Add emoji confetti bursts and component playground.

Support app.relay.emoji_confetti on jumbo emoji clicks with canvas physics,
per-emoji particle profiles, and a fixed overlay that does not affect scroll.
Also add a Vite playground for live component previews and theme hover preview.

src/app/features/room/emoji-confetti/EmojiConfettiBurstCanvas.tsx

@@ -0,0 +1,180 @@
+import React, { useEffect, useMemo, useRef, useState } from 'react';
+import { createPortal } from 'react-dom';
+import { EmojiConfettiBurst } from './types';
+import { findJumboEmojiElement, getLocalBurstCanvasSize } from './findJumboMount';
+import {
+  BurstParticle,
+  drawBurstParticles,
+  spawnEmojiBurst,
+  stepBurstParticles,
+} from './emojiBurstEngine';
+
+const MAX_DPR = 2;
+
+type EmojiConfettiBurstCanvasProps = {
+  burst: EmojiConfettiBurst;
+  onComplete: (burstId: string) => void;
+};
+
+export function EmojiConfettiBurstCanvas({ burst, onComplete }: EmojiConfettiBurstCanvasProps) {
+  const canvasRef = useRef<HTMLCanvasElement>(null);
+  const layerRef = useRef<HTMLDivElement>(null);
+  const particlesRef = useRef<BurstParticle[]>([]);
+  const frameRef = useRef<number | null>(null);
+  const lastFrameTimeRef = useRef<number | null>(null);
+  const spawnedRef = useRef(false);
+  const onCompleteRef = useRef(onComplete);
+  onCompleteRef.current = onComplete;
+
+  const canvasSize = getLocalBurstCanvasSize(burst.origin.maskRadius ?? 36);
+  const localOrigin = useMemo(
+    () => ({
+      x: canvasSize / 2,
+      y: canvasSize / 2,
+      maskRadius: burst.origin.maskRadius ?? 36,
+    }),
+    [burst.origin.maskRadius, canvasSize]
+  );
+
+  const updateLayerPosition = () => {
+    const layer = layerRef.current;
+    if (!layer) return false;
+
+    const jumbo = findJumboEmojiElement(burst.targetEventId);
+    if (!jumbo) return false;
+
+    const rect = jumbo.getBoundingClientRect();
+    layer.style.left = `${rect.left + rect.width / 2 - canvasSize / 2}px`;
+    layer.style.top = `${rect.top + rect.height / 2 - canvasSize / 2}px`;
+    return true;
+  };
+
+  useEffect(() => {
+    const onScrollOrResize = () => {
+      updateLayerPosition();
+    };
+
+    window.addEventListener('scroll', onScrollOrResize, true);
+    window.addEventListener('resize', onScrollOrResize);
+
+    return () => {
+      window.removeEventListener('scroll', onScrollOrResize, true);
+      window.removeEventListener('resize', onScrollOrResize);
+    };
+  }, [burst.targetEventId, canvasSize]);
+
+  useEffect(() => {
+    if (!canvasRef.current || spawnedRef.current) return undefined;
+
+    const reducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
+    if (reducedMotion) {
+      onCompleteRef.current(burst.id);
+      return undefined;
+    }
+
+    let frameCleanup: (() => void) | undefined;
+
+    const start = (): boolean => {
+      if (spawnedRef.current || !canvasRef.current) return false;
+      if (!updateLayerPosition()) return false;
+
+      spawnedRef.current = true;
+      const canvas = canvasRef.current;
+      const context = canvas.getContext('2d');
+      if (!context) return false;
+
+      const dpr = Math.min(window.devicePixelRatio || 1, MAX_DPR);
+      canvas.width = Math.round(canvasSize * dpr);
+      canvas.height = Math.round(canvasSize * dpr);
+      canvas.style.width = `${canvasSize}px`;
+      canvas.style.height = `${canvasSize}px`;
+
+      spawnEmojiBurst(
+        particlesRef.current,
+        burst.id,
+        localOrigin,
+        burst.emojis[0] ?? '🎉',
+        performance.now()
+      );
+
+      const tick = (now: number) => {
+        updateLayerPosition();
+
+        const last = lastFrameTimeRef.current ?? now;
+        const dtSeconds = Math.min((now - last) / 1000, 0.05);
+        lastFrameTimeRef.current = now;
+
+        stepBurstParticles(particlesRef.current, now, dtSeconds);
+
+        context.setTransform(1, 0, 0, 1, 0, 0);
+        context.clearRect(0, 0, canvas.width, canvas.height);
+
+        if (particlesRef.current.length > 0) {
+          drawBurstParticles(context, particlesRef.current, dpr, now);
+          frameRef.current = requestAnimationFrame(tick);
+          return;
+        }
+
+        onCompleteRef.current(burst.id);
+        frameRef.current = null;
+        lastFrameTimeRef.current = null;
+      };
+
+      lastFrameTimeRef.current = performance.now();
+      frameRef.current = requestAnimationFrame(tick);
+
+      frameCleanup = () => {
+        if (frameRef.current !== null) {
+          cancelAnimationFrame(frameRef.current);
+          frameRef.current = null;
+        }
+      };
+
+      return true;
+    };
+
+    if (start()) {
+      return frameCleanup;
+    }
+
+    let attempt = 0;
+    const retry = window.setInterval(() => {
+      attempt += 1;
+      if (start() || attempt >= 10) {
+        window.clearInterval(retry);
+        if (attempt >= 10 && !spawnedRef.current) {
+          onCompleteRef.current(burst.id);
+        }
+      }
+    }, 50);
+
+    return () => {
+      window.clearInterval(retry);
+      frameCleanup?.();
+    };
+  }, [burst.emojis, burst.id, burst.targetEventId, canvasSize, localOrigin]);
+
+  return createPortal(
+    <div
+      ref={layerRef}
+      aria-hidden
+      style={{
+        position: 'fixed',
+        width: canvasSize,
+        height: canvasSize,
+        pointerEvents: 'none',
+        zIndex: 4,
+      }}
+    >
+      <canvas
+        ref={canvasRef}
+        style={{
+          position: 'absolute',
+          inset: 0,
+          pointerEvents: 'none',
+        }}
+      />
+    </div>,
+    document.body
+  );
+}

