'use strict';

/**
 * Which stats may serve a calibrated number.
 *
 * The thing these protect is the meaning of PROVISIONAL: a provisional deploy
 * that cannot be taken away is just a deploy.
 */

const { createRegistry, STATUS, PROMOTION_DATE_CLUSTERS } = require('../../src/services/model/calibrationRegistry');

const MAP = [{ lo: 0.5, hi: 0.7, value: 0.55, n: 300 }];
const GOOD = { lodo_pass: true, ci: [-0.0061, -0.0045], map: MAP, certified_bands: [[0.6, 0.8]], date_clusters: 7, at: '2026-08-06' };

describe('deploy needs BOTH gates', () => {
  it('deploys when LODO passes and the interval excludes zero', () => {
    const r = createRegistry();
    expect(r.deploy('total_bases', GOOD).status).toBe(STATUS.PROVISIONAL);
  });

  it('refuses on a LODO failure however good the interval', () => {
    const r = createRegistry();
    const out = r.deploy('runs', { ...GOOD, lodo_pass: false });
    expect(out.ok).toBe(false);
    expect(out.reason).toMatch(/date-driven/);
  });

  it('refuses when the interval spans zero however clean the LODO', () => {
    const r = createRegistry();
    const out = r.deploy('hits', { ...GOOD, ci: [-0.01, 0.002] });
    expect(out.ok).toBe(false);
    expect(out.reason).toMatch(/does not exclude zero/);
  });

  it('refuses without a map — there is nothing to serve', () => {
    const r = createRegistry();
    expect(r.deploy('hits', { ...GOOD, map: null }).ok).toBe(false);
  });
});

describe('auto-demotion is what makes provisional honest', () => {
  it('demotes on the first date where the interval stops excluding zero', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    const out = r.reverify('total_bases', { ci: [-0.004, 0.001], date: '2026-08-07' });
    expect(out.status).toBe(STATUS.NONE);
    expect(out.reason).toBe('ci_no_longer_excludes_zero');
    expect(out.breaking_date).toBe('2026-08-07');
    expect(r.serves('total_bases', 0.65).serve).toBe(false);
  });

  it('demotes when the favourite over-prediction flips sign', () => {
    // A flip means the correction is now pushing the wrong way.
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    const out = r.reverify('total_bases', { ci: [-0.006, -0.004], favourite_bias: -0.03, date: '2026-08-08' });
    expect(out.status).toBe(STATUS.NONE);
    expect(out.reason).toBe('favourite_bias_flipped');
  });

  it('logs the demotion with its breaking date', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    r.reverify('total_bases', { ci: [0.001, 0.004], date: '2026-08-09' });
    const ev = r.log().find((e) => e.event === 'auto_demoted');
    expect(ev).toMatchObject({ stat: 'total_bases', at: '2026-08-09' });
  });

  it('stays deployed while both conditions hold', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    const out = r.reverify('total_bases', { ci: [-0.007, -0.003], favourite_bias: 0.17, date: '2026-08-07' });
    expect(out.status).toBe(STATUS.PROVISIONAL);
    expect(out.changed).toBe(false);
  });
});

describe('the >=40 date-cluster bar is the PROMOTION bar, not the deploy bar', () => {
  it('does not block deployment', () => {
    const r = createRegistry();
    expect(r.deploy('total_bases', { ...GOOD, date_clusters: 7 }).ok).toBe(true);
  });

  it('promotes out of provisional once it is met', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    const out = r.reverify('total_bases', { ci: [-0.006, -0.004], date_clusters: PROMOTION_DATE_CLUSTERS, date: '2026-09-15' });
    expect(out.status).toBe(STATUS.PROMOTED);
  });

  it('does not promote while the interval has stopped holding', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    const out = r.reverify('total_bases', { ci: [-0.001, 0.003], date_clusters: 60, date: '2026-09-15' });
    expect(out.status).toBe(STATUS.NONE);
  });
});

