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

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,
  };
}