/**
 * AAMOS Admin Panel — core JS
 */

'use strict';

// ─── API base URL ────────────────────────────────────────────────────────────

const API_BASE = (() => {
  if (typeof window.__AAMOS_API_BASE !== 'undefined') return window.__AAMOS_API_BASE;
  const stored = localStorage.getItem('aamos_api_base');
  if (stored) return stored.replace(/\/$/, '');
  return window.location.origin + '/api';
})();

// ─── State ───────────────────────────────────────────────────────────────────

const state = {
  currentUser: null,
  authToken: localStorage.getItem('aamos_token') || null,
  _polls: new Map(),
};

// ─── Auth helpers ─────────────────────────────────────────────────────────────

function getToken() {
  return state.authToken || localStorage.getItem('aamos_token');
}

function setToken(token) {
  state.authToken = token;
  if (token) {
    localStorage.setItem('aamos_token', token);
  } else {
    localStorage.removeItem('aamos_token');
  }
}

function setCurrentUser(user) {
  state.currentUser = user;
}

// ─── HTTP client ─────────────────────────────────────────────────────────────

async function apiFetch(path, options = {}) {
  const token = getToken();
  const headers = {
    'Content-Type': 'application/json',
    ...(token ? { Authorization: `Bearer ${token}` } : {}),
    ...(options.headers || {}),
  };

  const res = await fetch(`${API_BASE}${path}`, {
    ...options,
    headers,
  });

  if (res.status === 401) {
    logout();
    return null;
  }

  if (!res.ok) {
    const body = await res.text().catch(() => '');
    throw new Error(body || `HTTP ${res.status}`);
  }

  const ct = res.headers.get('content-type') || '';
  return ct.includes('application/json') ? res.json() : res.text();
}

// ─── Auth flow ────────────────────────────────────────────────────────────────

function checkAuth() {
  const token = getToken();
  const isLoginPage = window.location.pathname.endsWith('login.html')
    || window.location.pathname.endsWith('login');

  if (!token) {
    if (!isLoginPage) {
      const next = encodeURIComponent(window.location.href);
      window.location.href = `/login.html?next=${next}`;
    }
    return false;
  }

  if (isLoginPage) {
    window.location.href = '/index.html';
    return false;
  }

  return true;
}

async function login(username, password) {
  const data = await apiFetch('/auth/login', {
    method: 'POST',
    body: JSON.stringify({ username, password }),
  });
  if (!data) return false;
  setToken(data.token);
  setCurrentUser(data.user || { username });
  return true;
}

function logout() {
  stopAllPolling();
  setToken(null);
  state.currentUser = null;
  window.location.href = '/login.html';
}

async function fetchCurrentUser() {
  try {
    const user = await apiFetch('/auth/me');
    if (user) setCurrentUser(user);
    return user;
  } catch {
    return null;
  }
}

// ─── Navigation ───────────────────────────────────────────────────────────────

function setActivePage(pageId) {
  document.querySelectorAll('[data-page]').forEach(el => {
    el.classList.toggle('hidden', el.dataset.page !== pageId);
  });

  document.querySelectorAll('[data-nav]').forEach(el => {
    el.classList.toggle('active', el.dataset.nav === pageId);
  });

  history.pushState({ page: pageId }, '', `#${pageId}`);
}

function initRouter() {
  const hash = window.location.hash.replace('#', '');
  if (hash) setActivePage(hash);

  window.addEventListener('popstate', e => {
    const page = e.state?.page || window.location.hash.replace('#', '');
    if (page) setActivePage(page);
  });

  document.querySelectorAll('[data-nav]').forEach(el => {
    el.addEventListener('click', e => {
      e.preventDefault();
      setActivePage(el.dataset.nav);
    });
  });
}

// ─── Polling ─────────────────────────────────────────────────────────────────

function startPolling(endpoint, callback, intervalMs = 10_000) {
  if (state._polls.has(endpoint)) stopPolling(endpoint);

  const tick = async () => {
    try {
      const data = await apiFetch(endpoint);
      if (data !== null) callback(data);
    } catch (err) {
      console.warn(`[poll] ${endpoint}:`, err.message);
    }
  };

  tick();
  const id = setInterval(tick, intervalMs);
  state._polls.set(endpoint, id);
  return () => stopPolling(endpoint);
}

function stopPolling(endpoint) {
  const id = state._polls.get(endpoint);
  if (id !== undefined) {
    clearInterval(id);
    state._polls.delete(endpoint);
  }
}

function stopAllPolling() {
  state._polls.forEach(id => clearInterval(id));
  state._polls.clear();
}

