let initialized = false;
let resolveResultsFn = null;
let onSelectResultFn = null;
let currentResults = [];
let activeIndex = -1;
let searchTimerId = null;
let isOpen = false;

function escapeHtml(value) {
  return String(value)
    .replaceAll("&", "&")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#39;");
}

function getElements() {
  const isMobile = document.body.classList.contains("layout-mode-mobile");
  return {
    modal: document.getElementById("search-modal"),
    backdrop: document.getElementById("search-backdrop"),
    input: document.getElementById(
      isMobile ? "mobile-earth-search-input" : "earth-search-input",
    ),
    clear: document.getElementById(
      isMobile ? "mobile-earth-search-clear" : "earth-search-clear",
    ),
    meta: document.getElementById(
      isMobile ? "mobile-earth-search-meta" : "earth-search-meta",
    ),
    results: document.getElementById(
      isMobile ? "mobile-earth-search-results" : "earth-search-results",
    ),
    empty: document.getElementById(
      isMobile ? "mobile-earth-search-empty" : "earth-search-empty",
    ),
    close: document.getElementById("search-close"),
  };
}

function setMeta(text) {
  const { meta } = getElements();
  if (meta) meta.textContent = text;
}

function updateEmptyState(query) {
  const { empty } = getElements();
  if (!empty) return;
  if (!query) {
    empty.textContent = "支持搜索海缆、登陆点、卫星、算力中心、BGP 事件与观测站。";
    return;
  }
  empty.textContent = "未找到匹配对象，可尝试名称、地点、NORAD、ASN、前缀等关键词。";
}

function renderResults(query) {
  const { results, empty } = getElements();
  if (!results || !empty) return;

  results.innerHTML = "";
  const hasResults = currentResults.length > 0;
  empty.hidden = hasResults;
  updateEmptyState(query);

  if (!hasResults) return;

  currentResults.forEach((result, index) => {
    const button = document.createElement("button");
    button.type = "button";
    button.className = "earth-search-result";
    button.setAttribute("role", "option");
    button.dataset.index = String(index);
    button.innerHTML = `
      <span class="earth-search-result-icon" aria-hidden="true">
        <span class="material-symbols-rounded">${escapeHtml(result.icon || "search")}</span>
      </span>
      <span class="earth-search-result-copy">
        <span class="earth-search-result-title">${escapeHtml(result.title)}</span>
        <span class="earth-search-result-subtitle">${escapeHtml(result.subtitle || "")}</span>
      </span>
      <span class="earth-search-result-type">${escapeHtml(result.typeLabel || "")}</span>
    `;
    button.addEventListener("click", async () => {
      await selectResult(index);
    });
    results.appendChild(button);
  });

  syncActiveResult();
}

function syncActiveResult() {
  const { results } = getElements();
  if (!results) return;
  Array.from(results.children).forEach((node, index) => {
    node.classList.toggle("is-active", index === activeIndex);
  });
}

function moveActiveResult(delta) {
  if (currentResults.length === 0) return;
  activeIndex =
    ((activeIndex < 0 ? 0 : activeIndex) + delta + currentResults.length) %
    currentResults.length;
  syncActiveResult();
  const { results } = getElements();
  const activeNode = results?.children?.[activeIndex];
  activeNode?.scrollIntoView({ block: "nearest" });
}

async function selectResult(index) {
  const result = currentResults[index];
  if (!result || typeof onSelectResultFn !== "function") return;
  closeSearchPanel();
  try {
    await onSelectResultFn(result);
  } catch (error) {
    console.error("Search selection failed:", error);
  }
}

async function runSearch() {
  const { input, clear } = getElements();
  if (!input) return;

  const query = input.value.trim();
  if (clear) {
    clear.hidden = query.length === 0;
  }

  if (!query) {
    currentResults = [];
    activeIndex = -1;
    setMeta("输入关键词以搜索当前地球对象");
    renderResults("");
    return;
  }

  setMeta("正在检索…");

