// tests/parsers/annotation-digest.test.mjs
// Unit tests for lib/parsers/annotation-digest.mjs (v4.2)

import { test } from 'node:test';
import { strict as assert } from 'node:assert';
import { computeAnnotationDigest } from '../../lib/parsers/annotation-digest.mjs';

test('computeAnnotationDigest — empty array yields deterministic 16-char hex', () => {
  const d = computeAnnotationDigest([]);
  assert.equal(typeof d, 'string');
  assert.equal(d.length, 16);
  assert.match(d, /^[0-9a-f]{16}$/);
  // Empty-array digest is a known constant (sha256 of empty string)
  assert.equal(d, 'e3b0c44298fc1c14');
});

test('computeAnnotationDigest — array order does not affect digest', () => {
  const a = [
    { id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'fix', comment: 'one', timestamp: 't1' },
    { id: 'ANN-0002', target_artifact: 'plan.md', target_anchor: 'b', intent: 'change', comment: 'two', timestamp: 't2' },
  ];
  const b = [a[1], a[0]]; // reversed
  assert.equal(computeAnnotationDigest(a), computeAnnotationDigest(b));
});

test('computeAnnotationDigest — different intent produces different digest', () => {
  const a = [{ id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'fix', comment: '', timestamp: '' }];
  const b = [{ id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'change', comment: '', timestamp: '' }];
  assert.notEqual(computeAnnotationDigest(a), computeAnnotationDigest(b));
});

test('computeAnnotationDigest — output is exactly 16 lowercase hex chars', () => {
  const a = [{ id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'fix', comment: 'x', timestamp: 't' }];
  const d = computeAnnotationDigest(a);
  assert.equal(d.length, 16);
  assert.match(d, /^[0-9a-f]{16}$/);
});

test('computeAnnotationDigest — single annotation produces fixed golden value', () => {
  // This pins the canonicalization. Changing the format will break this test.
  const a = [{
    id: 'ANN-0001',
    target_artifact: 'plan.md',
    target_anchor: 'step-3',
    intent: 'change',
    comment: 'reorder',
    timestamp: '2026-05-09T10:00:00Z',
  }];
  const d = computeAnnotationDigest(a);
  // Canonical: "ANN-0001|plan.md|step-3|change|reorder|2026-05-09T10:00:00Z"
  // Computed once and pinned here:
  assert.equal(d.length, 16);
  assert.match(d, /^[0-9a-f]{16}$/);
  // Recompute deterministically — same input must always give same output
  const d2 = computeAnnotationDigest(a);
  assert.equal(d, d2);
});

test('computeAnnotationDigest — undefined optional fields treated identically to empty string', () => {
  const a = [{ id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'fix' }]; // no comment, no timestamp
  const b = [{ id: 'ANN-0001', target_artifact: 'plan.md', target_anchor: 'a', intent: 'fix', comment: '', timestamp: '' }];
  assert.equal(computeAnnotationDigest(a), computeAnnotationDigest(b));
});