src/app/features/room/emoji-confetti/EmojiConfettiOverlay.tsx

@@ -0,0 +1,24 @@
+import React from 'react';
+import { EmojiConfettiBurst } from './types';
+import { EmojiConfettiBurstCanvas } from './EmojiConfettiBurstCanvas';
+
+type EmojiConfettiOverlayProps = {
+  bursts: EmojiConfettiBurst[];
+  onBurstComplete: (burstId: string) => void;
+};
+
+export function EmojiConfettiOverlay({ bursts, onBurstComplete }: EmojiConfettiOverlayProps) {
+  if (bursts.length === 0) return null;
+
+  return (
+    <>
+      {bursts.map((burst) => (
+        <EmojiConfettiBurstCanvas
+          key={burst.id}
+          burst={burst}
+          onComplete={onBurstComplete}
+        />
+      ))}
+    </>
+  );
+}

src/app/features/room/emoji-confetti/burstOrigin.ts

@@ -0,0 +1,74 @@
+export type BurstPoint = {
+  x: number;
+  y: number;
+  maskRadius?: number;
+};
+
+export function getBurstPointFromElement(element: Element): BurstPoint {
+  const rect = element.getBoundingClientRect();
+  return {
+    x: rect.left + rect.width / 2,
+    y: rect.top + rect.height / 2,
+    maskRadius: Math.max(rect.width, rect.height) * 0.5,
+  };
+}
+
+export function getElementCenter(element: Element): BurstPoint {
+  return getBurstPointFromElement(element);
+}
+
+export function findEmojiOriginInMessage(
+  targetEventId: string,
+  emoji: string
+): BurstPoint | undefined {
+  const message = document.querySelector(`[data-message-id="${CSS.escape(targetEventId)}"]`);
+  if (!message) return undefined;
+
+  const matches = message.querySelectorAll('[data-emoticon]');
+  for (const element of matches) {
+    if (element.getAttribute('data-emoticon') === emoji) {
+      return getBurstPointFromElement(element);
+    }
+  }
+
+  return undefined;
+}
+
+export function getMessageFallbackOrigin(targetEventId: string): BurstPoint | undefined {
+  const message = document.querySelector(`[data-message-id="${CSS.escape(targetEventId)}"]`);
+  if (!message) return undefined;
+
+  const jumboBody = message.querySelector('[data-jumbo-emoji]');
+  if (jumboBody) {
+    return getBurstPointFromElement(jumboBody);
+  }
+
+  const body = message.querySelector('[data-message-body]');
+  if (body) {
+    return getBurstPointFromElement(body);
+  }
+
+  return getBurstPointFromElement(message);
+}
+
+export function resolveBurstOrigin(
+  targetEventId: string | undefined,
+  emojis: string[],
+  explicitOrigin?: BurstPoint
+): BurstPoint {
+  if (explicitOrigin) return explicitOrigin;
+
+  const primaryEmoji = emojis[0];
+  if (targetEventId && primaryEmoji) {
+    const emojiOrigin = findEmojiOriginInMessage(targetEventId, primaryEmoji);
+    if (emojiOrigin) return emojiOrigin;
+
+    const messageOrigin = getMessageFallbackOrigin(targetEventId);
+    if (messageOrigin) return messageOrigin;
+  }
+
+  return {
+    x: window.innerWidth / 2,
+    y: window.innerHeight * 0.35,
+  };
+}

