// Headless verification for Zuma.
//   node tools/verifyZuma.js
// Exits non-zero on any failure.
//
// 1. Path construction (arc-length parameterization).
// 2. Chain advance, spawning, intro transition, spacing invariant.
// 3. Insertion (front/behind/tail wedges, shove-merge clank).
// 4. Match detection and scoring.
// 5. Pull-back chains and catch-up clanks.
// 6. Power-ups (slow, reverse, accuracy, explosion).
// 7. Win/lose state machine, recolor, last-call spawns.
// 8. Determinism (seeded replay).
// 9. Tunnels: submerged chain is inert to flights, the laser and explosions.
// 10. Multi-path levels: independent spawners, shared shooter color pool,
//     physics-based shot targeting, either-path-loses, every-path-to-win.
// 11. Level bank lint (assets/gamedata/zuma/ manifest + per-level geometry/parameters).
// 12. Aimbot soak: every banked level is winnable, and the star curve sits
//     above what mechanical play achieves.

import { readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';

import {
  TUNING, POWER_KINDS, TUNNEL,
  buildPath, createLevel, step, fireBall, swapBalls,
  insertBall, popRun, findRun, segmentsOf, rayHit, colorsPresent,
  validateLevel, validateLevelParams,
  normalizeTunnels, isHidden, visibilityAt, pathSpans, sampleRange, nearestS,
} from '../src/games/zuma/ZumaLogic.js';
import { PORTAL_REACH } from '../src/games/zuma/ZumaPortal.js';

const __dirname = dirname(fileURLToPath(import.meta.url));
const T = TUNING;

let failures = 0;
function check(name, cond, detail = '') {
  if (cond) { console.log(`  ok  ${name}`); }
  else { failures += 1; console.error(`FAIL  ${name}${detail ? ` — ${detail}` : ''}`); }
}
const near = (a, b, tol = 0.5) => Math.abs(a - b) <= tol;

// ── Fixtures ─────────────────────────────────────────────────────────────────

const STRAIGHT = [[0, 500], [400, 500], [800, 500], [1200, 500], [1600, 500]];
const CURVY = [[0, 200], [400, 800], [800, 200], [1200, 800], [1600, 200]];

// Fixture chains are laid out in multiples of the tuned spacing, never in raw
// pixels — otherwise resizing the marbles silently turns "contiguous" fixtures
// into gapped ones and the insertion tests start asserting nonsense.
const SP = T.BALL_SPACING;

// Every existing single-path test passes flat overrides (points/tunnels/quota/
// introBalls/pushSpeed/powerUpRate) exactly as before genZuma.js's `paths`
// array existed — mkDef wraps them into a one-element paths array so none of
// those call sites need to change.
function mkDef(over = {}) {
  const { points, tunnels, quota, introBalls, pushSpeed, powerUpRate, shape, paths, ...rest } = over;
  return {
    level: 1, name: 'Test',
    frog: [800, 900], colors: 4, seed: 42, starScores: [100, 200, 300],
    paths: paths ?? [{
      shape: shape ?? 'line',
      points: points ?? STRAIGHT,
      tunnels,
      quota: quota ?? 10,
      introBalls: introBalls ?? 2,
      pushSpeed: pushSpeed ?? 100,
      powerUpRate: powerUpRate ?? 0,
    }],
    ...rest,
  };
}

// `over` used to be Object.assign'd straight onto state (back when `spawned`
// and `balls` lived at the top level); both now live on paths[0], so they're
// special-cased here and every existing call site keeps working unchanged.
function mkState(defOver = {}, over = {}) {
  const st = createLevel(mkDef(defOver));
  const { spawned, balls, ...rest } = over;
  Object.assign(st, rest);
  if (spawned !== undefined) st.paths[0].spawned = spawned;
  if (balls !== undefined) st.paths[0].balls = balls;
  return st;
}

// ── Aimbot ───────────────────────────────────────────────────────────────────
// Deliberately mechanical: it never sets up a chain, never banks a shot off a
// gap, and never holds a colour. Whatever it clears, a player clears. Scans
// every path for a target — the multi-path story is "physics decides which
// chain a shot lands on," so the bot has to consider all of them too.

// Walks the shot ray like rayHit does, but reports which ball (and which path)
// it lands on.
function firstHit(st, angle) {
  const dx = Math.cos(angle), dy = Math.sin(angle);
  const stepLen = T.BALL_RADIUS / 2;
  const max = Math.hypot(T.BOUNDS_W, T.BOUNDS_H);
  let x = st.frog.x + dx * T.FROG_MUZZLE;
  let y = st.frog.y + dy * T.FROG_MUZZLE;
  for (let d = 0; d < max; d += stepLen) {
    for (const p of st.paths) {
      for (const b of p.balls) {
        if (isHidden(p.tunnels, b.s)) continue;      // submerged: the shot flies over
        if (Math.hypot(x - b.x, y - b.y) < T.BALL_SPACING * T.HIT_PAD) return { ball: b, path: p };
      }
    }
    x += dx * stepLen; y += dy * stepLen;
  }
  return null;
}

