'use strict';

const AJV = require('ajv');
const ajv = new AJV();

ajv.addSchema({
  $id: 'urn:schema:foo',
  definitions: {
    foo: { type: 'string' }
  },

  type: 'object',
  properties: {
    foo: { $ref: '#/definitions/foo' }
  }
});

ajv.addSchema({
  $id: 'urn:schema:response',
  type: 'object',
  properties: {
    foo: { $ref: 'urn:schema:foo#/definitions/foo' }
  }
});

const fastify = require('fastify')();
fastify.setSchemaCompiler(schema => ajv.compile(schema));

fastify.route({
  path: '/',
  method: 'GET',
  schema: {
    response: {
      '2xx': ajv.getSchema('urn:schema:response').schema
    }
  },
  handler(req, reply) {
    reply.send({ foo: 'bar' });
  }
});

fastify.inject({ url: '/' }, (err, response) => {
  if (err) {
    throw err;
  }
  console.log(response.body);
});

/private/tmp/17/fastify-custom-ajv/index.js:44
    throw err;
    ^
FastifyError [FST_ERR_SCH_BUILD]: FST_ERR_SCH_BUILD: Failed building the schema for GET: /, due error Cannot read property '$ref' of undefined
    at Object.afterRouteAdded (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/fastify/2.8.0/node_modules/fastify/lib/route.js:224:37)
    at after (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/fastify/2.8.0/node_modules/fastify/lib/route.js:165:25)
    at Object._encapsulateThreeParam (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/boot.js:417:7)
    at Boot.callWithCbOrNextTick (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/boot.js:339:5)
    at Boot._after (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/boot.js:230:26)
    at Plugin.exec (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/plugin.js:89:17)
    at Boot.loadPlugin (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/plugin.js:175:10)
    at Task.release (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/fastq/1.6.0/node_modules/fastq/queue.js:127:16)
    at worked (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/fastq/1.6.0/node_modules/fastq/queue.js:169:10)
    at toLoad.finish (/private/tmp/17/fastify-custom-ajv/node_modules/.registry.npmjs.org/avvio/6.2.2/node_modules/avvio/plugin.js:178:7)