const loginPanel = document.querySelector("#login-panel");
const loginForm = document.querySelector("#login-form");
const keyInput = document.querySelector("#admin-key");
const loginError = document.querySelector("#login-error");
const dashboard = document.querySelector("#dashboard");
const headerActions = document.querySelector("#header-actions");
const createForm = document.querySelector("#create-form");
const namesInput = document.querySelector("#guest-names");
const createError = document.querySelector("#create-error");
const createButton = document.querySelector("#create-button");
const createdEmpty = document.querySelector("#created-empty");
const createdLinks = document.querySelector("#created-links");
const createdList = document.querySelector("#created-list");
const responseBody = document.querySelector("#response-body");
const tableEmpty = document.querySelector("#table-empty");
const responseDialog = document.querySelector("#response-dialog");
const responseEditorForm = document.querySelector("#response-editor-form");
const responseDialogTitle = document.querySelector("#response-dialog-title");
const adminAnswer = document.querySelector("#admin-answer");
const adminCompanionWrap = document.querySelector("#admin-companion-wrap");
const adminCompanionName = document.querySelector("#admin-companion-name");
const responseEditorError = document.querySelector("#response-editor-error");
const responseSaveButton = document.querySelector("#response-save-button");

let adminKey = sessionStorage.getItem("inviteAdminKey") || "";
let lastCreated = [];
let editingToken = "";

const answerLabels = {
  not_coming: "Kommt nicht",
  alone: "Kommt alleine",
  with_someone: "Mit Begleitung"
};

function authHeaders(extra = {}) {
  return { ...extra, Authorization: `Bearer ${adminKey}` };
}

function formatDate(value) {
  if (!value) return "—";
  return new Intl.DateTimeFormat("de-AT", {
    dateStyle: "short",
    timeStyle: "short",
    timeZone: "Europe/Vienna"
  }).format(new Date(value));
}

async function copyText(text, button) {
  await navigator.clipboard.writeText(text);
  const old = button.textContent;
  button.textContent = "Kopiert!";
  setTimeout(() => { button.textContent = old; }, 1200);
}

function cell(row, text) {
  const td = document.createElement("td");
  td.textContent = text;
  row.append(td);
  return td;
}

function toggleAdminCompanion() {
  const needsCompanion = adminAnswer.value === "with_someone";
  adminCompanionWrap.hidden = !needsCompanion;
  adminCompanionName.required = needsCompanion;
}

function openResponseEditor(invite) {
  editingToken = invite.token;
  responseDialogTitle.textContent = invite.guestName;
  adminAnswer.value = invite.answer || "";
  adminCompanionName.value = invite.companionName || "";
  responseEditorError.hidden = true;
  toggleAdminCompanion();
  responseDialog.showModal();
  adminAnswer.focus();
}

function renderTable(invites) {
  responseBody.replaceChildren();
  tableEmpty.hidden = invites.length > 0;
  for (const invite of [...invites].reverse()) {
    const row = document.createElement("tr");
    cell(row, invite.guestName);
    const statusCell = document.createElement("td");
    const status = document.createElement("span");
    status.className = `status ${invite.answer || ""}`;
    status.textContent = answerLabels[invite.answer] || (invite.firstOpenedAt ? "Geöffnet" : "Noch offen");
    statusCell.append(status);
    row.append(statusCell);
    cell(row, invite.companionName || "—");
    cell(row, formatDate(invite.firstOpenedAt));
    cell(row, invite.lastOpenedAt ? `${formatDate(invite.lastOpenedAt)} (${invite.openCount}×)` : "—");
    cell(row, formatDate(invite.lastSavedAt));
    const linkCell = document.createElement("td");
    const copyButton = document.createElement("button");
    copyButton.type = "button";
    copyButton.className = "link-button";
    copyButton.textContent = "Link kopieren";
    copyButton.addEventListener("click", () => copyText(invite.link, copyButton));
    linkCell.append(copyButton);
    row.append(linkCell);
    const actionCell = document.createElement("td");
    const editButton = document.createElement("button");
    editButton.type = "button";
    editButton.className = "link-button secondary";
    editButton.textContent = invite.answer ? "Antwort ändern" : "Antwort setzen";
    editButton.addEventListener("click", () => openResponseEditor(invite));
    actionCell.append(editButton);
    row.append(actionCell);
    responseBody.append(row);
  }
}

function renderCreated(invites) {
  lastCreated = invites;
  createdList.replaceChildren();
  createdEmpty.hidden = true;
  createdLinks.hidden = false;
  for (const invite of invites) {
    const item = document.createElement("li");
    const name = document.createElement("strong");
    name.textContent = invite.name;
    const link = document.createElement("a");
    link.href = invite.link;
    link.target = "_blank";
    link.rel = "noopener";
    link.textContent = invite.link;
    const button = document.createElement("button");
    button.type = "button";
    button.textContent = "Kopieren";
    button.addEventListener("click", () => copyText(invite.link, button));
    item.append(name, link, button);
    createdList.append(item);
  }
}

