"use strict";

const test = require("node:test");
const assert = require("node:assert/strict");
const { Readable, Writable } = require("node:stream");
const {
  createSkyscannerSampleHandler,
  buildSampleOffers,
} = require("../src/skyscannerSampleServer");

function createMockRequest({ method = "POST", url = "/skyscanner", body = "" } = {}) {
  const req = new Readable({
    read() {
      this.push(body);
      this.push(null);
    },
  });
  req.method = method;
  req.url = url;
  return req;
}

function createMockResponse() {
  const chunks = [];
  let statusCode = 0;
  let headers = {};
  let resolveDone;
  const done = new Promise((resolve) => {
    resolveDone = resolve;
  });

  const res = new Writable({
    write(chunk, _encoding, callback) {
      chunks.push(Buffer.from(chunk));
      callback();
    },
  });

  res.writeHead = (status, responseHeaders) => {
    statusCode = status;
    headers = responseHeaders || {};
  };

  res.end = (chunk) => {
    if (chunk) chunks.push(Buffer.from(chunk));
    resolveDone();
  };

  return {
    res,
    done,
    getStatusCode() {
      return statusCode;
    },
    getHeaders() {
      return headers;
    },
    getJsonBody() {
      return JSON.parse(Buffer.concat(chunks).toString("utf8"));
    },
  };
}

test("buildSampleOffers is deterministic for the same search params", () => {
  const searchParams = {
    segments: [{ from: "ICN", to: "MAD" }],
    passengers: { total: 2 },
  };

  const first = buildSampleOffers(searchParams);
  const second = buildSampleOffers(searchParams);

  assert.deepEqual(first, second);
  assert.equal(first[0].provider, "skyscanner");
  assert.equal(first[0].currency, "KRW");
});

test("sample handler returns skyscanner offers on POST /skyscanner", async () => {
  const handler = createSkyscannerSampleHandler();
  const req = createMockRequest({
    body: JSON.stringify({
      watchId: "watch-1",
      searchParams: {
        segments: [{ from: "ICN", to: "MAD" }],
      },
    }),
  });
  const response = createMockResponse();

  await handler(req, response.res);
  await response.done;

  assert.equal(response.getStatusCode(), 200);
  assert.equal(response.getHeaders()["content-type"], "application/json; charset=utf-8");
  const payload = response.getJsonBody();
  assert.equal(payload.currency, "KRW");
  assert.ok(Array.isArray(payload.offers));
  assert.equal(payload.offers.length, 3);
  assert.equal(payload.offers[0].provider, "skyscanner");
});

test("sample handler accepts wrapped request payload shape", async () => {
  const handler = createSkyscannerSampleHandler();
  const req = createMockRequest({
    body: JSON.stringify({
      request: {
        watchId: "watch-2",
        searchParams: {
          segments: [{ from: "ICN", to: "BCN" }],
        },
      },
    }),
  });
  const response = createMockResponse();

  await handler(req, response.res);
  await response.done;

  assert.equal(response.getStatusCode(), 200);
  const payload = response.getJsonBody();
  assert.equal(payload.offers[0].provider, "skyscanner");
});

test("sample handler returns 404 for unsupported route", async () => {
  const handler = createSkyscannerSampleHandler();
  const req = createMockRequest({
    url: "/not-skyscanner",
    body: JSON.stringify({}),
  });
  const response = createMockResponse();

  await handler(req, response.res);
  await response.done;

  assert.equal(response.getStatusCode(), 404);
  assert.match(response.getJsonBody().expected, /POST \/skyscanner/);
});