tarinai/js/item_dynamic_ball_system.js

"use strict";

// Layer: entity-runtime/items/dynamic-system
// Owns ball-like item motion, balloon drift/pop behavior, and fan wind.
// Item.prototype ball/balloon/fan methods delegate to this system.
(function (global) {
  function isBallLike(item) {
    return !!item && !item.dead && (item.type === "ball" || item.type === "balloon");
  }

  function update(item, dt, worldRef) {
    if (!isBallLike(item)) return false;
    if (item.type === "balloon") return updateBalloon(item, dt, worldRef);
    return updateBall(item, dt, worldRef);
  }

  function updateBall(item, dt, worldRef) {
    if (!item || item.dead || item.type !== "ball") return false;
    item.prevX = item.x;
    item.prevY = item.y;
    const moving = Math.hypot(item.vx || 0, item.vy || 0);
    if (moving > 0.04) {
      item.x += (item.vx || 0) * dt;
      item.y += (item.vy || 0) * dt;
      const p = Math.max(28, CONFIG.worldPadding || 30);
      if (item.x < p) { item.x = p; item.vx = Math.abs(item.vx || 0) * 0.72; item.spinVelocity *= -0.72; }
      if (item.x > worldRef.w - p) { item.x = worldRef.w - p; item.vx = -Math.abs(item.vx || 0) * 0.72; item.spinVelocity *= -0.72; }
      if (item.y < p) { item.y = p; item.vy = Math.abs(item.vy || 0) * 0.72; item.spinVelocity *= -0.72; }
      if (item.y > worldRef.h - p) { item.y = worldRef.h - p; item.vy = -Math.abs(item.vy || 0) * 0.72; item.spinVelocity *= -0.72; }
      resolveObstacleCollisions(item, dt, worldRef);
      global.TarinaiItemDynamicPinSystem.tryBallPickup(item, worldRef);
      item.x = clamp(item.x, p, worldRef.w - p);
      item.y = clamp(item.y, p, worldRef.h - p);
      const groundFriction = Math.pow(0.72, dt);
      item.vx *= groundFriction;
      item.vy *= groundFriction;
    }
    global.TarinaiItemDynamicPinSystem.tryBallPickup(item, worldRef);
    item.spin = (item.spin || 0) + (item.spinVelocity || 0) * dt + (item.vx || 0) * dt / Math.max(8, item.r || 18);
    item.spinVelocity *= Math.pow(0.65, dt);
    if (Math.hypot(item.vx || 0, item.vy || 0) < 0.18) { item.vx = 0; item.vy = 0; }
    return true;
  }

  function updateBalloon(item, dt, worldRef) {
    if (!item || item.dead || item.type !== "balloon") return false;
    const frameDt = Math.max(0.016, Number(dt || 0.016) || 0.016);
    item.prevX = item.x;
    item.prevY = item.y;

    // A balloon should never be completely inert: it slowly wobbles, then fans
    // and collisions can turn that small drift into visible motion.
    const phase = (worldRef?.time || 0) * 1.35 + (item.seed || 0) * 0.017 + (item.balloonWobble || 0);
    item.vx = (item.vx || 0) + Math.cos(phase * 0.83) * 6.5 * frameDt + Math.sin(phase * 0.31) * 2.4 * frameDt;
    item.vy = (item.vy || 0) + Math.sin(phase * 0.71) * 5.4 * frameDt;

    const maxSpeed = 560;
    const speedBefore = Math.hypot(item.vx || 0, item.vy || 0);
    if (speedBefore > maxSpeed) {
      const s = maxSpeed / speedBefore;
      item.vx *= s;
      item.vy *= s;
    }

    const moving = Math.hypot(item.vx || 0, item.vy || 0);
    if (moving > 0.04) {
      item.x += (item.vx || 0) * dt;
      item.y += (item.vy || 0) * dt;
      const p = Math.max(28, CONFIG.worldPadding || 30);
      if (item.x < p) { item.x = p; item.vx = Math.abs(item.vx || 0) * 0.58; item.spinVelocity *= -0.44; }
      if (item.x > worldRef.w - p) { item.x = worldRef.w - p; item.vx = -Math.abs(item.vx || 0) * 0.58; item.spinVelocity *= -0.44; }
      if (item.y < p) { item.y = p; item.vy = Math.abs(item.vy || 0) * 0.58; item.spinVelocity *= -0.44; }
      if (item.y > worldRef.h - p) { item.y = worldRef.h - p; item.vy = -Math.abs(item.vy || 0) * 0.58; item.spinVelocity *= -0.44; }
      resolveObstacleCollisions(item, dt, worldRef);
      item.x = clamp(item.x, p, worldRef.w - p);
      item.y = clamp(item.y, p, worldRef.h - p);
      const airFriction = Math.pow(0.47, frameDt);
      item.vx *= airFriction;
      item.vy *= airFriction;
    }

