import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import {
  assessFreshness,
  STALE_AFTER_DAYS_DEFAULT,
} from '../../scanners/lib/knowledge-refresh.mjs';

// Build a register with one entry verified on `verified`.
const entry = (id, verified, extra = {}) => ({
  id,
  claim: `claim for ${id}`,
  confidence: 'confirmed',
  source: { url: `https://example.com/${id}`, title: id, verified },
  ...extra,
});
const reg = (entries) => ({ version: 1, entries });

const REF = '2026-06-21';

describe('STALE_AFTER_DAYS_DEFAULT', () => {
  it('is 90 (quarterly re-verify cadence)', () => {
    assert.equal(STALE_AFTER_DAYS_DEFAULT, 90);
  });
});

describe('assessFreshness — classification', () => {
  it('classifies a recently-verified entry as fresh', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-06-01')]), { referenceDate: REF });
    assert.equal(r.counts.fresh, 1);
    assert.equal(r.counts.stale, 0);
    assert.equal(r.fresh[0].id, 'BP-A-001');
  });

  it('classifies an entry older than the threshold as stale', () => {
    // 2026-01-01 → 2026-06-21 is 171 days > 90
    const r = assessFreshness(reg([entry('BP-A-001', '2026-01-01')]), { referenceDate: REF });
    assert.equal(r.counts.stale, 1);
    assert.equal(r.counts.fresh, 0);
    assert.equal(r.stale[0].id, 'BP-A-001');
    assert.equal(r.stale[0].ageDays, 171);
  });

  it('treats exactly staleAfterDays as still fresh (strictly-greater is stale)', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-03-23')]), {
      referenceDate: REF,
      staleAfterDays: 90,
    });
    // 2026-03-23 → 2026-06-21 is exactly 90 days
    assert.equal(r.fresh[0].ageDays, 90);
    assert.equal(r.counts.fresh, 1);
    assert.equal(r.counts.stale, 0);
  });

  it('treats one day past the threshold as stale', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-03-22')]), {
      referenceDate: REF,
      staleAfterDays: 90,
    });
    assert.equal(r.stale[0].ageDays, 91);
    assert.equal(r.counts.stale, 1);
  });

  it('respects a custom staleAfterDays', () => {
    const entries = [entry('BP-A-001', '2026-06-01')]; // 20 days old
    assert.equal(assessFreshness(reg(entries), { referenceDate: REF, staleAfterDays: 90 }).counts.stale, 0);
    assert.equal(assessFreshness(reg(entries), { referenceDate: REF, staleAfterDays: 10 }).counts.stale, 1);
  });

  it('treats a future verified date as fresh (negative age)', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-12-31')]), { referenceDate: REF });
    assert.equal(r.counts.fresh, 1);
    assert.ok(r.fresh[0].ageDays < 0);
  });
});

describe('assessFreshness — output shape', () => {
  it('stale entries carry id, verified, ageDays, url, claim', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-01-01')]), { referenceDate: REF });
    const s = r.stale[0];
    assert.equal(s.id, 'BP-A-001');
    assert.equal(s.verified, '2026-01-01');
    assert.equal(typeof s.ageDays, 'number');
    assert.equal(s.url, 'https://example.com/BP-A-001');
    assert.equal(s.claim, 'claim for BP-A-001');
  });

  it('counts.total equals stale + fresh and matches entry count', () => {
    const r = assessFreshness(
      reg([entry('BP-A-001', '2026-01-01'), entry('BP-A-002', '2026-06-10'), entry('BP-A-003', '2025-01-01')]),
      { referenceDate: REF }
    );
    assert.equal(r.counts.total, 3);
    assert.equal(r.counts.stale + r.counts.fresh, 3);
  });

  it('normalizes referenceDate + echoes staleAfterDays in the result', () => {
    const r = assessFreshness(reg([entry('BP-A-001', '2026-06-01')]), { referenceDate: REF, staleAfterDays: 42 });
    assert.equal(r.referenceDate, '2026-06-21');
    assert.equal(r.staleAfterDays, 42);
  });
});

describe('assessFreshness — referenceDate input forms', () => {
  it('accepts a Date and a YYYY-MM-DD string identically', () => {
    const entries = [entry('BP-A-001', '2026-01-01')];
    const fromString = assessFreshness(reg(entries), { referenceDate: REF });
    const fromDate = assessFreshness(reg(entries), { referenceDate: new Date('2026-06-21T00:00:00Z') });
    assert.deepStrictEqual(fromDate.stale, fromString.stale);
    assert.equal(fromDate.referenceDate, '2026-06-21');
  });

  it('throws a TypeError on a missing or invalid referenceDate', () => {
    assert.throws(() => assessFreshness(reg([entry('BP-A-001', '2026-01-01')]), {}), TypeError);
    assert.throws(
      () => assessFreshness(reg([entry('BP-A-001', '2026-01-01')]), { referenceDate: 'not-a-date' }),
      TypeError
    );
  });
});

describe('assessFreshness — defensive cases', () => {
  it('returns all-zero counts for an empty register', () => {
    const r = assessFreshness(reg([]), { referenceDate: REF });
    assert.deepStrictEqual(r.counts, { total: 0, stale: 0, fresh: 0 });
    assert.deepStrictEqual(r.stale, []);
    assert.deepStrictEqual(r.fresh, []);
  });

  it('classifies an entry with an unparseable verified date as stale with ageDays null', () => {
    const bad = entry('BP-A-001', '2026-06-01');
    bad.source.verified = 'nope';
    const r = assessFreshness(reg([bad]), { referenceDate: REF });
    assert.equal(r.counts.stale, 1);
    assert.equal(r.stale[0].ageDays, null);
  });

  it('classifies an entry with a missing source as stale with ageDays null', () => {
    const r = assessFreshness(reg([{ id: 'BP-A-001', claim: 'x', confidence: 'confirmed' }]), {
      referenceDate: REF,
    });
    assert.equal(r.counts.stale, 1);
    assert.equal(r.stale[0].ageDays, null);
  });
});