// Rank every reachable ball across every path: landing between two of the
// held colour beats landing beside one, which beats landing on a bare match.
function chooseShot(st) {
  let best = null;
  for (const p of st.paths) {
    for (const target of p.balls) {
      if (isHidden(p.tunnels, target.s)) continue;
      const angle = Math.atan2(target.y - st.frog.y, target.x - st.frog.x);
      const hit = firstHit(st, angle);
      if (!hit) continue;
      const i = hit.path.balls.indexOf(hit.ball);
      const prev = hit.path.balls[i - 1], next = hit.path.balls[i + 1];
      let score = 0;
      if (hit.ball.color === st.current) {
        score += 5;
        if (prev?.color === st.current) score += 10;
        if (next?.color === st.current) score += 10;
      }
      if (prev?.color === st.current && next?.color === st.current) score += 8;
      if (score > 0 && (!best || score > best.score)) best = { angle, score };
    }
  }
  return best;
}

function aimbotPlay(def, seed) {
  const st = createLevel(def, seed ?? def.seed);
  const DT = 25;
  let sinceShot = 0;
  for (let t = 0; t < 400000; t += DT) {
    step(st, DT);
    if (st.status === 'won' || st.status === 'lost') break;
    if (st.status !== 'playing') continue;
    sinceShot += DT;
    if (sinceShot < 450) continue;
    let shot = chooseShot(st);
    if (!shot) { swapBalls(st); shot = chooseShot(st); }   // try the on-deck colour
    if (shot) { fireBall(st, shot.angle); sinceShot = 0; }
  }
  return { status: st.status, score: st.score };
}

// spec: [{ color, s, power? }] front-first (descending s). Defaults to
// paths[0] — every pre-multi-path fixture is single-path.
function mkChain(st, spec, pathIdx = 0) {
  const p = st.paths[pathIdx];
  p.balls = spec.map((b) => ({
    id: st.nextId++, color: b.color, power: b.power ?? null, s: b.s, x: 0, y: 0,
  }));
  for (const b of p.balls) {
    const pt = p.path.pointAt(b.s);
    b.x = pt.x; b.y = pt.y;
  }
  return st;
}

function spacingOk(balls) {
  for (let i = 0; i < balls.length - 1; i++) {
    const d = balls[i].s - balls[i + 1].s;
    if (d < T.BALL_SPACING - 0.01) return false;                       // overlap
    if (d > T.BALL_SPACING + 0.01 && d <= T.BALL_SPACING + T.GAP_EPS) return false; // not snapped
  }
  return true;
}

// ── 1. Path ──────────────────────────────────────────────────────────────────
console.log('\n— Path —');
{
  const p = buildPath(STRAIGHT);
  check('straight path length ≈ 1600', near(p.length, 1600, 3), `got ${p.length.toFixed(1)}`);
  const a = p.pointAt(0), b = p.pointAt(p.length);
  check('pointAt(0) at first control point', near(a.x, 0, 1) && near(a.y, 500, 1));
  check('pointAt(length) at last control point', near(b.x, 1600, 1) && near(b.y, 500, 1));

  const c = buildPath(CURVY);
  let maxErr = 0, maxTanErr = 0;
  const stepS = 37;
  for (let s = 0; s + stepS <= c.length; s += stepS) {
    const u = c.pointAt(s), v = c.pointAt(s + stepS);
    maxErr = Math.max(maxErr, Math.abs(Math.hypot(v.x - u.x, v.y - u.y) - stepS));
    maxTanErr = Math.max(maxTanErr, Math.abs(Math.hypot(u.tx, u.ty) - 1));
  }
  check('curved path constant-speed (equal s → equal distance)', maxErr < stepS * 0.05, `max err ${maxErr.toFixed(2)}px`);
  check('tangents unit length', maxTanErr < 1e-6);
  let mono = true;
  for (let i = 1; i < c.samples.length; i++) if (c.samples[i].s < c.samples[i - 1].s) mono = false;
  check('sample arc lengths monotonic', mono);
}

// ── 2. Advance & spawning ────────────────────────────────────────────────────
console.log('\n— Advance & spawning —');
{
  const st = mkState({ quota: 8, introBalls: 3 });
  let introSpawned = -1;
  for (let i = 0; i < 4000 && st.status === 'intro'; i++) {
    step(st, 16);
    if (st.status !== 'intro') introSpawned = st.paths[0].spawned;
  }
  check('intro → playing at introBalls', st.status === 'playing' && introSpawned >= 3, `spawned ${introSpawned}`);
  for (let i = 0; i < 4000 && st.paths[0].spawned < 8; i++) step(st, 16);
  check('spawn stops at quota', st.paths[0].spawned === 8 && st.paths[0].balls.length === 8);
  check('spacing invariant after spawning', spacingOk(st.paths[0].balls));

  const st2 = mkState({}, { status: 'playing', spawned: 10 });
  mkChain(st2, [{ color: 0, s: 600 + 2 * SP }, { color: 1, s: 600 + SP }, { color: 2, s: 600 }]);
  for (let i = 0; i < 20; i++) step(st2, 50);          // 1s at pushSpeed 100
  check('single segment drives at pushSpeed', near(st2.paths[0].balls[0].s, 600 + 2 * SP + 100, 1),
    `got ${st2.paths[0].balls[0].s.toFixed(1)}`);
  check('spacing preserved while driving', spacingOk(st2.paths[0].balls));
}