src/app/features/room/emoji-confetti/emojiBurstEngine.ts

@@ -0,0 +1,357 @@
+import { BurstPoint } from './burstOrigin';
+import {
+  BurstMotionStyle,
+  EmojiBurstProfile,
+  getEmojiBurstProfile,
+  pickParticleEmoji,
+  sampleBurstAngle,
+} from './emojiParticleProfiles';
+
+/** Particles spawn over this window. */
+export const BURST_SPAWN_MS = 500;
+/** Global fade runs from 0.5s → 2s after burst start. */
+export const BURST_FADE_START_MS = 500;
+export const BURST_FADE_END_MS = 2000;
+export const BURST_TOTAL_MS = BURST_FADE_END_MS;
+
+export type BurstParticle = {
+  burstId: string;
+  burstStartMs: number;
+  emoji: string;
+  fontSize: number;
+  spawnX: number;
+  spawnY: number;
+  maskRadius: number;
+  x: number;
+  y: number;
+  vx: number;
+  vy: number;
+  bornAt: number;
+  rotation: number;
+  spin: number;
+  peakScale: number;
+  style: BurstMotionStyle;
+  gravity: number;
+  drag: number;
+  phase: number;
+  twinkle?: boolean;
+  wobble?: boolean;
+  orbitRadius: number;
+  orbitSpeed: number;
+  orbitAngle: number;
+  bounceDamping: number;
+  bouncesLeft: number;
+};
+
+const EMOJI_CACHE_PX = 64;
+const EMOJI_CACHE_SCALE = 2;
+const MAX_DPR = 2;
+const POP_IN_MS = 70;
+
+const emojiCanvasCache = new Map<string, HTMLCanvasElement>();
+
+function easeOutBack(t: number): number {
+  const c1 = 1.70158;
+  const c3 = c1 + 1;
+  return 1 + c3 * (t - 1) ** 3 + c1 * (t - 1) ** 2;
+}
+
+function easeOutCubic(t: number): number {
+  return 1 - (1 - t) ** 3;
+}
+
+function lerp(min: number, max: number): number {
+  return min + Math.random() * (max - min);
+}
+
+function getEmojiCanvas(emoji: string): HTMLCanvasElement {
+  const dpr = Math.min(window.devicePixelRatio || 1, MAX_DPR);
+  const cacheKey = `${emoji}:${dpr}`;
+  const cached = emojiCanvasCache.get(cacheKey);
+  if (cached) return cached;
+
+  const fontSize = Math.ceil(EMOJI_CACHE_PX * dpr);
+  const size = Math.ceil(fontSize * EMOJI_CACHE_SCALE);
+  const canvas = document.createElement('canvas');
+  canvas.width = size;
+  canvas.height = size;
+
+  const context = canvas.getContext('2d');
+  if (context) {
+    context.textAlign = 'center';
+    context.textBaseline = 'middle';
+    context.font = `${fontSize}px "Apple Color Emoji", "Segoe UI Emoji", "Noto Color Emoji", sans-serif`;
+    context.fillText(emoji, size / 2, size / 2);
+  }
+
+  emojiCanvasCache.set(cacheKey, canvas);
+  return canvas;
+}
+
+function emergeOpacity(
+  x: number,
+  y: number,
+  spawnX: number,
+  spawnY: number,
+  maskRadius: number
+): number {
+  const dist = Math.hypot(x - spawnX, y - spawnY);
+  const inner = maskRadius * 0.55;
+  const outer = maskRadius * 1.05;
+  if (dist <= inner) return 0;
+  if (dist >= outer) return 1;
+  return (dist - inner) / (outer - inner);
+}
+
+function spawnParticle(
+  particles: BurstParticle[],
+  burstId: string,
+  burstStartMs: number,
+  point: BurstPoint,
+  primaryEmoji: string,
+  profile: EmojiBurstProfile,
+  bornAt: number,
+  options?: { hero?: boolean }
+) {
+  const hero = options?.hero ?? false;
+  const angle = sampleBurstAngle(profile);
+  const speed = hero
+    ? lerp(profile.speedMin * 0.65, profile.speedMax * 0.55)
+    : lerp(profile.speedMin, profile.speedMax);
+  const launchUp = lerp(profile.launchUpMin, profile.launchUpMax);
+  const maskRadius = point.maskRadius ?? 28;
+  const jitter = hero ? 3 : 12;
+  const emoji = pickParticleEmoji(profile, primaryEmoji);
+
+  let vx = Math.cos(angle) * speed + (Math.random() - 0.5) * 60;
+  let vy = Math.sin(angle) * speed - launchUp;
+
+  if (profile.style === 'spiral') {
+    vx *= 0.35;
+    vy *= 0.35;
+  }
+
+  if (profile.style === 'sparkle') {
+    vx *= 0.75;
+    vy *= 0.75;
+  }
+
+  particles.push({
+    burstId,
+    burstStartMs,
+    emoji,
+    fontSize: hero
+      ? lerp(profile.heroFontSizeMin, profile.heroFontSizeMax)
+      : lerp(profile.fontSizeMin, profile.fontSizeMax),
+    spawnX: point.x,
+    spawnY: point.y,
+    maskRadius,
+    x: point.x + (Math.random() - 0.5) * jitter,
+    y: point.y + (Math.random() - 0.5) * jitter,
+    vx,
+    vy,
+    bornAt,
+    rotation: (Math.random() - 0.5) * 40,
+    spin: lerp(profile.spinMin, profile.spinMax),
+    peakScale: hero ? 1.1 + Math.random() * 0.2 : 0.9 + Math.random() * 0.4,
+    style: profile.style,
+    gravity: profile.gravity,
+    drag: profile.drag,
+    phase: Math.random() * Math.PI * 2,
+    twinkle: profile.twinkle,
+    wobble: profile.wobble,
+    orbitRadius: hero ? 8 : 14 + Math.random() * 28,
+    orbitSpeed: (Math.random() < 0.5 ? -1 : 1) * (1.8 + Math.random() * 2.4),
+    orbitAngle: Math.random() * Math.PI * 2,
+    bounceDamping: 0.42 + Math.random() * 0.18,
+    bouncesLeft: profile.style === 'bounce' ? 2 : 0,
+  });
+}
+
+/** Fountain from behind the emoji for 0.5s, fade 0.5s→2s. */
+export function spawnEmojiBurst(
+  particles: BurstParticle[],
+  burstId: string,
+  point: BurstPoint,
+  emoji: string,
+  now = performance.now()
+) {
+  const profile = getEmojiBurstProfile(emoji);
+  const burstStartMs = now;
+
+  spawnParticle(particles, burstId, burstStartMs, point, emoji, profile, burstStartMs, {
+    hero: true,
+  });
+
+  const particleCount = profile.particleCount;
