kochwas/src/routes/api/recipes/extract-from-photo/+server.ts

import type { RequestHandler } from './$types';
import { json } from '@sveltejs/kit';
import { extractRecipeFromImage, GeminiError } from '$lib/server/ai/gemini-client';
import { preprocessImage } from '$lib/server/ai/image-preprocess';
import { pickRandomPhrase } from '$lib/server/ai/description-phrases';
import { createRateLimiter } from '$lib/server/ai/rate-limit';
import type { Ingredient, Step } from '$lib/types';

// 20 MB deckt auch Tablet- und iPad-Pro-Fotos ab (oft 10-15 MB JPEG/HEIC).
// Muss zusammen mit BODY_SIZE_LIMIT (docker-compose.prod.yml) hochgezogen werden --
// SvelteKit rejected groessere Bodies frueher und wirft dann undurchsichtige
// "Multipart erwartet"-Fehler.
const MAX_BYTES = 20 * 1024 * 1024;
const ALLOWED_MIME = new Set([
  'image/jpeg',
  'image/png',
  'image/webp',
  'image/heic',
  'image/heif'
]);

// Singleton-Limiter: 10 Requests/Minute pro IP. Verhindert Kosten-Runaways
// bei versehentlichem Dauer-Tappen.
const limiter = createRateLimiter({ windowMs: 60_000, max: 10 });

function errJson(status: number, code: string, message: string) {
  return json({ code, message }, { status });
}

function buildRawText(q: number | null, u: string | null, name: string): string {
  const parts: string[] = [];
  if (q !== null) parts.push(String(q).replace('.', ','));
  if (u) parts.push(u);
  parts.push(name);
  return parts.join(' ');
}

export const POST: RequestHandler = async ({ request, getClientAddress }) => {
  const ip = getClientAddress();
  if (!limiter.check(ip)) {
    return errJson(
      429,
      'RATE_LIMITED',
      'Zu viele Anfragen — bitte einen Moment warten.'
    );
  }

  let form: FormData;
  try {
    form = await request.formData();
  } catch {
    return errJson(400, 'BAD_REQUEST', 'Multipart body erwartet.');
  }
  const photo = form.get('photo');
  if (!(photo instanceof Blob)) {
    return errJson(400, 'BAD_REQUEST', 'Feld "photo" fehlt.');
  }
  if (photo.size > MAX_BYTES) {
    return errJson(
      413,
      'PAYLOAD_TOO_LARGE',
      `Foto zu groß (max ${MAX_BYTES / 1024 / 1024} MB).`
    );
  }
  if (!ALLOWED_MIME.has(photo.type)) {
    return errJson(
      415,
      'UNSUPPORTED_MEDIA_TYPE',
      `MIME "${photo.type}" nicht unterstützt.`
    );
  }

  const rawBuffer = Buffer.from(await photo.arrayBuffer());
  let preprocessed: { buffer: Buffer; mimeType: 'image/jpeg' };
  try {
    preprocessed = await preprocessImage(rawBuffer);
  } catch (e) {
    return errJson(
      415,
      'UNSUPPORTED_MEDIA_TYPE',
      `Bild konnte nicht gelesen werden: ${(e as Error).message}`
    );
  }

  const startedAt = Date.now();
  let extracted;
  try {
    extracted = await extractRecipeFromImage(
      preprocessed.buffer,
      preprocessed.mimeType
    );
  } catch (e) {
    if (e instanceof GeminiError) {
      const status =
        e.code === 'AI_RATE_LIMITED'
          ? 429
          : e.code === 'AI_TIMEOUT'
            ? 503
            : e.code === 'AI_NOT_CONFIGURED'
              ? 503
              : 503;
      // Nur Code + Meta loggen, niemals Prompt/Response-Inhalt.
      console.warn(
        `[extract-from-photo] ${e.code} after ${Date.now() - startedAt}ms, ${preprocessed.buffer.byteLength} bytes`
      );
      return errJson(status, e.code, 'Die Bild-Analyse ist fehlgeschlagen.');
    }
    console.warn(`[extract-from-photo] UNEXPECTED ${(e as Error).message}`);
    return errJson(503, 'AI_FAILED', 'Die Bild-Analyse ist fehlgeschlagen.');
  }

  // Minimum-Gültigkeit: Titel + (mind. 1 Zutat ODER mind. 1 Schritt).
  if (
    !extracted.title.trim() ||
    (extracted.ingredients.length === 0 && extracted.steps.length === 0)
  ) {
    return errJson(
      422,
      'NO_RECIPE_IN_IMAGE',
      'Ich konnte kein Rezept im Bild erkennen.'
    );
  }

  const ingredients: Ingredient[] = extracted.ingredients.map((i, idx) => ({
    position: idx + 1,
    quantity: i.quantity,
    unit: i.unit,
    name: i.name,
    note: i.note,
    raw_text: buildRawText(i.quantity, i.unit, i.name),
    section_heading: null
  }));

  const steps: Step[] = extracted.steps.map((s, idx) => ({
    position: idx + 1,
    text: s.text
  }));

  return json({
    recipe: {
      id: null,
      title: extracted.title,
      description: pickRandomPhrase(),
      source_url: null,
      source_domain: null,
      image_path: null,
      servings_default: extracted.servings_default,
      servings_unit: extracted.servings_unit,
      prep_time_min: extracted.prep_time_min,
      cook_time_min: extracted.cook_time_min,
      total_time_min: extracted.total_time_min,
      cuisine: null,
      category: null,
      ingredients,
      steps,
      tags: []
    }
  });
};