Initial import

backend/src/app.controller.spec.ts

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+import { Test, TestingModule } from '@nestjs/testing';
+import { AppController } from './app.controller';
+import { AppService } from './app.service';
+
+describe('AppController', () => {
+  let appController: AppController;
+
+  beforeEach(async () => {
+    const app: TestingModule = await Test.createTestingModule({
+      controllers: [AppController],
+      providers: [AppService],
+    }).compile();
+
+    appController = app.get<AppController>(AppController);
+  });
+
+  describe('root', () => {
+    it('should return "Hello World!"', () => {
+      expect(appController.getHello()).toBe('Hello World!');
+    });
+  });
+});

backend/src/app.controller.ts

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+import { Controller, Get } from '@nestjs/common';
+import { AppService } from './app.service';
+
+@Controller()
+export class AppController {
+  constructor(private readonly appService: AppService) {}
+
+  @Get()
+  getHello(): string {
+    return this.appService.getHello();
+  }
+}

backend/src/app.module.ts

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+import { Module } from '@nestjs/common';
+import { AppController } from './app.controller';
+import { AppService } from './app.service';
+import { GlobalWordsModule } from './global-words/global-words.module';
+import { ImageEngineModule } from './image-engine/image-engine.module';
+
+@Module({
+  imports: [ImageEngineModule, GlobalWordsModule],
+  controllers: [AppController],
+  providers: [AppService],
+})
+export class AppModule {}

backend/src/app.service.ts

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+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class AppService {
+  getHello(): string {
+    return 'Hello World!';
+  }
+}

backend/src/global-words/global-word.interface.ts

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+export interface GlobalWord {
+  palabra: string;
+  categoria: string;
+  tema: string;
+  descripcion: string;
+}
+
+export interface WordWithAsset extends GlobalWord {
+  slug: string;
+  imageUrl: string | null;
+  imageStatus: 'ready' | 'pending';
+}

backend/src/global-words/global-words.controller.ts

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+import {
+  Controller,
+  Get,
+  Param,
+  Post,
+  Res,
+  StreamableFile,
+  HttpStatus,
+  HttpCode,
+} from '@nestjs/common';
+import type { Response } from 'express';
+import { createReadStream } from 'node:fs';
+import { GlobalWordsService } from './global-words.service';
+
+@Controller('global-words')
+export class GlobalWordsController {
+  constructor(private readonly globalWordsService: GlobalWordsService) {}
+
+  @Get()
+  async getWords() {
+    return this.globalWordsService.listWords();
+  }
+
+  @Post('prefetch')
+  @HttpCode(HttpStatus.ACCEPTED)
+  async prefetchAll() {
+    this.globalWordsService.prefetchAll();
+    return { status: 'scheduled' };
+  }
+
+  @Post(':slug/generate')
+  async generateForWord(@Param('slug') slug: string) {
+    await this.globalWordsService.ensureImage(slug);
+    return { slug, status: 'ready' };
+  }
+
+  @Get(':slug/image')
+  async getImage(@Param('slug') slug: string, @Res({ passthrough: true }) res: Response) {
+    const asset = await this.globalWordsService.ensureImage(slug);
+    res.setHeader('Content-Type', asset.mimeType);
+    const file = createReadStream(asset.path);
+    return new StreamableFile(file);
+  }
+}

backend/src/global-words/global-words.module.ts

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+import { Module } from '@nestjs/common';
+import { GlobalWordsController } from './global-words.controller';
+import { GlobalWordsService } from './global-words.service';
+import { ImageEngineModule } from '../image-engine/image-engine.module';
+
+@Module({
+  imports: [ImageEngineModule],
+  controllers: [GlobalWordsController],
+  providers: [GlobalWordsService],
+  exports: [GlobalWordsService],
+})
+export class GlobalWordsModule {}