// ── 3. Insertion ─────────────────────────────────────────────────────────────
console.log('\n— Insertion —');
{
  const base = () => mkChain(
    mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 600 }, { color: 1, s: 600 - SP }, { color: 0, s: 600 - 2 * SP },
      { color: 1, s: 600 - 3 * SP }, { color: 2, s: 600 - 4 * SP }]
  );

  let st = base(); let ev = [];
  insertBall(st, st.paths[0], 3, 2, +1, ev);
  const balls = st.paths[0].balls;
  check('front insert lands in front of hit ball',
    balls[2].color === 3 && near(balls[2].s, 600 - SP, 0.01) && near(balls[3].s, 600 - 2 * SP, 0.01));
  check('front insert shoves balls ahead', near(balls[0].s, 600 + SP, 0.01) && near(balls[1].s, 600, 0.01));
  check('front insert keeps spacing', spacingOk(balls) && balls.length === 6);
  check('non-matching insert resets combo, no pop', st.combo === 0 && !ev.some((e) => e.type === 'pop'));

  st = base(); ev = [];
  insertBall(st, st.paths[0], 3, 2, -1, ev);
  check('behind insert wedges after hit ball',
    st.paths[0].balls[3].color === 3 && near(st.paths[0].balls[3].s, 600 - 2 * SP, 0.01)
    && near(st.paths[0].balls[2].s, 600 - SP, 0.01));
  check('behind insert keeps spacing', spacingOk(st.paths[0].balls));

  st = base(); ev = [];
  insertBall(st, st.paths[0], 3, 4, -1, ev);
  check('tail attach adds at rear without shoving',
    near(st.paths[0].balls[5].s, 600 - 5 * SP, 0.01) && near(st.paths[0].balls[0].s, 600, 0.01));

  // shove closes a gap → clank, no pop (junction colors differ)
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 900 }, { color: 1, s: 900 - SP }, { color: 2, s: 900 - 2.5 * SP },
      { color: 3, s: 900 - 3.5 * SP }]);
  ev = [];
  insertBall(st, st.paths[0], 3, 2, +1, ev);
  check('shove-merge emits clank', ev.some((e) => e.type === 'clank'));
  check('shove-merge joins segments', segmentsOf(st.paths[0].balls).length === 1 && spacingOk(st.paths[0].balls));
  check('shove-merge without matching junction does not pop', !ev.some((e) => e.type === 'pop'));

  // laser-sight ray helper
  st = mkChain(mkState({}, { status: 'playing' }), [{ color: 0, s: 600 }]);
  const ball = st.paths[0].balls[0];
  const ray = rayHit(st, Math.atan2(ball.y - st.frog.y, ball.x - st.frog.x));
  check('rayHit finds first chain ball', ray.hit && Math.hypot(ray.x - ball.x, ray.y - ball.y) < T.BALL_SPACING);
}

// ── 4. Matching ──────────────────────────────────────────────────────────────
console.log('\n— Matching —');
{
  let st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 600 }, { color: 0, s: 600 - SP }, { color: 1, s: 600 - 2 * SP }, { color: 1, s: 600 - 3 * SP }]);
  let ev = [];
  insertBall(st, st.paths[0], 0, 1, +1, ev);
  const pop = ev.find((e) => e.type === 'pop');
  check('insert completing 3 pops the run', !!pop && pop.ids.length === 3 && st.paths[0].balls.length === 2);
  check('3-pop score = 3 × SCORE_BALL', pop?.score === 3 * T.SCORE_BALL && st.score === 3 * T.SCORE_BALL);
  check('shot pop sets combo to 1', pop?.combo === 1);

  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 600 + 2 * SP }, { color: 0, s: 600 + SP }, { color: 0, s: 600 }, { color: 0, s: 600 - SP }]);
  ev = [];
  insertBall(st, st.paths[0], 0, 1, -1, ev);
  const pop5 = ev.find((e) => e.type === 'pop');
  check('2+2 around insert pops 5', !!pop5 && pop5.ids.length === 5 && st.paths[0].balls.length === 0);
  check('5-pop score', pop5?.score === 5 * T.SCORE_BALL);

  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 600 }, { color: 0, s: 600 - 2.5 * SP }, { color: 1, s: 600 - 3.5 * SP }]);
  ev = [];
  insertBall(st, st.paths[0], 0, 1, +1, ev);
  check('runs never cross a gap', !ev.some((e) => e.type === 'pop') && st.paths[0].balls.length === 4);

  const run = findRun(st.paths[0].balls, 1);
  check('findRun bounded by the gap', run.lo === 1 && run.hi === 2);
}

// ── 5. Pull-back & catch-up ──────────────────────────────────────────────────
console.log('\n— Pull-back & catch-up —');
{
  // matching gap edges → front segment retreats, contact pops with chain bonus
  let st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 1, s: 900 }, { color: 1, s: 900 - SP }, { color: 1, s: 900 - 5 * SP }, { color: 0, s: 900 - 6 * SP }]);
  let popEv = null, clankSeen = false, retreated = false;
  for (let i = 0; i < 200 && !popEv; i++) {
    const ev = step(st, 25);
    if (st.paths[0].balls.length && st.paths[0].balls[0].s < 900 - 1) retreated = true;
    if (ev.some((e) => e.type === 'clank')) clankSeen = true;
    popEv = ev.find((e) => e.type === 'pop') ?? popEv;
  }
  check('matching gap pulls front segment backward', retreated);
  check('pull-back contact clanks and pops', clankSeen && !!popEv && popEv.ids.length === 3);
  check('chain pop scores chain bonus', popEv?.cause === 'chain'
    && popEv?.score === 3 * T.SCORE_BALL + T.SCORE_CHAIN_BONUS);
  check('chain pop increments combo', popEv?.combo === 1);
  check('survivor remains after chain pop', st.paths[0].balls.length === 1 && st.paths[0].balls[0].color === 0);

