const STORAGE_KEY = "routes.links.v1";
const AUTH_SESSION_KEY = "routes.authenticated.v1";
// Simple shared secret. Change this before publishing if needed.
const AUTH_SECRET = "change-me";

const authScreen = document.querySelector("#auth-screen");
const authForm = document.querySelector("#auth-form");
const authSecretInput = document.querySelector("#auth-secret");
const authMessage = document.querySelector("#auth-message");
const appShell = document.querySelector("#app-shell");
const logoutButton = document.querySelector("#logout-button");
const form = document.querySelector("#route-form");
const idInput = document.querySelector("#route-id");
const nameInput = document.querySelector("#route-name");
const linkInput = document.querySelector("#route-link");
const dateInput = document.querySelector("#route-date");
const pictureInput = document.querySelector("#route-picture");
const descriptionInput = document.querySelector("#route-description");
const saveButton = document.querySelector("#save-button");
const cancelEditButton = document.querySelector("#cancel-edit");
const clearAllButton = document.querySelector("#clear-all");
const routeCount = document.querySelector("#route-count");
const emptyState = document.querySelector("#empty-state");
const routesList = document.querySelector("#routes-list");
const template = document.querySelector("#route-card-template");

let routes = loadRoutes();

authForm.addEventListener("submit", authenticate);
logoutButton.addEventListener("click", lockApp);
form.addEventListener("submit", saveRoute);
cancelEditButton.addEventListener("click", resetForm);
clearAllButton.addEventListener("click", removeAllRoutes);
routesList.addEventListener("click", handleRouteAction);

if (sessionStorage.getItem(AUTH_SESSION_KEY) === "yes") {
  unlockApp();
} else {
  lockApp();
}

function authenticate(event) {
  event.preventDefault();
  authMessage.textContent = "";

  if (authSecretInput.value.trim() !== AUTH_SECRET) {
    authMessage.textContent = "Wrong secret.";
    authSecretInput.select();
    return;
  }

  sessionStorage.setItem(AUTH_SESSION_KEY, "yes");
  unlockApp();
}

function unlockApp() {
  authScreen.hidden = true;
  appShell.hidden = false;
  authSecretInput.value = "";
  authMessage.textContent = "";
  renderRoutes();
}

function lockApp() {
  sessionStorage.removeItem(AUTH_SESSION_KEY);
  appShell.hidden = true;
  authScreen.hidden = false;
  resetForm();
  authSecretInput.focus();
}

function loadRoutes() {
  try {
    return JSON.parse(localStorage.getItem(STORAGE_KEY)) ?? [];
  } catch {
    return [];
  }
}

function storeRoutes() {
  localStorage.setItem(STORAGE_KEY, JSON.stringify(routes));
}

function saveRoute(event) {
  event.preventDefault();

  const route = {
    id: idInput.value || crypto.randomUUID(),
    name: nameInput.value.trim(),
    link: linkInput.value.trim(),
    date: dateInput.value,
    picture: pictureInput.value.trim(),
    description: descriptionInput.value.trim(),
    updatedAt: new Date().toISOString(),
  };

  if (!route.name || !route.link) {
    return;
  }

  if (!isValidUrl(route.link) || (route.picture && !isValidUrl(route.picture))) {
    alert("Please enter valid URLs for the map link and picture.");
    return;
  }

  const existingIndex = routes.findIndex((item) => item.id === route.id);
  if (existingIndex >= 0) {
    routes[existingIndex] = route;
  } else {
    routes.unshift(route);
  }

  storeRoutes();
  renderRoutes();
  resetForm();
}

function renderRoutes() {
  routesList.innerHTML = "";

  routeCount.textContent = routes.length === 1 ? "1 route saved." : `${routes.length} routes saved.`;
  emptyState.classList.toggle("hidden", routes.length > 0);
  clearAllButton.hidden = routes.length === 0;

  for (const route of routes) {
    const card = template.content.firstElementChild.cloneNode(true);
    const image = card.querySelector(".route-image");
    const meta = card.querySelector(".route-meta");
    const title = card.querySelector(".route-title");
    const description = card.querySelector(".route-description");
    const openLink = card.querySelector(".open-link");

    card.dataset.id = route.id;
    meta.textContent = route.date ? formatDate(route.date) : "No date";
    title.textContent = route.name;
    title.href = route.link;
    openLink.href = route.link;
    description.textContent = route.description || "No description added.";

    if (route.picture) {
      image.style.backgroundImage = `url("${cssUrlEscape(route.picture)}")`;
    }

    routesList.append(card);
  }
}

function handleRouteAction(event) {
  const button = event.target.closest("button");
  if (!button) {
    return;
  }

  const card = button.closest(".route-card");
  const route = routes.find((item) => item.id === card?.dataset.id);
  if (!route) {
    return;
  }

  if (button.classList.contains("edit-route")) {
    editRoute(route);
  }

  if (button.classList.contains("remove-route")) {
    removeRoute(route.id);
  }

  if (button.classList.contains("share-route")) {
    shareRoute(route);
  }
}

function editRoute(route) {
  idInput.value = route.id;
  nameInput.value = route.name;
  linkInput.value = route.link;
  dateInput.value = route.date;
  pictureInput.value = route.picture;
  descriptionInput.value = route.description;
  saveButton.textContent = "Save changes";
  cancelEditButton.hidden = false;
  form.scrollIntoView({ behavior: "smooth", block: "start" });
  nameInput.focus();
}

function removeRoute(id) {
  const route = routes.find((item) => item.id === id);
  if (!route || !confirm(`Remove "${route.name}"?`)) {
    return;
  }

  routes = routes.filter((item) => item.id !== id);
  storeRoutes();
  renderRoutes();
  if (idInput.value === id) {
    resetForm();
  }
}

function removeAllRoutes() {
  if (!routes.length || !confirm("Remove all saved routes?")) {
    return;
  }

  routes = [];
  storeRoutes();
  renderRoutes();
  resetForm();
}

async function shareRoute(route) {
  const shareData = {
    title: route.name,
    text: route.description || route.name,
    url: route.link,
  };

  if (navigator.share) {
    try {
      await navigator.share(shareData);
      return;
    } catch (error) {
      if (error.name === "AbortError") {
        return;
      }
    }
  }

  await navigator.clipboard.writeText(route.link);
  alert("Route link copied to clipboard.");
}

function resetForm() {
  form.reset();
  idInput.value = "";
  saveButton.textContent = "Add route";
  cancelEditButton.hidden = true;
}

function isValidUrl(value) {
  try {
    const url = new URL(value);
    return url.protocol === "http:" || url.protocol === "https:";
  } catch {
    return false;
  }
}

function formatDate(value) {
  return new Intl.DateTimeFormat(undefined, { dateStyle: "medium" }).format(new Date(`${value}T00:00:00`));
}

function cssUrlEscape(value) {
  return value.replaceAll("\\", "\\\\").replaceAll('"', '\\"');
}