vyndr/tests/unit/parkWeather.test.js

'use strict';

/**
 * Park geometry and air, read onto hit type.
 *
 * The failure these guard against is the one a single park multiplier cannot
 * even express: a deep gap and a short line push total bases in OPPOSITE
 * directions, and a model that collapses them to one number is confidently
 * wrong at both ends.
 */

const pw = require('../../src/services/model/parkWeather');

const LEAGUE_PARKS = [
  { left_line: 330, left_center: 375, center: 405, right_center: 375, right_line: 330 },
  { left_line: 335, left_center: 380, center: 410, right_center: 375, right_line: 325 },
  { left_line: 325, left_center: 370, center: 400, right_center: 370, right_line: 335 },
];
const league = pw.leagueGeometry(LEAGUE_PARKS);

const park = (o) => ({
  left_line: 330, left_center: 375, center: 405, right_center: 375, right_line: 330,
  roof_type: 'Open', elevation: 500, ...o,
});
const wx = (t) => ({ wx_temp_f: t, wx_wind_speed_mph: 12, wx_wind_direction_deg: 220 });

describe('geometry separates the two things one park factor cannot', () => {
  it('deep gaps make doubles and triples; short lines make home runs', () => {
    const deepGaps = pw.parkWeatherRead({ dims: park({ left_center: 410, right_center: 410, center: 440 }), wx: wx(72), league });
    const shortLines = pw.parkWeatherRead({ dims: park({ left_line: 300, right_line: 300 }), wx: wx(72), league });

    expect(deepGaps.multipliers.double).toBeGreaterThan(1);
    expect(deepGaps.multipliers.triple).toBeGreaterThan(1);
    expect(shortLines.multipliers.home_run).toBeGreaterThan(1);
    // The whole reason a single multiplier fails: these two parks both "inflate
    // offence" and they inflate completely different offence.
    expect(deepGaps.multipliers.home_run).toBeLessThan(shortLines.multipliers.home_run);
  });

  it('a deep park suppresses home runs relative to a shallow one', () => {
    const deep = pw.parkWeatherRead({ dims: park({ left_line: 360, right_line: 360 }), wx: wx(72), league });
    expect(deep.multipliers.home_run).toBeLessThan(1);
  });
});

describe('air is read where it exists and nowhere else', () => {
  it('heat adds carry, cold removes it', () => {
    const hot = pw.parkWeatherRead({ dims: park(), wx: wx(95), league });
    const cold = pw.parkWeatherRead({ dims: park(), wx: wx(45), league });
    expect(hot.multipliers.home_run).toBeGreaterThan(cold.multipliers.home_run);
    expect(hot.carry).toBeGreaterThan(0);
    expect(cold.carry).toBeLessThan(0);
  });

  it('altitude carries on its own', () => {
    const denver = pw.parkWeatherRead({ dims: park({ elevation: 5200 }), wx: wx(72), league });
    const sea = pw.parkWeatherRead({ dims: park({ elevation: 20 }), wx: wx(72), league });
    expect(denver.multipliers.home_run).toBeGreaterThan(sea.multipliers.home_run);
  });

  it('a CLOSED roof does not apply the outside temperature', () => {
    // The ball is not flying through the weather; pretending otherwise would
    // read a dome game off the sky above it.
    const domeHot = pw.parkWeatherRead({ dims: park({ roof_type: 'Dome' }), wx: wx(95), league });
    const domeCold = pw.parkWeatherRead({ dims: park({ roof_type: 'Dome' }), wx: wx(45), league });
    expect(domeHot.multipliers.home_run).toBeCloseTo(domeCold.multipliers.home_run, 6);
    expect(domeHot.air_inputs).not.toContain('temperature');
    expect(domeHot.air_inputs).toContain('elevation');
  });

  it('absent temperature contributes nothing rather than a reference value', () => {
    const r = pw.parkWeatherRead({ dims: park(), wx: { wx_temp_f: null }, league });
    expect(r.air_inputs).not.toContain('temperature');
    expect(r.readable).toBe(true);
  });
});

describe('wind is refused, loudly', () => {
  it('never reads wind, and says so on every read', () => {
    // Speed and bearing are both present. They are still not enough: without
    // park orientation the same bearing is blowing out at one park and in at
    // another, and using speed alone would assert an effect while discarding
    // the sign that decides what the effect is.
    const calm = pw.parkWeatherRead({ dims: park(), wx: { wx_temp_f: 72, wx_wind_speed_mph: 0, wx_wind_direction_deg: 0 }, league });
    const gale = pw.parkWeatherRead({ dims: park(), wx: { wx_temp_f: 72, wx_wind_speed_mph: 35, wx_wind_direction_deg: 220 }, league });
    expect(gale.multipliers).toEqual(calm.multipliers);
    expect(gale.wind_readable).toBe(false);
    expect(gale.wind_reason).toMatch(/orientation/);
  });
});

describe('honesty', () => {
  it('no park at all → null, not a neutral-looking read', () => {
    expect(pw.parkWeatherRead({ dims: null, wx: wx(72), league })).toBeNull();
    expect(pw.parkWeatherRead({ dims: park(), wx: wx(72), league: null })).toBeNull();
  });

  it('a league-average park in reference air leaves the shape alone', () => {
    const r = pw.parkWeatherRead({ dims: park({ left_line: league.left_line, right_line: league.right_line, left_center: league.left_center, right_center: league.right_center, center: league.center }), wx: wx(pw.REF_TEMP_F), league });
    expect(r.multipliers.home_run).toBeCloseTo(1, 2);
    expect(r.multipliers.double).toBeCloseTo(1, 2);
  });

  it('the effect is bounded however absurd the park', () => {
    const absurd = pw.parkWeatherRead({ dims: park({ left_line: 200, right_line: 200, elevation: 30000 }), wx: wx(130), league });
    for (const v of Object.values(absurd.multipliers)) {
      expect(v).toBeLessThanOrEqual(1 + pw.MAX_EFFECT + 1e-9);
      expect(v).toBeGreaterThanOrEqual(1 - pw.MAX_EFFECT - 1e-9);
    }
  });

  it('reshaped shares remain a distribution', () => {
    const r = pw.parkWeatherRead({ dims: park({ left_center: 410, right_center: 410 }), wx: wx(90), league });
    const out = pw.applyToShares({ single: 0.66, double: 0.20, triple: 0.02, home_run: 0.12 }, r);
    const sum = Object.values(out).reduce((a, b) => a + b, 0);
    expect(sum).toBeCloseTo(1, 3);
    expect(out.double).toBeGreaterThan(0.20);
  });

  it('NO read means NO sentence', () => {
    expect(pw.explain(null, 'Coors Field')).toBeNull();
    expect(pw.explain(pw.parkWeatherRead({ dims: park({ elevation: 5200 }), wx: wx(72), league }), 'Coors Field'))
      .toMatch(/Coors Field/);
  });
});