  // non-matching gap → rear catches up, front stays put, clank without pop
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 900 }, { color: 1, s: 900 - SP }, { color: 0, s: 900 - 5 * SP }, { color: 1, s: 900 - 6 * SP }]);
  let clankAt = null;
  for (let i = 0; i < 200 && !clankAt; i++) {
    const frontBefore = st.paths[0].balls[0].s;
    const ev = step(st, 25);
    if (ev.some((e) => e.type === 'clank')) clankAt = { frontBefore, rearFront: st.paths[0].balls[2].s };
  }
  check('non-matching gap: rear catches up to contact', !!clankAt && near(clankAt.rearFront, 900 - 2 * SP, 1.5),
    clankAt ? `rear front at ${clankAt.rearFront.toFixed(1)}` : 'no clank');
  check('non-matching gap: front segment stays put', !!clankAt && near(clankAt.frontBefore, 900, 0.01));
  check('no pop on non-matching junction', st.paths[0].balls.length === 4);
  const before = st.paths[0].balls[0].s;
  for (let i = 0; i < 8; i++) step(st, 50);
  check('merged chain resumes driving', st.paths[0].balls[0].s > before + 30);
}

// ── 6. Power-ups ─────────────────────────────────────────────────────────────
console.log('\n— Power-ups —');
{
  // slow: popped slow ball sets the timer; drive rate drops to SLOW_MULT
  let st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 800, power: 'slow' }, { color: 1, s: 800 - 3 * SP }]);
  let ev = [];
  popRun(st, st.paths[0], 0, 0, 'shot', ev);
  check('slow power sets effect timer', st.effects.slowUntil === st.elapsedMs + T.SLOW_MS
    && ev.some((e) => e.type === 'powerup' && e.kind === 'slow'));
  const s0 = st.paths[0].balls[0].s;
  for (let i = 0; i < 20; i++) step(st, 50);
  check('slow halves the drive (SLOW_MULT)', near(st.paths[0].balls[0].s - s0, 100 * T.SLOW_MULT, 1.5),
    `moved ${(st.paths[0].balls[0].s - s0).toFixed(1)}`);

  // reverse: chain rolls backward, then resumes forward when expired
  // (elapsedMs increments before the effect check, so 501 covers exactly 10 ticks)
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }), [{ color: 0, s: 800 }]);
  st.effects.reverseUntil = st.elapsedMs + 501;
  for (let i = 0; i < 10; i++) step(st, 50);
  check('reverse rolls the chain backward', near(st.paths[0].balls[0].s, 800 - T.REVERSE_SPEED * 0.5, 2),
    `at ${st.paths[0].balls[0].s.toFixed(1)}`);
  for (let i = 0; i < 10; i++) step(st, 50);
  check('drive resumes after reverse expires', near(st.paths[0].balls[0].s, 800 - T.REVERSE_SPEED * 0.5 + 100 * 0.5, 2),
    `at ${st.paths[0].balls[0].s.toFixed(1)}`);

  // accuracy: flag set on pop; fired flights move faster
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 800, power: 'accuracy' }, { color: 1, s: 800 - 3 * SP }]);
  ev = [];
  popRun(st, st.paths[0], 0, 0, 'shot', ev);
  check('accuracy power sets effect timer', st.effects.accuracyUntil === st.elapsedMs + T.ACCURACY_MS);
  const flight = fireBall(st, -Math.PI / 2);
  check('accuracy speeds up shots', !!flight && near(flight.speed, T.SHOT_SPEED * T.ACCURACY_SHOT_MULT, 0.01));

  // explosion: blast radius around the popped ball, nothing beyond
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }), [
    { color: 1, s: 900 }, { color: 1, s: 900 - SP }, { color: 0, s: 900 - 2 * SP, power: 'explosion' },
    { color: 2, s: 900 - 3 * SP }, { color: 2, s: 900 - 4 * SP },
    { color: 3, s: 900 - 5 * SP }, { color: 3, s: 900 - 6 * SP },
  ]);
  ev = [];
  popRun(st, st.paths[0], 2, 2, 'shot', ev);
  const boom = ev.find((e) => e.type === 'explosion');
  check('explosion pops everything in radius', !!boom && boom.ids.length === 4 && st.paths[0].balls.length === 2);
  check('explosion spares balls beyond radius', st.paths[0].balls.every((b) => b.color === 3));
}