  try {
    const nextResults = await resolveResultsFn?.(query);
    currentResults = Array.isArray(nextResults) ? nextResults : [];
    activeIndex = currentResults.length > 0 ? 0 : -1;
    setMeta(`找到 ${currentResults.length} 个结果`);
    renderResults(query);
  } catch (error) {
    console.error("Search failed:", error);
    currentResults = [];
    activeIndex = -1;
    setMeta("搜索失败");
    renderResults(query);
  }
}

function scheduleSearch() {
  if (searchTimerId) {
    clearTimeout(searchTimerId);
  }
  searchTimerId = window.setTimeout(() => {
    searchTimerId = null;
    runSearch();
  }, 120);
}

function handleKeydown(event) {
  const { modal, input } = getElements();
  const isMobile = document.body.classList.contains("layout-mode-mobile");
  if (!isMobile && !modal?.classList.contains("is-open")) return;

  if (event.key === "Escape") {
    event.preventDefault();
    closeSearchPanel();
    return;
  }

  if (event.target !== input) return;

  if (event.key === "ArrowDown") {
    event.preventDefault();
    moveActiveResult(1);
  } else if (event.key === "ArrowUp") {
    event.preventDefault();
    moveActiveResult(-1);
  } else if (event.key === "Enter" && activeIndex >= 0) {
    event.preventDefault();
    selectResult(activeIndex).catch((error) => {
      console.warn("Selecting search result failed:", error);
    });
  }
}

export function initSearchPanel({ resolveResults, onSelectResult } = {}) {
  resolveResultsFn = resolveResults;
  onSelectResultFn = onSelectResult;

  if (initialized) return;
  initialized = true;

  const inputs = ["earth-search-input", "mobile-earth-search-input"]
    .map((id) => document.getElementById(id))
    .filter((node) => node instanceof HTMLInputElement);
  const clears = ["earth-search-clear", "mobile-earth-search-clear"]
    .map((id) => document.getElementById(id))
    .filter((node) => node instanceof HTMLButtonElement);
  const close = document.getElementById("search-close");
  const backdrop = document.getElementById("search-backdrop");

  inputs.forEach((input) => {
    input.addEventListener("input", scheduleSearch);
    input.addEventListener("keydown", handleKeydown);
  });
  clears.forEach((clear) => {
    clear.addEventListener("click", () => {
      const { input } = getElements();
      if (!input) return;
      input.value = "";
      input.focus();
      runSearch().catch((error) => {
        console.warn("Clearing search failed:", error);
      });
    });
  });
  close?.addEventListener("click", () => {
    closeSearchPanel();
  });
  backdrop?.addEventListener("click", () => {
    closeSearchPanel();
  });
  document.addEventListener("keydown", handleKeydown);
}

export function openSearchPanel() {
  const { modal, input } = getElements();
  if (!modal && !document.body.classList.contains("layout-mode-mobile")) return;
  if (isOpen) return;
  isOpen = true;
  document.body.classList.add("earth-search-open");
  modal?.classList.add("is-open");
  modal?.setAttribute("aria-hidden", "false");
  window.dispatchEvent(
    new CustomEvent("earth:search-open-change", { detail: { open: true } }),
  );
  window.setTimeout(() => {
    input?.focus();
    input?.select();
    runSearch().catch((error) => {
      console.warn("Running search failed:", error);
    });
  }, 16);
}

export function focusSearchInput({ select = false } = {}) {
  const { input } = getElements();
  if (!(input instanceof HTMLInputElement)) return;
  input.focus();
  if (select) {
    input.select();
  }
}

export function refreshSearchResults() {
  return runSearch();
}

export function closeSearchPanel() {
  const { modal } = getElements();
  if (!modal && !document.body.classList.contains("layout-mode-mobile")) return;
  if (!isOpen) return;
  isOpen = false;
  document.body.classList.remove("earth-search-open");
  modal?.classList.remove("is-open");
  modal?.setAttribute("aria-hidden", "true");
  window.dispatchEvent(
    new CustomEvent("earth:search-open-change", { detail: { open: false } }),
  );
}

export function isSearchPanelOpen() {
  return isOpen;
}