let state;
let groups = [];
let selectedIndex = -1;
let loadedIndex = -1; // which document the PDF viewer currently shows/loads
let pdfViewer = null;
let loadRequestId = 0;

const people = document.querySelector("#people");
const fields = document.querySelector("#fields");
const viewer = document.querySelector(".viewer");
const pdfContainer = document.querySelector("#pdfViewer");
const pdfMessage = document.querySelector("#pdfMessage");
const status = document.querySelector("#status");
const search = document.querySelector("#search");
const errorBanner = document.querySelector("#errorBanner");

const fieldDefs = [
  ["Name / Company", "name_company"],
  ["Prospective Buyer", "prospective_buyer"],
  ["Company", "company"],
  null,
  ["Phone", "phone"],
  ["Cell", "cell"],
  ["Email", "email"],
  null,
  ["Address", "address"],
  ["State", "state"],
  null,
  ["Businesses from Notes", "notes_business_raw"],
  ["Types of Businesses", "types_of_business_raw"],
  ["Background Experience", "background_experience"],
  null,
  ["How Did You Hear", "how_did_you_hear"],
  ["Interested in Updates", "interested_in_updates"],
  ["Down Payment", { key: "down_payment_raw", fallback: "down_payment" }],
  ["Total Purchase Price", "total_purchase_price"],
  ["Date of Introduction", "date_of_introduction"],
  null,
  ["Notes Page", "_notes_page"],
  ["Buyer Info Page", "_info_page"],
  ["CA Page", "_ca_page"],
];

const esc = (value) =>
  String(value ?? "").replace(/[&<>"']/g, (char) =>
    ({
      "&": "&amp;",
      "<": "&lt;",
      ">": "&gt;",
      '"': "&quot;",
      "'": "&#39;",
    })[char]);

function buildGroups(docs) {
  const map = new Map();
  docs.forEach((doc, index) => {
    const key = doc.name_from_filename;
    const group = map.get(key) || {
      key,
      displayName: doc.prospective_buyer || key,
      docs: [],
      text: "",
    };
    group.docs.push({ ...doc, index });
    group.text += " " + [
      key,
      doc.prospective_buyer,
      doc.types_of_business_raw,
      doc.notes_business_raw,
      doc.address,
    ].filter(Boolean).join(" ");
    map.set(key, group);
  });
  return [...map.values()].sort((a, b) => a.key.localeCompare(b.key));
}

function visibleGroups() {
  const terms = search.value.toLowerCase().trim().split(/\s+/).filter(Boolean);
  return groups.filter((group) =>
    terms.every((term) => group.text.toLowerCase().includes(term))
  );
}

function updateStatus(shownCount = visibleGroups().length) {
  const source = state.dataSource === "sample" ? "sample data" : "JSON file";
  status.textContent =
    `${shownCount} people / ${state.documents.length} documents \u00b7 ${source}`;
  status.className = "";
}

function showError(message) {
  errorBanner.textContent = message;
  errorBanner.hidden = !message;
}

function renderList() {
  const shown = visibleGroups();
  people.innerHTML = shown.map((group) => `
    <div class="person">
      <div class="person-title">${
    esc(group.displayName)
  } <span class="muted">(${group.docs.length})</span></div>
      ${
    group.docs.map((doc) => `
        <button class="doc ${
      doc.index === selectedIndex ? "active" : ""
    }" data-index="${doc.index}">
          ${esc(doc.file_name)}
        </button>`).join("")
  }
    </div>
  `).join("");
  updateStatus(shown.length);
}

async function loadPdf(index) {
  const doc = state.documents[index];
  if (!doc) return;

  // Deduplicate: don't reload the document that is already shown.
  // NOTE: must compare against loadedIndex, NOT selectedIndex --
  // select() updates selectedIndex before calling loadPdf(), so a
  // selectedIndex comparison is always true and blocks every reload.
  if (index === loadedIndex && pdfViewer) {
    return;
  }
  loadedIndex = index;

  const previousZoom = pdfViewer ? pdfViewer.zoom : 1;
  if (pdfViewer) {
    pdfViewer.destroy();
  }
  pdfViewer = new PdfViewer(pdfContainer, { initialZoom: previousZoom });
  viewer.classList.remove("loaded");
  pdfMessage.hidden = false;
  pdfMessage.textContent = "Loading PDF\u2026";

  const reqId = "pdf-" + (++loadRequestId);
  console.log(
    `[BizMatch QC] PDF ${reqId} selection: ${doc._letter}/${doc.file_name}`,
  );
  console.log(`[BizMatch QC] PDF ${reqId} prepare requested`);

