import { getState, setPage } from "../src/state/hash.js";

/**
 * Delegate clicks on [data-page] within pagination containers to update the URL hash.
 * Also reflects active page state using aria-current='page' and 'is-active' class.
 */
function bindContainer(container) {
  if (!container || container.dataset.pageHashInitialized === "1") {
    return;
  }
  container.dataset.pageHashInitialized = "1";

  container.addEventListener("click", (e) => {
    const el = /** @type {HTMLElement|null} */ (
      e.target instanceof HTMLElement ? e.target.closest("[data-page]") : null
    );
    if (!el) {
      return;
    }
    const v = el.getAttribute("data-page");
    if (!v) {
      return;
    }
    const n = Number(v);
    if (!Number.isFinite(n) || n < 1) {
      return;
    }
    e.preventDefault();
    setPage(n);
  });
}

function reflectActive() {
  const { page } = getState();
  const current = Number.isFinite(page) && page > 0 ? page : null;
  const containers = [
    document.getElementById("pagination-top"),
    document.getElementById("pagination-bottom"),
  ].filter(Boolean);

  for (const c of containers) {
    const items = c.querySelectorAll("[data-page]");
    items.forEach((el) => {
      const n = Number(el.getAttribute("data-page"));
      const isActive = current != null && n === current;
      if (isActive) {
        el.classList.add("is-active");
        el.setAttribute("aria-current", "page");
      } else {
        el.classList.remove("is-active");
        el.removeAttribute("aria-current");
      }
    });
  }
}

export function initPageHash() {
  const top = document.getElementById("pagination-top");
  const bottom = document.getElementById("pagination-bottom");
  bindContainer(top);
  bindContainer(bottom);
  reflectActive();

  window.addEventListener("hashchange", reflectActive);
  document.addEventListener("qedit:hash:updated", reflectActive);
}

// Auto-init on DOM ready
if (document.readyState === "loading") {
  document.addEventListener("DOMContentLoaded", () => initPageHash(), { once: true });
} else {
  initPageHash();
}