import type { Request } from 'express'
import { ValidationError } from './errors'

export function getRawBodyString(req: Request) {
  if (!Buffer.isBuffer(req.body)) {
    throw new ValidationError('Webhook route must be mounted with express.raw before JSON parsing')
  }
  return req.body.toString('utf8')
}

export function parseRawJsonBody<T = unknown>(req: Request): T {
  const rawBody = getRawBodyString(req)
  try {
    return JSON.parse(rawBody) as T
  } catch {
    throw new ValidationError('Malformed webhook JSON')
  }
}