import assert from "node:assert/strict";
import { webcrypto } from "node:crypto";
import { describe, it } from "node:test";
import { z } from "zod";
import { createClientId } from "../src/frontend/utils/client-id.js";

const uuidV4 = /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/;

describe("client id", () => {
  it("uses crypto.randomUUID when the context provides it", () => {
    const id = createClientId({
      getRandomValues: () => {
        throw new Error("fallback must not be used");
      },
      randomUUID: () => "11111111-2222-4333-8444-555555555555",
    });
    assert.equal(id, "11111111-2222-4333-8444-555555555555");
  });

  it("falls back to getRandomValues outside a secure context", () => {
    const insecure = {
      getRandomValues: webcrypto.getRandomValues.bind(webcrypto),
    } as Pick<Crypto, "getRandomValues">;
    const ids = new Set<string>();
    for (let index = 0; index < 200; index += 1) {
      const id = createClientId(insecure);
      assert.match(id, uuidV4);
      assert.equal(z.string().uuid().safeParse(id).success, true);
      ids.add(id);
    }
    assert.equal(ids.size, 200);
  });

  it("sets version and variant bits regardless of the random bytes", () => {
    const allOnes = {
      getRandomValues: <T extends ArrayBufferView | null>(array: T) => {
        if (array instanceof Uint8Array) {
          array.fill(0xff);
        }
        return array;
      },
    } as Pick<Crypto, "getRandomValues">;
    assert.equal(createClientId(allOnes), "ffffffff-ffff-4fff-bfff-ffffffffffff");
  });
});