import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import {
  sha256Hex,
  buildMerkle,
  merkleProof,
  verifyProof,
  shardIndex,
} from '../src/merkle.js';

describe('merkle', () => {
  it('one leaf is its own root', () => {
    const leaf = sha256Hex('only');
    const t = buildMerkle([leaf]);
    assert.equal(t.root, leaf);
    assert.equal(verifyProof(leaf, merkleProof(t.layers, 0), t.root), true);
  });

  it('three leaves: each proof verifies, unknown leaf does not', () => {
    const leaves = ['a', 'b', 'c'].map((s) => sha256Hex(s));
    const t = buildMerkle(leaves);
    for (let i = 0; i < leaves.length; i += 1) {
      const proof = merkleProof(t.layers, i);
      assert.equal(verifyProof(leaves[i], proof, t.root), true);
    }
    assert.equal(verifyProof(sha256Hex('nope'), merkleProof(t.layers, 0), t.root), false);
  });

  it('shards stably into three nodes', () => {
    const h = sha256Hex('x');
    assert.equal(shardIndex(h, 3), shardIndex(h, 3));
    assert.ok(shardIndex(h, 3) >= 0 && shardIndex(h, 3) < 3);
  });
});