    checkBalloonHazards(item, worldRef);
    item.spin = (item.spin || 0) + (item.spinVelocity || 0) * frameDt + (item.vx || 0) * frameDt / Math.max(12, item.r || 20) * 0.42;
    item.spinVelocity *= Math.pow(0.58, frameDt);
    if (Math.hypot(item.vx || 0, item.vy || 0) < 0.08) { item.vx = 0; item.vy = 0; }
    return true;
  }

  function resolveObstacleCollisions(item, dt, worldRef) {
    if (!worldRef?.nearbyItems) return;
    const speed = Math.hypot(item.vx || 0, item.vy || 0);
    const searchRadius = Math.max(150, (item.r || 18) + speed * Math.max(dt || 0.016, 0.016) + 120);
    const items = worldRef.nearbyItems(item.x, item.y, searchRadius) || [];
    const seen = new Set(items);
    // 大きな機構は中心が近傍セル外でも当たる可能性がある。
    // 全item走査ではなく、機構type bucketだけを追加確認する。
    const mechanicalTypes = ["rotator", "poison_block", "reciprocator"];
    for (const type of mechanicalTypes) {
      const bucket = typeof worldRef.itemsOfType === "function" ? worldRef.itemsOfType(type) : (worldRef.items || []);
      for (const it of bucket || []) {
        if (!it || it.dead || it === item || !global.TarinaiMechanicalSystem.isMechanicalType(it.type) || seen.has(it)) continue;
        const reach = global.TarinaiMechanicalSystem.reach(it) || worldRef.rotatorExtent?.(it) || Math.max(64, it.r || 64);
        if (distXY(item.x, item.y, it.x, it.y) <= searchRadius + reach + 36) {
          items.push(it);
          seen.add(it);
        }
      }
    }
    for (const it of items) {
      if (!it || it === item || it.dead) continue;
      if (it.type === "bed") {
        applyHayDrag(item, it, dt, worldRef);
      } else if (it.type === "stone") {
        resolveCircleBounce(item, it, (it.r || 20) * 1.08 + (item.r || 18), item.type === "balloon" ? 0.48 : 0.82, worldRef);
      } else if (it.type === "fan" && item.type === "balloon") {
        const wind = fanWindAt(it, item.x, item.y);
        if (wind) {
          const a = itemAngleFor(it);
          item.vx += Math.cos(a) * 38 * wind.falloff * Math.max(0.016, dt || 0.016);
          item.vy += Math.sin(a) * 38 * wind.falloff * Math.max(0.016, dt || 0.016);
        }
      }
      const rects = worldRef.solidObstacleRects ? worldRef.solidObstacleRects(it) : [];
      if (!rects.length) continue;
      for (const rect of rects) resolveRectBounce(item, rect, worldRef, it);
    }
  }

  function applyHayDrag(item, bed, dt, worldRef) {
    const rx = Math.max(26, (bed.r || 37) * 1.72 + (item.r || 18) * 0.40);
    const ry = Math.max(18, (bed.r || 37) * 0.92 + (item.r || 18) * 0.34);
    const dx = item.x - bed.x;
    const dy = item.y - bed.y;
    const inside = (dx * dx) / (rx * rx) + (dy * dy) / (ry * ry) <= 1;
    if (!inside) return;
    const slow = Math.pow(item.type === "balloon" ? 0.28 : 0.16, Math.max(0.016, dt || 0.016));
    item.vx *= slow;
    item.vy *= slow;
    item.spinVelocity *= Math.pow(0.24, Math.max(0.016, dt || 0.016));
    if ((item.lastHaySlowLogAt || -999) + 3.5 < (worldRef.time || 0) && Math.hypot(item.vx || 0, item.vy || 0) > 120) {
      item.lastHaySlowLogAt = worldRef.time || 0;
      worldRef.effects?.push(new Effect("ring", item.x, item.y, { size: Math.max(14, item.r * 0.95), life: 0.20, color: "rgba(214,184,96,0.42)" }));
    }
  }

