// tests/kb-update/test-decisions-io.test.mjs
// Unit tests for scripts/kb-update/lib/decisions-io.mjs — the lag-2 decision
// ledger (data/decisions.json), the ONLY write-authorized bridge between
// detection and the KB/registry. Dedup policy = A (operatør 2026-06-19):
// isDecided(url) is true for ANY ledger entry (pending | approved | rejected),
// so discovery re-proposes only URLs entirely absent from the ledger.

import { test } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtempSync, rmSync, readFileSync, existsSync, readdirSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import {
  createLedger,
  loadDecisions,
  saveDecisions,
  isDecided,
  recordDecision,
  filterUndecided,
} from '../../scripts/kb-update/lib/decisions-io.mjs';

function withTmp(fn) {
  const dir = mkdtempSync(join(tmpdir(), 'dec-test-'));
  try {
    return fn(dir);
  } finally {
    rmSync(dir, { recursive: true, force: true });
  }
}

const U1 = 'https://learn.microsoft.com/azure/foundry/concepts/built-in-evaluators';
const U2 = 'https://learn.microsoft.com/azure/databricks/sql/language-manual/sql-ref-sharing';
const U3 = 'https://learn.microsoft.com/azure/ai-services/openai/whats-new';

// --- scaffold ---

test('createLedger — empty scaffold shape', () => {
  const led = createLedger();
  assert.equal(led.version, 1);
  assert.equal(led.updated_at, null);
  assert.deepEqual(led.decisions, {});
});

// --- load / save (atomic) ---

test('loadDecisions — missing file returns empty scaffold', () => {
  withTmp((dir) => {
    const led = loadDecisions(dir);
    assert.equal(led.version, 1);
    assert.deepEqual(led.decisions, {});
  });
});

test('saveDecisions + loadDecisions — round-trips', () => {
  withTmp((dir) => {
    let led = createLedger();
    led = recordDecision(led, U1, {
      status: 'rejected',
      decided_at: '2026-06-19',
      suggested_skill: 'ms-ai-engineering',
      suggested_category: 'data-engineering',
    });
    saveDecisions(led, dir);
    const back = loadDecisions(dir);
    assert.deepEqual(back, led);
  });
});

test('saveDecisions — leaves no .tmp orphan and writes decisions.json', () => {
  withTmp((dir) => {
    saveDecisions(createLedger(), dir);
    const files = readdirSync(dir);
    assert.ok(existsSync(join(dir, 'decisions.json')));
    assert.deepEqual(files.filter((f) => f.includes('.tmp')), []);
  });
});

// --- isDecided — DEDUP POLICY A ---

test('isDecided — true for ANY entry status (pending | approved | rejected)', () => {
  let led = createLedger();
  led = recordDecision(led, U1, { status: 'rejected', decided_at: '2026-06-19' });
  led = recordDecision(led, U2, { status: 'approved', decided_at: '2026-06-19' });
  led = recordDecision(led, U3, { status: 'pending', decided_at: '2026-06-19' });
  assert.equal(isDecided(led, U1), true, 'rejected must dedup');
  assert.equal(isDecided(led, U2), true, 'approved must dedup (policy A)');
  assert.equal(isDecided(led, U3), true, 'pending must dedup (policy A)');
});

test('isDecided — false for URL absent from ledger', () => {
  const led = createLedger();
  assert.equal(isDecided(led, U1), false);
});

// --- recordDecision — pure ---

test('recordDecision — sets entry, returns new ledger, does not mutate input', () => {
  const led = createLedger();
  const next = recordDecision(led, U1, {
    status: 'rejected',
    decided_at: '2026-06-19',
    suggested_skill: 'ms-ai-engineering',
    suggested_category: 'data-engineering',
    note: 'off-domain databricks page',
  });
  assert.equal(next.decisions[U1].status, 'rejected');
  assert.equal(next.decisions[U1].note, 'off-domain databricks page');
  // input untouched
  assert.deepEqual(led.decisions, {});
  assert.notEqual(next, led);
});

test('recordDecision — advances updated_at to the decision date', () => {
  const led = createLedger();
  const next = recordDecision(led, U1, { status: 'approved', decided_at: '2026-06-19' });
  assert.equal(next.updated_at, '2026-06-19');
});

// --- filterUndecided — the dedup gate discovery applies ---

test('filterUndecided — drops decided candidates (any status), keeps fresh ones', () => {
  let led = createLedger();
  led = recordDecision(led, U1, { status: 'rejected', decided_at: '2026-06-19' });
  led = recordDecision(led, U2, { status: 'approved', decided_at: '2026-06-19' });
  const candidates = [
    { url: U1, suggested_skill: 'ms-ai-engineering' }, // rejected → drop
    { url: U2, suggested_skill: 'ms-ai-engineering' }, // approved → drop
    { url: U3, suggested_skill: 'ms-ai-engineering' }, // fresh → keep
  ];
  const out = filterUndecided(led, candidates);
  assert.deepEqual(out.map((c) => c.url), [U3]);
});

// --- ACCEPTANCE CRITERION (roadmap §165): discovery 2x does not re-propose a rejected URL ---

test('dedup-diff — a rejected URL is re-proposed in round 1 but NOT in round 2', () => {
  // Round 1: empty ledger — the URL is a fresh candidate, passes the filter.
  let led = createLedger();
  const round1 = filterUndecided(led, [{ url: U1, suggested_skill: 'ms-ai-engineering' }]);
  assert.deepEqual(round1.map((c) => c.url), [U1], 'round 1 should surface the new URL');

  // Operatør rejects it through the gate — the ONLY write path.
  led = recordDecision(led, U1, { status: 'rejected', decided_at: '2026-06-19' });

  // Round 2: same discovery output, now the rejected URL must be filtered out.
  const round2 = filterUndecided(led, [{ url: U1, suggested_skill: 'ms-ai-engineering' }]);
  assert.deepEqual(round2, [], 'round 2 must NOT re-propose the rejected URL');
});