# Project Rules

## Language

- All code comments must be written in **English**.
- All git commit messages must be written in **English**.

## Localisation

**Rule:** Every table that stores human-readable text must have a companion `{table}_translations`
table. The base table always contains the English canonical text (used as fallback).
Translations live only in `_translations` tables — never as extra columns (`name_ru`, `title_de`).

### SQL pattern

```sql
-- Base table — English canonical text always present
CREATE TABLE cuisines (
    slug       VARCHAR(50) PRIMARY KEY,
    name       TEXT NOT NULL,
    sort_order SMALLINT NOT NULL DEFAULT 0
);
-- Translation companion
CREATE TABLE cuisine_translations (
    cuisine_slug VARCHAR(50) REFERENCES cuisines(slug) ON DELETE CASCADE,
    lang         VARCHAR(10) NOT NULL,
    name         TEXT NOT NULL,
    PRIMARY KEY  (cuisine_slug, lang)
);
```

### Query pattern

```sql
SELECT COALESCE(ct.name, c.name) AS name
FROM cuisines c
LEFT JOIN cuisine_translations ct ON ct.cuisine_slug = c.slug AND ct.lang = $lang
```

### Already compliant tables

`units` + `unit_translations`, `ingredient_categories` + `ingredient_category_translations`,
`ingredients` + `ingredient_translations` + `ingredient_aliases`,
`recipes` + `recipe_translations`, `cuisines` + `cuisine_translations`,
`tags` + `tag_translations`, `dish_categories` + `dish_category_translations`,
`dishes` + `dish_translations`, `recipe_ingredients` + `recipe_ingredient_translations`,
`recipe_steps` + `recipe_step_translations`.

### Rule when adding new entities

When adding a new entity with text fields, always create a `{table}_translations`
companion table and use LEFT JOIN COALESCE in all read queries.