const tableBody = document.querySelector("#visitors");
const count = document.querySelector("#count");
const message = document.querySelector("#message");
const csvButton = document.querySelector("#export-csv");
const printButton = document.querySelector("#print-list");
let visitors = [];
let sortKey = "createdAt";
let sortDirection = -1;
const sortCollator = new Intl.Collator("da", { numeric: true, sensitivity: "base" });

function sortVisitors() {
  // Move existing rows so unsaved result inputs are retained.
  const rows = new Map([...tableBody.querySelectorAll("tr")].map((row) =>
    [row.querySelector(".result-form")?.dataset.id, row]));
  const value = (visitor) => {
    const row = rows.get(String(visitor.id));
    if (sortKey === "result") return row?.querySelector('[name="result"]')?.value ?? visitor.result;
    if (sortKey === "x10") return row?.querySelector('[name="x10"]')?.value ?? visitor.x10;
    return visitor[sortKey];
  };
  visitors.sort((a, b) => {
    const av = value(a), bv = value(b);
    if (av === null || av === undefined || av === "") return bv === null || bv === undefined || bv === "" ? a.id - b.id : 1;
    if (bv === null || bv === undefined || bv === "") return -1;
    return sortDirection * sortCollator.compare(String(av), String(bv)) || a.id - b.id;
  });
  for (const visitor of visitors) {
    const row = rows.get(String(visitor.id));
    if (row) tableBody.append(row);
  }
  document.querySelectorAll("button[data-sort]").forEach((button) => {
    const active = button.dataset.sort === sortKey;
    button.closest("th").setAttribute("aria-sort", active ? (sortDirection === 1 ? "ascending" : "descending") : "none");
    button.querySelector(".sort-arrow").textContent = active ? (sortDirection === 1 ? " ↑" : " ↓") : " ↕";
  });
}

document.querySelectorAll("button[data-sort]").forEach((button) => {
  button.addEventListener("click", () => {
    sortDirection = sortKey === button.dataset.sort ? -sortDirection : 1;
    sortKey = button.dataset.sort;
    sortVisitors();
  });
});

function formatDateTime(value) {
  return new Intl.DateTimeFormat("da-DK", {
    dateStyle: "short",
    timeStyle: "short"
  }).format(new Date(value));
}

function showError(text) {
  message.textContent = text;
  message.className = "notice error";
  message.hidden = false;
}

function escapeHtml(value) {
  return String(value ?? "")
    .replaceAll("&", "&")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#039;");
}

async function loadVisitors() {
  csvButton.disabled = true;
  printButton.disabled = true;
  try {
    const response = await fetch("/api/visitors");
    if (!response.ok) {
      showError("Listen kunne ikke hentes. Tjek admin-login og databaseforbindelse.");
      count.textContent = "Fejl";
      return;
    }

    visitors = await response.json();
    updateParticipantMap(visitors);
    message.hidden = true;
    csvButton.disabled = false;
    printButton.disabled = false;
    count.textContent = `${visitors.length} registreret`;

    if (visitors.length === 0) {
      tableBody.innerHTML = '<tr><td colspan="11" class="empty">Ingen besøgende registreret endnu.</td></tr>';
      return;
    }

    tableBody.innerHTML = visitors.map((visitor) => `
      <tr>
        <td><strong>${visitor.id}</strong></td>
        <td>${escapeHtml(visitor.name)}</td>
        <td>${escapeHtml(visitor.streetAddress)}</td>
        <td>${escapeHtml(visitor.postalCode)}</td>
        <td>${escapeHtml(visitor.city)}</td>
        <td>${escapeHtml(visitor.birthday)}</td>
        <td>${visitor.email ? `<a href="mailto:${escapeHtml(visitor.email)}">${escapeHtml(visitor.email)}</a>` : ""}</td>
        <td>${escapeHtml(formatDateTime(visitor.createdAt))}</td>
        <td>
          <form id="result-${visitor.id}" class="result-form no-print" data-id="${visitor.id}">
            <input name="result" value="${escapeHtml(visitor.result)}" maxlength="100" aria-label="Resultat for ${escapeHtml(visitor.name)}" placeholder="Resultat">
            <span class="result-status" role="status"></span>
          </form>
          <span class="print-result">${escapeHtml(visitor.result)}</span>
        </td>
        <td>
          <input class="x10-input no-print" form="result-${visitor.id}" name="x10" type="number" min="0" step="1" value="${escapeHtml(visitor.x10)}" aria-label="X-10 for ${escapeHtml(visitor.name)}">
          <button class="save-result-button no-print" type="submit" form="result-${visitor.id}">Gem</button>
          <span class="print-result print-x10">${escapeHtml(visitor.x10)}</span>
        </td>
        <td class="no-print"><button type="button" class="delete-button" data-id="${visitor.id}" aria-label="Slet ${escapeHtml(visitor.name)}">Slet</button></td>
      </tr>
    `).join("");
    sortVisitors();
  } catch {
    showError("Der er ikke forbindelse til besøgslisten lige nu.");
    count.textContent = "Fejl";
  }
}

