// Game logic: ballistics, swings, serves, rules/scoring, AI, and the per-frame update.

import { TUNE, UI, EATEN_BURST, COURT, CONTACT, VOLLEY, ZONE_DEPTH, HOME, P_BOUNDS, TOSS, SHOT_DEPTH, POSE_TIME, BOUNCE_IDLE } from './config.js';
import { P, O, ball, score, crowd, G, other, deuceSide, setupPoint, sendBoy } from './state.js';
import { audio, pock, swish, applause, voice, sfx, aww, zombieMusic, zombieDuck } from './audio.js';
import { axisX, axisZ, takeFlickAim, touchPX } from './input.js';
import { W } from './render.js'; // runtime-only cycle (render imports gameplay), same pattern as input/zombies
import { updateZombies, spawnZombie, spawnRacketZombie, zombies, explode, meleeSwipe, extras, parts, playerGore } from './zombies.js';

// ------------------------------------------------------------- ballistics ----
// Launch ball from (x0,y0,z0) so it lands at (tx, tz) with horizontal speed s under gravity g.
export function solveShot(x0, y0, z0, tx, tz, s, g = TUNE.gravity) {
  const dx = tx - x0, dz = tz - z0, dist = Math.hypot(dx, dz), T = dist / s;
  return { vx: dx / T, vz: dz / T, vy: (0.08 - y0 + 0.5 * g * T * T) / T };
}

export function predictLanding() { // first-bounce point, closed form — exact, so the ring never jitters
  const g = ball.g || TUNE.gravity;
  const disc = ball.vy * ball.vy + 2 * g * ball.y;
  if (disc < 0) return null;
  const t = (ball.vy + Math.sqrt(disc)) / g; // time until y = 0
  return { x: ball.x + ball.vx * t, z: ball.z + ball.vz * t };
}

// splatter FREE-AIM (slingshot). The pull is a RAY, not a landing point: its DIRECTION picks the
// lane you fire down, its LENGTH is power — and nothing else. Pulling further does NOT reach
// further, which is the whole fix: a shambler at the far baseline costs the same short pull as
// one on top of you, so the gesture always fits on the screen. The first body standing in the
// lane is the target; the cone widens with range so distant lanes stay pickable.
export const pullFrac = mag => Math.max(0, Math.min(1, (mag - TUNE.pullMin) / (TUNE.pullFull - TUNE.pullMin)));
export const pullQuality = mag => TUNE.pullQMin + pullFrac(mag) * (1 - TUNE.pullQMin);

export function flickTarget(ch, aim) { // exported: render draws the live reticle with it
  const q = pullQuality(aim.mag), f = pullFrac(aim.mag);
  if (aim.mag < TUNE.pullMin) return { q, f }; // barely drawn: no lane yet, so no target
  const ax = aim.fx, az = aim.fy;              // unit vector; input already inverted the pull. screen up = -z
  let zt = null, near = 1e9;
  for (const zb of zombies) {
    const dx = zb.x - ch.x, dz = zb.z - ch.z;
    const along = dx * ax + dz * az;                       // how far down the lane it stands
    if (along <= 0) continue;                              // behind the shot
    if (Math.abs(dx * az - dz * ax) > TUNE.zSnap + TUNE.aimCone * along) continue; // outside the cone
    if (along < near) { near = along; zt = zb; }           // the FIRST one in the lane eats it
  }
  const R = zt ? near : TUNE.aimReach; // empty lane: the ball just flies the full length of it
  const tx = Math.max(-6.5, Math.min(6.5, ch.x + ax * R));
  const tz = Math.max(1, Math.min(24.5, ch.z + az * R));
  return { tx, tz, zt, q, f };
}

// splatter tap/lane aiming (no flick): the shot locks onto the best-matching zombie
// anywhere on the court — including your own side of the net.
function zombieTarget(aim) {
  if (!zombies.length) return null;
  const none = !aim || (!aim.ax && !aim.az);
  if (none) return null; // no direction, no lock. Free predictive auto-aim was the reason a
                         // bare rhythm of taps could clear the court without any aiming at all.
  let best = null, bs = 1e9;
  for (const zb of zombies) {
    let s = Math.abs(zb.x - (P.x + aim.ax * 4));    // lane relative to where YOU stand
    if (aim.az < 0) s += zb.z * 0.35;               // flick up: prefer the far ones
    if (aim.az > 0) s += (COURT.L - zb.z) * 0.35;   // flick down: the close ones on your side
    if (s < bs) { bs = s; best = zb; }
  }
  return best;
}

function doHit(ch, quality, aim) {
  // aim: {ax: -1|0|1, az: -1|0|1} from held keys / flick at contact (az -1 = deep, 1 = short)
  const toFar = ch.side === 'P';
  // snap the ball to the racket at the contact frame so the hit visually connects
  ball.x = ch.x + ch.facing * 0.5;
  ball.z = ch.z + (toFar ? -0.3 : 0.3);
  const err = () => (Math.random() * 2 - 1) * TUNE.aimError * (1 - quality);
  let tx, tz;
  let s = TUNE.baseShotSpeed + quality * TUNE.qualityShotSpeed;
  const ft = G.mode !== 'tennis' && !G.interlude && ch.side === 'P' // the duel aims like tennis: lanes, not free-aim
    ? (aim && aim.fx !== undefined ? flickTarget(ch, aim) : { zt: zombieTarget(aim) }) : null;
  if (ft && ft.zt) {
    const zt = ft.zt;
    tx = zt.x + err() * 0.4;
    const T0 = Math.hypot(zt.x - ball.x, zt.z - ball.z) / s;
    tz = Math.min(23, zt.z + zt.v * T0) + err() * 0.3; // lead the shambler's walk
  } else if (ft && ft.tx !== undefined) {
    tx = ft.tx + err() * 0.4; tz = ft.tz + err() * 0.3; // no magnet: the ball goes where you flicked
  } else {
    tx = aim.ax * (toFar ? 3.3 : 2.7) + err(); // your aimed shots go properly wide
    const tzBase = aim.az < 0 ? SHOT_DEPTH.deep : aim.az > 0 ? SHOT_DEPTH.short : SHOT_DEPTH.mid;
    tz = (toFar ? tzBase : COURT.L - tzBase) + err() * 0.8;
  }
  tx = Math.max(-5, Math.min(5, tx));
  // topspin: quality shots dive under extra effective gravity, which is what lets real
  // pace arc over the net and still land in — the core tennis trade-off
  const g = TUNE.gravity * (1 + quality * TUNE.spinFactor);
  let v = solveShot(ball.x, ball.y, ball.z, tx, tz, s, g);
  // low contact → trade pace for loft until the net is cleared; good timing gets a
  // comfortable margin, sloppy timing keeps some tape risk
  const margin = 0.06 + 0.22 * quality;
  for (let i = 0; i < NET_LOFT_TRIES; i++) {
    const tN = (COURT.netZ - ball.z) / v.vz;
    const yN = ball.y + v.vy * tN - 0.5 * g * tN * tN;
    if (tN <= 0 || yN >= COURT.netH + margin) break;
    s *= 0.9; v = solveShot(ball.x, ball.y, ball.z, tx, tz, s, g);
  }
  ball.g = g;
  ball.vx = v.vx; ball.vy = v.vy; ball.vz = v.vz;
  ball.lastHit = ch.side; ball.bounces = 0; ball.firstLand = null;
  G.wasServe = false; // a serve volleyed back pre-bounce must not fault-check the return
  ball.pow = quality; // carried pace: zombies splatter only above zSplatQ
  ball.kills = 0;     // fresh shot: multi-kill streak restarts
  ball.bomb = false; ball.flame = false; // only a consuming serve arms these; any other hit clears them
  if (ch.side === 'P') { // shot marker: where this will land — red means it's going out
    const ok = G.mode !== 'tennis' || (Math.abs(tx) <= COURT.W / 2 + 0.02 && tz >= -0.02 && tz <= COURT.netZ);
    G.outMarker = { x: tx, z: tz, out: !ok, t: 1.3 };
    G.aiReactT = 0; // CPU hasn't read the shot yet
  }
  sfx(ch.side === 'P' ? 'tennis-player' : 'tennis-opponent', 0.9, { reverb: true }); // recorded racket strike, per side
  if (quality > 0.999) { G.hitstop = 0.05; G.flash = { text: 'PERFECT', t: 0.7 }; pock(0.5, 1600); }
  ch.pose = 'swing'; ch.poseT = 0;
}