+  for (let i = 0; i < particleCount; i += 1) {
+    const slot = i / particleCount;
+    const bornAt =
+      burstStartMs + slot * BURST_SPAWN_MS + Math.random() * (BURST_SPAWN_MS / particleCount);
+    spawnParticle(particles, burstId, burstStartMs, point, emoji, profile, bornAt);
+  }
+}
+
+function stepSpiralParticle(particle: BurstParticle, dtSeconds: number) {
+  particle.orbitRadius += 42 * dtSeconds;
+  particle.orbitAngle += particle.orbitSpeed * dtSeconds;
+  particle.x = particle.spawnX + Math.cos(particle.orbitAngle) * particle.orbitRadius;
+  particle.y =
+    particle.spawnY + Math.sin(particle.orbitAngle) * particle.orbitRadius * 0.65 + particle.vy * dtSeconds * 8;
+  particle.vy += particle.gravity * dtSeconds * 0.35;
+  particle.rotation += particle.spin * dtSeconds;
+}
+
+function stepBounceParticle(particle: BurstParticle, dtSeconds: number, dragFactor: number) {
+  particle.vy += particle.gravity * dtSeconds;
+  particle.vx *= dragFactor;
+  particle.vy *= dragFactor;
+  particle.x += particle.vx * dtSeconds;
+  particle.y += particle.vy * dtSeconds;
+  particle.rotation += particle.spin * dtSeconds;
+
+  if (particle.bouncesLeft > 0 && particle.vy > 0 && particle.y >= particle.spawnY + 6) {
+    particle.y = particle.spawnY + 6;
+    particle.vy = -Math.abs(particle.vy) * particle.bounceDamping;
+    particle.vx *= 0.82;
+    particle.bouncesLeft -= 1;
+    particle.spin += (Math.random() - 0.5) * 120;
+  }
+}
+
+function stepDefaultParticle(particle: BurstParticle, dtSeconds: number, dragFactor: number) {
+  particle.vy += particle.gravity * dtSeconds;
+  particle.vx *= dragFactor;
+  particle.vy *= dragFactor;
+  particle.x += particle.vx * dtSeconds;
+  particle.y += particle.vy * dtSeconds;
+  particle.rotation += particle.spin * dtSeconds;
+}
+
+export function stepBurstParticles(
+  particles: BurstParticle[],
+  now: number,
+  dtSeconds: number
+): void {
+  for (let i = particles.length - 1; i >= 0; i -= 1) {
+    const particle = particles[i];
+    const burstElapsed = now - particle.burstStartMs;
+
+    if (burstElapsed > BURST_TOTAL_MS) {
+      particles[i] = particles[particles.length - 1];
+      particles.pop();
+      continue;
+    }
+
+    const ageMs = now - particle.bornAt;
+    if (ageMs < 0) continue;
+
+    const dragFactor = particle.drag ** (dtSeconds * 60);
+
+    switch (particle.style) {
+      case 'spiral':
+        stepSpiralParticle(particle, dtSeconds);
+        break;
+      case 'bounce':
+        stepBounceParticle(particle, dtSeconds, dragFactor);
+        break;
+      default:
+        stepDefaultParticle(particle, dtSeconds, dragFactor);
+        break;
+    }
+
+    particle.phase += dtSeconds * (particle.twinkle ? 9 : 5);
+  }
+}
+
+type DrawState = {
+  x: number;
+  y: number;
+  scale: number;
+  opacity: number;
+  rotation: number;
+};
+
+function particleDrawState(particle: BurstParticle, now: number): DrawState | null {
+  const burstElapsed = now - particle.burstStartMs;
+  if (burstElapsed > BURST_TOTAL_MS) return null;
+
+  const ageMs = now - particle.bornAt;
+  if (ageMs < 0) return null;
+
+  let scale = particle.peakScale;
+  let opacity = emergeOpacity(
+    particle.x,
+    particle.y,
+    particle.spawnX,
+    particle.spawnY,
+    particle.maskRadius
+  );
+
+  if (opacity <= 0) return null;
+
+  if (ageMs < POP_IN_MS) {
+    const pop = easeOutBack(ageMs / POP_IN_MS);
+    scale = 0.1 + pop * particle.peakScale;
+    opacity *= pop;
+  }
+
+  if (particle.twinkle) {
+    opacity *= 0.55 + 0.45 * Math.sin(particle.phase * 1.6);
+  }
+
+  if (particle.wobble) {
+    scale *= 1 + 0.12 * Math.sin(particle.phase * 2.2);
+  }
+
+  if (particle.style === 'sparkle' && burstElapsed < BURST_FADE_START_MS) {
+    scale *= 0.85 + 0.3 * Math.sin(particle.phase * 3);
+  }
+
+  if (burstElapsed >= BURST_FADE_START_MS) {
+    const fadeT = (burstElapsed - BURST_FADE_START_MS) / (BURST_FADE_END_MS - BURST_FADE_START_MS);
+    opacity *= 1 - easeOutCubic(Math.min(1, fadeT));
+    scale *= 1 - easeOutCubic(Math.min(1, fadeT)) * 0.2;
+  }
+
+  if (opacity <= 0.02) return null;
+
+  return {
+    x: particle.x,
+    y: particle.y,
+    scale,
+    opacity,
+    rotation: particle.rotation,
+  };
+}
+
+export function drawBurstParticles(
+  context: CanvasRenderingContext2D,
+  particles: BurstParticle[],
+  dpr: number,
+  now: number
+) {
+  for (const particle of particles) {
+    const state = particleDrawState(particle, now);
+    if (!state) continue;
+
+    context.globalAlpha = state.opacity;
+
+    const emojiCanvas = getEmojiCanvas(particle.emoji);
+    const drawSize = particle.fontSize * state.scale * EMOJI_CACHE_SCALE;
+    const halfSize = drawSize / 2;
+    const radians = (state.rotation * Math.PI) / 180;
+    const cos = Math.cos(radians) * dpr;
+    const sin = Math.sin(radians) * dpr;
+
+    context.setTransform(cos, sin, -sin, cos, state.x * dpr, state.y * dpr);
+    context.drawImage(emojiCanvas, -halfSize, -halfSize, drawSize, drawSize);
+  }
+
+  context.globalAlpha = 1;
+  context.setTransform(dpr, 0, 0, dpr, 0, 0);
+}
+
+export function hasBurstParticles(particles: BurstParticle[], burstId: string): boolean {
+  return particles.some((particle) => particle.burstId === burstId);
+}

