batchCooking/apps/api/src/lib/recipe-translation.ts

import type { ParsedRecipe, ParsedRecipeStep } from "./recipe-source-adapter.js";
import {
  type TechStepMappingRule,
  loadTechStepMappingRules,
  matchTechSteps,
} from "./tech-step-matcher.js";

/**
 * The "Traduction en étapes" stage of the import pipeline described in
 * specs/batch-cooking-architecture.md (Import depuis source → **Traduction
 * en étapes** → Sauvegarde) — takes a source-agnostic {@link ParsedRecipe}
 * (recipe-source-adapter.ts's `parse()` output) and declares each step's
 * technique sequence, the same `techStepIds: number[]` shape
 * `Step.techSteps`/`StepTechStep` (schema.prisma) will eventually persist.
 *
 * Deliberately doesn't touch ingredients — resolving free-text ingredient
 * lines against our `Ingredient`/`Unit` catalogs is a separate, not-yet-built
 * concern (see `ParsedRecipeIngredient`'s doc comment) — and doesn't turn
 * the result into a saveable `Recipe` either (no `dietIds`/`visibility`/
 * author, a source can't know those). This is one step of the pipeline, not
 * the whole thing.
 *
 * `translateRecipeSteps` is pure (takes `techStepMappings` as a plain
 * argument, same convention as `matchTechSteps` itself) so it's unit-testable
 * without a database; `translateRecipe` is the DB-backed convenience wrapper
 * a caller reaches for in practice, mirroring `tech-step-matcher.ts`'s own
 * pure/DB-touching split.
 */

/** A {@link ParsedRecipeStep}, after tech-step detection — declares its technique sequence alongside the description/picture it already had. */
export interface TranslatedRecipeStep extends ParsedRecipeStep {
  /** Ordered sequence of detected `TechStep` ids (see `matchTechSteps`) — empty if this step doesn't mention any known technique. */
  techStepIds: number[];
}

/** A {@link ParsedRecipe} whose `steps` have been translated — everything else (name, ingredients, portions, …) passes through unchanged. */
export interface TranslatedRecipe extends Omit<ParsedRecipe, "steps"> {
  steps: TranslatedRecipeStep[];
}

/**
 * Declares each of `recipe`'s steps' technique sequence against
 * `techStepMappings`, leaving everything else about the recipe untouched.
 * Pure — testable with a hand-built mapping list, no database involved (see
 * `translateRecipe` for the DB-backed loader). `techStepMappings` should
 * already be filtered to the locale the caller cares about, same
 * requirement `matchTechSteps` itself has.
 */
export function translateRecipeSteps(
  recipe: ParsedRecipe,
  techStepMappings: TechStepMappingRule[],
): TranslatedRecipe {
  return {
    ...recipe,
    steps: recipe.steps.map((step) => ({
      ...step,
      techStepIds: matchTechSteps(step.description, techStepMappings),
    })),
  };
}

/**
 * Convenience wrapper around {@link translateRecipeSteps} that loads
 * `locale`'s mapping catalog itself — what a caller reaches for when
 * translating a single recipe on its own (e.g. the eventual "import this
 * one recipe" endpoint). A caller translating many recipes at once should
 * call `loadTechStepMappingRules` once and reuse it across
 * `translateRecipeSteps` calls instead, the same "don't requery per item"
 * reasoning `recipe.service.ts`'s `createRecipe`/`updateRecipe` already
 * follow for manually-authored recipes.
 *
 * No user- or recipe-level language preference exists anywhere in the app
 * yet (see `tech-step-matcher.ts`'s `loadTechStepMappingRules`) — callers
 * pass a locale explicitly rather than this module guessing one. Note that
 * an English-language source (e.g. TheMealDB) translated against `"fr"`
 * mappings will currently get an empty `techStepIds` sequence on every
 * step — matching-language mappings for that source's language don't exist
 * yet, this stage doesn't invent them.
 */
export async function translateRecipe(
  recipe: ParsedRecipe,
  locale: string,
): Promise<TranslatedRecipe> {
  const techStepMappings = await loadTechStepMappingRules(locale);
  return translateRecipeSteps(recipe, techStepMappings);
}