  function resolveCircleBounce(item, obstacle, hitRadius, restitution, worldRef) {
    let dx = item.x - obstacle.x;
    let dy = item.y - obstacle.y;
    let d = Math.hypot(dx, dy);
    if (d >= hitRadius) {
      const px = item.prevX;
      const py = item.prevY;
      if (!Number.isFinite(px) || !Number.isFinite(py)) return;
      const sx = item.x - px;
      const sy = item.y - py;
      const len2 = sx * sx + sy * sy;
      if (len2 <= 0.0001) return;
      const t = clamp(((obstacle.x - px) * sx + (obstacle.y - py) * sy) / len2, 0, 1);
      const cx = px + sx * t;
      const cy = py + sy * t;
      dx = cx - obstacle.x;
      dy = cy - obstacle.y;
      d = Math.hypot(dx, dy);
      if (d >= hitRadius) return;
      if (d < 0.001) {
        const speed = Math.hypot(item.vx || 0, item.vy || 0);
        if (speed > 0.001) { dx = -(item.vx || 0) / speed; dy = -(item.vy || 0) / speed; d = 1; }
        else { dx = -sx / Math.sqrt(len2); dy = -sy / Math.sqrt(len2); d = 1; }
      }
    }
    if (d < 0.001) {
      const speed = Math.hypot(item.vx || 0, item.vy || 0);
      if (speed > 0.001) { dx = -(item.vx || 0) / speed; dy = -(item.vy || 0) / speed; d = 1; }
      else { dx = Math.cos(item.seed || 0); dy = Math.sin(item.seed || 0); d = 1; }
    }
    const nx = dx / d;
    const ny = dy / d;
    const toward = (item.vx || 0) * nx + (item.vy || 0) * ny;
    item.x = obstacle.x + nx * (hitRadius + 0.5);
    item.y = obstacle.y + ny * (hitRadius + 0.5);
    if (toward < 0) {
      item.vx = (item.vx || 0) - (1 + restitution) * toward * nx;
      item.vy = (item.vy || 0) - (1 + restitution) * toward * ny;
    } else {
      const push = item.type === "balloon" ? 12 : 24;
      item.vx = (item.vx || 0) + nx * push;
      item.vy = (item.vy || 0) + ny * push;
    }
    const damp = item.type === "balloon" ? 0.84 : 0.96;
    item.vx *= damp;
    item.vy *= damp;
    item.spinVelocity = clamp((item.spinVelocity || 0) + (nx >= 0 ? -1 : 1) * (item.type === "balloon" ? 2.2 : 5.5), -38, 38);
    emitBounce(item, worldRef, obstacle);
  }

  function resolveRectBounce(item, rect, worldRef, source = null) {
    if (!rect) return;
    const bounceCircleOffRect = global.TarinaiPhysics?.bounceCircleOffRect;
    if (typeof bounceCircleOffRect !== "function") return;
    const hitRadius = (item.r || 18) + 2;
    const restitution = Number.isFinite(rect.restitution) ? rect.restitution : (item.type === "balloon" ? 0.54 : 0.78);
    const velocityDamp = rect.bounce ? 1.0 : (item.type === "balloon" ? 0.82 : 0.94);
    const minBounceSpeed = Math.max(0, Number(rect.minBounceSpeed || 0) || 0);
    const bounced = bounceCircleOffRect(item, rect, hitRadius, restitution, worldRef, {
      minBounceSpeed: rect.bounce ? minBounceSpeed : 0,
      fallbackImpulse: item.type === "balloon" ? 10 : 18,
      spinKick: item.type === "balloon" ? 2.4 : 6.2,
      spinLimit: 38,
    });
    if (!bounced) return;
    item.vx *= velocityDamp;
    item.vy *= velocityDamp;
    emitBounce(item, worldRef, source || rect.item || rect);
  }

  function emitBounce(item, worldRef, obstacle) {
    const now = worldRef?.time || 0;
    if ((item.lastObstacleBounceAt || -999) + 0.08 > now) return;
    item.lastObstacleBounceAt = now;
    const color = item.type === "balloon" ? "rgba(248,122,166,0.36)" : ((obstacle?.type === "bounce_fence" || obstacle?.type === "bounce_fence_v") ? "rgba(82,153,230,0.46)" : (obstacle?.type === "stone" ? "rgba(165,165,150,0.45)" : "rgba(160,116,64,0.42)"));
    worldRef?.effects?.push(new Effect("ring", item.x, item.y, { size: Math.max(13, (item.r || 18) * 0.82), life: 0.18, color }));
  }

  function normalizeAngleLocal(angle = 0, fallback = 0) {
    if (typeof normalizedItemAngle === "function") return normalizedItemAngle(angle, fallback);
    const twoPi = Math.PI * 2;
    const n = Number(angle);
    const base = Number.isFinite(n) ? n : (Number.isFinite(Number(fallback)) ? Number(fallback) : 0);
    return ((base % twoPi) + twoPi) % twoPi;
  }

  function fanWindAngleFor(item) {
    return normalizeAngleLocal(item?.angle, item?.fanSwingCenter ?? 0);
  }

  function ensureFanBodyAngle(item) {
    if (!item || item.type !== "fan") return 0;
    const body = Number(item.fanBodyAngle);
    if (Number.isFinite(body)) return normalizeAngleLocal(body, item.angle || 0);
    item.fanBodyAngle = normalizeAngleLocal(item.angle || item.fanSwingCenter || 0, 0);
    return item.fanBodyAngle;
  }

