import assert from "node:assert/strict";
import { fileURLToPath } from "node:url";
import { test } from "node:test";
import { build } from "esbuild";

const out = await build({ entryPoints: [fileURLToPath(new URL("../src/ui/paging.ts", import.meta.url))],
  bundle: true, write: false, format: "esm", platform: "node", logLevel: "silent" });
const { pageNumbers } = await import(`data:text/javascript;base64,${Buffer.from(out.outputFiles[0].text).toString("base64")}`);

test("few pages are all listed", () => {
  assert.deepEqual(pageNumbers(0, 1), [0]);
  assert.deepEqual(pageNumbers(2, 5), [0, 1, 2, 3, 4]);
  assert.deepEqual(pageNumbers(0, 7), [0, 1, 2, null, 6]);
});

test("a long list keeps the ends and the neighbourhood, with gaps between", () => {
  assert.deepEqual(pageNumbers(0, 100), [0, 1, 2, null, 99]);
  assert.deepEqual(pageNumbers(50, 100), [0, null, 48, 49, 50, 51, 52, null, 99]);
  assert.deepEqual(pageNumbers(99, 100), [0, null, 97, 98, 99]);
});

test("a gap of exactly one page shows that page instead of dots", () => {
  assert.deepEqual(pageNumbers(4, 10), [0, 1, 2, 3, 4, 5, 6, null, 9]);
  assert.deepEqual(pageNumbers(3, 10), [0, 1, 2, 3, 4, 5, null, 9]);
});