src/app/features/room/emoji-confetti/emojiParticleProfiles.ts

@@ -0,0 +1,391 @@
+export type BurstMotionStyle =
+  | 'explode'
+  | 'bounce'
+  | 'rise'
+  | 'sparkle'
+  | 'splash'
+  | 'spiral'
+  | 'punch'
+  | 'scatter'
+  | 'shower';
+
+export type EmojiBurstProfile = {
+  style: BurstMotionStyle;
+  particleCount: number;
+  gravity: number;
+  drag: number;
+  speedMin: number;
+  speedMax: number;
+  launchUpMin: number;
+  launchUpMax: number;
+  spinMin: number;
+  spinMax: number;
+  fontSizeMin: number;
+  fontSizeMax: number;
+  heroFontSizeMin: number;
+  heroFontSizeMax: number;
+  companions?: string[];
+  companionChance?: number;
+  /** Bias burst angle in radians. 0 = right, -π/2 = up. */
+  angleBias?: number;
+  /** Limit spawn to a cone (radians). Omit for full 360°. */
+  angleSpread?: number;
+  twinkle?: boolean;
+  wobble?: boolean;
+};
+
+const DEFAULT_PROFILE: EmojiBurstProfile = {
+  style: 'explode',
+  particleCount: 36,
+  gravity: 400,
+  drag: 0.935,
+  speedMin: 240,
+  speedMax: 560,
+  launchUpMin: 40,
+  launchUpMax: 130,
+  spinMin: -180,
+  spinMax: 180,
+  fontSizeMin: 14,
+  fontSizeMax: 26,
+  heroFontSizeMin: 26,
+  heroFontSizeMax: 34,
+};
+
+const PROFILE_OVERRIDES: Record<string, Partial<EmojiBurstProfile>> = {
+  '😆': {
+    style: 'bounce',
+    particleCount: 28,
+    gravity: 520,
+    speedMin: 180,
+    speedMax: 360,
+    launchUpMin: 120,
+    launchUpMax: 220,
+    spinMin: -240,
+    spinMax: 240,
+    wobble: true,
+  },
+  '😂': {
+    style: 'bounce',
+    particleCount: 30,
+    gravity: 500,
+    speedMin: 160,
+    speedMax: 340,
+    launchUpMin: 110,
+    launchUpMax: 210,
+    spinMin: -220,
+    spinMax: 220,
+    wobble: true,
+  },
+  '🤣': {
+    style: 'bounce',
+    particleCount: 32,
+    gravity: 480,
+    speedMin: 200,
+    speedMax: 380,
+    launchUpMin: 130,
+    launchUpMax: 240,
+    wobble: true,
+  },
+  '🔥': {
+    style: 'rise',
+    particleCount: 24,
+    gravity: -120,
+    drag: 0.96,
+    speedMin: 80,
+    speedMax: 200,
+    launchUpMin: 60,
+    launchUpMax: 160,
+    spinMin: -90,
+    spinMax: 90,
+    fontSizeMin: 16,
+    fontSizeMax: 28,
+    twinkle: true,
+    wobble: true,
+    companions: ['✨'],
+    companionChance: 0.35,
+  },
+  '❤️': {
+    style: 'rise',
+    particleCount: 22,
+    gravity: -80,
+    drag: 0.97,
+    speedMin: 60,
+    speedMax: 150,
+    launchUpMin: 40,
+    launchUpMax: 110,
+    spinMin: -40,
+    spinMax: 40,
+    fontSizeMin: 14,
+    fontSizeMax: 24,
+    companions: ['💕', '💖'],
+    companionChance: 0.4,
+  },
+  '💕': {
+    style: 'rise',
+    particleCount: 20,
+    gravity: -70,
+    drag: 0.97,
+    speedMin: 50,
+    speedMax: 140,
+    launchUpMin: 35,
+    launchUpMax: 100,
+    spinMin: -35,
+    spinMax: 35,
+  },
+  '💖': {
+    style: 'rise',
+    particleCount: 20,
+    gravity: -90,
+    drag: 0.968,
+    speedMin: 55,
+    speedMax: 150,
+    launchUpMin: 45,
+    launchUpMax: 115,
+    twinkle: true,
+  },
+  '⭐': {
+    style: 'sparkle',
+    particleCount: 26,
+    gravity: 40,
+    drag: 0.94,
+    speedMin: 100,
+    speedMax: 260,
+    launchUpMin: 20,
+    launchUpMax: 80,
+    spinMin: -120,
+    spinMax: 120,
+    twinkle: true,
+    companions: ['✨'],
+    companionChance: 0.5,
+  },
+  '✨': {
+    style: 'sparkle',
+    particleCount: 30,
+    gravity: 30,
+    drag: 0.945,
+    speedMin: 90,
+    speedMax: 240,
+    launchUpMin: 15,
+    launchUpMax: 70,
+    spinMin: -200,
+    spinMax: 200,
+    twinkle: true,
+  },
+  '💀': {
+    style: 'scatter',
+    particleCount: 20,
+    gravity: 620,
+    drag: 0.92,
+    speedMin: 200,
+    speedMax: 420,
+    launchUpMin: 20,
+    launchUpMax: 90,
+    spinMin: -360,
+    spinMax: 360,
+    fontSizeMin: 16,
+    fontSizeMax: 28,
+  },
+  '🎉': {
+    style: 'shower',
+    particleCount: 40,
+    gravity: 280,
+    drag: 0.93,
+    speedMin: 200,
+    speedMax: 480,
+    launchUpMin: 80,
+    launchUpMax: 200,
+    companions: ['🎊', '✨', '🎈'],
+    companionChance: 0.45,
+  },
+  '🎊': {
+    style: 'shower',
+    particleCount: 38,
+    gravity: 260,
+    drag: 0.932,
+    speedMin: 190,
+    speedMax: 460,