// ----------------------------------------------------------------- serve ----
function tossBall(sv) {
  ball.active = true; ball.bounces = 0; ball.firstLand = null; ball.collected = false;
  ball.x = sv.x + 0.35 * (sv.side === 'P' ? 1 : -1); ball.z = sv.z; ball.y = TOSS.y0;
  ball.vx = 0; ball.vz = 0; ball.vy = TOSS.vy; ball.g = TUNE.gravity;
  G.phase = 'toss';
}
export function serveApexY() { return TOSS.y0 + TOSS.vy * TOSS.vy / (2 * TUNE.gravity); } // ~2.95

// how many 10%-pace cuts a shot may take to get over the net. 8 wasn't enough for a target
// sitting right behind the tape — that needs a near-vertical drop, so ~10 cuts (pace × 0.35).
const NET_LOFT_TRIES = 12;

function hitServe(sv, quality, aim = null) {
  const toFar = sv.side === 'P';
  let s = TUNE.serveSpeed + quality * TUNE.serveQualitySpeed;
  let boxX, tzs;
  const ft = G.mode !== 'tennis' && !G.interlude // the duel serves like tennis: to the box, not free-aim
    ? (aim && aim.fx !== undefined ? flickTarget(sv, aim) : { zt: zombieTarget(aim) }) : null;
  if (ft && ft.zt) { // magnet hit, or (tap) the most advanced zombie
    const zt = ft.zt;
    boxX = zt.x + (Math.random() * 2 - 1) * (1 - quality) * 0.8;
    const T0 = Math.hypot(zt.x - ball.x, zt.z - ball.z) / s;
    tzs = Math.min(23, zt.z + zt.v * T0);
  } else if (ft && ft.tx !== undefined) { // free-aim, no magnet: serve to the flicked spot
    boxX = ft.tx; tzs = ft.tz;
  } else {
    // target: diagonal service box. Serving from deuce side → target box is across.
    boxX = (deuceSide() ? -1 : 1) * (toFar ? 1 : -1) * 2.0 + (Math.random() * 2 - 1) * TUNE.aimError * 0.8 * (1 - quality);
    const boxZ = toFar ? COURT.svcFar + 1.6 : COURT.svcNear - 1.6;
    tzs = boxZ + (Math.random() * 2 - 1) * (1 - quality) * 1.5;
  }
  const g = TUNE.gravity * (1 + quality * TUNE.serveSpin); // the harder you hit it, the harder it dips
  // CLEAR THE NET. A shambler standing just the other side of the tape is only reachable on a
  // loft, so trade pace for arc until the ball actually gets over. doHit has done this since
  // forever; the serve never did, which is why every shot at a net-hugger died in the tape.
  // The trade is real: the loftier it goes the slower it arrives, and the walk-lead below was
  // computed for the original pace — a lob is a genuinely less reliable shot.
  let v = solveShot(ball.x, ball.y, ball.z, boxX, tzs, s, g);
  for (let i = 0; i < NET_LOFT_TRIES; i++) {
    const tN = (COURT.netZ - ball.z) / v.vz;
    const yN = ball.y + v.vy * tN - 0.5 * g * tN * tN;
    // The sim only samples the net plane once a frame, so a steeply DIVING ball can test below
    // the tape even when the closed form clears it. Charge margin for exactly that sampling
    // error (descent rate × the worst frame step) instead of doHit's flat quality cushion —
    // that cushion is paid for in pace, and it was taxing precisely the shots meant to hurt.
    const margin = 0.06 + Math.abs(v.vy - g * tN) * 0.04; // 0.04 s = main.js's dt clamp
    if (tN <= 0 || yN >= COURT.netH + margin) break;
    s *= 0.9; v = solveShot(ball.x, ball.y, ball.z, boxX, tzs, s, g);
  }
  ball.g = g;
  ball.vx = v.vx; ball.vy = v.vy; ball.vz = v.vz;
  ball.lastHit = sv.side; ball.bounces = 0;
  ball.pow = quality;
  ball.kills = 0;     // fresh serve: multi-kill streak restarts
  // the SELECTED tin arms the serve; slot 0 (PLAIN) throws a normal ball and banks your
  // specials for later. Placement still follows the flick — only WHICH ball flies is the
  // rack's call now. GUN (slot 4) never reaches here; it starts a burst before the serve.
  const wsel = G.mode === 'splatter' ? G.weapon : 0;
  ball.bomb = wsel === 1 && G.bombs > 0;
  if (ball.bomb) G.bombs--;
  ball.flame = wsel === 3 && G.flames > 0;
  if (ball.flame) G.flames--;
  if (wsel === 2 && G.triples > 0) { // one serve, three balls: clones fanned ±6°
    G.triples--;
    for (const deg of [-6, 6]) {
      const r = deg * Math.PI / 180, c = Math.cos(r), sn = Math.sin(r);
      extras.push({ x: ball.x, y: ball.y, z: ball.z, vy: ball.vy, pow: quality, t: 2.5,
        vx: ball.vx * c - ball.vz * sn, vz: ball.vx * sn + ball.vz * c });
    }
  }
  if (wsel > 0 && slotStock(wsel) <= 0) G.weapon = 0; // that was the last tin — hand back to plain balls
  if (sv.side === 'P') G.outMarker = { x: boxX, z: tzs, out: G.mode === 'tennis' && !inServeBox(boxX, tzs), t: 1.3 };
  G.phase = 'rally'; sfx(sv.side === 'P' ? 'tennis-player' : 'tennis-opponent', 0.9, { reverb: true }); // recorded serve strike, per side
  sv.pose = 'serve'; sv.poseT = 0;
  if (quality > 0.999) { G.flash = { text: 'PERFECT', t: 0.7 }; G.hitstop = 0.05; }
}

// ---------------------------------------------------------------- scoring ----
function scoreKey() {
  const N = ['love', 'fifteen', 'thirty', 'forty'];
  const s = score.server === 'P' ? [score.pts[0], score.pts[1]] : [score.pts[1], score.pts[0]];
  if (s[0] >= 3 && s[1] >= 3) {
    if (s[0] === s[1]) return 'deuce';
    return (s[0] > s[1]) === (score.server === 'P') ? 'advantage_player' : 'advantage_receiver';
  }
  if (s[0] === s[1]) return N[s[0]] + '_all';
  return N[s[0]] + '_' + N[s[1]];
}