backend/src/global-words/global-words.service.ts

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+import { Injectable, Logger, NotFoundException, OnModuleInit } from '@nestjs/common';
+import { promises as fs } from 'node:fs';
+import * as path from 'node:path';
+import type { GlobalWord, WordWithAsset } from './global-word.interface';
+import { ImageEngineService } from '../image-engine/image-engine.service';
+
+@Injectable()
+export class GlobalWordsService implements OnModuleInit {
+  private readonly logger = new Logger(GlobalWordsService.name);
+  private readonly repoRoot = path.resolve(process.cwd(), '..');
+  private readonly contentRoot = path.join(this.repoRoot, 'content');
+  private readonly wordsPath = path.join(this.contentRoot, 'palabras-globales.json');
+  private readonly assetsDir = path.join(this.contentRoot, 'generated', 'global-words');
+  private wordsCache: GlobalWord[] | null = null;
+
+  constructor(private readonly imageEngine: ImageEngineService) {}
+
+  async onModuleInit() {
+    await fs.mkdir(this.assetsDir, { recursive: true });
+    // Lanzamos prefetch en background.
+    this.prefetchAll().catch((error) =>
+      this.logger.error('No se pudieron precargar todas las imágenes', error as Error),
+    );
+  }
+
+  private async loadWords(): Promise<GlobalWord[]> {
+    if (!this.wordsCache) {
+      const raw = await fs.readFile(this.wordsPath, 'utf8');
+      this.wordsCache = JSON.parse(raw) as GlobalWord[];
+    }
+    return this.wordsCache;
+  }
+
+  private slugify(text: string) {
+    return text
+      .normalize('NFD')
+      .replace(/[\u0300-\u036f]/g, '')
+      .replace(/[^a-zA-Z0-9]+/g, '-')
+      .replace(/^-+|-+$/g, '')
+      .toLowerCase();
+  }
+
+  private readonly mimeByExtension: Record<string, string> = {
+    png: 'image/png',
+    webp: 'image/webp',
+    jpg: 'image/jpeg',
+    jpeg: 'image/jpeg',
+    svg: 'image/svg+xml',
+  };
+
+  private async resolveExistingAsset(slug: string) {
+    for (const ext of Object.keys(this.mimeByExtension)) {
+      const candidate = path.join(this.assetsDir, `${slug}.${ext}`);
+      try {
+        await fs.access(candidate);
+        return { path: candidate, mimeType: this.mimeByExtension[ext] };
+      } catch {
+        // keep iterating
+      }
+    }
+    return null;
+  }
+
+  private buildPrompt(word: GlobalWord) {
+    return `Ilustración infantil estilo acuarela, vibrante y amigable para niños pequeños. Palabra clave: "${word.palabra}". Tema: ${word.tema}. Categoría: ${word.categoria}. Descripción: ${word.descripcion}. Usa los colores azul y oro si es un elemento de fútbol o autos. Fondo suave, detalles simples.`;
+  }
+
+  async listWords(): Promise<WordWithAsset[]> {
+    const words = await this.loadWords();
+    return Promise.all(
+      words.map(async (word) => {
+        const slug = this.slugify(word.palabra);
+        const existing = await this.resolveExistingAsset(slug);
+        return {
+          ...word,
+          slug,
+          imageUrl: existing ? `/global-words/${slug}/image` : null,
+          imageStatus: existing ? 'ready' : 'pending',
+        };
+      }),
+    );
+  }
+
+  private async findWordBySlug(slug: string): Promise<GlobalWord & { slug: string }> {
+    const words = await this.loadWords();
+    const found = words
+      .map((word) => ({ ...word, slug: this.slugify(word.palabra) }))
+      .find((word) => word.slug === slug);
+    if (!found) {
+      throw new NotFoundException(`No existe la palabra con slug ${slug}`);
+    }
+    return found;
+  }
+
+  async ensureImage(slug: string) {
+    const word = await this.findWordBySlug(slug);
+    const existing = await this.resolveExistingAsset(slug);
+    if (existing) {
+      return existing;
+    }
+    this.logger.log(`Generando imagen para ${word.palabra}`);
+    const prompt = this.buildPrompt(word);
+    try {
+      const asset = await this.imageEngine.generate(word, slug, prompt);
+      return asset;
+    } catch (error) {
+      this.logger.warn(
+        `No se pudo generar ${word.palabra} con el motor local, usando placeholder. Motivo: ${
+          (error as Error).message
+        }`,
+      );
+      const svgBuffer = this.buildPlaceholder(word);
+      const filePath = path.join(this.assetsDir, `${slug}.svg`);
+      await fs.writeFile(filePath, svgBuffer);
+      return { path: filePath, mimeType: this.mimeByExtension.svg };
+    }
+  }
+
+  async prefetchAll() {
+    const words = await this.loadWords();
+    for (const word of words) {
+      const slug = this.slugify(word.palabra);
+      if (await this.resolveExistingAsset(slug)) continue;
+      await this.ensureImage(slug);
+      await new Promise((resolve) => setTimeout(resolve, 400)); // evita saturar API
+    }
+  }
+
+  private buildPlaceholder(word: GlobalWord) {
+    const background = word.categoria === 'fútbol' ? '#13347a' : '#ffe6b3';
+    const accent = word.categoria === 'fútbol' ? '#f7c948' : '#1967d2';
+    const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="512" height="512">
+      <defs>
+        <linearGradient id="grad" x1="0%" y1="0%" x2="100%" y2="100%">
+          <stop offset="0%" stop-color="${background}" stop-opacity="0.9"/>
+          <stop offset="100%" stop-color="${accent}" stop-opacity="0.9"/>
+        </linearGradient>
+      </defs>
+      <rect width="512" height="512" fill="url(#grad)" rx="42" ry="42"/>
+      <text x="50%" y="45%" font-size="120" font-family="Nunito, Arial" font-weight="800" text-anchor="middle" fill="#ffffff">${word.palabra}</text>
+      <text x="50%" y="62%" font-size="36" font-family="Nunito, Arial" text-anchor="middle" fill="#ffffff" opacity="0.85">${word.categoria}</text>
+      <foreignObject x="56" y="320" width="400" height="160">
+        <div xmlns="http://www.w3.org/1999/xhtml" style="font-size:28px;font-family:Nunito,Arial;text-align:center;color:#fff;">
+          ${word.descripcion}
+        </div>
+      </foreignObject>
+    </svg>`;
+    return Buffer.from(svg);
+  }
+}

