// tests/kb-update/test-decisions-courses.test.mjs
// Spor C / C3.5 (Sesjon 36): the ADDITIVE course-lead layer on the lag-2
// decision ledger. Courses are a THIRD entity type (UID-keyed) — the URL-keyed
// `decisions` map (Spor A) and the skill-keyed `actions` map (Spor B) are both
// untouched. Their contracts stay covered by test-decisions-io.test.mjs and
// test-decisions-actions.test.mjs, which remain green UNMODIFIED, proving this
// extension is non-regressive. Here we cover only the new `courses` collection:
// recordCourseLead (pure), isCourseLeadDecided (dedup policy A per UID),
// setCourseLeadStatus (pure transition), and backward-compatible normalization
// of pre-course ledgers.
//
// WHY a separate collection (spec §4.5): an approved course lead must NEVER
// reach the doc-transform/ingest pipeline (auto-ingest is an explicit non-goal).
// Keeping leads UID-keyed in `courses` holds them structurally out of the
// `decisions` stream the apply-path reads — the apply-path (apply-skill-op.mjs,
// discover-new-urls.mjs) reads only `actions`/`decisions`, never `courses`.

import { test } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import {
  createLedger,
  loadDecisions,
  saveDecisions,
  recordDecision,
  isDecided,
  recordAction,
  isActionDecided,
  actionKey,
  recordCourseLead,
  isCourseLeadDecided,
  setCourseLeadStatus,
} from '../../scripts/kb-update/lib/decisions-io.mjs';

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

const UID = 'learn.wwl.introduction-to-azure-openai';
const LEAD = {
  kind: 'new', // "new" | "updated"
  status: 'pending', // pending | approved | rejected (dedup policy A)
  title: 'Introduction to Azure OpenAI Service',
  url: 'https://learn.microsoft.com/training/modules/intro-azure-openai/',
  products: ['azure-openai'],
  suggested_skill: 'ms-ai-engineering',
  suggested_category: 'azure-ai-services',
  updated_at: '2026-06-20T08:00:00Z',
  detected_at: '2026-06-23T12:00:00Z',
  decided_at: null,
  note: '',
};

// --- scaffold now carries an empty courses collection (additive) ---

test('createLedger — additive courses:{} alongside untouched decisions:{} + actions:{}', () => {
  const led = createLedger();
  assert.equal(led.version, 1, 'version stays 1 — no migration needed');
  assert.deepEqual(led.decisions, {}, 'URL-keyed map unchanged');
  assert.deepEqual(led.actions, {}, 'skill-op map unchanged');
  assert.deepEqual(led.courses, {}, 'new UID-keyed course-lead collection present and empty');
});

// --- isCourseLeadDecided — dedup gate (policy A: any status counts) ---

test('isCourseLeadDecided — false when absent, true for ANY recorded status (policy A)', () => {
  let led = createLedger();
  assert.equal(isCourseLeadDecided(led, UID), false, 'absent UID is undecided');
  led = recordCourseLead(led, UID, { ...LEAD, status: 'rejected', decided_at: '2026-06-23' });
  assert.equal(isCourseLeadDecided(led, UID), true, 'rejected lead still dedups (policy A)');
});

test('isCourseLeadDecided — true for pending and approved alike (policy A)', () => {
  let led = createLedger();
  led = recordCourseLead(led, 'uid-pending', { ...LEAD, status: 'pending', decided_at: '2026-06-23' });
  led = recordCourseLead(led, 'uid-approved', { ...LEAD, status: 'approved', decided_at: '2026-06-23' });
  assert.equal(isCourseLeadDecided(led, 'uid-pending'), true, 'pending dedups (policy A)');
  assert.equal(isCourseLeadDecided(led, 'uid-approved'), true, 'approved dedups (policy A)');
});

// --- recordCourseLead — pure, mirrors recordAction ---

test('recordCourseLead — records under UID, returns new ledger, does not mutate input', () => {
  const led = createLedger();
  const next = recordCourseLead(led, UID, LEAD);
  assert.deepEqual(led.courses, {}, 'input untouched');
  assert.notEqual(next, led);
  assert.equal(next.courses[UID].kind, 'new');
  assert.equal(next.courses[UID].status, 'pending');
  assert.equal(next.courses[UID].suggested_skill, 'ms-ai-engineering');
  assert.deepEqual(next.courses[UID].products, ['azure-openai']);
});

test('recordCourseLead — advances updated_at to the decision date', () => {
  const next = recordCourseLead(createLedger(), UID, {
    ...LEAD,
    status: 'approved',
    decided_at: '2026-06-23',
  });
  assert.equal(next.updated_at, '2026-06-23');
});

test('recordCourseLead — a pending lead (decided_at null) leaves updated_at unchanged', () => {
  const next = recordCourseLead(createLedger(), UID, LEAD); // decided_at: null
  assert.equal(next.updated_at, null, 'no decision date -> ledger updated_at untouched');
});

test('recordCourseLead — keyed by stable UID, not URL (dedup survives a URL change)', () => {
  let led = recordCourseLead(createLedger(), UID, LEAD);
  // Same course re-detected later with a changed URL but the SAME UID.
  led = recordCourseLead(led, UID, { ...LEAD, url: 'https://learn.microsoft.com/training/modules/renamed/' });
  assert.equal(Object.keys(led.courses).length, 1, 'same UID dedups to one entry despite URL change');
  assert.equal(isCourseLeadDecided(led, UID), true);
});

test('recordCourseLead — does NOT touch the URL-keyed decisions or skill-keyed actions maps', () => {
  let led = recordDecision(createLedger(), 'https://learn.microsoft.com/x', {
    status: 'approved',
    decided_at: '2026-06-19',
  });
  led = recordAction(led, {
    operation_type: 'sanitize_skill',
    status: 'approved',
    decided_at: '2026-06-20',
    targets: { skill: 'ms-ai-governance' },
  });
  const next = recordCourseLead(led, UID, LEAD);
  assert.equal(isDecided(next, 'https://learn.microsoft.com/x'), true, 'URL decision survives');
  assert.equal(isActionDecided(next, actionKey({ operation_type: 'sanitize_skill', targets: { skill: 'ms-ai-governance' } })), true, 'action survives');
  assert.equal(isCourseLeadDecided(next, UID), true, 'course lead recorded alongside');
});

