// ESM
import { testApiHandler } from 'next-test-api-route-handler';

/* File: test/unit.test.ts */

import { testApiHandler } from 'next-test-api-route-handler';
// Import the handler under test from the pages/api directory
import endpoint, { config } from '../pages/api/your-endpoint';
import type { PageConfig } from 'next';

// Respect the Next.js config object if it's exported
const handler: typeof endpoint & { config?: PageConfig } = endpoint;
handler.config = config;

await testApiHandler({
  handler,
  requestPatcher: (req) => (req.headers = { key: process.env.SPECIAL_TOKEN }),
  test: async ({ fetch }) => {
    const res = await fetch({ method: 'POST', body: 'data' });
    console.log(await res.json()); // ◄ outputs: "{hello: 'world'}"
  }
});

// NTARH also supports typed response data via TypeScript generics:
await testApiHandler<{ hello: string }>({
  // The next line would cause TypeScript to complain:
  // handler: (_, res) => res.status(200).send({ hello: false }),
  handler: (_, res) => res.status(200).send({ hello: 'world' }),
  requestPatcher: (req) => (req.headers = { key: process.env.SPECIAL_TOKEN }),
  test: async ({ fetch }) => {
    const res = await fetch({ method: 'POST', body: 'data' });
    // The next line would cause TypeScript to complain:
    // const { goodbye } = await res.json();
    const { hello } = await res.json();
    console.log(hello); // ◄ outputs: "world"
  }
});

async function testApiHandler({
  requestPatcher,
  responsePatcher,
  paramsPatcher,
  params,
  url,
  handler,
  test
}: {
  requestPatcher?: (req: IncomingMessage) => void;
  responsePatcher?: (res: ServerResponse) => void;
  paramsPatcher?: (params: Record<string, unknown>) => void;
  params?: Record<string, unknown>;
  url?: string;
  handler: (req: NextApiRequest, res: NextApiResponse) => Promise<void>;
  test: ({
    fetch: (init?: RequestInit) => ReturnType<typeof fetch>;
  }) => Promise<void>;
});

/* File: examples/api-routes-apollo-server-and-client/tests/my.test.js */

import { testApiHandler } from 'next-test-api-route-handler';
// Import the handler under test from the pages/api directory
import handler, { config } from '../pages/api/graphql';
// Respect the Next.js config object if it's exported
handler.config = config;

describe('my-test', () => {
  it('does what I want 1', async () => {
    expect.hasAssertions();

    await testApiHandler({
      handler,
      url: '/api/graphql', // Set the request url to the path graphql expects
      test: async ({ fetch }) => {
        const query = `query ViewerQuery {
          viewer {
            id
            name
            status
          }
        }`;

        const res = await fetch({
          method: 'POST',
          headers: {
            'content-type': 'application/json' // Must use correct content type
          },
          body: JSON.stringify({
            query
          })
        });

        expect(await res.json()).toStrictEqual({
          data: { viewer: { id: '1', name: 'John Smith', status: 'cached' } }
        });
      }
    });
  });

  it('does what I want 2', async () => {
    // Exactly the same as the above...
  });

  it('does what I want 3', async () => {
    // Exactly the same as the above...
  });
});

/* File: test/unit.test.ts */

// Import the handler under test from the pages/api directory
import endpoint, { config } from '../pages/api/unreliable';
import { testApiHandler } from 'next-test-api-route-handler';

import type { PageConfig } from 'next';

const expectedReqPerError = 10;

// Respect the Next.js config object if it's exported
const handler: typeof endpoint & { config?: PageConfig } = endpoint;
handler.config = config;

it('injects contrived errors at the required rate', async () => {
  expect.hasAssertions();

  // Signal to the endpoint (which is configurable) that there should be 1
  // error among every 10 requests
  process.env.REQUESTS_PER_CONTRIVED_ERROR = expectedReqPerError.toString();

  await testApiHandler({
    handler,
    test: async ({ fetch }) => {
      // Run 20 requests with REQUESTS_PER_CONTRIVED_ERROR = '10' and
      // record the results
      const results1 = await Promise.all(
        [
          ...Array.from({ length: expectedReqPerError - 1 }).map(() =>
            fetch({ method: 'GET' })
          ),
          fetch({ method: 'POST' }),
          ...Array.from({ length: expectedReqPerError - 1 }).map(() =>
            fetch({ method: 'PUT' })
          ),
          fetch({ method: 'DELETE' })
        ].map((p) => p.then((r) => r.status))
      );

      process.env.REQUESTS_PER_CONTRIVED_ERROR = '0';

      // Run 10 requests with REQUESTS_PER_CONTRIVED_ERROR = '0' and record the
      // results
      const results2 = await Promise.all(
        Array.from({ length: expectedReqPerError }).map(() =>
          fetch().then((r) => r.status)
        )
      );

