vyndr/tests/unit/matchupAxis.test.js

'use strict';

/**
 * MATCHUP (platoon) axis — 2026-08-02.
 *
 * It was wired and firing on 0/634 prod rows. Three separate absences kept it
 * silent: oppPitcherByTeam 0, handById 0, bats 0/120. These lock the joins that
 * fixed each, and the honest-absent behaviour when any one is missing.
 */

const env = require('../../src/services/environmentContext');
const { adjust } = require('../../src/services/challengerProjection');

const GAME = {
  teams: {
    home: { team: { name: 'Philadelphia Phillies' }, probablePitcher: { id: 111 } },
    away: { team: { name: 'New York Mets' }, probablePitcher: { id: 222 } },
  },
};
const SCHED = { dates: [{ games: [GAME] }] };
const PEOPLE = { people: [{ id: 111, pitchHand: { code: 'L' } }, { id: 222, pitchHand: { code: 'R' } }] };
const PLAYERS = { people: [{ id: 900, batSide: { code: 'L' } }, { id: 901, batSide: { code: 'S' } }] };

const deps = (over = {}) => ({
  origin: '',
  schedule: { games: [] },
  pitchers: { games: [] },          // self-origin route returns nothing, as in prod
  probableSchedule: SCHED,
  people: PEOPLE,
  seasonPlayers: PLAYERS,
  fetchJson: async () => { throw new Error('no network in tests'); },
  ...over,
});

describe('buildContext — the three joins that were absent', () => {
  it('falls back to the statsapi probable-pitcher hydrate when the self-origin route is empty', async () => {
    const ctx = await env.buildContext('mlb', deps());
    expect(ctx._internals.oppPitcherByTeam.get('PHI')).toBe(222);  // opposing = away SP
    expect(ctx._internals.oppPitcherByTeam.get('NYM')).toBe(111);
    expect(ctx.stats.opp_declared).toBe(2);
  });

  it('resolves pitcher handedness for the declared starters', async () => {
    const ctx = await env.buildContext('mlb', deps());
    expect(ctx._internals.handById.get(222)).toBe('R');
    expect(ctx.stats.pitchers_with_hand).toBe(2);
  });

  it('joins BATTER handedness off the cached season player list', async () => {
    const ctx = await env.buildContext('mlb', deps());
    expect(ctx._internals.batsById.get(900)).toBe('L');
    expect(ctx._internals.batsById.get(901)).toBe('S');   // switch-hitters preserved
    expect(ctx.stats.batters_with_hand).toBe(2);
  });

  it('ABSTAINS — no starter, no hand, or no batter hand produces NO matchup', async () => {
    const noSp = await env.buildContext('mlb', deps({ probableSchedule: { dates: [] } }));
    const r1 = await noSp.contextFor({ stat_type: 'hits', team: 'PHI', playerId: 900 });
    expect(r1.matchup).toBeNull();

    const ctx = await env.buildContext('mlb', deps());
    // known team + known starter, but the batter's hand is unknown
    const r2 = await ctx.contextFor({ stat_type: 'hits', team: 'PHI', playerId: 999 });
    expect(r2.matchup).toBeNull();
  });
});

describe('the fallback ladder is LABELLED, and never invents a higher rung', () => {
  it('a firing matchup carries its tier through to the challenger adjustment', () => {
    const r = adjust({
      pWin: 0.55, direction: 'over', statType: 'hits',
      matchup: { multiplier: 0.95, label: 'PLATOON', tier: 'batter_own_split', batter_hand: 'L', pitcher_hand: 'R' },
    });
    const m = r.adjustments.find((a) => a.axis === 'matchup');
    expect(m.tier).toBe('batter_own_split');
    expect(r.p_win_challenger).toBeLessThan(0.55);
  });

  it('a neutral multiplier produces NO adjustment — never a fabricated zero-nudge row', () => {
    const r = adjust({
      pWin: 0.55, direction: 'over', statType: 'hits',
      matchup: { multiplier: 1, label: 'PLATOON', tier: 'batter_own_split' },
    });
    expect(r.adjustments.find((a) => a.axis === 'matchup')).toBeUndefined();
  });
});