// Unit tests for src/main.js, run by script/frontend-test with Node's
// built-in test runner. Importing the module does not start the page.

import { after, before, test } from "node:test";
import assert from "node:assert/strict";
import { createServer } from "node:http";
import { CONFIG, measureLatency } from "../../src/main.js";

// measureLatency writes timeouts to the debug log, which looks for its
// panel in the page. There is no page here.
globalThis.document = { getElementById: () => null };

// A target that answers after the number of milliseconds in the path,
// e.g. /600.
let server;
let target;

before(async () => {
    server = createServer((req, res) => {
        const delay = Number(new URL(req.url, "http://x").pathname.slice(1));
        setTimeout(() => res.end(), delay);
    });
    await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));
    target = `http://127.0.0.1:${server.address().port}`;
});

after(() => {
    server.closeAllConnections();
    server.close();
});

test("the timeout is 80% of the refresh interval", () => {
    CONFIG.updateInterval = 30000;
    assert.equal(CONFIG.requestTimeout, 24000);
    CONFIG.updateInterval = 3000;
    assert.equal(CONFIG.requestTimeout, 2400);
});

test("an answer within the timeout is recorded with its real time, a later one as a timeout", async () => {
    // 600ms is past the 400ms timeout of a 500ms interval...
    CONFIG.updateInterval = 500;
    assert.deepEqual(await measureLatency(`${target}/600`), {
        latency: null,
        error: "timeout",
    });

    // ...and within the 1200ms timeout of a 1500ms interval.
    CONFIG.updateInterval = 1500;
    const { latency, error } = await measureLatency(`${target}/600`);
    assert.equal(error, null);
    assert.ok(latency >= 600 && latency < 1200, `latency ${latency}ms`);
});