/* Auth state helpers shared across all pages */

const Auth = (() => {
  const KEY = 'bb_token';
  const USER_KEY = 'bb_user';

  function getToken() { return localStorage.getItem(KEY); }
  function saveToken(token) { localStorage.setItem(KEY, token); }

  function getUser() {
    const raw = localStorage.getItem(USER_KEY);
    return raw ? JSON.parse(raw) : null;
  }

  function saveUser(user) { localStorage.setItem(USER_KEY, JSON.stringify(user)); }

  function _decodePayload() {
    const token = getToken();
    if (!token) return null;
    try { return JSON.parse(atob(token.split('.')[1])); } catch (_) { return null; }
  }

  function logout() {
    localStorage.removeItem(KEY);
    localStorage.removeItem(USER_KEY);
    window.location.href = '/login.html';
  }

  function isLoggedIn() { return !!getToken(); }

  function requireAuth() {
    if (!isLoggedIn()) {
      window.location.href = '/login.html';
      return false;
    }
    return true;
  }

  function redirectIfLoggedIn() {
    if (isLoggedIn()) window.location.href = '/dashboard.html';
  }

  async function renderNav(activePage) {
    const navLinksEl = document.getElementById('nav-links');
    const navUserEl  = document.getElementById('nav-user');
    if (!navLinksEl || !navUserEl) return;

    if (isLoggedIn()) {
      let user = getUser();
      if (!user) {
        try { user = await API.users.me(); saveUser(user); } catch (_) {}
      }

      const payload = _decodePayload();
      const isImpersonating = !!(payload && payload.admin_id);

      navLinksEl.innerHTML = `
        <a href="/dashboard.html" class="btn btn-ghost btn-sm${activePage === 'dashboard' ? ' active' : ''}">My Bottle</a>
        <a href="/log.html" class="btn btn-ghost btn-sm${activePage === 'log' ? ' active' : ''}">Log Entry</a>
      `;

      if (isImpersonating) {
        navUserEl.innerHTML = `
          <span class="nav-impersonating">Viewing as <strong>${escHtml(user?.display_name || user?.email || 'User')}</strong></span>
          <button onclick="Auth.returnToAdmin()" class="btn btn-sm btn-amber">&#8617; Return to Admin</button>
        `;
      } else {
        navUserEl.innerHTML = `
          <span class="nav-username">${escHtml(user?.display_name || user?.email || 'Account')}</span>
          ${user?.is_admin ? '<a href="/admin.html" class="btn btn-sm btn-ghost">Admin</a>' : ''}
          <button onclick="Auth.showSettingsModal()" class="btn btn-sm btn-ghost" title="Settings">&#9881;</button>
          <button onclick="Auth.logout()" class="btn btn-sm btn-ghost">Logout</button>
        `;
        _injectSettingsModal(user);
      }
    } else {
      navLinksEl.innerHTML = '';
      navUserEl.innerHTML = `<a href="/login.html" class="btn btn-primary btn-sm">Login</a>`;
    }
  }

  function _buildTimezoneOptions(selected) {
    let allTz;
    try {
      allTz = Intl.supportedValuesOf('timeZone');
    } catch (_) {
      allTz = ['UTC', 'America/New_York', 'America/Chicago', 'America/Denver',
               'America/Los_Angeles', 'America/Anchorage', 'Pacific/Honolulu',
               'Europe/London', 'Europe/Paris', 'Europe/Berlin', 'Asia/Tokyo',
               'Asia/Shanghai', 'Australia/Sydney'];
    }
    const groups = {};
    for (const tz of allTz) {
      const slash = tz.indexOf('/');
      const group = slash === -1 ? 'Other' : tz.slice(0, slash);
      (groups[group] = groups[group] || []).push(tz);
    }
    return Object.keys(groups).sort().map(group => {
      const opts = groups[group].map(tz => {
        const label = tz.slice(tz.indexOf('/') + 1).replace(/_/g, ' ').replace(/\//g, ' / ');
        return `<option value="${tz}"${tz === selected ? ' selected' : ''}>${label}</option>`;
      }).join('');
      return `<optgroup label="${group}">${opts}</optgroup>`;
    }).join('');
  }

  function _injectSettingsModal(user) {
    if (document.getElementById('settings-modal')) return;
    const tzOptions = _buildTimezoneOptions(user?.timezone || 'UTC');
    document.body.insertAdjacentHTML('beforeend', `
      <div id="settings-modal" class="modal-overlay" style="display:none">
        <div class="modal-box">
          <h2>Settings</h2>
          <div id="settings-msg"></div>

          <h3 class="settings-section-title">Profile</h3>
          <div class="form-group" style="margin-bottom:1.25rem">
            <label for="settings-display-name">Display Name</label>
            <input type="text" id="settings-display-name" value="${escHtml(user?.display_name || '')}" maxlength="100" />
          </div>

