const dedupeWithin = (root: ParentNode): void => {
  const seen = new Set<string>();
  const elements = root.querySelectorAll<HTMLElement>(":scope > [data-id]");

  elements.forEach((item) => {
    const id = item.dataset.id;
    if (!id) {
      return;
    }

    if (seen.has(id)) {
      item.remove();
      return;
    }

    seen.add(id);
  });
};

const dedupe = (): void => {
  const containers = new Set<ParentNode>();
  const elements = document.querySelectorAll<HTMLElement>("[data-id]");

  elements.forEach((item) => {
    if (item.parentElement) {
      containers.add(item.parentElement);
    }
  });

  containers.forEach((container) => {
    dedupeWithin(container);
  });
};

const dedupeSwapTarget = (target: EventTarget | null): void => {
  if (!(target instanceof HTMLElement)) {
    return;
  }

  if (target.matches("[data-id]")) {
    const parent = target.parentElement;
    if (parent) {
      dedupeWithin(parent);
    }
    return;
  }

  const containers = new Set<ParentNode>();
  const elements = target.querySelectorAll<HTMLElement>("[data-id]");
  elements.forEach((item) => {
    if (item.parentElement) {
      containers.add(item.parentElement);
    }
  });

  containers.forEach((container) => {
    dedupeWithin(container);
  });
};

if (document.readyState === "loading") {
  document.addEventListener("DOMContentLoaded", dedupe);
} else {
  dedupe();
}

window.addEventListener("load", dedupe);

document.addEventListener("htmx:afterSwap", (event: Event): void => {
  const customEvent = event as CustomEvent<{ target?: EventTarget | null }>;
  dedupeSwapTarget(customEvent.detail?.target ?? event.target);
});