const LOGIN_KEY = "iron_access_token";

const loginCard = document.querySelector("#login-card");
const appCard = document.querySelector("#app-card");
const loginForm = document.querySelector("#login-form");
const loginError = document.querySelector("#login-error");
const appError = document.querySelector("#app-error");
const usernameInput = document.querySelector("#username");
const passwordInput = document.querySelector("#password");
const welcomeTitle = document.querySelector("#welcome-title");
const sessionUser = document.querySelector("#session-user");
const rootName = document.querySelector("#root-name");
const itemsCount = document.querySelector("#items-count");
const rootItems = document.querySelector("#root-items");
const backendCount = document.querySelector("#backend-count");
const backendsList = document.querySelector("#backends-list");
const refreshButton = document.querySelector("#refresh-button");
const logoutButton = document.querySelector("#logout-button");

function getToken() {
  return window.localStorage.getItem(LOGIN_KEY);
}

function setToken(token) {
  window.localStorage.setItem(LOGIN_KEY, token);
}

function clearToken() {
  window.localStorage.removeItem(LOGIN_KEY);
}

async function apiFetch(path, options = {}) {
  const headers = new Headers(options.headers || {});
  const token = getToken();
  if (token) {
    headers.set("Authorization", `Bearer ${token}`);
  }

  const response = await fetch(path, { ...options, headers });
  if (!response.ok) {
    let message = `Request failed with status ${response.status}`;
    try {
      const payload = await response.json();
      message = payload.error?.message || message;
    } catch {
      // keep fallback message
    }
    throw new Error(message);
  }
  return response;
}

function renderList(container, items, renderItem) {
  container.innerHTML = "";
  if (items.length === 0) {
    const empty = document.createElement("li");
    empty.textContent = "Nothing here yet.";
    container.append(empty);
    return;
  }
  for (const item of items) {
    container.append(renderItem(item));
  }
}

function renderRootItem(item) {
  const element = document.createElement("li");
  const left = document.createElement("div");
  const right = document.createElement("div");
  right.className = "item-meta";

  left.innerHTML = `<strong>${item.name}</strong>`;
  if (item.kind === "file" && item.mime_type) {
    right.textContent = item.mime_type;
  } else {
    right.textContent = item.kind;
  }

  element.append(left, right);
  return element;
}

function renderBackendItem(item) {
  const element = document.createElement("li");
  const left = document.createElement("div");
  left.innerHTML = `<strong>${item.name}</strong>`;
  const right = document.createElement("div");
  right.className = "item-meta";
  right.textContent = `${item.type} · ${item.is_enabled ? "enabled" : "disabled"}`;
  element.append(left, right);
  return element;
}

function showLogin(errorMessage = "") {
  loginCard.hidden = false;
  appCard.hidden = true;
  loginError.hidden = !errorMessage;
  loginError.textContent = errorMessage;
}

function showApp() {
  loginCard.hidden = true;
  appCard.hidden = false;
  appError.hidden = true;
}

async function loadWorkspace() {
  try {
    const [meResponse, directoryResponse, backendResponse] = await Promise.all([
      apiFetch("/api/auth/me"),
      apiFetch("/api/directories/dir_root/children"),
      apiFetch("/api/backends"),
    ]);

    const me = await meResponse.json();
    const directory = await directoryResponse.json();
    const backends = await backendResponse.json();

    welcomeTitle.textContent = `Welcome, ${me.user.username}`;
    sessionUser.textContent = me.user.username;
    rootName.textContent = directory.directory.name;
    itemsCount.textContent = `${directory.items.length} items`;
    backendCount.textContent = String(backends.items.length);

    renderList(rootItems, directory.items, renderRootItem);
    renderList(backendsList, backends.items, renderBackendItem);
    showApp();
  } catch (error) {
    if (String(error.message).includes("Authentication")) {
      clearToken();
      showLogin("Your session expired. Please sign in again.");
      return;
    }
    appError.hidden = false;
    appError.textContent = error.message;
  }
}

loginForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  loginError.hidden = true;

  try {
    const response = await fetch("/api/auth/login", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        username: usernameInput.value,
        password: passwordInput.value,
      }),
    });
    const payload = await response.json();
    if (!response.ok) {
      throw new Error(payload.error?.message || "Unable to sign in.");
    }

    setToken(payload.access_token);
    passwordInput.value = "";
    await loadWorkspace();
  } catch (error) {
    showLogin(error.message);
  }
});

refreshButton.addEventListener("click", async () => {
  await loadWorkspace();
});

logoutButton.addEventListener("click", async () => {
  try {
    await apiFetch("/api/auth/logout", { method: "POST" });
  } catch {
    // best-effort logout
  }
  clearToken();
  showLogin();
});

if (getToken()) {
  void loadWorkspace();
} else {
  showLogin();
}