// ---- the modal: the only thing in the game that stops the world. Play resumes on a tap, not
// on a timer, so a popup can be READ. showModal never clobbers an open one (a kill cascade can
// try to open two in the same frame) and only ever touches G — never the zombie array it may
// be called from mid-iteration.
export function showModal(m) { if (!G.modal) G.modal = m; }
export function dismissModal() {
  const m = G.modal; if (!m) return false;
  G.modal = null; if (m.onDismiss) m.onDismiss();
  return true; // the caller must swallow the gesture: dismissing must never also serve
}

export function cheer(seconds, vol) {
  sfx('tennis-applaus', Math.min(1.5, vol * 2.2)); // recorded crowd; vol scales with the size of the moment (gain > 1 amplifies)
  crowd.cheer = Math.max(crowd.cheer, seconds);
}

function advancePoint(side) { // shared scoring math; returns whether a game was won
  const i = side === 'P' ? 0 : 1, j = 1 - i;
  score.pts[i]++;
  if (score.pts[i] >= 4 && score.pts[i] - score.pts[j] >= 2) {
    score.games[i]++; score.pts = [0, 0];
    return true;
  }
  return false;
}

function pointTo(side, reason) {
  if (G.mode === 'tennis' && side === 'O' && ball.lastHit === 'O' && G.rallyNear && !G.swung) { // their ball died on your side untouched — and no whiff already explains it
    const n = G.rallyNear;
    logSwing({ result: 'PASSED', reason: `never swung in range — ball got ${r2(n.d)}m away at y=${r2(n.y)}m`,
      dMin: r2(n.d), y: r2(n.y), ballZ: r2(n.bz), px: r2(n.px), pz: r2(n.pz) });
  }
  const gameOver = advancePoint(side);
  G.phase = 'over'; G.overT = gameOver ? 3.2 : 2.2;
  sendBoy();
  if (side === 'O') aww(0.8); // you dropped the point — the crowd sighs
  if (reason) voice(reason);
  if (gameOver) {
    if (G.mode === 'tennis' && side === 'P' && !G.everTransitioned) return startTransition();
    voice(side === 'P' ? 'game_player' : 'game_opponent', 0.7);
    cheer(2.8, 0.6);
    score.server = other(score.server);
  } else {
    voice(scoreKey(), 0.7);
    if (side === 'P') cheer(1.2, 0.3);
  }
  G.serveNum = 1;
}

// splatter-mode scoring: points land mid-flight without interrupting play.
// quiet (during a horde) rate-limits the umpire so he doesn't call every rapid-fire point.
// The scoreboard IS the progression: games drive spawn pressure, 6 games = a set = a horde,
// odd games end in a changeover breather.
export function splatPoint(side, quiet = false) {
  if (side === 'P' && ++G.killCount < TUNE.killsPerPoint) return; // K kills bank one point; the rest just splatter
  if (side === 'P') G.killCount = 0;
  const gameOver = advancePoint(side);
  if (gameOver) {
    G.runGames++;
    // the schedule calls a DUEL, not a tin: it comes round on its own so there's always a chance
    // at a weapon, but you still have to win the point to be handed one. Fires at the next clear.
    if (G.runGames === TUNE.duelFirst ||
        (G.runGames > TUNE.duelFirst && (G.runGames - TUNE.duelFirst) % TUNE.duelEvery === 0))
      G.duelDue = true;
    voice(side === 'P' ? 'game_set_massacre' : 'game_opponent', 0.5); // game-win lines always speak
    if (side === 'P') cheer(2.2, 0.5); else aww(0.85); // your game = applause, theirs = a groan
    const i = side === 'P' ? 0 : 1;
    if (score.games[i] >= 6) { G.sets[i]++; score.games = [0, 0]; G.afterClear = 'set'; } // set banked; a horde follows the card
    else if ((score.games[0] + score.games[1]) % 2 === 1) G.afterClear = 'changeover'; // real rule: after odd games
    else G.afterClear = 'game';                                                         // even game: a beat, then the next wave
    G.clearWinner = side;
    if (side === 'P' && !zombies.some(z => z.variant === 'r'))
      spawnRacketZombie(); // every game you win, an opponent takes the far court (rally it, or splat it)
    // The wave does NOT auto-collapse anymore: the survivors stay and must be cleared BY HAND before
    // play advances — only no NEW shamblers spawn. When the last one is down, proceedAfterClear()
    // fires (see update()). If the winning shot already emptied the court, proceed at once.
    if (zombies.some(z => z.variant !== 'r')) {
      G.clearing = true; ball.active = false;
      G.flash = { text: 'CLEAR THE COURT', t: 1.8 };
      G.phase = 'over'; G.overT = TUNE.gameBeatT; // a short beat to register the game, then the serve loop resumes for the mop-up
    } else proceedAfterClear();
  } else if (!quiet || G.idleT - G.lastScoreT > 2) {
    voice(scoreKey(), 0.45); G.lastScoreT = G.idleT;
    if (side === 'P' && !quiet) cheer(0.7, 0.25);
  }
}

// the court is mopped up (or was already clear): play advances to whatever the won game earned —
// a changeover breather, a plain even-game beat, or (on a set) the centered SET card then a horde.
export function proceedAfterClear() {
  G.clearing = false;
  const mode = G.afterClear, side = G.clearWinner;
  G.afterClear = null;
  // A clear is the ONE moment the court is guaranteed empty — the natural slot for the scheduled
  // duel. (A wall-clock timer would need its own "wait for a safe moment" and could fire mid-swarm.)
  // The set/horde beat outranks it; the duel just waits for the next clear.
  if (mode !== 'set' && G.duelDue) { G.duelDue = false; G.afterDuel = mode || 'game'; startDuel(); return; }
  if (mode === 'set') {
    G.card = { title: 'SET ' + (G.sets[0] + G.sets[1]),                 // the set just banked (sets already ++'d at game over)
      sub1: side === 'P' ? 'THE SET IS YOURS' : 'SET TO THEM',
      sub2: 'SETS  ' + G.sets[0] + ' – ' + G.sets[1],
      color: side === 'P' ? UI.pick : UI.hot, t: TUNE.setCardT };
    G.pendingHorde = true;                                              // the horde begins when the card's pause ends
    ball.active = false; G.phase = 'over'; G.overT = TUNE.setCardT;
  } else if (mode === 'changeover') {
    G.pendingGame = true; startChangeover();                            // 'GAME N' after the breather
  } else {                                                              // 'game': even-game beat, then GAME N announces the next wave
    G.pendingGame = true; ball.active = false; G.phase = 'over'; G.overT = TUNE.gameBeatT;
  }
}

// changeover (after odd games, as the rules demand): a forced breather — no spawns,
// no serving, the boys mop. Zombies already on court keep walking; it's calm, not safe.
function startChangeover() {
  G.changeover = true;
  G.phase = 'over'; G.overT = TUNE.changeoverT;
  // out with the mop, across the near court where the gore is — NOT to the ball: a dead ball
  // parked off the field (sendBoy's z guard) meant no boy came out at all, and the breather is
  // now long enough that an empty court reads as the game having stalled.
  sendBoy(0, COURT.L * 0.75, true); // near enough the camera to actually watch him work
  G.flash = { text: 'CHANGEOVER', t: 1.4 };
  // no tins here anymore — weapons are won in the duel, never handed out on a schedule
}

// ---- the courtside rack: five slots, PLAIN plus the four tins. Stock lives on G; slot 0 is
// infinite plain balls. selectWeapon is the tap/key target — an empty special can't be picked.
export const SLOTS = ['PLAIN', 'BOMB', 'TRIPLE', 'FIRE', 'GUN'];
export const slotStock = i => [Infinity, G.bombs, G.triples, G.flames, G.guns][i];
export function selectWeapon(i) {
  if (G.interlude) return; // the sudden-death duel is played under tennis rules — plain balls only
  if (i > 0 && slotStock(i) <= 0) return; // dud: no tins of that kind on the rack
  G.weapon = i; pock(0.3, 1100);
}

// the weapon ladder: each delivery opens the next tin in the cycle and ADDS it to the rack
// (capped per type at TUNE.wCap) — old stock is kept, so you can bank a bomb for the horde
// instead of spending it now. G.weapon picks which tin the next serve throws.
const WDESC = { // what the tin you just won actually does — one line, shown on the pickup modal
  BOMB:   ['DETONATES ON CONTACT', 'CLEARS A WHOLE CROWD AT ONCE'],
  TRIPLE: ['ONE SERVE, THREE BALLS', 'FANNED WIDE ACROSS THE LANE'],
  FIRE:   ['KILLS ON ANY TOUCH', 'AND SETS THE OTHERS ALIGHT'],
  GUN:    ['HOLD THE LINE AND SPRAY', 'A BURST, NOT A SERVE'],
};
export function deliverTin() {
  const w = G.deliveries++ % 4, add = k => Math.min(TUNE.wCap, k);
  if (w === 0) G.bombs = add(G.bombs + TUNE.bombMax);
  else if (w === 1) G.triples = add(G.triples + TUNE.tinTriples);
  else if (w === 2) G.flames = add(G.flames + TUNE.tinFlames);
  else G.guns = add(G.guns + TUNE.tinGuns); // machine-gun charges — a burst you pop when you choose, not on arrival
  if (G.weapon !== 0) G.weapon = w + 1; // equip the new tin — but never yank you off a deliberate PLAIN (banking)
  sendBoy(); voice('new_balls', 0.6);
  const name = SLOTS[w + 1];
  showModal({ title: name, body: WDESC[name], icon: ['w_bomb', 'w_triple', 'w_fire', 'w_gun'][w],
              iconH: 40, color: UI.warm });
}

