vyndr/scripts/champion-vs-fair-baseline.js

#!/usr/bin/env node
'use strict';

/**
 * PHASES 0-1 — is the champion really worse than a frequency table?
 *
 * The prior comparison used a leave-one-out baseline that saw the evaluation
 * window. This one does not: for every prop, the naive forecast is that player's
 * rate of clearing THAT LINE over games strictly BEFORE that date — the same
 * temporal discipline the champion is held to. If the champion still loses, the
 * defect is real and not an artefact of the peek.
 *
 * Then the champion's own knobs are ablated. Its core is
 *
 *     p = 0.6 * season_frequency + 0.4 * last5_frequency
 *
 * plus a +/-0.03 opponent nudge, a +/-0.015 home nudge, and a cv pull. Each is
 * tested for whether it COSTS resolution. This is accounting on the champion's
 * existing knobs, not a causal claim, so no Bonferroni slot.
 */

require('dotenv').config();
const fs = require('fs');
const path = require('path');
const { createClient } = require('@supabase/supabase-js');
const guards = require('../src/services/model/calibrationGuards');
const { knownNumber } = require('../src/utils/known');

const BOX = path.join(process.cwd(), '.seq-cache', 'batting-lines.json');
const STATS = ['hits', 'total_bases', 'rbi', 'runs'];
const FIELD = { hits: (b) => b.hits, total_bases: (b) => b.totalBases, rbi: (b) => b.rbi, runs: (b) => b.runs };
const mean = (xs) => (xs.length ? xs.reduce((a, b) => a + b, 0) / xs.length : null);
/** Games a player needs before we will read his own rate at all. */
const MIN_PRIOR_GAMES = 10;

async function page(sb, t, sel, orderBy, apply) {
  const out = [];
  for (let i = 0; ; i += 1000) {
    const { data, error } = await apply(sb.from(t).select(sel)).order(orderBy, { ascending: true }).range(i, i + 999);
    if (error) throw new Error(`${t}: ${error.message}`);
    if (!data || !data.length) break;
    out.push(...data);
    if (data.length < 1000) break;
  }
  return out;
}
const isPreGame = (c, g) => {
  const et = new Date(new Date(c).getTime() - 4 * 3600 * 1000);
  const d = et.toISOString().slice(0, 10);
  return d < g || (d === g && et.getUTCHours() < 19);
};
function makeRnd(seed) { let s = seed >>> 0; return () => { s ^= s << 13; s >>>= 0; s ^= s >>> 17; s ^= s << 5; s >>>= 0; return s / 4294967296; }; }

function resolutionOf(rows, key) {
  const base = mean(rows.map((r) => r.won));
  let res = 0;
  for (let k = 0; k < 10; k += 1) {
    const lo = k / 10; const hi = (k + 1) / 10;
    const sl = rows.filter((r) => r[key] >= lo && (hi >= 1 ? r[key] <= 1 : r[key] < hi));
    if (!sl.length) continue;
    res += (sl.length / rows.length) * (mean(sl.map((x) => x.won)) - base) ** 2;
  }
  return res;
}

/** Paired date-block bootstrap on a resolution difference (a − b). */
function dateBlockResCI(rows, a, b, seed) {
  const byDate = new Map();
  for (const r of rows) { if (!byDate.has(r.date)) byDate.set(r.date, []); byDate.get(r.date).push(r); }
  const keys = [...byDate.keys()]; const rnd = makeRnd(seed); const d = [];
  for (let it = 0; it < 3000; it += 1) {
    const s = [];
    for (let i = 0; i < keys.length; i += 1) s.push(...byDate.get(keys[Math.floor(rnd() * keys.length)]));
    d.push(resolutionOf(s, a) - resolutionOf(s, b));
  }
  d.sort((x, y) => x - y);
  return { ci: [r5(d[Math.floor(d.length * 0.025)]), r5(d[Math.floor(d.length * 0.975)])], date_blocks: keys.length };
}

(async () => {
  const sb = createClient(process.env.SUPABASE_URL, process.env.SUPABASE_SERVICE_ROLE_KEY || process.env.SUPABASE_SERVICE_KEY, { auth: { persistSession: false } });
  const lines = JSON.parse(fs.readFileSync(BOX, 'utf8')).lines;