          <hr class="settings-divider">

          <h3 class="settings-section-title">Timezone</h3>
          <div class="form-group" style="margin-bottom:0.5rem">
            <label for="settings-tz">Your timezone</label>
            <select id="settings-tz">${tzOptions}</select>
          </div>
          <div style="display:flex;gap:0.5rem;align-items:center;margin-bottom:1.25rem">
            <button class="btn btn-sm btn-ghost" onclick="Auth.detectTimezone()">Detect automatically</button>
            <button class="btn btn-primary btn-sm" onclick="Auth.saveProfile()">Save Profile &amp; Timezone</button>
          </div>

          <hr class="settings-divider">

          <h3 class="settings-section-title">Change Password</h3>
          <div class="form-group" style="margin-bottom:0.75rem">
            <label>Current Password</label>
            <input type="password" id="settings-pw-current" autocomplete="current-password" />
          </div>
          <div class="form-group" style="margin-bottom:0.75rem">
            <label>New Password</label>
            <input type="password" id="settings-pw-new" autocomplete="new-password" />
          </div>
          <div class="form-group" style="margin-bottom:1rem">
            <label>Confirm New Password</label>
            <input type="password" id="settings-pw-confirm" autocomplete="new-password" />
          </div>
          <div style="display:flex;gap:0.5rem;justify-content:flex-end">
            <button class="btn btn-ghost" onclick="Auth.hideSettingsModal()">Close</button>
            <button class="btn btn-primary" onclick="Auth.submitPasswordChange()">Update Password</button>
          </div>
        </div>
      </div>
    `);

    document.addEventListener('click', (e) => {
      if (e.target.id === 'settings-modal') hideSettingsModal();
    });
  }

  function showSettingsModal() {
    document.getElementById('settings-modal').style.display = 'flex';
    const msg = document.getElementById('settings-msg');
    if (msg) msg.innerHTML = '';
    document.getElementById('settings-pw-current').value = '';
    document.getElementById('settings-pw-new').value = '';
    document.getElementById('settings-pw-confirm').value = '';
  }

  function hideSettingsModal() {
    document.getElementById('settings-modal').style.display = 'none';
  }

  function detectTimezone() {
    const detected = Intl.DateTimeFormat().resolvedOptions().timeZone;
    const sel = document.getElementById('settings-tz');
    if (sel) sel.value = detected;
  }

  async function saveProfile() {
    const displayName = document.getElementById('settings-display-name').value.trim();
    const timezone    = document.getElementById('settings-tz').value;
    try {
      const user = await API.users.update({ display_name: displayName || null, timezone });
      saveUser(user);
      const usernameEl = document.querySelector('.nav-username');
      if (usernameEl) usernameEl.textContent = user.display_name || user.email || 'Account';
      _showSettingsMsg('Profile saved.', 'success');
    } catch (err) {
      _showSettingsMsg(err.message, 'error');
    }
  }

  async function submitPasswordChange() {
    const current = document.getElementById('settings-pw-current').value;
    const newPw   = document.getElementById('settings-pw-new').value;
    const confirm = document.getElementById('settings-pw-confirm').value;

    if (newPw !== confirm) { _showSettingsMsg('New passwords do not match.', 'error'); return; }
    if (newPw.length < 8)  { _showSettingsMsg('Password must be at least 8 characters.', 'error'); return; }

    try {
      await API.users.changePassword({ current_password: current, new_password: newPw });
      _showSettingsMsg('Password updated!', 'success');
      document.getElementById('settings-pw-current').value = '';
      document.getElementById('settings-pw-new').value = '';
      document.getElementById('settings-pw-confirm').value = '';
    } catch (err) {
      _showSettingsMsg(err.message, 'error');
    }
  }

  function _showSettingsMsg(text, type) {
    const el = document.getElementById('settings-msg');
    if (!el) return;
    const cls = type === 'success' ? 'alert-success' : 'alert-error';
    el.innerHTML = `<div class="alert ${cls}" style="margin-bottom:1rem">${escHtml(text)}</div>`;
    if (type === 'success') setTimeout(() => { el.innerHTML = ''; }, 3000);
  }

  async function returnToAdmin() {
    try {
      const data = await API.post('/admin/unimpersonate', {});
      saveToken(data.access_token);
      const user = await API.users.me();
      saveUser(user);
      window.location.href = '/admin.html';
    } catch (_) {
      logout();
    }
  }

  return {
    getToken, saveToken, getUser, saveUser,
    logout, isLoggedIn, requireAuth, redirectIfLoggedIn, renderNav,
    showSettingsModal, hideSettingsModal, detectTimezone, saveProfile, submitPasswordChange,
    returnToAdmin,
  };
})();