  function updateFanSwing(item, dt) {
    if (!item || item.dead || item.type !== "fan") return false;
    ensureFanBodyAngle(item);
    if (!item.fanSwingOn) {
      item.fanSwingCenter = Number.isFinite(Number(item.fanSwingCenter)) ? Number(item.fanSwingCenter) : fanWindAngleFor(item);
      item.angle = normalizeAngleLocal(item.fanSwingCenter, item.angle || 0);
      return false;
    }
    const center = normalizeAngleLocal(item.fanSwingCenter, fanWindAngleFor(item));
    const range = clamp(Number(item.fanSwingRange ?? (35 * Math.PI / 180)) || 0, 0, 150 * Math.PI / 180);
    const speed = clamp(Number(item.fanSwingSpeed ?? (48 * Math.PI / 180)) || 0, 0, 360 * Math.PI / 180);
    item.fanSwingCenter = center;
    item.fanSwingRange = range;
    item.fanSwingSpeed = speed;
    item.fanSwingPhase = Number(item.fanSwingPhase || 0) + speed * Math.max(0.016, Number(dt || 0.016) || 0.016);
    item.angle = normalizeAngleLocal(center + Math.sin(item.fanSwingPhase || 0) * range, center);
    return true;
  }

  const FAN_WIND_ITEM_TYPES = Object.freeze(["balloon", "ball", "pushpin", "oshibyo", "water", "zunda_juice", "mercury", "zunchi", "fire"]);

  function fanWindItemCandidates(fan, worldRef, cx, cy, radius) {
    if (!worldRef) return [];
    if (typeof worldRef.itemsOfType === "function") {
      const out = [];
      const seen = new Set();
      const r2 = Math.max(1, Number(radius || 0) || 0) ** 2;
      for (const type of FAN_WIND_ITEM_TYPES) {
        for (const it of worldRef.itemsOfType(type) || []) {
          if (!it || it.dead || it === fan || seen.has(it.id || it)) continue;
          const dx = Number(it.x || 0) - cx;
          const dy = Number(it.y || 0) - cy;
          const reach = radius + Math.max(0, Number(it.r || it.radius || 0) || 0);
          if (dx * dx + dy * dy > Math.max(r2, reach * reach)) continue;
          seen.add(it.id || it);
          out.push(it);
        }
      }
      return out;
    }
    return worldRef.nearbyItems?.(cx, cy, radius) || worldRef.items || [];
  }

  function fanWindAt(fan, x, y, opts = {}) {
    if (!fan || fan.dead || fan.type !== "fan") return null;
    const range = Math.max(80, Number(opts.range || 300) || 300);
    const spread = Math.max(0.18, Number(opts.spread || 0.62) || 0.62);
    const dx = x - fan.x;
    const dy = y - fan.y;
    const angle = fanWindAngleFor(fan);
    const ax = Math.cos(angle);
    const ay = Math.sin(angle);
    const along = dx * ax + dy * ay;
    if (along < 8 || along > range) return null;
    const lateral = Math.abs(-dx * ay + dy * ax);
    const halfWidth = 26 + along * Math.tan(spread);
    if (lateral > halfWidth) return null;
    const distFalloff = clamp(1 - along / range, 0, 1);
    const edgeFalloff = clamp(1 - lateral / Math.max(1, halfWidth), 0, 1);
    const falloff = Math.pow(distFalloff, 0.64) * Math.pow(edgeFalloff, 0.34);
    if (falloff <= 0.02) return null;
    return { angle, along, lateral, halfWidth, range, falloff };
  }

  function updateFan(item, dt, worldRef) {
    if (!item || item.dead || item.type !== "fan") return false;
    const frameDt = Math.max(0.016, Number(dt || 0.016) || 0.016);
    const now = worldRef?.time || 0;
    item.prevX = item.x;
    item.prevY = item.y;
    ensureFanBodyAngle(item);
    item.fanSpin = (item.fanSpin || 0) + 11.5 * frameDt;
    item.fanPulse = (item.fanPulse || 0) + 2.2 * frameDt;
    updateFanSwing(item, frameDt);

    const angle = fanWindAngleFor(item);
    const ax = Math.cos(angle);
    const ay = Math.sin(angle);
    const range = 320;
    const searchRadius = range + 40;
    const queryX = item.x + ax * range * 0.45;
    const queryY = item.y + ay * range * 0.45;
    const nearbyItems = fanWindItemCandidates(item, worldRef, queryX, queryY, searchRadius);
    for (const target of nearbyItems) {
      if (!target || target.dead || target === item) continue;
      const wind = fanWindAt(item, target.x, target.y, { range });
      if (!wind) continue;
      applyFanToItem(item, target, wind, frameDt, worldRef);
    }

    const nearbyTarinai = worldRef?.nearbyTarinai?.(queryX, queryY, searchRadius) || [];
    for (const t of nearbyTarinai) {
      if (!t || t.dead || worldRef?.isTarinaiHiddenInNestBox?.(t)) continue;
      const wind = fanWindAt(item, t.x, t.y, { range });
      if (!wind) continue;
      applyFanToTarinai(item, t, wind, frameDt, worldRef);
    }