async function loadDashboard() {
  const response = await fetch("/api/admin/invites", { headers: authHeaders() });
  if (!response.ok) throw new Error("Der Admin-Schlüssel ist nicht gültig.");
  const data = await response.json();
  document.querySelector("#stat-total").textContent = data.summary.total;
  document.querySelector("#stat-opened").textContent = data.summary.opened;
  document.querySelector("#stat-responded").textContent = data.summary.responded;
  document.querySelector("#stat-attending").textContent = data.summary.attending;
  renderTable(data.invites);
  loginPanel.hidden = true;
  dashboard.hidden = false;
  headerActions.hidden = false;
}

loginForm.addEventListener("submit", async event => {
  event.preventDefault();
  loginError.hidden = true;
  adminKey = keyInput.value;
  try {
    await loadDashboard();
    sessionStorage.setItem("inviteAdminKey", adminKey);
  } catch (error) {
    loginError.textContent = error.message;
    loginError.hidden = false;
  }
});

createForm.addEventListener("submit", async event => {
  event.preventDefault();
  createError.hidden = true;
  const names = namesInput.value.split(/\r?\n/).map(name => name.trim()).filter(Boolean);
  createButton.disabled = true;
  createButton.textContent = "Links werden erstellt …";
  try {
    const response = await fetch("/api/admin/invites", {
      method: "POST",
      headers: authHeaders({ "Content-Type": "application/json" }),
      body: JSON.stringify({ names })
    });
    const data = await response.json();
    if (!response.ok) throw new Error(data.error || "Links konnten nicht erstellt werden.");
    renderCreated(data.invites);
    namesInput.value = "";
    await loadDashboard();
  } catch (error) {
    createError.textContent = error.message;
    createError.hidden = false;
  } finally {
    createButton.disabled = false;
    createButton.textContent = "Persönliche Links erstellen";
  }
});

document.querySelector("#copy-all-button").addEventListener("click", event => {
  const text = lastCreated.map(invite => `${invite.name}: ${invite.link}`).join("\n");
  copyText(text, event.currentTarget);
});

document.querySelector("#refresh-button").addEventListener("click", async event => {
  event.currentTarget.disabled = true;
  try { await loadDashboard(); } finally { event.currentTarget.disabled = false; }
});

document.querySelector("#logout-button").addEventListener("click", () => {
  sessionStorage.removeItem("inviteAdminKey");
  window.location.reload();
});

adminAnswer.addEventListener("change", () => {
  responseEditorError.hidden = true;
  toggleAdminCompanion();
  if (!adminCompanionWrap.hidden) adminCompanionName.focus();
});

function closeResponseDialog() {
  responseDialog.close();
  editingToken = "";
}

document.querySelector("#response-dialog-close").addEventListener("click", closeResponseDialog);
document.querySelector("#response-dialog-cancel").addEventListener("click", closeResponseDialog);

responseEditorForm.addEventListener("submit", async event => {
  event.preventDefault();
  responseEditorError.hidden = true;
  const answer = adminAnswer.value;
  const companionName = adminCompanionName.value.trim();

  if (!answer) {
    responseEditorError.textContent = "Bitte wähle eine Antwort aus.";
    responseEditorError.hidden = false;
    return;
  }
  if (answer === "with_someone" && !companionName) {
    responseEditorError.textContent = "Bitte gib den Namen der Begleitung an.";
    responseEditorError.hidden = false;
    adminCompanionName.focus();
    return;
  }

  responseSaveButton.disabled = true;
  responseSaveButton.textContent = "Wird gespeichert …";
  try {
    const response = await fetch(`/api/admin/invites/${encodeURIComponent(editingToken)}/rsvp`, {
      method: "PATCH",
      headers: authHeaders({ "Content-Type": "application/json" }),
      body: JSON.stringify({ answer, companionName })
    });
    const data = await response.json();
    if (!response.ok) throw new Error(data.error || "Antwort konnte nicht gespeichert werden.");
    closeResponseDialog();
    await loadDashboard();
  } catch (error) {
    responseEditorError.textContent = error.message;
    responseEditorError.hidden = false;
  } finally {
    responseSaveButton.disabled = false;
    responseSaveButton.textContent = "Antwort speichern";
  }
});

document.querySelector("#csv-button").addEventListener("click", async event => {
  event.currentTarget.disabled = true;
  try {
    const response = await fetch("/api/admin/responses.csv", { headers: authHeaders() });
    if (!response.ok) throw new Error("CSV konnte nicht geladen werden.");
    const blob = await response.blob();
    const link = document.createElement("a");
    link.href = URL.createObjectURL(blob);
    link.download = "zusagen.csv";
    link.click();
    URL.revokeObjectURL(link.href);
  } finally {
    event.currentTarget.disabled = false;
  }
});

loadDashboard().catch(() => {
  sessionStorage.removeItem("inviteAdminKey");
  adminKey = "";
  loginPanel.hidden = false;
  dashboard.hidden = true;
  headerActions.hidden = true;
});