  // Per-player, date-ordered history. The ONLY source of the naive forecast.
  const hist = new Map();
  for (const [k, b] of Object.entries(lines)) {
    const [date, key] = k.split('|');
    if (!hist.has(key)) hist.set(key, []);
    hist.get(key).push({ date, b });
  }
  for (const v of hist.values()) v.sort((x, y) => x.date.localeCompare(y.date));

  const out = {};
  for (const stat of STATS) {
    const snaps = await page(sb, 'model_snapshots',
      'id, game_date, captured_at, stat, player_key, line, side, p_win, refused, features', 'id',
      (q) => q.eq('sport', 'mlb').eq('stat', stat));
    const picked = new Map();
    for (const r of snaps) {
      if (!isPreGame(r.captured_at, r.game_date) || r.refused || knownNumber(r.p_win) === null) continue;
      const k = [r.game_date, r.player_key, r.line].join('|');
      const prev = picked.get(k);
      if (!prev || knownNumber(r.p_win) > knownNumber(prev.p_win)) picked.set(k, r);
    }
    guards.assertPickedSideDedup([...picked.values()].map((r) => ({ propKey: [r.game_date, r.player_key, r.line].join('|'), side: r.side, p: knownNumber(r.p_win) })));

    const rows = [];
    for (const r of picked.values()) {
      const b = lines[`${r.game_date}|${r.player_key}`]; const L = knownNumber(r.line);
      if (!b || L === null || !r.side) continue;
      const v = knownNumber(FIELD[stat](b)); if (v === null) continue;
      const isUnder = String(r.side).toLowerCase() === 'under';
      const won = (isUnder ? !(v > L) : (v > L)) ? 1 : 0;

      // ── THE FAIR COMPETITOR: strictly prior games only. ──
      const prior = (hist.get(r.player_key) || []).filter((g) => g.date < r.game_date);
      if (prior.length < MIN_PRIOR_GAMES) continue;
      const vals = prior.map((g) => knownNumber(FIELD[stat](g.b))).filter((x) => x !== null);
      if (vals.length < MIN_PRIOR_GAMES) continue;
      const season = vals.filter((x) => x > L).length / vals.length;
      const last5 = vals.slice(-5);
      const recent = last5.filter((x) => x > L).length / last5.length;

      const f = r.features || {};
      const homeAdj = f.home_away === 1.0 ? 0.015 : f.home_away === 0.0 ? -0.015 : 0;
      const oppR = knownNumber(f.opp_rank_stat);
      const oppAdj = oppR === null ? 0 : (oppR >= 0.70 ? 0.03 : (oppR <= 0.30 ? -0.03 : 0));

      const flip = (p) => Math.max(0.01, Math.min(0.99, isUnder ? 1 - p : p));
      const blend = (w) => flip(0.6 === null ? season : (1 - w) * season + w * recent);

      rows.push({
        date: r.game_date, won,
        champion: knownNumber(r.p_win),
        // Reconstructions, all point-in-time.
        season_only: flip(season),
        w40: flip(0.6 * season + 0.4 * recent),          // the current blend
        w20: flip(0.8 * season + 0.2 * recent),
        w60: flip(0.4 * season + 0.6 * recent),
        w40_nudged: flip(Math.max(0.01, Math.min(0.99, 0.6 * season + 0.4 * recent + oppAdj + homeAdj))),
        season_nudged: flip(Math.max(0.01, Math.min(0.99, season + oppAdj + homeAdj))),
      });
    }
    if (rows.length < 100) { out[stat] = { n: rows.length, note: 'too few rows with 10+ prior games' }; continue; }

    // The REPAIRED champion: full-season window + recency weight 0.20, which is
    // exactly what the code change produces.
    for (const r of rows) r.repaired = r.w20;
    const keys = ['champion', 'repaired', 'season_only', 'w20', 'w40', 'w60', 'w40_nudged', 'season_nudged'];
    const res = Object.fromEntries(keys.map((k) => [k, r5(resolutionOf(rows, k))]));
    const gap = dateBlockResCI(rows, 'champion', 'season_only', 20260807);

    out[stat] = {
      n: rows.length,
      dates: new Set(rows.map((r) => r.date)).size,
      resolution: res,
      champion_minus_fair_baseline: r5(res.champion - res.season_only),
      ci_champion_minus_fair: gap.ci,
      date_blocks: gap.date_blocks,
      champion_loses_fairly: res.champion < res.season_only,
      best_variant: keys.reduce((a, k) => (res[k] > res[a] ? k : a), keys[0]),
      recency_cost: r5(res.w40 - res.season_only),
      nudge_cost: r5(res.w40_nudged - res.w40),
      REPAIRED_vs_fair: r5(res.repaired - res.season_only),
      REPAIRED_ci: dateBlockResCI(rows, 'repaired', 'season_only', 20260807).ci,
      REPAIRED_vs_old_champion: r5(res.repaired - res.champion),
      REPAIRED_beats_old_ci: dateBlockResCI(rows, 'repaired', 'champion', 20260807).ci,
    };
  }
  console.log(JSON.stringify(out, null, 2));
  process.exit(0);
})().catch((e) => { console.error('FAILED:', e.message); process.exit(1); });

const r5 = (v) => (v == null || !Number.isFinite(v) ? null : Math.round(v * 100000) / 100000);