describe('serving is band-limited', () => {
  it('serves inside the certified band and refuses outside it', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    expect(r.serves('total_bases', 0.65).serve).toBe(true);
    expect(r.serves('total_bases', 0.65).provisional).toBe(true);
    expect(r.serves('total_bases', 0.95).serve).toBe(false);
    expect(r.serves('total_bases', 0.95).reason).toMatch(/outside the certified band/);
  });

  it('an undeployed stat never serves', () => {
    const r = createRegistry();
    expect(r.serves('hits', 0.6).serve).toBe(false);
    expect(r.serves('hits', 0.6).reason).toBe('not deployed');
  });

  it('a missing p_win serves nothing', () => {
    const r = createRegistry();
    r.deploy('total_bases', GOOD);
    expect(r.serves('total_bases', null).serve).toBe(false);
  });
});

describe('the LODO test is a COHERENT pair, not a bar plus an unrelated rule', () => {
  const { LODO_K, LODO_TEST, LODO_POWER_FLOOR } = require('../../src/services/model/calibrationRegistry');

  const normCdf = (z) => {
    const t = 1 / (1 + 0.2316419 * Math.abs(z));
    const d = 0.3989422804014327 * Math.exp(-z * z / 2);
    const p = d * t * (0.319381530 + t * (-0.356563782 + t * (1.781477937 + t * (-1.821255978 + t * 1.330274429))));
    return z >= 0 ? 1 - p : p;
  };
  const binomPmf = (n, k, p) => {
    let logC = 0;
    for (let i = 0; i < k; i += 1) logC += Math.log(n - i) - Math.log(i + 1);
    return Math.exp(logC + k * Math.log(p) + (n - k) * Math.log(1 - p));
  };
  const tail = (n, c, p) => { let s = 0; for (let k = c + 1; k <= n; k += 1) s += binomPmf(n, k, p); return s; };

  it('each n* is what its own (sigma_row, g) produce — no pooled value', () => {
    for (const [stat, t] of Object.entries(LODO_TEST)) {
      expect(Math.ceil(LODO_K ** 2 * (t.sigma_row / Math.abs(t.g)) ** 2)).toBe(t.n_star);
    }
    // And the four differ, which is exactly why one pooled number mis-credited them.
    const stars = Object.values(LODO_TEST).map((t) => t.n_star);
    expect(new Set(stars).size).toBeGreaterThan(1);
  });

  it('each cutoff is the smallest one holding the false-positive rate at 0.05', () => {
    const p = normCdf(-LODO_K);
    for (const [stat, t] of Object.entries(LODO_TEST)) {
      expect(tail(t.informative_drops, t.cutoff, p)).toBeLessThanOrEqual(0.05);
      if (t.cutoff > 0) expect(tail(t.informative_drops, t.cutoff - 1, p)).toBeGreaterThan(0.05);
      expect(t.fp).toBeCloseTo(tail(t.informative_drops, t.cutoff, p), 3);
    }
  });

  it('the OLD rule is demonstrably incoherent — it failed stable stats ~half the time', () => {
    // Zero-reversal rule at a 1-SE bar, on four informative drops.
    const pNoise = normCdf(-1);
    const falseFail = 1 - (1 - pNoise) ** 4;
    expect(falseFail).toBeGreaterThan(0.45);
    expect(falseFail).toBeLessThan(0.55);
  });

  it('every stat falls below the power floor, so none may claim LODO stability', () => {
    // A gate that cannot fail is not a gate. This is the honest state at this
    // date count, and the floor makes it structural rather than a footnote.
    for (const [stat, t] of Object.entries(LODO_TEST)) {
      expect(t.power).toBeLessThan(LODO_POWER_FLOOR);
    }
  });

  it('the stale pooled threshold is nulled so nothing can read it', () => {
    const { LODO_MIN_HELD_ROWS } = require('../../src/services/model/calibrationRegistry');
    expect(LODO_MIN_HELD_ROWS).toBeNull();
  });
});