    if ((item.lastFanEffectAt || -999) + 0.18 < now) {
      item.lastFanEffectAt = now;
      const phase = Math.sin(item.fanPulse || 0);
      const px = item.x + ax * (42 + 24 * phase);
      const py = item.y + ay * (42 + 24 * phase);
      worldRef?.effects?.push(new Effect("ring", px, py, { size: 12 + 7 * Math.abs(phase), life: 0.18, color: "rgba(174,214,236,0.26)" }));
    }
    return true;
  }

  function spreadFireByFan(fan, fire, wind, dt, worldRef) {
    if (!fan || !fire || !worldRef || fire.dead || fire.type !== "fire") return false;
    const now = worldRef.time || 0;
    const falloff = Math.max(0, Number(wind?.falloff || 0) || 0);
    if (falloff < 0.16 || (fire.amount || 0) < 18) return false;
    const interval = Math.max(0.10, 0.34 - falloff * 0.18);
    if ((fire.lastFanSpreadAt || -999) + interval > now) return false;
    fire.lastFanSpreadAt = now;
    const ax = Math.cos(wind.angle);
    const ay = Math.sin(wind.angle);
    const side = global.deterministicRange(worldRef, "fan-fire-side", -22, 22, fan, fire, Math.round(now * 10));
    const dist = global.deterministicRange(worldRef, "fan-fire-distance", 58, 118, fan, fire, Math.round(now * 10)) * (0.82 + falloff * 0.58);
    const x = clamp((fire.x || 0) + ax * dist - ay * side, CONFIG.worldPadding || 30, Math.max(CONFIG.worldPadding || 30, (worldRef.w || 0) - (CONFIG.worldPadding || 30)));
    const y = clamp((fire.y || 0) + ay * dist + ax * side, CONFIG.worldPadding || 30, Math.max(CONFIG.worldPadding || 30, (worldRef.h || 0) - (CONFIG.worldPadding || 30)));
    const spawned = global.TarinaiItemDynamicToolSystem?.spawnFireAt?.(worldRef, x, y, {
      radius: Math.max(8, (fire.r || 14) * (0.55 + falloff * 0.22)),
      amount: Math.max(18, Math.min(86, (fire.amount || 60) * (0.20 + falloff * 0.22))),
      life: 2.2 + falloff * 3.4,
      source: fan,
      mergeRadius: 24,
    });
    if (spawned) {
      // A fan should carry embers forward instead of merely dimming the source flame.
      // The source loses a little fuel, while the downwind flame handles normal fire contacts.
      fire.amount = Math.max(4, (fire.amount || 0) - (2.2 + falloff * 3.8));
      worldRef.effects?.push(new Effect("flame", fire.x + ax * Math.max(12, fire.r || 14), fire.y + ay * Math.max(12, fire.r || 14), {
        size: Math.max(7, (fire.r || 14) * 0.72),
        life: 0.22,
        color: "rgba(255,126,54,0.58)",
        vx: ax * (80 + falloff * 120),
        vy: ay * (80 + falloff * 120),
      }));
      worldRef.markItemBucketsDirty?.("fan-fire-spread");
      worldRef.markSpatialDirty?.("fan-fire-spread");
      worldRef.drawListDirty = true;
      return true;
    }
    return false;
  }

  function applyFanToItem(fan, target, wind, dt, worldRef) {
    const type = target.type || "";
    let massFactor = 0;
    if (type === "balloon") massFactor = 1.85;
    else if (type === "ball") massFactor = 0.72;
    else if (type === "pushpin" || type === "oshibyo") massFactor = 0.90;
    else if (type === "water" || type === "zunda_juice" || type === "mercury") massFactor = 0.42;
    else if (type === "zunchi") massFactor = 0.30;
    else if (type === "fire") {
      spreadFireByFan(fan, target, wind, dt, worldRef);
      return;
    }
    else return;

    const force = 236 * wind.falloff * massFactor;
    const ax = Math.cos(wind.angle);
    const ay = Math.sin(wind.angle);
    target.prevX = Number.isFinite(target.prevX) ? target.prevX : target.x;
    target.prevY = Number.isFinite(target.prevY) ? target.prevY : target.y;
    target.vx = clamp((target.vx || 0) + ax * force * dt, -820, 820);
    target.vy = clamp((target.vy || 0) + ay * force * dt, -820, 820);
    if (type === "balloon") target.spinVelocity = clamp((target.spinVelocity || 0) + 3.2 * wind.falloff * dt, -12, 12);
    else if (type === "ball") target.spinVelocity = clamp((target.spinVelocity || 0) + 5.4 * wind.falloff * dt, -38, 38);
    worldRef?.markSpatialDirty?.("fan-wind-item");
  }