      // We expect results1 to be an array with eighteen `200`s and two
      // `555`s in any order
      //
      // https://github.com/jest-community/jest-extended#toincludesamemembersmembers
      // because responses could be received out of order
      expect(results1).toIncludeSameMembers([
        ...Array.from({ length: expectedReqPerError - 1 }).map(() => 200),
        555,
        ...Array.from({ length: expectedReqPerError - 1 }).map(() => 200),
        555
      ]);

      // We expect results2 to be an array with ten `200`s
      expect(results2).toStrictEqual([
        ...Array.from({ length: expectedReqPerError }).map(() => 200)
      ]);
    }
  });
});

/* File: test/unit.test.ts */

import endpoint, { config } from '../pages/api/v3/flights/search';
import { testApiHandler } from 'next-test-api-route-handler';
import { DUMMY_API_KEY as KEY, getFlightData, RESULT_SIZE } from '../backend';

import type { PageConfig } from 'next';

// Respect the Next.js config object if it's exported
const handler: typeof endpoint & { config?: PageConfig } = endpoint;
handler.config = config;

it('returns expected public flights with respect to match', async () => {
  expect.hasAssertions();

  // Get the flight data currently in the test database
  const expectedFlights = getFlightData();

  // Take any JSON object and stringify it into a URL-ready string
  const encode = (o: Record<string, unknown>) =>
    encodeURIComponent(JSON.stringify(o));

  // This function will return in order the URIs we're interested in testing
  // against our handler. Query strings are parsed by NTARH automatically.
  //
  // DO NOTE: setting the request url manually using encode(), while valid, is
  // unnecessary here; we could have used `params` or `paramPatcher` to do this
  // more easily without explicitly setting a dummy request url.
  //
  // Example URI for `https://site.io/path?param=yes` would be `/path?param=yes`
  const genUrl = (function* () {
    // For example, the first should match all the flights from Spirit airlines!
    yield `/?match=${encode({ airline: 'Spirit' })}`;
    yield `/?match=${encode({ type: 'departure' })}`;
    yield `/?match=${encode({ landingAt: 'F1A' })}`;
    yield `/?match=${encode({ seatPrice: 500 })}`;
    yield `/?match=${encode({ seatPrice: { $gt: 500 } })}`;
    yield `/?match=${encode({ seatPrice: { $gte: 500 } })}`;
    yield `/?match=${encode({ seatPrice: { $lt: 500 } })}`;
    yield `/?match=${encode({ seatPrice: { $lte: 500 } })}`;
  })();

  await testApiHandler({
    // Patch the request object to include our dummy URI
    requestPatcher: (req) => {
      req.url = genUrl.next().value || undefined;
      // Could have done this instead of `fetch({ headers: { KEY }})` below:
      // req.headers = { KEY };
    },

    handler,

    test: async ({ fetch }) => {
      // 8 URLS from genUrl means 8 calls to fetch:
      const responses = await Promise.all(
        Array.from({ length: 8 }).map(() =>
          fetch({ headers: { KEY } }).then(async (r) => [
            r.status,
            await r.json()
          ])
        )
      );

      // We expect all of the responses to be 200
      expect(responses.some(([status]) => status != 200)).toBe(false);

      // We expect the array of flights returned to match our
      // expectations given we already know what dummy data will be
      // returned:

      // https://github.com/jest-community/jest-extended#toincludesamemembersmembers
      // because responses could be received out of order
      expect(responses.map(([, r]) => r.flights)).toIncludeSameMembers([
        expectedFlights
          .filter((f) => f.airline == 'Spirit')
          .slice(0, RESULT_SIZE),
        expectedFlights
          .filter((f) => f.type == 'departure')
          .slice(0, RESULT_SIZE),
        expectedFlights
          .filter((f) => f.landingAt == 'F1A')
          .slice(0, RESULT_SIZE),
        expectedFlights.filter((f) => f.seatPrice == 500).slice(0, RESULT_SIZE),
        expectedFlights.filter((f) => f.seatPrice > 500).slice(0, RESULT_SIZE),
        expectedFlights.filter((f) => f.seatPrice >= 500).slice(0, RESULT_SIZE),
        expectedFlights.filter((f) => f.seatPrice < 500).slice(0, RESULT_SIZE),
        expectedFlights.filter((f) => f.seatPrice <= 500).slice(0, RESULT_SIZE)
      ]);
    }
  });

  // We expect these two to fail with 400 errors

  await testApiHandler({
    handler,
    url: `/?match=${encode({ ffms: { $eq: 500 } })}`,
    test: async ({ fetch }) =>
      expect((await fetch({ headers: { KEY } })).status).toBe(400)
  });

  await testApiHandler({
    handler,
    url: `/?match=${encode({ bad: 500 })}`,
    test: async ({ fetch }) =>
      expect((await fetch({ headers: { KEY } })).status).toBe(400)
  });
});