/**
 * The complete webhook event payload sent by Peanuts
 */
interface WebhookEvent {
  /** The type of event that triggered the webhook */
  event: "entry.created" | "entry.updated" | "entry.deleted";
  
  /** ISO 8601 timestamp of when the event occurred */
  timestamp: string;
  
  /** Information about the Helper that owns the entry */
  helper: HelperInfo;
  
  /** The entry data that triggered the event */
  entry: EntryData;
}

/**
 * Metadata about the Helper (mini-app)
 */
interface HelperInfo {
  /** Unique identifier for the Helper */
  id: string;
  
  /** Display name of the Helper */
  name: string;
  
  /** The slash command used to create this Helper */
  command: string;
}

/**
 * The entry that was created, updated, or deleted
 */
interface EntryData {
  /** Unique identifier for the entry */
  id: string;
  
  /** 
   * Dynamic key-value pairs matching the Helper's field configuration.
   * Keys are field names, values depend on field type.
   */
  data: Record<string, unknown>;
  
  /** ISO 8601 timestamp of when the entry was created */
  created_at: string;
}

{
  "event": "entry.created",
  "timestamp": "2025-01-15T14:32:00.000Z",
  "helper": {
    "id": "abc123-def456-789",
    "name": "Daily Expenses",
    "command": "/expenses"
  },
  "entry": {
    "id": "entry-789-xyz",
    "data": {
      "amount": 42.50,
      "category": "Food & Dining",
      "description": "Team lunch at Olive Garden",
      "date": "2025-01-15"
    },
    "created_at": "2025-01-15T14:32:00.000Z"
  }
}

POST /your-webhook-endpoint HTTP/1.1
Host: your-server.com
Content-Type: application/json
User-Agent: Peanuts-Webhook/1.0
X-Peanuts-Signature: sha256=a1b2c3d4e5f6...

sha256={hex_encoded_signature}

import { createHmac, timingSafeEqual } from 'crypto';

function verifySignature(
  payload: string, 
  signature: string, 
  secret: string
): boolean {
  const expected = createHmac('sha256', secret)
    .update(payload)
    .digest('hex');
  
  const sig = signature.replace('sha256=', '');
  
  return timingSafeEqual(
    Buffer.from(sig, 'hex'),
    Buffer.from(expected, 'hex')
  );
}