tableBody.addEventListener("submit", async (event) => {
  const form = event.target.closest(".result-form");
  if (!form) return;
  event.preventDefault();
  const button = form.closest("tr").querySelector(".save-result-button");
  if (button.disabled) return;
  const status = form.querySelector(".result-status");
  const result = form.elements.result.value.trim();
  const x10 = form.elements.x10.value === "" ? null : Number(form.elements.x10.value);
  button.disabled = true;
  status.textContent = "Gemmer...";
  try {
    const response = await fetch(`/api/visitors/${form.dataset.id}/result`, {
      method: "PUT", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ result, x10 })
    });
    if (!response.ok) throw new Error("Resultat kunne ikke gemmes.");
    const saved = await response.json();
    const visitor = visitors.find((item) => String(item.id) === form.dataset.id);
    if (visitor) { visitor.result = saved.result; visitor.x10 = saved.x10; }
    form.elements.result.value = saved.result;
    form.parentElement.querySelector(".print-result").textContent = saved.result;
    form.elements.x10.value = saved.x10 ?? "";
    form.closest("tr").querySelector(".print-x10").textContent = saved.x10 ?? "";
    status.textContent = "Gemt";
  } catch {
    status.textContent = "Ikke gemt. Prøv igen.";
  } finally { button.disabled = false; }
});

tableBody.addEventListener("click", async (event) => {
  const button = event.target.closest("button[data-id]");
  if (!button || button.disabled) return;
  const visitor = visitors.find((item) => String(item.id) === button.dataset.id);
  if (!visitor || !window.confirm(`Slet registreringen for ${visitor.name}? Dette kan ikke fortrydes.`)) return;
  button.disabled = true;
  csvButton.disabled = true;
  printButton.disabled = true;
  try {
    const response = await fetch(`/api/visitors/${visitor.id}`, { method: "DELETE" });
    if (!response.ok && response.status !== 404) throw new Error("Sletning mislykkedes.");
    await loadVisitors();
  } catch {
    showError("Registreringen kunne ikke slettes. Prøv igen.");
    button.disabled = false;
    csvButton.disabled = false;
    printButton.disabled = false;
  }
});

function csvCell(value) {
  let text = String(value ?? "");
  // Prevent spreadsheet programs from evaluating visitor input as formulas.
  if (/^[\s]*[=+@-]/.test(text)) text = "'" + text;
  return `"${text.replaceAll('"', '""')}"`;
}

csvButton.addEventListener("click", () => {
  const rows = [
    ["Skivenr.", "Navn", "Vejnavn og husnummer", "Postnummer", "Postby", "Fødselsdag", "Email", "Registreret", "Resultat", "X-10"],
    ...visitors.map((visitor) => [visitor.id, visitor.name, visitor.streetAddress, visitor.postalCode,
      visitor.city, visitor.birthday, visitor.email, formatDateTime(visitor.createdAt), visitor.result, visitor.x10])
  ];
  const csv = "\uFEFF" + rows.map((row) => row.map(csvCell).join(";")).join("\r\n") + "\r\n";
  const url = URL.createObjectURL(new Blob([csv], { type: "text/csv;charset=utf-8" }));
  const link = document.createElement("a");
  link.href = url;
  link.download = "skydesportens-dag-besogende.csv";
  link.click();
  setTimeout(() => URL.revokeObjectURL(url), 1000);
});

printButton.addEventListener("click", () => window.print());

loadVisitors();