StaticText "Hello, world!"`.
// 2. Add NAMESPACE_PlainTranslator menu item in your menu as the first item.
// 3. Add translations in `language`, if needed. String id is derived from the
//    plain text string: `NAMESPACE_Hello__world_ = "¡Hola Mundo!";`
//
// Features:
//
// - Automatic submenu translation: it's enough to only put Translator in the
//   top-level menu.
// - Supports item labels and menu titles.
//
// Limitations:
//
// - Doesn't support dynamic menus: if the number of menu item changes in
//   runtime, the translation stops updating.
// - Translator doesn't work if it's the last item in a menu, works best if it's
//   the first.
// - After the language is changed, the old string is shown for one frame.
// - Plain text must contain only numbers, latin letters, spaces, ',', '.', '!',
//   '?', '-'. In string id spaces and punctuation are replaced with "_".
// - Translator takes one line.
class OptionMenuItemNAMESPACE_PlainTranslator : OptionMenuItem
{
  override int draw(OptionMenuDescriptor descriptor, int y, int indent, bool selected)
  {
    translate(descriptor);
    return -1;
  }

  override bool selectable()
  {
    return false;
  }

  void init()
  {
    Super.init("", 'None');
  }

  private void translate(OptionMenuDescriptor descriptor)
  {
    if (!mIsInitialized)
    {
      mIsInitialized = true;
      mOldLanguage = language;

      mOriginalTitle = descriptor.mTitle;
      mTitleId = makeId(descriptor.mTitle);

      foreach (item : descriptor.mItems)
      {
        if (item is "OptionMenuItemSubmenu")
        {
          let submenuDescriptor =
            OptionMenuDescriptor(MenuDescriptor.getDescriptor(item.getAction()));

          if (submenuDescriptor != NULL)
          {
            submenuDescriptor.mItems.
              insert(0, new("OptionMenuItemNAMESPACE_PlainTranslator"));
          }
        }

        addLabel(item.mLabel);
      }

      replaceLabels(descriptor);
      return;
    }

    if (language == mOldLanguage) return;

    mOldLanguage = language;

    replaceLabels(descriptor);
  }

  private void replaceLabels(OptionMenuDescriptor descriptor)
  {
    descriptor.mTitle = getLocalizedLabel(mTitleId, mOriginalTitle);

    int itemsNumber = descriptor.mItems.size();

    // Items number changed, cannot match items with their labels by index.
    if (mOriginalLabels.size() != itemsNumber) return;

    for (int i = 0; i < itemsNumber; ++i)
      descriptor.mItems[i].mLabel = getLocalizedLabel(mLabelIds[i], mOriginalLabels[i]);
  }

  private void addLabel(string label)
  {
    mOriginalLabels.push(label);
    mLabelIds.push(makeId(label));
  }

  private string makeId(string label)
  {
    static const string toReplaces[] = {" ", ",", "!", "?", "-"};
    foreach (toReplace : toReplaces) label.replace(toReplace, "_");
    return "NAMESPACE_" .. label;
  }

  private string getLocalizedLabel(string labelId, string originalLabel)
  {
    string localizedLabel = StringTable.localize(labelId, false);
    bool localizationFound = localizedLabel != labelId;

    return localizationFound ? localizedLabel : originalLabel;
  }

  private bool mIsInitialized;
  private string mOldLanguage;

  private Array<string> mOriginalLabels;
  private Array<string> mLabelIds;
  private string mOriginalTitle;
  private string mTitleId;
}