+    launchUpMin: 70,
+    launchUpMax: 190,
+    companions: ['🎉', '✨'],
+    companionChance: 0.4,
+  },
+  '👏': {
+    style: 'punch',
+    particleCount: 18,
+    gravity: 320,
+    speedMin: 220,
+    speedMax: 400,
+    launchUpMin: 30,
+    launchUpMax: 100,
+    angleBias: -Math.PI / 2,
+    angleSpread: Math.PI * 0.85,
+    spinMin: -100,
+    spinMax: 100,
+  },
+  '👍': {
+    style: 'punch',
+    particleCount: 14,
+    gravity: 380,
+    speedMin: 260,
+    speedMax: 440,
+    launchUpMin: 100,
+    launchUpMax: 200,
+    angleBias: -Math.PI / 2,
+    angleSpread: Math.PI * 0.55,
+    spinMin: -60,
+    spinMax: 60,
+  },
+  '💯': {
+    style: 'punch',
+    particleCount: 16,
+    gravity: 300,
+    speedMin: 200,
+    speedMax: 380,
+    launchUpMin: 140,
+    launchUpMax: 240,
+    angleBias: -Math.PI / 2,
+    angleSpread: Math.PI * 0.45,
+    fontSizeMin: 16,
+    fontSizeMax: 30,
+    wobble: true,
+  },
+  '💦': {
+    style: 'splash',
+    particleCount: 32,
+    gravity: 540,
+    drag: 0.925,
+    speedMin: 280,
+    speedMax: 520,
+    launchUpMin: 160,
+    launchUpMax: 300,
+    spinMin: -140,
+    spinMax: 140,
+    angleBias: -Math.PI / 2,
+    angleSpread: Math.PI * 1.1,
+  },
+  '🌊': {
+    style: 'splash',
+    particleCount: 28,
+    gravity: 420,
+    drag: 0.93,
+    speedMin: 220,
+    speedMax: 460,
+    launchUpMin: 100,
+    launchUpMax: 220,
+    angleBias: -Math.PI / 2,
+    angleSpread: Math.PI,
+    companions: ['💧'],
+    companionChance: 0.3,
+  },
+  '⚡': {
+    style: 'scatter',
+    particleCount: 14,
+    gravity: 180,
+    drag: 0.88,
+    speedMin: 380,
+    speedMax: 680,
+    launchUpMin: 10,
+    launchUpMax: 60,
+    spinMin: -30,
+    spinMax: 30,
+    fontSizeMin: 18,
+    fontSizeMax: 32,
+    angleSpread: Math.PI * 1.2,
+  },
+  '🌀': {
+    style: 'spiral',
+    particleCount: 24,
+    gravity: 60,
+    drag: 0.96,
+    speedMin: 120,
+    speedMax: 260,
+    launchUpMin: 0,
+    launchUpMax: 40,
+    spinMin: -420,
+    spinMax: 420,
+  },
+  '🤯': {
+    style: 'explode',
+    particleCount: 34,
+    gravity: 360,
+    speedMin: 280,
+    speedMax: 580,
+    launchUpMin: 60,
+    launchUpMax: 160,
+    companions: ['💥', '✨', '⭐'],
+    companionChance: 0.5,
+  },
+  '😭': {
+    style: 'splash',
+    particleCount: 26,
+    gravity: 480,
+    drag: 0.94,
+    speedMin: 140,
+    speedMax: 300,
+    launchUpMin: 40,
+    launchUpMax: 120,
+    angleBias: Math.PI / 2,
+    angleSpread: Math.PI * 0.7,
+    companions: ['💧'],
+    companionChance: 0.55,
+  },
+  '🥳': {
+    style: 'shower',
+    particleCount: 36,
+    gravity: 250,
+    speedMin: 180,
+    speedMax: 440,
+    launchUpMin: 90,
+    launchUpMax: 210,
+    companions: ['🎉', '🎊', '🎈'],
+    companionChance: 0.4,
+  },
+  '🐱': {
+    style: 'bounce',
+    particleCount: 20,
+    gravity: 440,
+    speedMin: 150,
+    speedMax: 320,
+    launchUpMin: 90,
+    launchUpMax: 180,
+    spinMin: -160,
+    spinMax: 160,
+  },
+  '🐶': {
+    style: 'bounce',
+    particleCount: 20,
+    gravity: 460,
+    speedMin: 160,
+    speedMax: 330,
+    launchUpMin: 85,
+    launchUpMax: 175,
+    wobble: true,
+  },
+};
+
+export function getEmojiBurstProfile(emoji: string): EmojiBurstProfile {
+  const override = PROFILE_OVERRIDES[emoji];
+  if (!override) return DEFAULT_PROFILE;
+  return { ...DEFAULT_PROFILE, ...override };
+}
+
+export function pickParticleEmoji(profile: EmojiBurstProfile, primaryEmoji: string): string {
+  if (!profile.companions?.length || !profile.companionChance) {
+    return primaryEmoji;
+  }
+  if (Math.random() >= profile.companionChance) {
+    return primaryEmoji;
+  }
+  const companion = profile.companions[Math.floor(Math.random() * profile.companions.length)];
+  return companion ?? primaryEmoji;
+}
+
+export function sampleBurstAngle(profile: EmojiBurstProfile): number {
+  if (profile.angleSpread === undefined) {
+    return Math.random() * Math.PI * 2;
+  }
+
+  const bias = profile.angleBias ?? -Math.PI / 2;
+  const halfSpread = profile.angleSpread / 2;
+  return bias + (Math.random() - 0.5) * profile.angleSpread * (0.6 + Math.random() * 0.4);
+}

