guts/web/js/combat/index.js

// combat/index.js (Lane B) — the createCombat factory. Composes enemies + weapons + hazards
// + pickups and feeds them Lane C's level events. All the wiring, none of the behaviour.
//
// Update order inside a frame is load-bearing:
//   boot: player.update(dt)  ->  combat.update(dt)
//   here: enemies.update(dt) ->  weapons.update(dt) -> hazards.update(dt) -> pickups.update(dt)
// Enemies move first so weapons hit-test against this frame's positions, not last frame's.
// Hazards after weapons so a torpedo fired THIS frame can neutralize a surge THIS frame
// (weapons emits level:neutralize on detonation; hazards listens).

import { createEnemies } from './enemies.js';
import { createWeapons } from './weapons.js';
import { createHazards } from './hazards.js';
import { createPickups } from './pickups.js';
import { getEnemy } from '../levels/enemies.js';

export function createCombat({ scene, world, bus, rng, flags = {}, assets = null, player }) {
  const enemies = createEnemies({ scene, world, bus, rng, assets });
  const weapons = createWeapons({ scene, world, bus, rng, player, targets: enemies });
  const hazards = createHazards({ scene, world, bus, rng, player });
  const pickups = createPickups({ scene, world, bus, rng, player, weapons });

  enemies.setBlastFx((pos, size, dur) => weapons.spawnBlast(pos, size, dur));
  enemies.setOnDeath((e) => weapons.spawnBlast(e.pos, e.radius * 1.6, 0.3));

  const score = { value: 0, kills: 0, samples: 0 };

  // Fan a group of `count` out along s. C's `spread` is the authored span of the group
  // ("count 4 spread 120" = a field, not a wall); without one, a tight default fan keeps
  // a count from stacking at a single arclength.
  const fan = (ev, i) => {
    const n = ev.count ?? 1;
    if (n <= 1) return ev.s ?? 0;
    const span = ev.spread ?? (n - 1) * 3.5;
    return (ev.s ?? 0) + (i / (n - 1)) * span;
  };
  // C authors `theta` as a scalar (whole group) or an array (per-member — "two blooms
  // covering opposite arcs"). Placement is composition, so C's word is law here.
  const thetaFor = (ev, i) =>
    (Array.isArray(ev.theta) ? ev.theta[i % ev.theta.length] : (ev.theta ?? null));

  // Lane C's events arrive on the bus as the player crosses their `s`. Spawns and pickups are
  // consumed here; hazards run their own timeline off world.level.events (they need lookahead
  // for the warn telegraph — see hazards.js header); checkpoints/gates are boot's (the pump
  // owns respawn/complete semantics); unknown types are ignored on purpose so C can add event
  // kinds without breaking combat.
  const offEvent = bus.on('level:event', (ev) => {
    if (!ev) return;
    if (ev.type === 'spawn') {
      // Levels name enemies in fiction ("bolus_chunk"); pools are keyed by archetype
      // ("floater"). levels/enemies.js is the join table (C's catalogue, round-2 task #1).
      const spec = getEnemy(ev.enemy);
      if (!spec) { console.warn(`[combat] spawn "${ev.enemy}" is not in levels/enemies.js — skipped`); return; }
      for (let i = 0; i < (ev.count ?? 1); i++)
        enemies.spawn(spec.archetype, { s: fan(ev, i), theta: thetaFor(ev, i), rho: ev.rho ?? null });
    } else if (ev.type === 'pickup') {
      for (let i = 0; i < (ev.count ?? 1); i++)
        pickups.spawn(ev.kind, { s: fan(ev, i), theta: thetaFor(ev, i), rho: ev.rho ?? null });
    }
  });

  const offDie = bus.on('enemy:die', (e) => {
    score.value += e.score ?? 0;
    score.kills++;
  });

  // pickups.js applies the effect (refill/ammo) and announces; the score lives here so
  // combat:state stays the one scoreboard E reads.
  const offPickup = bus.on('pickup', (e) => {
    score.value += e.score ?? 0;
    score.samples += e.sample ?? 0;
  });

  function update(dt) {
    enemies.update(dt, player);
    weapons.update(dt);
    hazards.update(dt);
    pickups.update(dt);
    // combat's slice of the HUD state (E reads player:state for the flight half)
    bus.emit('combat:state', {
      heat: weapons.heat, heatMax: weapons.heatMax, overheated: weapons.overheated,
      ammo: weapons.ammo, ammoMax: weapons.ammoMax,
      score: score.value, kills: score.kills, samples: score.samples, enemies: enemies.count,
    });
  }

  return {
    update,
    enemies, weapons, hazards, pickups, score,
    // Respawn support (boot calls this from its death->checkpoint glue): re-arm hazard
    // timelines at/ahead of the respawn s. Enemies and uncollected pickups persist — the
    // pump never re-fires past events, so nothing double-spawns.
    reset(fromS = 0) { hazards.reset(fromS); },
    dispose() {
      offEvent(); offDie(); offPickup();
      enemies.dispose(); weapons.dispose(); hazards.dispose(); pickups.dispose();
    },
  };
}