// ---- the interlude: order is restored, one sudden-death point vs the racket zombie.
// Tennis rules apply for exactly one point — the absurdity peak: the umpire never stopped watching.
// This is now the ONLY source of weapons in the game: win the point or leave empty-handed.
export function startDuel() {
  if (G.interlude) return;
  if (!zombies.some(z => z.variant === 'r')) spawnRacketZombie(); // the schedule guarantees an opponent
  for (const z of zombies) if (z.variant === 'r') z.dueled = true; // a veteran can be challenged again — this marks the fresh duel
  G.weapon = 0;                  // tennis rules for the duel: plain balls, no tins
  G.interlude = { introT: 2.4 }; // the intro beat: serving blocked while the umpire announces
  ball.active = false; setupPoint();
  zombieDuck(true);              // fade the zombie music out for the 1:1 duel
  voice('play_resume', 0.2); voice('sudden_death', 2.4);
  if (!G.seen.duel) { // the rules change back — worth one real interruption, once per run
    G.seen.duel = true;
    showModal({ title: 'SUDDEN DEATH', color: UI.hot,
      body: ["IT'S TENNIS AGAIN — ONE POINT", 'WIN IT AND THEY HAND YOU A WEAPON'] });
  } else G.flash = { text: 'SUDDEN DEATH', t: 1.6 };
}

export function resolveInterlude(side) {
  if (!G.interlude) return;
  G.interlude = false;
  zombieDuck(false); // duel over — bring the music back up
  ball.active = false; G.phase = 'over'; G.overT = 2.2;
  if (side === 'P') {
    cheer(3, 0.7);
    deliverTin(); // win the point, win the next tin — on the spot
  } else {
    voice('game_opponent', 0.4); aww(0.85); // lost the sudden-death duel
    score.games[1]++; G.runGames++; // it goes on the scoreboard
    if (score.games[1] >= 6) { G.sets[1]++; score.games = [0, 0]; }
    G.flash = { text: 'GAME. THEM.', t: 1.6 };
    for (let k = 0; k < 5; k++) // and the dead lose their patience: an instant surge
      spawnZombie((Math.random() * 2 - 1) * 5, -1.5 - Math.random() * 2, Math.random() < 0.5 ? 'a' : 'b');
  }
  if (G.afterDuel) { // a scheduled duel interrupted a game beat — hand it back now that it's settled
    G.afterClear = G.afterDuel; G.afterDuel = null;
    proceedAfterClear();
  }
}

// retire the splatter ball; a running changeover's long beat must not be clobbered short
export function spentBall() {
  ball.active = false;
  G.phase = 'over';
  if (!G.changeover) G.overT = TUNE.splatterOverT;
}

// the swarm keeps coming: no serving, the racket auto-fires, the thumb drag steers you
function startHorde() {
  if (G.horde) return;
  G.changeover = false; // a cheat-forced horde mid-changeover must not leave spawns locked
  G.pendingGame = false; // the horde IS the announcement
  G.horde = { t: TUNE.hordeLen, spawnT: 0, mgT: 0 };
  ball.active = false; G.phase = 'rally';           // ball gone; 'rally' lets the movement block steer P
  P.pose = 'idle'; P.poseT = 0; P.swingT = -1;      // clear the triggering shot's serve/swing pose
  P.z = HOME.P.z;                                   // brace at the baseline — the horde is a hold-the-line stand (finger steers x only)
  voice('remain_seated', 0.3);
  G.flash = { text: 'THEY KEEP COMING', t: 1.2 };
}

// hidden shortcut: tapping the umpire three times summons the horror early
export function forceZombies() {
  if (G.mode === 'splatter') { startHorde(); return; } // in splatter the cheat forces a horde wave
  if (G.mode !== 'tennis') return;
  ball.active = false;
  startTransition();
}

// -------------------------------------------------------------- transition ----
// You won your first game. The applause dies. The match... continues.
function startTransition() {
  G.mode = 'transition'; G.transT = 0; G.tFlags = {}; G.everTransitioned = true;
  G.overT = 9999; // hold the point flow; the timeline below releases it
  applause(0.7, 0.5); // the clap that gets cut off
  G.serveNum = 1;
}

function transition(dt) {
  const t = (G.transT += dt);
  const once = (key, at, fn) => { if (t >= at && !G.tFlags[key]) { G.tFlags[key] = true; fn(); } };
  once('quiet', 1.8, () => voice('quiet_dark', 0, 0.82));
  once('turn', 3.4, () => { spawnZombie(O.x, O.z, 'c'); G.hideO = true; }); // the opponent... turns
  once('mob', 4.8, () => { spawnZombie(-3.5, -1.6, 'a'); spawnZombie(2.5, -2.1, 'b'); });
  once('seated', 5.4, () => voice('remain_seated', 0, 0.95));
  once('go', 8.2, () => {
    G.mode = 'splatter'; score.server = 'P'; setupPoint(); voice('play', 0.4, 0.9); zombieMusic();
    // the mechanic changed under you — the one popup that gets an illustration, because it has
    // to TEACH the gesture, not just announce it
    showModal({ title: 'THE MATCH HAS CHANGED', color: UI.hot, icon: 'x_howto', iconH: 120,
      body: ['PULL BACK TO AIM — THEN LET GO', 'THE FURTHER YOU PULL, THE HARDER IT HITS',
             'A WEAK SHOT ONLY STAGGERS THEM'] });
  });
}

function fault() {
  if (G.serveNum === 1) { G.serveNum = 2; voice('fault'); G.phase = 'over'; G.overT = 1.4; sendBoy(); }
  else pointTo(other(score.server), 'double_fault');
}

export function inCourt(x, z) { return Math.abs(x) <= COURT.W / 2 + 0.02 && z >= -0.02 && z <= COURT.L + 0.02; }
export function inServeBox(x, z) {
  const toFar = score.server === 'P';
  const xOK = deuceSide() ? (toFar ? x <= 0.02 : x >= -0.02) : (toFar ? x >= -0.02 : x <= 0.02);
  const zOK = toFar ? (z >= COURT.svcFar - 0.02 && z <= COURT.netZ) : (z >= COURT.netZ && z <= COURT.svcNear + 0.02);
  return xOK && Math.abs(x) <= COURT.W / 2 + 0.02 && zOK;
}

function onBounce() {
  ball.bounces++;
  pock(0.35, 500);
  if (G.mode === 'splatter' && ball.bomb && ball.bounces === 1) { // a bomb that missed everyone still blows up
    explode(ball.x, ball.z); ball.bomb = false;
    spentBall(); return;
  }
  if (G.mode === 'splatter' && G.interlude) { // sudden death: the lines are LIVE again
    if (ball.bounces === 1) {
      const okSide = ball.lastHit === 'P' ? ball.z < COURT.netZ : ball.z > COURT.netZ;
      if (!inCourt(ball.x, ball.z) || !okSide) { ball.active = false; resolveInterlude(other(ball.lastHit)); voice('out'); }
    } else if (ball.bounces === 2) { ball.active = false; resolveInterlude(ball.lastHit); }
    return;
  }
  if (G.mode !== 'tennis') return; // no lines, no faults — the umpire has other concerns
  if (ball.bounces === 1) {
    ball.firstLand = { x: ball.x, z: ball.z };
    const wasServe = G.wasServe; G.wasServe = false;
    if (wasServe) {
      if (!inServeBox(ball.x, ball.z)) { ball.active = false; fault(); }
      return;
    }
    // must land on the side opposite the hitter
    const okSide = ball.lastHit === 'P' ? ball.z < COURT.netZ : ball.z > COURT.netZ;
    if (!inCourt(ball.x, ball.z) || !okSide) {
      ball.active = false; pointTo(other(ball.lastHit), 'out');
    }
  } else if (ball.bounces === 2) {
    ball.active = false; pointTo(ball.lastHit, null);
  }
}