// ── 7. State machine ─────────────────────────────────────────────────────────
console.log('\n— State machine —');
{
  let st = mkState({}, { status: 'playing', spawned: 10 });
  mkChain(st, [{ color: 0, s: st.paths[0].path.length - 20 }]);
  let lostEv = false;
  for (let i = 0; i < 10 && st.status === 'playing'; i++) {
    if (step(st, 50).some((e) => e.type === 'lost')) lostEv = true;
  }
  check('ball reaching the hole loses', st.status === 'lost' && lostEv);
  check('terminal state ignores further steps', step(st, 50).length === 0);

  st = mkState({}, { status: 'playing', spawned: 10, balls: [] });
  const ev = step(st, 16);
  const won = ev.find((e) => e.type === 'won');
  const expectBonus = Math.max(0, Math.ceil((10 * T.TIME_PAR_MS_PER_BALL - st.elapsedMs) / 1000)) * T.TIME_BONUS_PER_SEC;
  check('cleared board after quota wins', st.status === 'won' && !!won);
  check('win time bonus math', won?.timeBonus === expectBonus && st.score === expectBonus,
    `bonus ${won?.timeBonus} expected ${expectBonus}`);

  st = mkState();   // status 'intro'
  check('firing rejected during intro', fireBall(st, 0) === null);
  st.status = 'won';
  check('firing rejected after game over', fireBall(st, 0) === null);
  const c0 = st.current, n0 = st.next;
  swapBalls(st);
  check('swap rejected after game over', st.current === c0 && st.next === n0);
  st.status = 'playing';
  swapBalls(st);
  check('swap exchanges current and next', st.current === n0 && st.next === c0);

  // recolor: shooter colors must exist on the board after a pop
  st = mkChain(mkState({}, { status: 'playing', spawned: 10 }),
    [{ color: 0, s: 600 }, { color: 0, s: 552 }, { color: 2, s: 504 }, { color: 2, s: 456 }]);
  st.current = 0; st.next = 0;
  const ev2 = [];
  popRun(st, st.paths[0], 0, 1, 'shot', ev2);
  check('shooter recolors to colors still present', st.current === 2 && st.next === 2
    && ev2.filter((e) => e.type === 'recolor').length === 2);

  // last-call: final spawns only deal colors still on the board
  st = mkChain(mkState({}, { status: 'playing', spawned: 5 }),
    [{ color: 3, s: 2 * SP }, { color: 3, s: SP }]);
  for (let i = 0; i < 400 && st.paths[0].spawned < 10; i++) step(st, 50);
  check('last-call spawns restrict to present colors',
    st.paths[0].spawned === 10 && st.paths[0].balls.every((b) => b.color === 3));
}

// ── 8. Determinism ───────────────────────────────────────────────────────────
console.log('\n— Determinism —');
{
  const run = () => {
    const st = createLevel(mkDef({ quota: 20, powerUpRate: 0.1, seed: 777 }));
    const log = [];
    for (let tick = 0; tick < 600 && st.status !== 'lost' && st.status !== 'won'; tick++) {
      if (tick === 80) fireBall(st, -Math.PI / 2 + 0.3);
      if (tick === 160) swapBalls(st);
      if (tick === 200) fireBall(st, -Math.PI / 2 - 0.2);
      if (tick === 300) fireBall(st, -Math.PI / 2);
      for (const e of step(st, 25)) log.push(e.type + (e.ids ? `:${e.ids.length}` : ''));
    }
    return {
      log: log.join(','), score: st.score, status: st.status,
      balls: st.paths[0].balls.map((b) => `${b.color}@${b.s.toFixed(2)}`).join('|'),
    };
  };
  const a = run(), b = run();
  check('identical seed + script → identical events', a.log === b.log);
  check('identical final score and chain', a.score === b.score && a.balls === b.balls && a.status === b.status);
  check('scripted run produced activity', a.log.includes('pop') || a.log.includes('inserted'));
}

// ── 9. Tunnels ───────────────────────────────────────────────────────────────
console.log('\n— Tunnels —');
{
  // normalization: the stored form is loose, the runtime form is not
  check('tunnels accept [enter, exit] pairs and object form',
    JSON.stringify(normalizeTunnels([[200, 300]], 1000))
    === JSON.stringify(normalizeTunnels([{ enter: 200, exit: 300 }], 1000)));
  check('tunnels are sorted by entrance',
    normalizeTunnels([[600, 700], [100, 200]], 1000).map((t) => t.enter).join() === '100,600');
  check('tunnels clamp to the path', JSON.stringify(normalizeTunnels([[-50, 1200]], 1000))
    === JSON.stringify([{ enter: 0, exit: 1000 }]));
  check('degenerate tunnels are dropped', normalizeTunnels([[300, 200], [400, 400]], 1000).length === 0);
  check('a missing tunnels field is no tunnels', normalizeTunnels(undefined, 1000).length === 0);

  // the gameplay predicate: an open interval, so a mouth itself stays fair game
  const tun = normalizeTunnels([[200, 400], [700, 900]], 1200);
  check('inside a tunnel is hidden', isHidden(tun, 300) && isHidden(tun, 800));
  check('outside every tunnel is visible',
    !isHidden(tun, 100) && !isHidden(tun, 550) && !isHidden(tun, 1100));
  check('a ball exactly on a mouth is still hittable', !isHidden(tun, 200) && !isHidden(tun, 400));

  // the cosmetic ramp is a separate thing and must not leak into the hit rule
  check('visibility is 1 outside a tunnel', visibilityAt(tun, 100) === 1);
  check('visibility ramps to 0 within TUNNEL.FADE of a mouth',
    visibilityAt(tun, 200 + TUNNEL.FADE) === 0
    && near(visibilityAt(tun, 200 + TUNNEL.FADE / 2), 0.5, 1e-9));
  check('visibility is 0 deep inside', visibilityAt(tun, 300) === 0);

