import type { FastifyInstance } from 'fastify';

export function registerJsonBodyParser(app: FastifyInstance) {
  app.addContentTypeParser('application/json', { parseAs: 'string' }, (request, body, done) => {
    const rawBody = typeof body === 'string' ? body : '';
    const normalizedBody = rawBody.trim();

    if (!normalizedBody) {
      done(null, {});
      return;
    }

    try {
      done(null, JSON.parse(normalizedBody));
    } catch {
      const error = new Error('Body is not valid JSON.') as Error & {
        statusCode?: number;
        code?: string;
      };
      error.statusCode = 400;
      error.code = 'FST_ERR_CTP_INVALID_JSON_BODY';
      done(error, undefined);
    }
  });
}