// -------------------------------------------------------------- movement ----
// Where should a player run to? Simulate the ball forward and take the first point in
// their half at hitting height that they can actually REACH IN TIME; otherwise chase the
// deepest hittable point. This is the "every ball is catchable, timing is the skill" contract.
function intercept(side) {
  const ch = side === 'O' ? O : P;
  const spd = side === 'O' ? TUNE.aiSpeed : TUNE.playerSpeed * TUNE.autoAssist;
  let { x, y, z, vx, vy, vz } = ball;
  const g = ball.g || TUNE.gravity, dt = 0.01;
  const inZone = side === 'O' ? zz => zz <= ZONE_DEPTH : zz => zz >= COURT.L - ZONE_DEPTH;
  const home = HOME[side];
  let fallback = null, deepest = null;
  for (let i = 0; i < 300; i++) {
    vy -= g * dt; x += vx * dt; y += vy * dt; z += vz * dt;
    if (y <= 0 && vy < 0) { y = 0; vy = -vy * TUNE.bounceY; vx *= TUNE.bounceXZ; vz *= TUNE.bounceXZ; }
    if (i > 5 && inZone(z) && y < 1.6 && y > 0.3) {
      const pt = { x, z: side === 'O' ? Math.max(0.8, z) : Math.min(24.5, z) };
      const reachable = Math.hypot(pt.x - ch.x, pt.z - ch.z) / spd <= i * dt;
      if (y > 0.7 && reachable) return pt;          // waist-high AND arrivable in time
      if (reachable && !fallback) fallback = pt;    // low but arrivable
      deepest = pt;                                 // last resort: run at the deepest hittable point
    }
  }
  return fallback || deepest || home;
}

// ---------------------------------------------------------- miss diagnostics ----
// Every player swing in tennis mode gets logged: HIT with quality, or MISS with the
// gate that rejected it and the ball's closest approach. Balls that pass without a
// swing log as PASSED when the point ends. Inspect live via T.G.missLog; the latest
// miss reason is drawn on the HUD (TUNE.missHud).
const r2 = x => Math.round(x * 100) / 100;

function logSwing(entry) {
  entry.at = r2(G.idleT);
  G.missLog.push(entry);
  if (G.missLog.length > 50) G.missLog.shift();
  if (entry.result !== 'HIT') G.lastMiss = { text: entry.reason, at: G.idleT };
}

function logWhiff() {
  const snaps = G.swingSnaps; G.swingSnaps = null;
  if (G.mode !== 'tennis') return;
  if (!snaps || !snaps.length) {
    logSwing({ result: 'MISS', reason: !ball.active ? 'no live ball' : 'ball was yours — already hit' });
    return;
  }
  const best = snaps.reduce((a, b) => (b.d < a.d ? b : a));
  const inReach = snaps.filter(s => s.d <= s.r);
  let reason;
  if (!inReach.length) {
    // never in reach during the swing: was the swing mistimed, or the ball line simply wide?
    const tX = ball.active && ball.vz > 0.1 ? (P.z - ball.z) / ball.vz : -1; // time until ball reaches your depth
    const lat = tX > 0 ? Math.abs(ball.x + ball.vx * tX - P.x) : null;      // how wide it will pass
    const nearD = G.rallyNear ? G.rallyNear.d : 1e9;                        // closest true pass so far this rally
    if (lat !== null && lat > best.r) reason = `ball line ${r2(lat)}m wide of you — run, don't swing`;
    else if (tX > 0) reason = `tap too early — ball still ${r2(best.d)}m out, arrives ${Math.round(tX * 1000)}ms after swing ended`;
    else if (nearD > best.r) reason = `ball passed ${r2(nearD)}m wide of you — never reachable from where you stood`;
    else reason = `tap too late — ball already gone (it came within ${r2(nearD)}m of you earlier)`;
  } else {
    const inWin = inReach.filter(s => s.t >= TUNE.swingWindup && s.t <= TUNE.swingWindup + s.w);
    if (!inWin.length) {
      const first = inReach[0], last = inReach[inReach.length - 1];
      reason = last.t < TUNE.swingWindup
        ? `tap too late — ball already passing ${Math.round((TUNE.swingWindup - last.t) * 1000)}ms before swing opened`
        : `tap too early — ball arrived ${Math.round((first.t - (TUNE.swingWindup + first.w)) * 1000)}ms after window closed`;
    } else if (inWin.every(s => s.y > CONTACT.maxY)) reason = `too high — ball at ${r2(best.y)}m overhead`;
    else if (inWin.every(s => s.y < CONTACT.minY)) reason = `too low — ball at ${r2(best.y)}m, past you`;
    else reason = 'unclassified — in reach, in window, in height band'; // should not happen
  }
  logSwing({ result: 'MISS', reason, dMin: r2(best.d), y: r2(best.y), tSwing: r2(best.t),
    ballZ: r2(best.bz), bounces: best.bounces, px: r2(P.x), pz: r2(P.z) });
}

function trySwing(ch, isAI, qCap = TUNE.aiQualityMax) {
  // Contact happens if the ball is inside reach while the swing window is open.
  // Player volleys (pre-bounce) get wider reach + window: full-speed ball, no bounce cue.
  const volley = !isAI && ball.bounces === 0;
  const reach = isAI ? TUNE.aiReach : TUNE.reach * (volley ? VOLLEY.reach : 1);
  const win = TUNE.swingWindow * (volley ? VOLLEY.window : 1);
  const t = ch.swingT;
  if (t < TUNE.swingWindup || t > TUNE.swingWindup + win) return;
  if (!ball.active || G.phase !== 'rally') return;
  // splatter: your OWN ball is fair game. It rebounds off the backstop and comes back at you —
  // volleying it is how you keep firing without walking it down. (The duel is tennis: one touch.)
  const own = G.mode === 'splatter' && !G.interlude && ch.side === 'P';
  if (ball.lastHit === ch.side && !own) return;
  const dx = ball.x - ch.x, dz = ball.z - ch.z;
  if (Math.hypot(dx, dz * 0.8) > reach || ball.y > CONTACT.maxY) return;
  if (ball.y < CONTACT.minY && ball.vy <= 0) return; // a DROPPING ball below the ankles is past you — but a rising one is a half-volley, always scoopable
  // quality: how centered in the window the contact lands
  const center = TUNE.swingWindup + win / 2;
  const off = Math.abs(t - center) / (win / 2);
  let q = Math.max(0.05, 1 - off);
  if (Math.abs(t - center) * 1000 < TUNE.perfectMs) q = 1;
  ch.facing = dx >= 0 ? 1 : -1; // forehand right (righty), backhand left → mirrored sprite
  const flick = isAI ? null : takeFlickAim();
  const aim = isAI
    ? { ax: [ -1, 0, 1 ][Math.floor(Math.random() * 3)], az: Math.random() < 0.25 ? -1 : 0 }
    : flick || { ax: axisX(), az: axisZ() * (ch.side === 'P' ? 1 : -1) };
  if (isAI) q = Math.min(q, TUNE.aiQualityMin + Math.random() * (qCap - TUNE.aiQualityMin));
  if (!isAI && G.mode === 'tennis') {
    G.swingSnaps = null; G.rallyNear = null;
    logSwing({ result: 'HIT', reason: `contact q=${Math.round(q * 100) / 100}`, d: Math.round(Math.hypot(dx, dz * 0.8) * 100) / 100, y: Math.round(ball.y * 100) / 100 });
  }
  doHit(ch, q, aim);
  ch.swingT = -1;
}