  // spans partition the path exactly
  const spans = pathSpans(1200, tun);
  check('visible spans fill the gaps between tunnels',
    JSON.stringify(spans.visible) === JSON.stringify([[0, 200], [400, 700], [900, 1200]]));
  check('hidden spans are the tunnels',
    JSON.stringify(spans.hidden) === JSON.stringify([[200, 400], [700, 900]]));
  const covered = [...spans.visible, ...spans.hidden].reduce((a, [s0, s1]) => a + (s1 - s0), 0);
  check('spans cover the whole path exactly once', near(covered, 1200, 1e-9));
  check('no tunnels means one span', pathSpans(1200, []).visible.length === 1);

  const sp = buildPath(STRAIGHT);
  const range = sampleRange(sp, 300, 700);
  check('sampleRange stops dead on its endpoints',
    near(range[0].x, 300, 0.5) && near(range[range.length - 1].x, 700, 0.5));
  check('nearestS projects a point onto the path', near(nearestS(sp, 700, 560).s, 700, 4));

  // ── the three interaction rules ──
  const shootAt = (st, ball) => fireBall(st, Math.atan2(ball.y - st.frog.y, ball.x - st.frog.x));
  const runFlights = (st) => {
    let missed = false;
    for (let i = 0; i < 200 && st.flights.length; i++) {
      if (step(st, 25).some((e) => e.type === 'missed')) missed = true;
    }
    return missed;
  };

  let st = mkState({ tunnels: [[560, 660]], pushSpeed: 0 }, { status: 'playing', spawned: 10 });
  mkChain(st, [{ color: 0, s: 600 }]);
  shootAt(st, st.paths[0].balls[0]);
  check('a shot flies over a submerged ball', runFlights(st) && st.paths[0].balls.length === 1);

  st = mkState({ pushSpeed: 0 }, { status: 'playing', spawned: 10 });
  mkChain(st, [{ color: 0, s: 600 }]);
  shootAt(st, st.paths[0].balls[0]);
  check('the same shot lands once the tunnel is gone', !runFlights(st) && st.paths[0].balls.length === 2);

  st = mkState({ tunnels: [[560, 660]], pushSpeed: 0 }, { status: 'playing', spawned: 10 });
  mkChain(st, [{ color: 0, s: 600 }]);
  step(st, 16);
  const ball = st.paths[0].balls[0];
  check('a submerged ball is flagged hidden and invisible', ball.hidden === true && ball.vis === 0);
  check('the laser sight ignores submerged chain',
    !rayHit(st, Math.atan2(ball.y - st.frog.y, ball.x - st.frog.x)).hit);

  // a blast is stopped by the ground, not just by distance
  st = mkState({ tunnels: [[620, 720]], pushSpeed: 0 }, { status: 'playing', spawned: 10 });
  mkChain(st, [
    { color: 1, s: 900 }, { color: 1, s: 836 }, { color: 0, s: 772, power: 'explosion' },
    { color: 2, s: 708 }, { color: 2, s: 644 },
  ]);
  step(st, 16);
  const ev = [];
  popRun(st, st.paths[0], 2, 2, 'shot', ev);
  const boom = ev.find((e) => e.type === 'explosion');
  check('an explosion cannot reach through a tunnel',
    !!boom && boom.ids.length === 2 && st.paths[0].balls.length === 2,
    `caught ${boom?.ids.length}`);
  check('the submerged pair survives the blast', st.paths[0].balls.every((b) => b.color === 2));

  // and the chain itself notices nothing
  st = mkState({ tunnels: [[400, 700]] }, { status: 'playing', spawned: 10 });
  mkChain(st, [{ color: 0, s: 300 }, { color: 1, s: 300 - SP }, { color: 2, s: 300 - 2 * SP }]);
  for (let i = 0; i < 40; i++) step(st, 50);          // 2s at pushSpeed 100
  check('the chain rolls straight on through a tunnel',
    near(st.paths[0].balls[0].s, 500, 1) && spacingOk(st.paths[0].balls),
    `front at ${st.paths[0].balls[0].s.toFixed(1)}`);
  check('every ball inside is submerged', st.paths[0].balls.every((b) => b.hidden === (b.s > 400)));

  // ── lint ──
  // A 4000px straight: TUNNEL.MIN_LEN plus the mouth clearances no longer fit
  // two tunnels on the 1600px fixture the rest of the suite uses. It runs off
  // the canvas, so only the tunnel errors are read here — the bounds and
  // curvature rules are what the bank lint below covers.
  const LONG = [[0, 500], [1000, 500], [2000, 500], [3000, 500], [4000, 500]];
  const lint = (tunnels) => validateLevel(mkDef({ points: LONG, tunnels })).errs
    .filter((e) => /tunnel/i.test(e)).join(' | ');
  check('lint accepts a well-spaced pair', lint([[400, 1000], [1400, 2000]]) === '',
    lint([[400, 1000], [1400, 2000]]));
  check('lint rejects a stub tunnel', lint([[400, 700]]).includes('only 300px long'));
  check('lint rejects a mouth in the spawn lead-in', lint([[100, 700]]).includes('spawn lead-in'));
  check('lint rejects an exit on top of the hole', lint([[3300, 3900]]).includes('crowds the hole'));
  check('lint rejects crowded tunnels', lint([[400, 1000], [1100, 1700]]).includes('crowd at'));
  check('lint rejects burying too much of the path',
    lint([[400, 1300], [1600, 2500]]).includes('is tunnelled'));
  check('lint rejects an inverted tunnel', lint([[900, 400]]).includes('exit <= enter'));

