# Translating God's Eye View

Shipped languages: **English** (source and fallback), **Spanish** (`es`) and **Russian** (`ru`).

## How it works

The English text is the key: code calls `t('Save keys')`, and markup marks elements with `data-i18n`. How developers mark text is in [I18N.md](./I18N.md).

Every other language is one flat JSON file, `src/i18n/locales/<code>.json`, keyed by the English text:

```json
{
  "Save keys": "Сохранить ключи",
  "{count} cameras": {
    "one": "{count} камера",
    "few": "{count} камеры",
    "many": "{count} камер",
    "other": "{count} камеры"
  }
}
```

A `tn()` entry is keyed by the English plural form and holds one string per `Intl.PluralRules` category of that language. A missing entry falls back to English.

The page picks its language from `?lang=`, then the choice stored by the language switch in the Visual Presets dock, then the browser languages, then English. `?lang=` is not stored, and copied share links leave it out. Switching reloads the page.

## The check

```sh
npm run i18n                      # what is missing, unused or broken, per language
npm run i18n -- --missing ru      # missing ru entries as JSON, ready to translate
npm run i18n -- --prune           # drop entries the code no longer uses
```

`npm test` runs the same check (`src/i18n/catalog.test.mjs`). It fails when a translation is missing or empty, when an entry is no longer used, when placeholders differ from the English, when a plural entry lacks a form, or when a translation, or any form of a plural entry, is still the English text. The `--missing` template is not a translation: its strings are empty and its plural forms are the English, so the check fails until every one is translated. If an entry is right as it is in English (a code such as HDG, a product name, a word spelled the same in your language), add it under your language code in `src/i18n/same-as-english.json`.

Changing English text changes its key: the old translation becomes unused and the new text shows as missing. Translate it and prune.

## Fixing a translation

Edit `src/i18n/locales/<code>.json` and run `npm run i18n`. To see your change, open the app with `?lang=<code>`.

## Adding a language

1. Create `src/i18n/locales/<code>.json`, fill it from `npm run i18n -- --missing <code>` (start from `{}`), and translate every entry.
2. Import it in `src/i18n/index.js` and add it to `CATALOGS`.
3. Add the code to `LOCALES` and its own-language name to `LOCALE_NAMES` in `src/i18n/locale.js`. Right-to-left languages also go in `RTL_LOCALES`.
4. Add `src/i18n/locales/<code>.json` next to `ru.json` in `scripts/package-boundaries.json`.
5. Write `docs/translations/<code>.md`: glossary, plural forms, units and style (copy the structure of `ru.md`).
6. Run `npm run i18n` and `npm test`, then check the panels in the app at narrow widths.

## Rules

- Keep every `{placeholder}` name exactly as in the English: do not rename, drop or add one. Its position inside the sentence follows the grammar of your language, e.g. `"{accepted} of {raw} records accepted"` → `"принято записей: {accepted} из {raw}"`.
- UPPERCASE English stays UPPERCASE. Short labels, chips and HUD readouts should stay short; prefer an abbreviation over a wrapped line.
- Keep the separators `·`, `—`, `→`, `↗`, `…`.
- Leave product, provider and data names in their original form: Google Maps, Cesium ion, OpenAI, ChatGPT, NASA FIRMS, USGS, OpenSky, ADS-B, AIS, CCTV, HUD, TomTom, OpenStreetMap, Mapillary, and keyboard keys (Space, Esc, H, 1–9).
- Units follow the language's convention; see the language notes.

## Never translated

These are contracts, not copy: layer ids and registry keys, status enums and other machine values (translate only the label shown for them), share-link and hash parameters, `?lang=`, storage schemas, API fields, voice tool names and schemas, provider and dataset names, data from feeds (callsigns, vessel, satellite, station and place names, headlines), attribution, console diagnostics, and user-authored content.

## Language notes

Each language keeps its glossary, plural forms, units and style in its own file, `docs/translations/<code>.md`: [Spanish](./translations/es.md), [Russian](./translations/ru.md). Read it before translating, and add a term there when you settle on one.