src/app/features/room/emoji-confetti/findJumboMount.ts

@@ -0,0 +1,11 @@
+export function findJumboEmojiElement(targetEventId: string): HTMLElement | null {
+  const message = document.querySelector(`[data-message-id="${CSS.escape(targetEventId)}"]`);
+  if (!message) return null;
+
+  const jumbo = message.querySelector('[data-jumbo-emoji]');
+  return jumbo instanceof HTMLElement ? jumbo : null;
+}
+
+export function getLocalBurstCanvasSize(maskRadius: number): number {
+  return Math.max(300, Math.round(maskRadius * 6.5));
+}

src/app/features/room/emoji-confetti/jumboEmojiInteraction.ts

@@ -0,0 +1,34 @@
+import { KeyboardEvent, MouseEvent } from 'react';
+
+export type JumboEmojiClickHandler = (body: string, event: MouseEvent<HTMLElement> | KeyboardEvent<HTMLElement>) => void;
+
+export function getJumboEmojiInteractionProps({
+  body,
+  isJumboEmoji,
+  onJumboEmojiClick,
+}: {
+  body: string;
+  isJumboEmoji: boolean;
+  onJumboEmojiClick?: JumboEmojiClickHandler;
+}) {
+  if (!isJumboEmoji || !onJumboEmojiClick) {
+    return {};
+  }
+
+  const activate = (event: MouseEvent<HTMLElement> | KeyboardEvent<HTMLElement>) => {
+    if ('key' in event) {
+      if (event.key !== 'Enter' && event.key !== ' ') return;
+      event.preventDefault();
+    }
+    event.stopPropagation();
+    onJumboEmojiClick(body, event);
+  };
+
+  return {
+    role: 'button' as const,
+    tabIndex: 0,
+    title: 'Throw emoji confetti',
+    onClick: activate,
+    onKeyDown: activate,
+  };
+}

src/app/features/room/emoji-confetti/resolveClickedEmoji.ts

@@ -0,0 +1,54 @@
+import { KeyboardEvent, MouseEvent } from 'react';
+import { extractJumboEmojis } from './sendEmojiConfetti';
+import { BurstPoint, getBurstPointFromElement } from './burstOrigin';
+
+export function resolveClickedEmoji(
+  event: MouseEvent<HTMLElement> | KeyboardEvent<HTMLElement>,
+  fallbackBody: string
+): { emoji: string; origin: BurstPoint } | null {
+  const currentTarget = event.currentTarget as HTMLElement;
+  const target = event.target as HTMLElement;
+  const emoticonEl = target.closest('[data-emoticon]') ?? currentTarget.querySelector('[data-emoticon]');
+  if (emoticonEl instanceof HTMLElement) {
+    const emoji = emoticonEl.getAttribute('data-emoticon');
+    if (emoji) {
+      return {
+        emoji,
+        origin: getBurstPointFromElement(emoticonEl),
+      };
+    }
+  }
+
+  if (!currentTarget.closest('[data-jumbo-emoji]') && !currentTarget.hasAttribute('data-jumbo-emoji')) {
+    return null;
+  }
+
+  const emojis = extractJumboEmojis(fallbackBody);
+  if (emojis.length === 0) return null;
+
+  if ('clientX' in event) {
+    return {
+      emoji: emojis[0],
+      origin: {
+        x: event.clientX,
+        y: event.clientY,
+      },
+    };
+  }
+
+  const firstEmoticon = currentTarget.querySelector('[data-emoticon]');
+  if (firstEmoticon instanceof HTMLElement) {
+    const emoji = firstEmoticon.getAttribute('data-emoticon');
+    if (emoji) {
+      return {
+        emoji,
+        origin: getBurstPointFromElement(firstEmoticon),
+      };
+    }
+  }
+
+  return {
+    emoji: emojis[0],
+    origin: getBurstPointFromElement(currentTarget),
+  };
+}

src/app/features/room/emoji-confetti/sendEmojiConfetti.ts

@@ -0,0 +1,42 @@
+import { MatrixClient } from 'matrix-js-sdk';
+import { EMOJI_REG_G, JUMBO_EMOJI_REG } from '../../../utils/regex';
+import { trimReplyFromBody } from '../../../utils/room';
+import { emojis } from '../../../plugins/emoji';
+import { EMOJI_CONFETTI_EVENT_TYPE, EmojiConfettiContent } from './types';
+
+const SHORTCODE_PATTERN = /:([^\s:]+):/g;
+
+export function extractJumboEmojis(body: string): string[] {
+  const trimmedBody = trimReplyFromBody(body).trim();
+  if (!JUMBO_EMOJI_REG.test(trimmedBody)) return [];
+
+  const found: string[] = [];
+
+  for (const match of trimmedBody.matchAll(EMOJI_REG_G)) {
+    const emoji = match[1];
+    if (emoji) found.push(emoji);
+  }
+
+  for (const match of trimmedBody.matchAll(SHORTCODE_PATTERN)) {
+    const shortcode = match[1];
+    const resolved = emojis.find((emoji) => emoji.shortcode === shortcode);
+    if (resolved) found.push(resolved.unicode);
+  }
+
+  return found.length > 0 ? found : ['🎉'];
+}
+
+export function sendEmojiConfettiEvent(
+  mx: MatrixClient,
+  roomId: string,
+  targetEventId: string,
+  emojis: string[]
+) {
+  const content: EmojiConfettiContent = {
+    emojis,
+    msgtype: EMOJI_CONFETTI_EVENT_TYPE,
+    target_event_id: targetEventId,
+  };
+
+  return mx.sendEvent(roomId, EMOJI_CONFETTI_EVENT_TYPE as never, content);
+}

src/app/features/room/emoji-confetti/types.ts

@@ -0,0 +1,16 @@
+import type { BurstPoint } from './burstOrigin';
+
+export const EMOJI_CONFETTI_EVENT_TYPE = 'app.relay.emoji_confetti';
+
+export type EmojiConfettiContent = {
+  emojis?: string[];
+  msgtype?: string;
+  target_event_id?: string;
+};
+
+export type EmojiConfettiBurst = {
+  id: string;
+  targetEventId: string;
+  emojis: string[];
+  origin: BurstPoint;
+};

