// Sources arrived in retrieval order — an order the reader never sees and
// cannot follow. An answer whose first citation was [7] opened a list that
// began at [1], so matching a marker to a source meant hunting for it.
//
// Borrowed from the quiz app, where validating citations and ordering them fall
// out of the same pass: it collects the sources the answer actually used into an
// insertion-ordered map, so the list comes back in first-citation order for
// free. Reference lists in published writing are numbered by first appearance
// for the same reason.
const test = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const vm = require('node:vm');

function load() {
  const src = fs.readFileSync(path.join(__dirname, '..', 'public/js/assistant/citations.js'), 'utf8')
    .replace(/^import[\s\S]*?from ['"][^'"]+['"];\s*/gm, '')
    .replace(/^export /gm, '');
  const ctx = { window: {}, document: undefined, console };
  vm.createContext(ctx);
  vm.runInContext(src + '\nthis.orderSourcesByCitation = orderSourcesByCitation;', ctx);
  return ctx;
}

const four = [
  { number: 1, title: 'Alpha' }, { number: 2, title: 'Beta' },
  { number: 3, title: 'Gamma' }, { number: 4, title: 'Delta' }
];

test('sources come back in the order the answer cites them', () => {
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('Third first [3]. Then the first [1].', four);
  assert.deepEqual(Array.from(out.sources.slice(0, 2), s => s.title), ['Gamma', 'Alpha']);
  assert.equal(out.text, 'Third first [1]. Then the first [2].');
});

test('a cluster is renumbered as a whole, in its own order', () => {
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('Both of these [4, 2] agree.', four);
  assert.equal(out.text, 'Both of these [1, 2] agree.');
  assert.deepEqual(Array.from(out.sources.slice(0, 2), s => s.title), ['Delta', 'Beta']);
});

test('renumbering happens in one pass, so nothing is renumbered twice', () => {
  // Rewriting number by number turns 2 into 1, then that 1 into whatever 1
  // maps to. The whole text is rewritten once instead.
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('[2] then [1] then [2] again.', four);
  assert.equal(out.text, '[1] then [2] then [1] again.');
});

test('a source cited twice keeps its first position', () => {
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('[3] ... [1] ... [3] again.', four);
  assert.deepEqual(Array.from(out.sources.slice(0, 2), s => s.title), ['Gamma', 'Alpha']);
});

test('retrieved but uncited sources follow, marked and still numbered', () => {
  // The panel is also a view of what the search returned, so they stay — just
  // no longer mixed in among the numbers the answer used.
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('Only this one [2].', four);
  assert.equal(out.sources[0].title, 'Beta');
  assert.equal(out.sources[0].uncited, undefined);
  assert.equal(out.sources.length, 4, 'nothing is dropped');
  assert.deepEqual(Array.from(out.sources.slice(1), s => s.uncited), [true, true, true]);
  assert.deepEqual(Array.from(out.sources, s => s.number), [1, 2, 3, 4], 'numbering stays contiguous');
});

test('an invented citation reserves no place and is left alone', () => {
  // It is not turned into a link either; the audit records it. What matters
  // here is that it cannot push a real source down the list.
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('Invented [9]. Real [2].', four);
  assert.equal(out.sources[0].title, 'Beta');
  assert.match(out.text, /Invented \[9\]/, 'the unresolved marker is untouched');
  assert.match(out.text, /Real \[1\]/);
});

test('a cluster containing an invented number is left whole', () => {
  // Renumbering half of it would silently change which source the good half
  // points at.
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('Mixed [2, 9].', four);
  assert.equal(out.text, 'Mixed [2, 9].');
});

test('an answer that cites nothing is returned untouched', () => {
  const { orderSourcesByCitation } = load();
  const out = orderSourcesByCitation('No citations here.', four);
  assert.equal(out.text, 'No citations here.');
  assert.deepEqual(Array.from(out.sources), four);
});

test('the originals are not mutated, so a stored answer stays readable', () => {
  // Its text still holds the original markers; renumbering in place would make
  // the two disagree.
  const { orderSourcesByCitation } = load();
  const before = JSON.parse(JSON.stringify(four));
  orderSourcesByCitation('[3] [1]', four);
  assert.deepEqual(four, before);
});

test('sources with no number field fall back to position', () => {
  const { orderSourcesByCitation } = load();
  const bare = [{ title: 'One' }, { title: 'Two' }, { title: 'Three' }];
  const out = orderSourcesByCitation('Cite the third [3].', bare);
  assert.equal(out.sources[0].title, 'Three');
  assert.equal(out.text, 'Cite the third [1].');
});