  // TUNNEL.MIN_LEN exists to keep a tunnel's own two maws from growing through
  // each other, so it has to track the art. Asserted rather than imported: the
  // engine has no business depending on a drawing module.
  check(`MIN_LEN (${TUNNEL.MIN_LEN}) clears two portal heads (2 × ${PORTAL_REACH})`,
    TUNNEL.MIN_LEN >= 2 * PORTAL_REACH);
}

// ── 10. Multi-path ───────────────────────────────────────────────────────────
console.log('\n— Multi-path —');
{
  // Two independent straight lanes, well apart on screen, frog centred between
  // them — the "opposite sides" layout the feature is built around.
  const LANE_A = [[0, 200], [400, 200], [800, 200], [1200, 200], [1600, 200]];
  const LANE_B = [[0, 800], [400, 800], [800, 800], [1200, 800], [1600, 800]];
  const twoLanes = (pushSpeed = 100) => ({
    level: 1, name: 'Two Lanes', frog: [800, 500], colors: 4, seed: 99,
    starScores: [100, 200, 300],
    paths: [
      { shape: 'line', points: LANE_A, tunnels: [], quota: 10, introBalls: 2, pushSpeed, powerUpRate: 0 },
      { shape: 'line', points: LANE_B, tunnels: [], quota: 10, introBalls: 2, pushSpeed, powerUpRate: 0 },
    ],
  });
  // freeze both spawners at their quota so a hand-built chain fixture isn't
  // added to mid-test — the same spawned:quota convention the single-path
  // fixtures use, just applied to both paths.
  const freeze = (st) => { for (const p of st.paths) p.spawned = p.quota; };

  // independent spawners: both paths reach their own quota on their own clock
  let st = createLevel(twoLanes(100));
  for (let i = 0; i < 4000 && (st.paths[0].spawned < 10 || st.paths[1].spawned < 10); i++) step(st, 16);
  check('each path spawns to its own quota independently',
    st.paths[0].spawned === 10 && st.paths[1].spawned === 10
    && st.paths[0].balls.length === 10 && st.paths[1].balls.length === 10);

  // shooter color pool unions across paths: path A all color 0, path B all
  // color 1 — current/next must be reassignable to whatever is on EITHER lane
  st = createLevel(twoLanes());
  freeze(st);
  mkChain(st, [{ color: 0, s: 300 }, { color: 0, s: 300 - SP }], 0);
  mkChain(st, [{ color: 1, s: 300 }, { color: 1, s: 300 - SP }], 1);
  st.status = 'playing';
  st.current = 2; st.next = 3;   // neither color is present anywhere
  popRun(st, st.paths[0], 0, 0, 'shot', []);
  check('shooter recolors from the union of both paths\' present colors',
    (st.current === 0 || st.current === 1) && (st.next === 0 || st.next === 1));

  // a shot lands on whichever path it is physically aimed at — no special
  // targeting, purely the nearest ball to the ray
  st = createLevel(twoLanes(0));
  freeze(st);
  mkChain(st, [{ color: 0, s: 600 }], 0);
  mkChain(st, [{ color: 1, s: 600 }], 1);
  st.status = 'playing';
  const ballB = st.paths[1].balls[0];
  st.current = 1;
  fireBall(st, Math.atan2(ballB.y - st.frog.y, ballB.x - st.frog.x));
  for (let i = 0; i < 200 && st.flights.length; i++) step(st, 16);
  check('a shot lands on the path it is aimed at, not always path 0',
    st.paths[1].balls.length === 2 && st.paths[0].balls.length === 1);

  // either path (not just path 0) reaching its own pit loses the whole level
  st = createLevel(twoLanes(100));
  freeze(st);
  mkChain(st, [{ color: 1, s: st.paths[1].path.length - 20 }], 1);
  mkChain(st, [{ color: 0, s: 400 }], 0);
  st.status = 'playing';
  let lostEv = false;
  for (let i = 0; i < 10 && st.status === 'playing'; i++) {
    if (step(st, 50).some((e) => e.type === 'lost')) lostEv = true;
  }
  check('either path reaching the hole loses the whole level', st.status === 'lost' && lostEv);

  // winning requires EVERY path cleared, not just one
  st = createLevel(twoLanes());
  freeze(st);
  st.status = 'playing';
  mkChain(st, [{ color: 0, s: 400 }], 1);
  let won = step(st, 16).some((e) => e.type === 'won');
  check('one path cleared but not the other does not win', !won && st.status === 'playing');
  st.paths[1].balls = [];
  won = step(st, 16).some((e) => e.type === 'won');
  check('every path cleared wins', won && st.status === 'won');
}

