(function() {
  var STORAGE_KEY = 'crank_user';
  var sessionCache = null;
  var sessionPromise = null;

  function isLoginPage() {
    return /\/html\/login\.html$/.test(window.location.pathname);
  }

  function loginUrl() {
    return (window.APP_BASE || '') + 'html/login.html';
  }

  function homeUrl() {
    return (window.APP_BASE || '') + 'index.html';
  }

  function clearUserMirror() {
    sessionCache = null;
    sessionPromise = null;
    try {
      localStorage.removeItem(STORAGE_KEY);
    } catch (_error) {}
  }

  function primaryMembership(session) {
    return session && session.memberships && session.memberships.length
      ? session.memberships[0]
      : null;
  }

  function initials(displayName, email) {
    var source = displayName || email || 'Crank';
    return source
      .split(/\s+/)
      .filter(Boolean)
      .slice(0, 2)
      .map(function(part) { return part.charAt(0).toUpperCase(); })
      .join('') || 'CR';
  }

  function persistUserMirror(session) {
    var membership = primaryMembership(session);
    var user = {
      id: session.user.id,
      name: session.user.display_name,
      email: session.user.email,
      role: membership ? String(membership.role || '').replace(/^\w/, function(char) { return char.toUpperCase(); }) : 'Viewer',
      workspace: membership ? membership.workspace.slug : '',
      workspaceId: membership ? membership.workspace.id : '',
      initials: initials(session.user.display_name, session.user.email),
    };

    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(user));
    } catch (_error) {}
  }

  function replaceSession(session) {
    sessionCache = session;
    persistUserMirror(session);
    return session;
  }

  async function fetchSession(force) {
    if (!force && sessionCache) {
      return sessionCache;
    }
    if (!force && sessionPromise) {
      return sessionPromise;
    }

    sessionPromise = window.CrankApi.getSession()
      .then(function(session) {
        return replaceSession(session);
      })
      .catch(function(error) {
        clearUserMirror();
        throw error;
      })
      .finally(function() {
        sessionPromise = null;
      });

    return sessionPromise;
  }

  async function guardProtectedPage() {
    try {
      return await fetchSession(false);
    } catch (error) {
      if (error && error.status === 401) {
        window.location.replace(loginUrl());
        return null;
      }
      throw error;
    }
  }

  async function guardLoginPage() {
    try {
      await fetchSession(false);
      window.location.replace(homeUrl());
    } catch (error) {
      if (!error || error.status !== 401) {
        throw error;
      }
    }
  }

  async function login(email, password) {
    var session = await window.CrankApi.login({
      email: email,
      password: password,
    });
    replaceSession(session);
    window.location.href = homeUrl();
  }

  async function logout() {
    try {
      await window.CrankApi.logout();
    } finally {
      clearUserMirror();
      window.location.href = loginUrl();
    }
  }

  function handleUnauthorized() {
    if (isLoginPage()) {
      clearUserMirror();
      return;
    }
    clearUserMirror();
    window.location.replace(loginUrl());
  }

  window.CrankAuth = {
    fetchSession: fetchSession,
    replaceSession: replaceSession,
    guardProtectedPage: guardProtectedPage,
    guardLoginPage: guardLoginPage,
    login: login,
    logout: logout,
    handleUnauthorized: handleUnauthorized,
  };
}());