backend/src/image-engine/image-engine.module.ts

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+import { Module } from '@nestjs/common';
+import { ImageEngineService } from './image-engine.service';
+
+@Module({
+  providers: [ImageEngineService],
+  exports: [ImageEngineService],
+})
+export class ImageEngineModule {}

backend/src/image-engine/image-engine.service.ts

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+import { Injectable, Logger } from '@nestjs/common';
+import { fetch } from 'undici';
+import type { GlobalWord } from '../global-words/global-word.interface';
+
+interface GenerateResponse {
+  path: string;
+  mimeType?: string;
+}
+
+@Injectable()
+export class ImageEngineService {
+  private readonly logger = new Logger(ImageEngineService.name);
+  private readonly baseUrl = process.env.IMAGE_SERVICE_URL ?? 'http://localhost:8001';
+
+  async generate(word: GlobalWord, slug: string, prompt: string) {
+    const response = await fetch(`${this.baseUrl}/generate`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        prompt,
+        slug,
+        negative_prompt: 'text, watermark, logo, disfigured, deformed',
+        width: 640,
+        height: 512,
+        steps: 4,
+      }),
+    });
+
+    if (!response.ok) {
+      const errorText = await response.text();
+      this.logger.error(
+        `Image service error ${response.status}: ${errorText}`,
+      );
+      throw new Error(
+        `Image service responded with ${response.status}: ${errorText}`,
+      );
+    }
+
+    const data = (await response.json()) as GenerateResponse;
+    if (!data?.path) {
+      throw new Error('Image service did not return a file path');
+    }
+
+    return {
+      path: data.path,
+      mimeType: data.mimeType ?? 'image/png',
+    };
+  }
+}

backend/src/main.ts

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+import { config } from 'dotenv';
+import * as path from 'node:path';
+import { NestFactory } from '@nestjs/core';
+import { AppModule } from './app.module';
+
+config({ path: path.resolve(process.cwd(), '..', '.env') });
+
+async function bootstrap() {
+  const app = await NestFactory.create(AppModule);
+  app.enableCors({
+    origin: process.env.CLIENT_ORIGIN ?? true,
+  });
+  await app.listen(process.env.PORT ?? 3000);
+}
+bootstrap();