// racket zombie (splatter mini-boss): a slimmed tennis CPU that holds the far court and returns
// your SOFT shots as live balls. Splat-quality balls it won't rally — those wound its HP instead.
function racketAI(rz, dt) {
  expirePose(rz, dt);
  rz.swingCool -= dt;
  const incoming = ball.active && ball.lastHit === 'P' && ball.vz < 0
    && (G.interlude || (ball.pow || 0) < TUNE.zSplatQ); // in the duel it plays EVERY ball — it's tennis now
  if (!incoming) { if (rz.pose === 'run') rz.pose = 'idle'; return; }
  const tz = Math.max(1.5, Math.min(COURT.svcFar, ball.z)); // chase laterally, hold deep on the far court
  const dx = ball.x - rz.x, dz = tz - rz.z, d = Math.hypot(dx, dz);
  if (d > 0.15) {
    const step = Math.min(TUNE.racketSpeed * dt, d);
    rz.x += dx / d * step; rz.z += dz / d * step; rz.runT += dt;
    if (rz.pose !== 'swing') rz.pose = 'run';
    if (Math.abs(dx) > 0.2) rz.facing = dx > 0 ? 1 : -1;
  } else if (rz.pose === 'run') rz.pose = 'idle';
  if (rz.swingCool <= 0 && rz.swingT < 0
      && Math.hypot(ball.x - rz.x, (ball.z - rz.z) * 0.8) < TUNE.aiReach
      && ball.y < CONTACT.maxY && ball.y > CONTACT.minY) {
    if (Math.random() < TUNE.racketFlub) rz.swingCool = 0.5; // whiff — it hesitates
    else { rz.swingT = TUNE.swingWindup + TUNE.swingWindow / 2; trySwing(rz, true, TUNE.racketQMax); rz.swingT = -1; rz.swingCool = 0.3; }
  }
}

// GUN in the rack isn't a ball — committing a charge starts an mgT auto-fire burst (the same
// mode a horde uses). With GUN selected, any serve gesture spends one charge instead of serving.
function tryGunBurst() {
  if (G.mode !== 'splatter' || G.weapon !== 4 || G.guns <= 0) return false;
  G.guns--; if (G.guns <= 0) G.weapon = 0; // spent the last tin — back to plain balls
  G.mgT = TUNE.mgPickupLen; G.mgCool = 0;
  ball.active = false; G.phase = 'rally';
  P.pose = 'idle'; P.poseT = 0; P.swingT = -1;
  P.z = HOME.P.z;                        // brace at the baseline for the burst (finger steers x only)
  G.flash = { text: 'GUN', t: 1.0 };
  return true;
}

// slingshot serve, stage one: the pull-back starts the toss animation. The ball rises while
// you aim (dotted line, render.js); the release (dragServe) fires it. Only from a fresh pretoss.
export function serveToss() {
  if (score.server === 'P' && G.phase === 'pretoss' && !ball.active) tossBall(P);
}

// release of the slingshot aim: an instant serve to the reticle (quality fixed — placement
// is this serve's power; the toss ritual keeps the PERFECT-timing power ceiling)
export function dragServe(aim) {
  if (G.mode !== 'splatter' || score.server !== 'P') return;
  if (G.interlude || G.horde || G.mgT > 0 || G.changeover) return; // the duel serves like tennis, not the reticle
  if (G.phase === 'over') { ball.active = false; setupPoint(); } // mid-beat pull: arm the next shot now
  if (G.phase !== 'pretoss' && G.phase !== 'toss' && G.phase !== 'rally') return;
  if (tryGunBurst()) return;
  if (aim.mag < TUNE.pullMin) return; // released without really drawing: cancel, nothing spent
  // Firing while the last ball still flies is fine again — the brake is the pull itself, not the
  // rally clock. This is what lets the drag mean ONE thing at all times: a second gesture that
  // walked the player around between shots was the confusing part, not the fire rate.
  if (ball.active && G.phase !== 'toss') // the old ball flies on as a ballistic clone
    extras.push({ x: ball.x, y: ball.y, z: ball.z, vx: ball.vx, vy: ball.vy, vz: ball.vz, pow: ball.pow || 0.5, t: 2.5 });
  ball.active = true; ball.collected = false; ball.bounces = 0; ball.firstLand = null;
  ball.x = P.x + 0.35; ball.z = P.z; ball.y = 2.2; ball.g = TUNE.gravity;
  hitServe(P, pullQuality(aim.mag), aim); // a full pull is quality 1.0 — PERFECT, hitstop and all
}

export function keyPressed(code) {
  if (code !== 'Space') return;
  audio(); // unlock on first gesture
  // a swish cleaves adjacent shamblers — but it's on a cooldown now: the panic button, not the
  // default attack. A whiff costs nothing (nothing was in range), a connect locks it for meleeCool.
  if (G.mode === 'splatter' && G.meleeT <= 0 && meleeSwipe(P.x, P.z, TUNE.meleeRange)) G.meleeT = TUNE.meleeCool;
  if (G.horde || G.mgT > 0) return; // auto-fire modes: a tap only swishes, never serves
  if (G.changeover) return; // the breather is mandatory — the melee swish above still works
  if (G.interlude && G.interlude.introT > 0) return; // let the umpire finish announcing the duel
  // splatter: a tap/flick during the brief 'over' beat re-arms the next serve immediately
  if (G.mode === 'splatter' && G.phase === 'over') { ball.active = false; setupPoint(); }
  // splatter serve stays a TWO-STAGE ritual — toss up, THEN fire. It can only start from
  // pretoss WITH a ball in hand: one ball, and it has to come back before you fire it again.
  // A flick is the aimed one-motion variant (the reticle). The duel is exempt: it serves like tennis.
  if (G.mode === 'splatter' && !G.interlude && score.server === 'P' && G.phase === 'pretoss') {
    const flick = takeFlickAim();
    if (flick) { dragServe(flick); return; } // dragServe handles GUN (burst) and the ball check
  }
  if (G.phase === 'pretoss' && score.server === 'P') {
    if (tryGunBurst()) return; // GUN selected: the serve gesture pops a burst, no ball
    tossBall(P); return; // plain tap: the two-stage toss ritual (tennis, and the duel)
  }
  if (G.phase === 'toss' && score.server === 'P') {
    // serve timing: distance from apex = quality — a real serve, not a free tap
    const dy = Math.abs(ball.y - serveApexY());
    if (ball.y < 2.0) return; // too low, let it drop (re-toss)
    let q = Math.max(0.05, 1 - dy / 0.9);
    if (dy < 0.12) q = 1;
    G.wasServe = true;
    // a flick at the apex (or held arrows) makes this a DELIBERATE serve: aimed + consumes a special
    const flick = G.mode === 'splatter' && !G.interlude ? takeFlickAim() : null;
    const kb = { ax: axisX(), az: axisZ() };
    hitServe(P, q, flick || (kb.ax || kb.az ? kb : null));
    return;
  }
  if (G.phase === 'rally' && P.swingT < 0) { P.swingT = 0; P.pose = 'swing'; P.poseT = 0; G.swung = true; }
}

function expirePose(ch, dt) {
  if (ch.pose === 'swing' || ch.pose === 'serve') { ch.poseT += dt; if (ch.poseT > POSE_TIME) ch.pose = 'idle'; }
}