  const startTime = performance.now();
  try {
    const response = await fetch("/api/pdf/prepare", {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({ index, requestId: reqId }),
    });
    if (!response.ok) {
      const body = await response.json().catch(() => ({}));
      throw new Error(body.error || `Prepare failed: HTTP ${response.status}`);
    }
    const data = await response.json();
    const prepareMs = Math.round(performance.now() - startTime);
    console.log(
      `[BizMatch QC] PDF ${reqId} prepare: ${prepareMs}ms, disk cache ${data.cacheStatus}`,
    );

    if (index !== selectedIndex) {
      // A newer selection happened while preparing, don't show stale result
      return;
    }

    viewer.classList.add("loaded");
    pdfMessage.hidden = true;
    console.log(`[BizMatch QC] PDF ${reqId} viewer load started`);
    await pdfViewer.load(data.url, data.size);
    console.log(`[BizMatch QC] PDF ${reqId} rendering complete`);
  } catch (error) {
    if (index !== selectedIndex) return;
    loadedIndex = -1; // allow retry: clicking the same document again reloads it
    const message = error instanceof Error ? error.message : String(error);
    pdfMessage.textContent = `Cannot open PDF: ${message}`;
    pdfMessage.hidden = false;
  }
}

function select(index) {
  selectedIndex = index;
  const doc = state.documents[index];
  if (!doc) return;

  let rowIdx = 0;
  fields.innerHTML = `
    <h2>${esc(doc.name_from_filename)}</h2>
    <p class="muted">${esc(doc.file_name)} \u00b7 ${
    esc(doc._doc_type || "unknown")
  } \u00b7 ${esc(doc._pages_total ?? "?")} pages</p>
    ${
    doc._vision_error
      ? `<p class="error">Vision error: ${esc(doc._vision_error)}</p>`
      : ""
  }
    ${
    fieldDefs.map((def) => {
      if (!def) return '<hr class="field-sep">';
      const [label, keyOrObj] = def;
      let value;
      if (typeof keyOrObj === "object") {
        value = esc(doc[keyOrObj.key] || doc[keyOrObj.fallback] || "\u2014");
      } else {
        value = esc(doc[keyOrObj] || "\u2014");
      }
      const bgClass = rowIdx % 2 === 0 ? "row-even" : "row-odd";
      rowIdx++;
      return `<div class="field ${bgClass}"><b>${label}</b><div>${value}</div></div>`;
    }).join("")
  }
  `;
  void loadPdf(index);
  renderList();
}

people.addEventListener("click", (event) => {
  const button = event.target.closest("[data-index]");
  if (button) select(Number(button.dataset.index));
});

search.addEventListener("input", renderList);

document.addEventListener("keydown", (event) => {
  if (["INPUT", "TEXTAREA"].includes(document.activeElement.tagName)) return;
  if (event.key === "ArrowDown" || event.key === "ArrowUp") {
    event.preventDefault();
    const delta = event.key === "ArrowDown" ? 1 : -1;
    select(
      Math.max(
        0,
        Math.min(
          state.documents.length - 1,
          selectedIndex < 0 ? 0 : selectedIndex + delta,
        ),
      ),
    );
  }
});

const dialog = document.querySelector("#settingsDialog");
const jsonPath = document.querySelector("#jsonPath");
const pdfBase = document.querySelector("#pdfBase");
const useAnonData = document.querySelector("#useAnonData");
const settingsError = document.querySelector("#settingsError");
const saveSettings = document.querySelector("#saveSettings");

document.querySelector("#settings").onclick = () => {
  jsonPath.value = state.config.jsonPath || "";
  pdfBase.value = state.config.pdfBaseDirectory || "";
  useAnonData.checked = !!state.config.useAnonymousData;
  settingsError.hidden = true;
  settingsError.textContent = "";
  dialog.showModal();
};

saveSettings.onclick = async (event) => {
  event.preventDefault();
  saveSettings.disabled = true;
  settingsError.hidden = true;
  try {
    const response = await fetch("/api/config", {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({
        jsonPath: jsonPath.value,
        pdfBaseDirectory: pdfBase.value,
        useAnonymousData: useAnonData.checked,
      }),
    });
    const body = await response.json();
    if (!response.ok) throw new Error(body.error || "Could not save settings.");
    dialog.close();
    await load();
  } catch (error) {
    settingsError.textContent = error instanceof Error
      ? error.message
      : String(error);
    settingsError.hidden = false;
  } finally {
    saveSettings.disabled = false;
  }
};

async function load() {
  try {
    const response = await fetch("/api/state", { cache: "no-store" });
    if (!response.ok) {
      throw new Error(`State request failed with HTTP ${response.status}.`);
    }
    state = await response.json();
    loadedIndex = -1; // document set changed; index-based dedup is invalid now
    groups = buildGroups(state.documents);
    showError(state.loadError || "");
    renderList();
    if (state.documents.length) select(0);
  } catch (error) {
    showError(error instanceof Error ? error.message : String(error));
  }
}

void load();