  function applyFanToTarinai(fan, t, wind, dt, worldRef) {
    const ax = Math.cos(wind.angle);
    const ay = Math.sin(wind.angle);
    const radius = t.radius || 18;
    const speed = 30 * wind.falloff;
    t.vx = clamp((t.vx || 0) + ax * speed * dt, -360, 360);
    t.vy = clamp((t.vy || 0) + ay * speed * dt, -360, 360);
    t.fanBreezeTimer = Math.max(t.fanBreezeTimer || 0, 0.35);
    if (wind.falloff > 0.58 && (worldRef?.time || 0) - (t.lastFanSurpriseAt || -999) > 2.2) {
      t.lastFanSurpriseAt = worldRef?.time || 0;
      t.surpriseTimer = Math.max(t.surpriseTimer || 0, 0.12);
      if (typeof t.spawnBubble === "function") t.spawnBubble("~", { life: 0.55 });
      worldRef?.effects?.push(new Effect("ring", t.x + ax * radius * 0.4, t.y + ay * radius * 0.2, { size: Math.max(12, radius * 0.72), life: 0.16, color: "rgba(174,214,236,0.28)" }));
    }
  }

  function checkBalloonHazards(balloon, worldRef) {
    if (!balloon || balloon.dead || balloon.type !== "balloon" || !worldRef?.nearbyItems) return;
    const now = worldRef.time || 0;
    if ((balloon.balloonPoppedAt || -999) + 0.5 > now) return;
    const radius = Math.max(26, (balloon.r || 20) + 22);
    for (const it of worldRef.nearbyItems(balloon.x, balloon.y, radius) || []) {
      if (!it || it.dead || it === balloon) continue;
      if ((typeof isPinType === "function" && isPinType(it.type) && it.pinState !== "lodged") || it.type === "fire" || it.type === "flame_firecracker" || it.type === "firecracker") {
        const extra = it.type === "fire" ? 16 : (it.type === "firecracker" || it.type === "flame_firecracker" ? 8 : 4);
        const hit = distXY(balloon.x, balloon.y, it.x, it.y) <= (balloon.r || 20) + (it.r || 10) + extra;
        if (hit) {
          popBalloon(balloon, worldRef, it);
          return;
        }
      }
    }
  }

  const WATER_BALLOON_SURPRISE_TEXT = "水風船が割れておどろいている。";

  function tarinaiOpennessValue(t) {
    const v = (typeof global.effectivePersonalityValue === "function")
      ? global.effectivePersonalityValue(t, "openness")
      : (t?.currentPersonality?.openness ?? t?.birthPersonality?.openness ?? t?.personality?.openness ?? 0);
    return Number(v) || 0;
  }

  function shouldPanicFromWaterBalloon(t, strength, worldRef, balloon) {
    const openness = tarinaiOpennessValue(t);
    if (openness >= -0.08) return false;
    if (openness <= -0.48) return true;
    const chance = clamp(0.32 + Math.max(0, -openness) * 0.70 + Math.max(0, strength) * 0.26, 0.34, 0.92);
    return deterministicChance(worldRef || t?.world || null, "water-balloon-low-openness-panic", chance, t, balloon, Math.round(strength * 1000));
  }

  function setWaterBalloonSurpriseBehavior(t, target, panic = false) {
    if (!t || t.dead) return false;
    t.lastPanicDetail = WATER_BALLOON_SURPRISE_TEXT;
    t.thought = WATER_BALLOON_SURPRISE_TEXT;
    if (typeof global.setBehavior === "function") {
      global.setBehavior(t, {
        actionId: panic ? "panic_escape" : "water_balloon_surprise",
        need: "safety",
        label: WATER_BALLOON_SURPRISE_TEXT,
        text: WATER_BALLOON_SURPRISE_TEXT,
        reason: WATER_BALLOON_SURPRISE_TEXT,
        target: target || null,
        phase: "perform",
        source: "behavior",
        tiedNeeds: ["safety"],
        lockSeconds: panic ? 2.6 : 1.1,
        minDuration: panic ? 1.2 : 0.55,
      });
      return true;
    }
    if (typeof global.setBehaviorText === "function") {
      global.setBehaviorText(t, { need: "safety", actionId: panic ? "panic_escape" : "water_balloon_surprise", actionLabel: WATER_BALLOON_SURPRISE_TEXT, reasonText: WATER_BALLOON_SURPRISE_TEXT, target: target || null, phase: "perform", source: "behavior" });
      return true;
    }
    return false;
  }