// ---------------------------------------------------------------- update ----
export function update(dt) {
  if (G.hitstop > 0) { G.hitstop -= dt; return; }
  if (G.mode === 'eaten') { // the match is over in the truest sense
    G.idleT += dt;
    const was = G.eatenT; G.eatenT += dt;
    if (was < EATEN_BURST && G.eatenT >= EATEN_BURST) playerGore(); // phase B: you become the gore
    if (G.shake && (G.shake.t -= dt) <= 0) G.shake = null;
    if (G.boomFlash > 0) G.boomFlash -= dt;
    updateZombies(dt);
    return;
  }
  if (G.flash) { G.flash.t -= dt; if (G.flash.t <= 0) G.flash = null; }
  if (G.card) { G.card.t -= dt; if (G.card.t <= 0) G.card = null; }
  if (G.shake && (G.shake.t -= dt) <= 0) G.shake = null;
  if (G.boomFlash > 0) G.boomFlash -= dt;
  // A modal freezes the WORLD, not the clock: no zombie steps, no ball flight, no spawn timers,
  // so nobody gets eaten while reading a popup. idleT keeps running for the blink.
  if (G.modal) { G.idleT += dt; return; }
  crowd.cheer = Math.max(0, crowd.cheer - dt);
  G.idleT += dt;
  const w = BOUNCE_IDLE.tempo;
  if (G.phase === 'pretoss' && Math.sin(G.idleT * w) * Math.sin((G.idleT - dt) * w) < 0) pock(0.12, 420); // ball bounce
  if (G.phase === 'toss') { const sv = score.server === 'P' ? P : O; sv.pose = 'serve'; sv.poseT = 0; }

  // --- player movement (near half only, generous margins)
  if (G.phase === 'rally') {
    if (G.mode === 'tennis' && ball.active && ball.lastHit === 'O') { // closest approach, for never-swung passes
      const d = Math.hypot(ball.x - P.x, (ball.z - P.z) * 0.8);
      if (!G.rallyNear || d < G.rallyNear.d) G.rallyNear = { d, y: ball.y, bz: ball.z, px: P.x, pz: P.z };
    }
    // auto-fire steering is ABSOLUTE: the finger x IS the player x — zero lag, and clamped
    // to what the camera can see (portrait's world bounds are wider than its viewport)
    const mgMode = G.horde || G.mgT > 0;
    const xVis = Math.min(P_BOUNDS.x, (W / 2 - 14) / (TUNE.camF / (TUNE.camZ - P.z)));
    let mgSteer = false;
    if (mgMode && touchPX() !== null) {
      mgSteer = true;
      const tx = Math.max(-xVis, Math.min(xVis, touchPX() * xVis));
      if (Math.abs(tx - P.x) > 0.04) { P.facing = tx > P.x ? 1 : -1; P.runT += dt; P.pose = 'run'; }
      else P.pose = 'idle';
      P.x = tx;
    }
    const slow = P.swingT >= 0 ? 0.35 : 1;
    const mx = mgSteer ? 0 : axisX(), mz = mgSteer ? 0 : axisZ();
    P.x += mx * TUNE.playerSpeed * slow * dt;
    P.z += mz * TUNE.playerSpeed * slow * dt;
    let assist = 0;
    if (!mx && !mz && TUNE.autoAssist > 0 && ball.active && !G.horde && !(G.mgT > 0)) { // auto-fire: you aim by hand, no assist
      // splatter: anything travelling back toward you is yours to run down — your own rebound
      // included. The assist puts you there; the volley timing stays honest.
      const chasing = ball.lastHit === 'O' || (G.mode === 'splatter' && !G.interlude && ball.vz > 0);
      // no `slow` here: tapping must not freeze your legs, or anticipating a shot loses it
      const rate = TUNE.playerSpeed * TUNE.autoAssist * dt * (chasing ? 1 : 0.55);
      const tgt = chasing ? intercept('P') : HOME.P; // run to the ball, then recover home
      const dx = tgt.x - P.x, dz = tgt.z - P.z, d = Math.hypot(dx, dz);
      if (d > 0.35) { // deadzone: stand ready near the spot instead of dithering over it
        P.x += dx / d * Math.min(rate, d);
        P.z += dz / d * Math.min(rate, d);
        assist = dx;
      }
    }
    const xLim = mgMode ? xVis : P_BOUNDS.x; // auto-fire keeps even keyboard players on screen
    P.x = Math.max(-xLim, Math.min(xLim, P.x));
    P.z = Math.max(P_BOUNDS.zMin, Math.min(P_BOUNDS.zMax, P.z));
    const moving = mx || mz || assist !== 0;
    P.runT += moving ? dt : 0;
    if (!mgSteer && P.pose !== 'swing' && P.pose !== 'serve') P.pose = moving ? 'run' : 'idle';
    if (mx) P.facing = mx > 0 ? 1 : -1;
    else if (Math.abs(assist) > 0.25) P.facing = assist > 0 ? 1 : -1; // hysteresis: small corrections don't flip facing
  }
  // splatter: you START at the baseline but you're free to advance up-court (bounded at the net by
  // P_BOUNDS) — hunt the shamblers down, especially when mopping up a won game. Auto-assist still
  // recovers you toward the baseline between shots on touch; the duel is plain tennis as ever.
  if (P.swingT >= 0) {
    P.swingT += dt;
    if (G.mode === 'tennis' && ball.active && ball.lastHit === 'O') { // sample the approach for the miss log (t = what trySwing tests this frame)
      const volley = ball.bounces === 0;
      (G.swingSnaps ||= []).push({ t: P.swingT, d: Math.hypot(ball.x - P.x, (ball.z - P.z) * 0.8), y: ball.y,
        bz: ball.z, bounces: ball.bounces,
        r: TUNE.reach * (volley ? VOLLEY.reach : 1), w: TUNE.swingWindow * (volley ? VOLLEY.window : 1) });
    }
    trySwing(P, false); // a contact resets swingT to -1 inside trySwing
    const win = TUNE.swingWindow * (ball.active && ball.bounces === 0 ? VOLLEY.window : 1); // match trySwing's volley window
    if (P.swingT > TUNE.swingWindup + win + 0.02) { P.swingT = -1; if (G.phase === 'rally') swish(); logWhiff(); } // log even if the point ended mid-swing
  }
  expirePose(P, dt);

  // --- zombies + transition timeline
  if (G.mode !== 'tennis') updateZombies(dt);
  if (G.meleeT > 0) G.meleeT -= dt;
  if (G.clearing && !zombies.some(z => z.variant !== 'r')) proceedAfterClear(); // the won-game wave is mopped up — advance
  if (G.mode === 'transition') transition(dt);

  // --- interlude trigger: the court is clear, an opponent holds the far court, you're about
  // to serve — the umpire recognizes a legal match and restores order. One point. Sudden death.
  // The schedule is a FLOOR, not a ceiling: this lucky-clear trigger stays, and a bonus duel is
  // pure upside for weapon supply.
  if (G.mode === 'splatter' && !G.interlude && !G.horde && !G.changeover && !(G.mgT > 0)
      && G.phase === 'pretoss' && zombies.length === 1 && zombies[0].variant === 'r' && !zombies[0].dueled)
    startDuel();
  if (G.interlude && G.interlude.introT > 0) G.interlude.introT -= dt;
  // the duel is played under tennis lights: lerp the palette home while it runs, back after
  G.duelLerp = Math.max(0, Math.min(1, G.duelLerp + (G.interlude ? dt : -dt) / 0.8));

  // --- AI (the opponent only exists in tennis mode)
  if (G.mode === 'tennis' && score.server === 'O' && G.phase === 'pretoss') {
    G.aiServeT -= dt;
    if (G.aiServeT <= 0) tossBall(O);
  } else if (G.mode === 'tennis' && score.server === 'O' && G.phase === 'toss') {
    if (ball.vy < 0 && ball.y < serveApexY() - 0.1) { G.wasServe = true; hitServe(O, 0.6 + Math.random() * 0.35); }
  }
  if (G.mode === 'tennis' && G.phase === 'rally') {
    G.aiReactT += dt;
    const incoming = ball.active && ball.lastHit === 'P' && G.aiReactT >= TUNE.aiReaction;
    const tgt = incoming ? intercept('O') : HOME.O;
    const spd = TUNE.aiSpeed * (incoming ? 1 : 0.5); // slow recovery: wrong-footing wins points
    const dx = tgt.x - O.x, dz = tgt.z - O.z, d = Math.hypot(dx, dz);
    if (d > 0.1) {
      O.x += dx / d * Math.min(spd * dt, d);
      O.z += dz / d * Math.min(spd * dt, d);
      O.pose = O.pose === 'swing' ? 'swing' : 'run'; O.runT += dt;
      if (Math.abs(dx) > 0.25) O.facing = dx > 0 ? 1 : -1;
    } else if (O.pose === 'run') O.pose = 'idle';
    G.aiSwingCool -= dt;
    if (incoming && G.aiSwingCool <= 0 && O.swingT < 0) {
      // same radius trySwing uses for contact, so an armed swing actually connects
      const near = Math.hypot(ball.x - O.x, (ball.z - O.z) * 0.8) < TUNE.aiReach
        && ball.y < CONTACT.maxY && ball.y > CONTACT.minY && ball.vz < 0;
      if (near) {
        if (Math.random() < TUNE.aiFlub) G.aiSwingCool = 0.5; // whiff: hesitates and misses
        else {
          O.swingT = TUNE.swingWindup + TUNE.swingWindow / 2;
          trySwing(O, true); O.swingT = -1;
          G.aiSwingCool = ball.lastHit === 'O' ? 0.4 : 0.12;
        }
      }
    }
  }
  expirePose(O, dt);

