my-adobe-project/
├── src/
│   ├── adobe/                     # Adobe client layer
│   │   ├── auth.ts                # OAuth Server-to-Server token management
│   │   ├── firefly-client.ts      # Firefly API wrapper (generate, fill, expand)
│   │   ├── pdf-client.ts          # PDF Services wrapper (create, extract, merge)
│   │   ├── photoshop-client.ts    # Photoshop API wrapper (cutout, actions)
│   │   ├── events-client.ts       # I/O Events registration and verification
│   │   ├── types.ts               # Shared Adobe types
│   │   └── errors.ts              # Error classification (retryable vs permanent)
│   ├── services/                  # Business logic layer
│   │   ├── image-generation.ts    # Orchestrates Firefly + Photoshop workflows
│   │   ├── document-pipeline.ts   # Orchestrates PDF create/extract/merge
│   │   └── event-processor.ts     # Routes and processes I/O Events
│   ├── api/                       # API layer (routes, controllers)
│   │   ├── health.ts              # Health check including Adobe IMS
│   │   ├── webhooks/adobe.ts      # I/O Events webhook endpoint
│   │   └── routes/
│   │       ├── images.ts          # Image generation endpoints
│   │       └── documents.ts       # Document processing endpoints
│   ├── jobs/                      # Background job layer
│   │   ├── firefly-batch.ts       # Batch image generation queue
│   │   └── pdf-extraction.ts      # Async PDF extraction worker
│   └── index.ts
├── tests/
│   ├── unit/
│   │   ├── adobe/auth.test.ts
│   │   └── services/
│   └── integration/
│       └── adobe/
│           ├── firefly.test.ts
│           └── pdf-services.test.ts
├── config/
│   ├── adobe.development.json
│   ├── adobe.staging.json
│   └── adobe.production.json
└── package.json

┌─────────────────────────────────────────────────────┐
│                    API Layer                         │
│   Routes, Controllers, Webhook Endpoints            │
├─────────────────────────────────────────────────────┤
│                  Service Layer                       │
│   Business Logic, Workflow Orchestration             │
│   (image-generation.ts, document-pipeline.ts)       │
├─────────────────────────────────────────────────────┤
│                Adobe Client Layer                    │
│   auth.ts, firefly-client.ts, pdf-client.ts         │
│   Token caching, retry, error classification        │
├─────────────────────────────────────────────────────┤
│              Infrastructure Layer                    │
│   Cache (LRU/Redis), Queue (BullMQ), Monitoring     │
└─────────────────────────────────────────────────────┘

// src/adobe/errors.ts
export class AdobeServiceError extends Error {
  constructor(
    message: string,
    public readonly code: string,
    public readonly httpStatus: number,
    public readonly retryable: boolean,
    public readonly api: 'firefly' | 'pdf-services' | 'photoshop' | 'events',
    public readonly retryAfter?: number,
    public readonly originalError?: Error
  ) {
    super(message);
    this.name = 'AdobeServiceError';
  }

  static fromResponse(api: string, status: number, body: string, headers?: Headers): AdobeServiceError {
    const retryAfter = headers?.get('Retry-After');
    return new AdobeServiceError(
      `Adobe ${api} API error (${status}): ${body.slice(0, 200)}`,
      status === 429 ? 'RATE_LIMITED' :
      status === 401 ? 'AUTH_EXPIRED' :
      status >= 500 ? 'SERVER_ERROR' : 'CLIENT_ERROR',
      status,
      status === 429 || status >= 500,
      api as any,
      retryAfter ? parseInt(retryAfter) : undefined,
    );
  }
}

// config/adobe.ts
export interface AdobeConfig {
  clientId: string;
  clientSecret: string;
  scopes: string;
  environment: 'development' | 'staging' | 'production';
  apis: {
    firefly: { enabled: boolean; baseUrl: string };
    pdfServices: { enabled: boolean };
    photoshop: { enabled: boolean; baseUrl: string };
    events: { enabled: boolean; webhookUrl: string };
  };
  retry: { maxRetries: number; baseDelayMs: number };
  cache: { enabled: boolean; ttlSeconds: number };
}

export function loadConfig(): AdobeConfig {
  const env = process.env.NODE_ENV || 'development';
  const base = require(`./adobe.${env}.json`);
  return {
    ...base,
    clientId: process.env.ADOBE_CLIENT_ID!,
    clientSecret: process.env.ADOBE_CLIENT_SECRET!,
    scopes: process.env.ADOBE_SCOPES!,
    environment: env as any,
  };
}

// src/api/health.ts
export async function adobeHealthCheck(config: AdobeConfig) {
  const checks: Record<string, any> = {};

  // Always check IMS auth
  try {
    const start = Date.now();
    await getCachedToken();
    checks.ims = { status: 'healthy', latencyMs: Date.now() - start };
  } catch (e: any) {
    checks.ims = { status: 'unhealthy', error: e.message };
  }

  // Check enabled APIs
  if (config.apis.firefly.enabled) {
    checks.firefly = await pingEndpoint('https://firefly-api.adobe.io');
  }
  if (config.apis.photoshop.enabled) {
    checks.photoshop = await pingEndpoint('https://image.adobe.io');
  }

  const overall = Object.values(checks).every(
    (c: any) => c.status === 'healthy'
  ) ? 'healthy' : 'degraded';

  return { status: overall, services: checks };
}

User Request
     │
     ▼
┌─────────────┐
│   Express    │ ← Webhook from Adobe I/O Events
│   Router     │
└──────┬───┬──┘
       │   │
       ▼   ▼
┌────────┐ ┌────────────┐
│Service │ │Event       │
│Layer   │ │Processor   │
└───┬────┘ └──────┬─────┘
    │              │
    ▼              ▼
┌──────────────────────┐    ┌─────────┐
│  Adobe Client Layer  │───▶│  Cache   │
│  (auth + API calls)  │    │ LRU/Redis│
└──────────┬───────────┘    └─────────┘
           │
    ┌──────┼──────┐
    ▼      ▼      ▼
┌──────┐┌──────┐┌──────┐
│Firefly││PDF   ││Photo │
│API   ││Svc   ││shop  │
└──────┘└──────┘└──────┘