  function spawnWaterFromBalloon(balloon, worldRef) {
    if (!balloon || !worldRef) return 0;
    const baseR = Math.max(14, Number(balloon.r || 20) || 20);
    const count = Math.max(12, Math.min(22, Math.round(baseR * 0.68)));
    let spawned = 0;
    for (let i = 0; i < count; i++) {
      if (typeof global.Item !== "function") break;
      const a = deterministicAngle(worldRef || balloon, "water-balloon-splash-angle", balloon, i);
      const d = deterministicRange(worldRef || balloon, "water-balloon-splash-dist", baseR * 0.12, baseR * 0.95, balloon, i);
      const speed = deterministicRange(worldRef || balloon, "water-balloon-drop-speed", 280, 760, balloon, i);
      const x = balloon.x + Math.cos(a) * d;
      const y = balloon.y + Math.sin(a) * d;
      const vx = Math.cos(a) * speed + (Number(balloon.vx || 0) || 0) * 0.28;
      const vy = Math.sin(a) * speed + (Number(balloon.vy || 0) || 0) * 0.28;
      const flight = deterministicRange(worldRef || balloon, "water-balloon-drop-flight", 0.42, 0.88, balloon, i);
      const amount = deterministicRange(worldRef || balloon, "water-balloon-drop-amount", 24, 58, balloon, i);
      const drop = global.TarinaiWeatherSystem?.createRainWaterItem
        ? global.TarinaiWeatherSystem.createRainWaterItem(worldRef, { x, y, amount, vx, vy, splashFlightTimer: flight })
        : new global.Item("water", x, y);
      if (!Number.isFinite(Number(drop.amount))) drop.amount = amount;
      if (!Number.isFinite(Number(drop.vx))) drop.vx = vx;
      if (!Number.isFinite(Number(drop.vy))) drop.vy = vy;
      if (!Number.isFinite(Number(drop.splashFlightTimer))) drop.splashFlightTimer = flight;
      const addedDrop = worldRef.addItem?.(drop, "water-balloon-splash", { terrain: false }) || null;
      if (!addedDrop) continue;
      spawned += 1;
      if (i < 8) {
        worldRef.effects?.push(new Effect("fight", drop.x, drop.y, {
          size: deterministicRange(worldRef || balloon, "water-balloon-drop-spark-size", 3.5, 7.0, balloon, i),
          life: deterministicRange(worldRef || balloon, "water-balloon-drop-spark-life", 0.24, 0.42, balloon, i),
          color: "rgba(96,196,244,0.66)",
          vx: drop.vx * 0.42,
          vy: drop.vy * 0.42,
        }));
      }
    }
    if (spawned) {
      worldRef.markItemBucketsDirty?.("water-balloon-splash");
      worldRef.markSpatialDirty?.("water-balloon-splash");
      worldRef.markTerrainDirtyAt?.(balloon.x, balloon.y, Math.max(70, baseR * 5.2), "water-balloon-splash");
    }
    return spawned;
  }

  function updateWaterDropMotion(item, dt, worldRef) {
    if (!item || item.dead || item.type !== "water") return false;
    const frameDt = Math.max(0.016, Number(dt || 0.016) || 0.016);
    const speed = Math.hypot(item.vx || 0, item.vy || 0);
    if (speed <= 0.05 && !(item.splashFlightTimer > 0)) return false;
    item.prevX = Number.isFinite(Number(item.x)) ? item.x : 0;
    item.prevY = Number.isFinite(Number(item.y)) ? item.y : 0;
    item.x += (Number(item.vx || 0) || 0) * frameDt;
    item.y += (Number(item.vy || 0) || 0) * frameDt;
    const pad = Math.max(28, CONFIG.worldPadding || 30);
    const r = Math.max(5, Number(item.r || 8) || 8);
    if (worldRef) {
      if (item.x < pad) { item.x = pad; item.vx = Math.abs(item.vx || 0) * 0.30; }
      if (item.x > worldRef.w - pad) { item.x = worldRef.w - pad; item.vx = -Math.abs(item.vx || 0) * 0.30; }
      if (item.y < pad) { item.y = pad; item.vy = Math.abs(item.vy || 0) * 0.30; }
      if (item.y > worldRef.h - pad) { item.y = worldRef.h - pad; item.vy = -Math.abs(item.vy || 0) * 0.30; }
    }
    item.splashFlightTimer = Math.max(0, Number(item.splashFlightTimer || 0) - frameDt);
    const damp = item.splashFlightTimer > 0 ? Math.pow(0.78, frameDt * 60) : Math.pow(0.58, frameDt * 60);
    item.vx *= damp;
    item.vy *= damp;
    if (Math.hypot(item.vx || 0, item.vy || 0) < 8 && item.splashFlightTimer <= 0) {
      item.vx = 0;
      item.vy = 0;
    }
    if (worldRef && ((item.lastSplashTrailAt || -999) + 0.12 < (worldRef.time || 0)) && Math.hypot(item.vx || 0, item.vy || 0) > 72) {
      item.lastSplashTrailAt = worldRef.time || 0;
      worldRef.effects?.push(new Effect("fight", item.x, item.y, { size: Math.max(2.8, r * 0.55), life: 0.18, color: "rgba(112,206,248,0.36)", vx: -(item.vx || 0) * 0.05, vy: -(item.vy || 0) * 0.05 }));
    }
    worldRef?.markSpatialDirty?.("water-drop-motion");
    worldRef?.markTerrainDirtyAt?.(item.x, item.y, Math.max(28, r * 3.2), "water-drop-motion");
    if (worldRef) worldRef.drawListDirty = true;
    return true;
  }