  // --- racket zombies rally from the far court (splatter only, between hordes)
  if (G.mode === 'splatter' && !G.horde)
    for (const rz of zombies) if (rz.variant === 'r') racketAI(rz, dt);

  // --- ball physics
  if (ball.active) {
    if (ball.flame) parts.push({ // fire trail: one ember per frame, brief and rising
      x: ball.x, y: ball.y, z: ball.z, t: 0.22, fire: true,
      vx: (Math.random() * 2 - 1) * 0.6, vy: 0.8, vz: (Math.random() * 2 - 1) * 0.6 });
    ball.vy -= (ball.g || TUNE.gravity) * dt;
    const oldZ = ball.z;
    ball.x += ball.vx * dt; ball.y += ball.vy * dt; ball.z += ball.vz * dt;
    // net: plane at netZ, only during rally flight
    if (G.phase === 'rally' && (oldZ - COURT.netZ) * (ball.z - COURT.netZ) < 0 && Math.abs(ball.x) < COURT.netW / 2) {
      const tCross = (COURT.netZ - oldZ) / (ball.z - oldZ);
      const yAt = ball.y - ball.vy * dt * (1 - tCross); // approx height at crossing
      if (yAt < COURT.netH) {
        ball.z = COURT.netZ + (oldZ < COURT.netZ ? -0.05 : 0.05);
        ball.vz *= -0.08; ball.vx *= 0.3; ball.vy = Math.min(ball.vy, 0);
        pock(0.4, 300);
      }
    }
    if (ball.y <= 0 && ball.vy < 0) {
      ball.y = 0; ball.vy = -ball.vy * TUNE.bounceY;
      ball.vx *= TUNE.bounceXZ; ball.vz *= TUNE.bounceXZ;
      onBounce();
      if (ball.active && Math.abs(ball.vy) < 0.8) { // rolled out — dead ball
        ball.active = false;
        if (G.mode === 'splatter' && G.interlude) { // a roller nobody returned: point to the hitter
          if (ball.lastHit === 'X') spentBall();    // spent on the boss's body — no point, re-serve the duel
          else resolveInterlude(ball.lastHit);
        } else if (G.mode === 'splatter') { // hand the server a fresh one, fast — they're coming
          spentBall(); sendBoy();
          if (Math.random() < 0.12) voice('new_balls', 0.3);
        } else if (ball.bounces === 1) pointTo(ball.lastHit, null);
      }
    }
    // a racket zombie's return that gets past you (crosses your baseline) is a point for THEM
    if (G.mode === 'splatter' && ball.active && ball.lastHit === 'O' && ball.z > COURT.L + 0.3) {
      ball.active = false;
      if (G.interlude) resolveInterlude('O'); // sudden death: its passing shot ends the duel
      else { if (!G.horde && !G.clearing) splatPoint('O'); spentBall(); } // clearing = mop-up, no scoring either way
    }
    // the far backstop: a LIVE ball doesn't leave the field, it rebounds off the fence and comes
    // back down-court — still lethal on the way home, and yours to volley. Spent balls just die.
    if (G.mode === 'splatter' && !G.interlude && ball.active && ball.lastHit === 'P'
        && ball.z < TUNE.backstopZ && ball.vz < -3) { // only a ball with real pace left comes back; a roller just stops
      ball.z = TUNE.backstopZ;
      ball.vz *= -TUNE.backstopKeep; ball.vx *= 0.7;
      ball.vy = Math.max(ball.vy, TUNE.backstopPop); // the fence kicks it up, so it carries back through the crowd
      pock(0.5, 200); // chain-link thud
    }
    // splatter: retire spent or hopeless balls fast so the next serve comes right up.
    // z-bounds gate on travel direction — a serve born behind the baseline (P.z up to 26)
    // heads to the far court (vz<0), so it must not read as "out the back" on frame one.
    // (during the interlude only spent balls retire early — flying balls must reach their
    // bounce so the line call can happen; the umpire is watching again)
    if (G.mode === 'splatter' && ball.active &&
        ((ball.lastHit === 'X' && ball.bounces >= 1)
         || (!G.interlude &&
             ((ball.z < -2 && ball.vz < 0) || (ball.z > 25.5 && ball.vz > 0) || Math.abs(ball.x) > 7.5)))) {
      spentBall();
    }
    if (G.phase === 'toss' && ball.y <= 1.4 && ball.vy < 0 && !G.aim) { // uncaught toss → retoss (a held slingshot aim keeps the toss up)
      ball.active = false; G.phase = 'pretoss';
      if (score.server === 'O') G.aiServeT = 0.8;
    }
  }

  // ball boy: sprint across, scoop the ball in passing, despawn off the far side
  const boy = G.boy;
  if (boy) {
    // mopping is not sprinting. `dist` is what drives his animation frames (render.drawBoy), so
    // the legs are tied to the ground he covers and can never out-run or lag behind the walk.
    const step = boy.dir * (boy.mop ? TUNE.boyMopSpeed : 7.5) * dt;
    boy.x += step; boy.runT += dt; boy.dist = (boy.dist || 0) + Math.abs(step);
    if (!boy.mop && !ball.collected && !ball.active) { // a mop boy has no ball to chase — he must hold his lane and clean it
      const dz = ball.z - boy.z;
      boy.z += Math.sign(dz) * Math.min(Math.abs(dz), 3 * dt); // track the rolling ball a little
      if (Math.abs(boy.x - ball.x) < 0.4 && Math.abs(dz) < 1.2) ball.collected = true;
    }
    if (Math.abs(boy.x) > 13.5) G.boy = null; // off the far wing — his round is done
  }
  if (G.outMarker && (G.outMarker.t -= dt) <= 0) G.outMarker = null;

  if (G.phase === 'over') {
    G.overT -= dt;
    if (G.overT <= 0) {
      if (G.pendingHorde) { // the set card's pause is over — but the horde is a different CONTROL MODE
        G.pendingHorde = false;                                  // (racket auto-fires, the finger steers you absolutely),
        showModal({ title: 'THEY KEEP COMING', color: UI.hot,    // so it gets a real block, not just a card
          body: ['THE RACKET FIRES ON ITS OWN', 'SLIDE TO AIM · HOLD THE BASELINE'],
          onDismiss: startHorde });
        return;
      }
      if (G.changeover) { G.changeover = false; voice('time', 0, 0.95); } // "Time." — play resumes
      // auto-fire modes must NEVER re-enter the serve loop: an 'over' beat expiring into
      // setupPoint() -> pretoss left the player locked in the serve posture while the gun
      // fired (no movement outside 'rally', no serving during auto-fire). Back to rally.
      if (G.horde || G.mgT > 0) {
        G.phase = 'rally'; ball.active = false;
        P.pose = 'idle'; P.poseT = 0; P.swingT = -1;
      } else {
        setupPoint();
        if (G.pendingGame && G.mode === 'splatter') { // the next wave is announced as it arms
          G.pendingGame = false;
          G.flash = { text: 'GAME ' + (G.runGames + 1), t: 1.1 };
        }
      }
    }
  }
}