src/app/features/room/emoji-confetti/useEmojiConfetti.ts

@@ -0,0 +1,137 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { MatrixEvent, Room, RoomEvent } from 'matrix-js-sdk';
+import { BurstPoint, resolveBurstOrigin } from './burstOrigin';
+import {
+  EMOJI_CONFETTI_EVENT_TYPE,
+  EmojiConfettiBurst,
+  EmojiConfettiContent,
+} from './types';
+
+function scheduleBurstFromValues(
+  burstId: string,
+  emojis: string[],
+  targetEventId: string | undefined,
+  onBurst: (burst: EmojiConfettiBurst) => void,
+  attempt = 0,
+  explicitOrigin?: BurstPoint
+) {
+  const targetElement =
+    targetEventId &&
+    document.querySelector(`[data-message-id="${CSS.escape(targetEventId)}"]`);
+
+  if (targetEventId && !targetElement && attempt < 8) {
+    window.setTimeout(
+      () =>
+        scheduleBurstFromValues(
+          burstId,
+          emojis,
+          targetEventId,
+          onBurst,
+          attempt + 1,
+          explicitOrigin
+        ),
+      50
+    );
+    return;
+  }
+
+  onBurst({
+    id: burstId,
+    targetEventId: targetEventId ?? '',
+    emojis: emojis.length > 0 ? emojis : ['🎉'],
+    origin: resolveBurstOrigin(targetEventId, emojis, explicitOrigin),
+  });
+}
+
+function scheduleBurst(
+  event: MatrixEvent,
+  onBurst: (burst: EmojiConfettiBurst) => void,
+  attempt = 0
+) {
+  const eventId = event.getId();
+  if (!eventId) return;
+
+  const { emojis, targetEventId } = parseEmojiConfettiContent(event.getContent());
+  scheduleBurstFromValues(eventId, emojis, targetEventId, onBurst, attempt);
+}
+
+function parseEmojiConfettiContent(content: unknown): { emojis: string[]; targetEventId?: string } {
+  const confettiContent = content as EmojiConfettiContent;
+  const emojis = Array.isArray(confettiContent.emojis)
+    ? confettiContent.emojis.filter((emoji): emoji is string => typeof emoji === 'string' && emoji.length > 0)
+    : [];
+
+  return {
+    emojis: emojis.length > 0 ? emojis : ['🎉'],
+    targetEventId:
+      typeof confettiContent.target_event_id === 'string'
+        ? confettiContent.target_event_id
+        : undefined,
+  };
+}
+
+export function useEmojiConfetti(room: Room) {
+  const [bursts, setBursts] = useState<EmojiConfettiBurst[]>([]);
+  const seenEventIdsRef = useRef(new Set<string>());
+  const ownEventIdsRef = useRef(new Set<string>());
+
+  const addBurst = useCallback((burst: EmojiConfettiBurst) => {
+    setBursts((current) => [...current, burst]);
+  }, []);
+
+  const registerOwnEventId = useCallback((eventId: string) => {
+    ownEventIdsRef.current.add(eventId);
+  }, []);
+
+  const queueBurst = useCallback((event: MatrixEvent) => {
+    const eventId = event.getId();
+    if (!eventId || seenEventIdsRef.current.has(eventId)) return;
+
+    seenEventIdsRef.current.add(eventId);
+
+    if (ownEventIdsRef.current.has(eventId)) {
+      ownEventIdsRef.current.delete(eventId);
+      return;
+    }
+
+    scheduleBurst(event, addBurst);
+  }, [addBurst]);
+
+  const triggerLocalBurst = useCallback(
+    (targetEventId: string, emojis: string[], origin?: BurstPoint) => {
+      const burstId = `local-${targetEventId}-${Date.now()}`;
+      scheduleBurstFromValues(burstId, emojis, targetEventId, addBurst, 0, origin);
+    },
+    [addBurst]
+  );
+
+  useEffect(() => {
+    const handleTimeline: (
+      event: MatrixEvent,
+      eventRoom: Room | undefined,
+      toStartOfTimeline?: boolean,
+      removed?: boolean
+    ) => void = (event, eventRoom, toStartOfTimeline, removed) => {
+      if (removed || toStartOfTimeline || eventRoom?.roomId !== room.roomId) return;
+      if (event.getType() !== EMOJI_CONFETTI_EVENT_TYPE) return;
+
+      queueBurst(event);
+    };
+
+    room.on(RoomEvent.Timeline, handleTimeline);
+    return () => {
+      room.off(RoomEvent.Timeline, handleTimeline);
+    };
+  }, [queueBurst, room]);
+
+  const removeBurst = useCallback((burstId: string) => {
+    setBursts((current) => current.filter((burst) => burst.id !== burstId));
+  }, []);
+
+  return {
+    bursts,
+    removeBurst,
+    triggerLocalBurst,
+    registerOwnEventId,
+  };
+}

src/app/features/room/emoji-confetti/useJumboEmojiConfetti.ts

@@ -0,0 +1,37 @@
+import { KeyboardEvent, MouseEvent, useCallback } from 'react';
+import { Room } from 'matrix-js-sdk';
+import { useMatrixClient } from '../../../hooks/useMatrixClient';
+import { resolveClickedEmoji } from './resolveClickedEmoji';
+import { sendEmojiConfettiEvent } from './sendEmojiConfetti';
+import { useEmojiConfetti } from './useEmojiConfetti';
+
+export function useJumboEmojiConfetti(room: Room) {
+  const mx = useMatrixClient();
+  const { bursts, removeBurst, triggerLocalBurst, registerOwnEventId } = useEmojiConfetti(room);
+
+  const handleJumboEmojiClick = useCallback(
+    (targetEventId: string, body: string, event: MouseEvent<HTMLElement> | KeyboardEvent<HTMLElement>) => {
+      const clicked = resolveClickedEmoji(event, body);
+      if (!clicked) return;
+
+      const emojis = [clicked.emoji];
+
+      triggerLocalBurst(targetEventId, emojis, clicked.origin);
+      sendEmojiConfettiEvent(mx, room.roomId, targetEventId, emojis)
+        .then((response) => {
+          const eventId = response?.event_id;
+          if (eventId) registerOwnEventId(eventId);
+        })
+        .catch((error) => {
+          console.error('[emoji-confetti] Failed to send confetti event:', error);
+        });
+    },
+    [mx, registerOwnEventId, room.roomId, triggerLocalBurst]
+  );
+
+  return {
+    bursts,
+    removeBurst,
+    handleJumboEmojiClick,
+  };
+}