// ── 11. Level bank lint ──────────────────────────────────────────────────────
console.log('\n— Level bank —');
{
  const bankDir = join(__dirname, '../assets/gamedata/zuma');
  let manifest = null;
  try {
    manifest = JSON.parse(readFileSync(join(bankDir, 'levels.json'), 'utf8'));
  } catch (_) { /* handled below */ }
  check('manifest exists (run genZuma.js)', !!manifest);
  let levels = [];
  let manifestMismatch = '';
  if (manifest) {
    levels = (manifest.levels ?? []).map((entry) => {
      const def = JSON.parse(readFileSync(join(bankDir, entry.file), 'utf8'));
      if (!manifestMismatch && (entry.level !== def.level || entry.name !== def.name)) {
        manifestMismatch = `${entry.file}: manifest says L${entry.level} "${entry.name}", `
          + `file says L${def.level} "${def.name}"`;
      }
      return def;
    });
  }
  check('every manifest entry matches its level file', !manifestMismatch, manifestMismatch);
  if (manifest) {
    check('bank has 20 levels', levels.length === 20);
    check('levels numbered 1..N contiguously', levels.every((l, i) => l.level === i + 1));
    // Geometry and parameters both come from ZumaLogic — the same lint
    // genZuma.js gates on and the editor shows live, so the three can't drift.
    let geomOk = true, paramOk = true, geomDetail = '', paramDetail = '';
    for (const l of levels) {
      const perr = validateLevelParams(l);
      if (perr.length) { paramOk = false; paramDetail = `level ${l.level}: ${perr[0]}`; }
      const gerr = validateLevel(l).errs;
      if (gerr.length) { geomOk = false; geomDetail = `level ${l.level}: ${gerr[0]}`; }
    }
    check('level parameters in range', paramOk, paramDetail);
    check(`geometry lint (length, bounds, curvature ≥ ${(T.BALL_RADIUS * 1.7).toFixed(0)}px, frog clear ≥ ${T.FROG_CLEARANCE}px)`,
      geomOk, geomDetail);

    const tunnelCount = (l) => l.paths.reduce((a, p) => a + (p.tunnels?.length ?? 0), 0);
    const tunnelled = levels.filter((l) => tunnelCount(l) > 0);
    console.log(`  ..  ${tunnelled.length} of ${levels.length} levels carry tunnels`
      + ` (${tunnelled.map((l) => `L${l.level}×${tunnelCount(l)}`).join(' ')})`);

    // ── 12. Winnability soak ─────────────────────────────────────────────────
    // If a bot that only ever takes the best immediately available shot can
    // clear a level, a player can. This is what catches a quota the path can
    // technically hold but nobody could actually survive.
    //
    // Over SEEDS seeds, not one: a single seed makes this check hostage to
    // chain luck, so any unrelated tuning nudge (moving the muzzle by 26px,
    // say) flips levels between pass and fail for no real reason.
    console.log('\n— Aimbot soak —');
    const SEEDS = 8;
    const FLOOR = 5;                // per-level clears required out of SEEDS
    const totalQuota = (l) => l.paths.reduce((a, p) => a + p.quota, 0);
    const rows = levels.map((l) => {
      const runs = [];
      for (let k = 0; k < SEEDS; k++) runs.push(aimbotPlay(l, l.seed + k * 7919));
      return {
        level: l.level,
        wins: runs.filter((r) => r.status === 'won').length,
        best: Math.max(...runs.map((r) => r.score)),
        mean: runs.reduce((a, r) => a + r.score, 0) / SEEDS,
      };
    });

    const weak = rows.filter((r) => r.wins < FLOOR);
    check(`aimbot clears every level at least ${FLOOR}/${SEEDS} times`, weak.length === 0,
      weak.map((r) => `L${r.level} ${r.wins}/${SEEDS}`).join(', '));
    const totalWins = rows.reduce((a, r) => a + r.wins, 0);
    const rate = totalWins / (rows.length * SEEDS);
    console.log(`  ..  aimbot clear rate: ${(rate * 100).toFixed(0)}%  (worst level ${Math.min(...rows.map((r) => r.wins))}/${SEEDS})`);
    check('bank-wide clear rate ≥ 80%', rate >= 0.8, `${(rate * 100).toFixed(0)}%`);

    const perMarble = rows.reduce((a, r, i) => a + r.mean / totalQuota(levels[i]), 0) / rows.length;
    console.log(`  ..  mean score per quota marble: ${perMarble.toFixed(1)}`);
    // Medals are judged on the bot's MEAN run, not its best: best-of-N is a
    // measure of chain luck, and the question here is where the star curve
    // sits relative to ordinary mechanical play.
    const threeStar = rows.filter((r, i) => r.mean >= levels[i].starScores[2]).length;
    const twoStar = rows.filter((r, i) => r.mean >= levels[i].starScores[1]).length;
    const ceiling = rows.filter((r, i) => r.best >= levels[i].starScores[2]).length;
    console.log(`  ..  aimbot medals (mean run): ★★★ on ${threeStar}, ★★+ on ${twoStar} of ${levels.length}`
      + `  —  ★★★ within reach on a lucky run for ${ceiling}`);
    check('three stars stays a stretch for the aimbot', threeStar < levels.length / 2, `${threeStar}/${levels.length}`);
    check('three stars is not out of reach either', ceiling >= 3, `only ${ceiling}/${levels.length} even on a best run`);
    check('two stars is within the aimbot\'s reach', twoStar >= levels.length / 2, `${twoStar}/${levels.length}`);
  }
}

// ── Result ───────────────────────────────────────────────────────────────────
console.log('');
if (failures) {
  console.error(`${failures} failure(s)`);
  process.exit(1);
}
console.log('All Zuma checks passed.');