  function applyWaterBalloonSurprise(balloon, worldRef) {
    for (const t of worldRef?.nearbyTarinai?.(balloon.x, balloon.y, 165) || []) {
      if (!t || t.dead || worldRef?.isTarinaiHiddenInNestBox?.(t)) continue;
      const d = Math.max(1, distXY(balloon.x, balloon.y, t.x, t.y));
      const strength = clamp(1 - d / 165, 0, 1);
      t.surpriseTimer = Math.max(t.surpriseTimer || 0, 0.34 + strength * 0.44);
      if (typeof t.addStress === "function") t.addStress(0.18 + strength * 0.42, "水風船が割れて驚いた");
      if (typeof t.spawnBubble === "function" && strength > 0.35) t.spawnBubble("!", { life: 0.72 });
      const awayX = (t.x - balloon.x) / d;
      const awayY = (t.y - balloon.y) / d;
      t.vx = clamp((t.vx || 0) + awayX * 68 * strength, -360, 360);
      t.vy = clamp((t.vy || 0) + awayY * 68 * strength, -360, 360);

      const panic = shouldPanicFromWaterBalloon(t, strength, worldRef, balloon);
      if (panic) {
        const threat = { x: balloon.x, y: balloon.y, dead: true, type: "water_balloon_pop" };
        const destination = t.panicDestination?.(threat, true) || { x: t.x + awayX * 190, y: t.y + awayY * 190, dead: false, panic: true };
        t.enterPanic?.({
          threat,
          destination,
          target: destination,
          reason: WATER_BALLOON_SURPRISE_TEXT,
          cause: "water_balloon_pop",
          fearTimer: 1.35 + strength * 1.30,
          stress: 14 + strength * 24,
          surpriseTimer: 0.70 + strength * 0.45,
          wake: true,
          forceDestination: true,
          bubble: "!!",
          bubbleCooldown: 0.7,
        }) || t.setActionState?.("panic", { target: destination, reason: WATER_BALLOON_SURPRISE_TEXT, wake: true, sleeping: false });
        t.fearTimer = Math.max(t.fearTimer || 0, 1.85 + strength * 1.40);
        t.panicStartedAt = worldRef?.time || t.panicStartedAt || 0;
        t.panicHardStopAt = Math.max(t.panicHardStopAt || 0, (worldRef?.time || 0) + 5.5);
        t.lastPanicCause = "water_balloon_pop";
        setWaterBalloonSurpriseBehavior(t, destination, true);
      } else {
        setWaterBalloonSurpriseBehavior(t, null, false);
      }
    }
  }

  function popBalloon(balloon, worldRef, cause = null) {
    if (!balloon || balloon.dead) return;
    const now = worldRef?.time || 0;
    balloon.balloonPoppedAt = now;
    // Item.dead is a getter based on amount, so mark the water balloon gone
    // through amount/hp instead of assigning to .dead directly.
    balloon.amount = 0;
    balloon.hp = 0;
    worldRef?.effects?.push(new Effect("ring", balloon.x, balloon.y, { size: Math.max(32, (balloon.r || 20) * 1.9), life: 0.28, color: "rgba(76,178,236,0.62)" }));
    for (let i = 0; i < 9; i++) {
      const a = deterministicAngle(worldRef || balloon, "water-balloon-pop-piece", balloon, i);
      const s = deterministicRange(worldRef || balloon, "water-balloon-pop-speed", 24, 96, balloon, i);
      worldRef?.effects?.push(new Effect("fight", balloon.x, balloon.y, { size: deterministicRange(worldRef || balloon, "water-balloon-pop-size", 4, 10, balloon, i), life: 0.28, color: "rgba(95,204,246,0.72)", vx: Math.cos(a) * s, vy: Math.sin(a) * s }));
    }
    spawnWaterFromBalloon(balloon, worldRef);
    const sourceLabel = cause?.type === "fire" || cause?.type === "flame_firecracker" ? "火"
      : (cause?.type === "firecracker" ? "爆竹"
      : (cause?.type === "shoot" ? "射撃"
      : (cause?.type === "genkotsu" ? "げんこつ"
      : (cause && typeof isPinType === "function" && isPinType(cause.type) ? "鋲" : "強い衝撃"))));
    if (worldRef?.relationNotice?.(balloon.id || "balloon", cause?.id || sourceLabel, "water-balloon-pop", 1.4)) {
      worldRef.log?.(`水風船が${sourceLabel}に触れて割れた。`, "accident", { participants: [] });
    }
    applyWaterBalloonSurprise(balloon, worldRef);
    worldRef?.markSpatialDirty?.("water-balloon-pop");
  }

  global.TarinaiItemDynamicBallSystem = Object.freeze({
    update,
    updateFan,
    updateWaterDropMotion,
    resolveObstacleCollisions,
    popBalloon,
  });
})(typeof window !== "undefined" ? window : globalThis);