// --- ACCEPTANCE CRITERION (gate dedup): a decided course is NOT re-proposed ---
// Mirrors the discovery dedup-diff acceptance test (test-decisions-io.test.mjs):
// the gate filters report candidates through isCourseLeadDecided, so a course
// the operator has already touched (any status) never resurfaces.

test('dedup-diff — a decided course UID is surfaced in round 1 but filtered in round 2', () => {
  const filterUndecidedCourses = (ledger, candidates) =>
    candidates.filter((c) => !isCourseLeadDecided(ledger, c.uid));

  // Round 1: empty ledger — the course is a fresh candidate.
  let led = createLedger();
  const round1 = filterUndecidedCourses(led, [{ uid: UID }]);
  assert.deepEqual(round1.map((c) => c.uid), [UID], 'round 1 surfaces the new course');

  // Operator rejects it through the gate — the ONLY write path.
  led = recordCourseLead(led, UID, { ...LEAD, status: 'rejected', decided_at: '2026-06-23' });

  // Round 2: same detection output, the decided course must be filtered out.
  const round2 = filterUndecidedCourses(led, [{ uid: UID }]);
  assert.deepEqual(round2, [], 'round 2 must NOT re-propose the decided course');
});

// --- setCourseLeadStatus — pure status transition (mirrors setActionStatus) ---

test('setCourseLeadStatus — transitions status, preserves every other field, is pure', () => {
  const led = recordCourseLead(createLedger(), UID, { ...LEAD, status: 'pending' });
  const next = setCourseLeadStatus(led, UID, 'approved', '2026-06-24');

  assert.equal(led.courses[UID].status, 'pending', 'input ledger untouched (pure)');
  assert.notEqual(next, led);
  assert.equal(next.courses[UID].status, 'approved');
  assert.equal(next.courses[UID].title, LEAD.title, 'title preserved');
  assert.deepEqual(next.courses[UID].products, LEAD.products, 'products preserved');
  assert.equal(next.courses[UID].suggested_skill, LEAD.suggested_skill, 'suggested_skill preserved');
});

test('setCourseLeadStatus — advances entry decided_at and ledger updated_at', () => {
  const led = recordCourseLead(createLedger(), UID, { ...LEAD, status: 'pending' });
  const next = setCourseLeadStatus(led, UID, 'approved', '2026-06-24');
  assert.equal(next.courses[UID].decided_at, '2026-06-24', 'entry date advances');
  assert.equal(next.updated_at, '2026-06-24');
});

test('setCourseLeadStatus — without a date keeps the entry decided_at and ledger updated_at', () => {
  let led = recordCourseLead(createLedger(), UID, { ...LEAD, status: 'pending', decided_at: '2026-06-23' });
  const next = setCourseLeadStatus(led, UID, 'approved');
  assert.equal(next.courses[UID].decided_at, '2026-06-23', 'no date -> keep original');
});

test('setCourseLeadStatus — throws on an unknown UID (cannot transition a non-entry)', () => {
  const led = recordCourseLead(createLedger(), UID, LEAD);
  assert.throws(() => setCourseLeadStatus(led, 'uid-ghost', 'approved'), /no course|ghost/i);
});

test('setCourseLeadStatus — leaves decisions, actions, and sibling courses untouched', () => {
  let led = recordDecision(createLedger(), 'https://learn.microsoft.com/x', {
    status: 'approved',
    decided_at: '2026-06-19',
  });
  led = recordCourseLead(led, UID, { ...LEAD, status: 'pending' });
  led = recordCourseLead(led, 'uid-sibling', { ...LEAD, status: 'pending' });
  const next = setCourseLeadStatus(led, UID, 'approved', '2026-06-24');

  assert.equal(isDecided(next, 'https://learn.microsoft.com/x'), true, 'URL decision survives');
  assert.equal(next.courses['uid-sibling'].status, 'pending', 'sibling course untouched');
});

// --- backward compatibility: a pre-course ledger on disk loads cleanly ---

test('loadDecisions — normalizes a pre-course (no courses key) ledger to courses:{}', () => {
  withTmp((dir) => {
    // Simulate an on-disk ledger written before the course layer existed.
    writeFileSync(
      join(dir, 'decisions.json'),
      JSON.stringify({ version: 1, updated_at: null, decisions: {}, actions: {} }, null, 2),
    );
    const led = loadDecisions(dir);
    assert.deepEqual(led.courses, {}, 'missing courses key is backfilled, not undefined');
    // and recording a course lead on the loaded ledger works
    const next = recordCourseLead(led, UID, LEAD);
    assert.equal(isCourseLeadDecided(next, UID), true);
  });
});

test('saveDecisions + loadDecisions — courses round-trip through disk', () => {
  withTmp((dir) => {
    const led = recordCourseLead(createLedger(), UID, LEAD);
    saveDecisions(led, dir);
    const back = loadDecisions(dir);
    assert.deepEqual(back, led);
  });
});