// ─── Toast notifications ──────────────────────────────────────────────────────

const TOAST_TYPES = {
  success: 'toast--success',
  error: 'toast--error',
  warning: 'toast--warning',
  info: 'toast--info',
};

const TOAST_ICONS = {
  success: '✓',
  error: '✕',
  warning: '⚠',
  info: 'ℹ',
};

function getOrCreateToastContainer() {
  let container = document.getElementById('toast-container');
  if (!container) {
    container = document.createElement('div');
    container.id = 'toast-container';
    container.setAttribute('role', 'alert');
    container.setAttribute('aria-live', 'polite');
    Object.assign(container.style, {
      position: 'fixed',
      bottom: '1.5rem',
      right: '1.5rem',
      zIndex: '9999',
      display: 'flex',
      flexDirection: 'column',
      gap: '0.5rem',
    });
    document.body.appendChild(container);
  }
  return container;
}

function showToast(msg, type = 'info', durationMs = 4000) {
  const container = getOrCreateToastContainer();

  const toast = document.createElement('div');
  toast.className = `toast ${TOAST_TYPES[type] || TOAST_TYPES.info}`;
  toast.innerHTML = `<span class="toast__icon">${TOAST_ICONS[type] || TOAST_ICONS.info}</span>
    <span class="toast__msg">${escapeHtml(msg)}</span>
    <button class="toast__close" aria-label="Stäng">×</button>`;

  Object.assign(toast.style, {
    display: 'flex',
    alignItems: 'center',
    gap: '0.5rem',
    padding: '0.75rem 1rem',
    borderRadius: '0.375rem',
    background: typeToColor(type),
    color: '#fff',
    boxShadow: '0 4px 12px rgba(0,0,0,.2)',
    minWidth: '240px',
    maxWidth: '400px',
    fontSize: '0.9rem',
    opacity: '0',
    transform: 'translateX(2rem)',
    transition: 'opacity 0.2s, transform 0.2s',
  });

  const dismiss = () => {
    toast.style.opacity = '0';
    toast.style.transform = 'translateX(2rem)';
    setTimeout(() => toast.remove(), 220);
  };

  toast.querySelector('.toast__close').addEventListener('click', dismiss);

  container.appendChild(toast);

  requestAnimationFrame(() => {
    toast.style.opacity = '1';
    toast.style.transform = 'translateX(0)';
  });

  if (durationMs > 0) setTimeout(dismiss, durationMs);

  return dismiss;
}

function typeToColor(type) {
  return { success: '#16a34a', error: '#dc2626', warning: '#d97706', info: '#2563eb' }[type] || '#2563eb';
}

// ─── Date / time formatters ───────────────────────────────────────────────────

const DATE_FMT = new Intl.DateTimeFormat('sv-SE', {
  year: 'numeric', month: '2-digit', day: '2-digit',
  hour: '2-digit', minute: '2-digit', second: '2-digit',
});

function formatDate(ts) {
  if (!ts) return '—';
  const d = ts instanceof Date ? ts : new Date(typeof ts === 'number' && ts < 1e12 ? ts * 1000 : ts);
  return isNaN(d) ? String(ts) : DATE_FMT.format(d);
}

function formatRelative(ts) {
  if (!ts) return '—';
  const d = ts instanceof Date ? ts : new Date(typeof ts === 'number' && ts < 1e12 ? ts * 1000 : ts);
  if (isNaN(d)) return String(ts);

  const diffMs = Date.now() - d.getTime();
  const diffSec = Math.floor(diffMs / 1000);
  const diffMin = Math.floor(diffSec / 60);
  const diffH   = Math.floor(diffMin / 60);
  const diffD   = Math.floor(diffH / 24);

  if (diffSec < 5)   return 'just nu';
  if (diffSec < 60)  return `${diffSec}s sedan`;
  if (diffMin < 60)  return `${diffMin} min sedan`;
  if (diffH < 24)    return `${diffH} tim sedan`;
  if (diffD < 7)     return `${diffD} d sedan`;
  return formatDate(d);
}

// ─── UI utilities ─────────────────────────────────────────────────────────────

function debounce(fn, waitMs = 300) {
  let timer;
  return function (...args) {
    clearTimeout(timer);
    timer = setTimeout(() => fn.apply(this, args), waitMs);
  };
}

function loadingState(btn, active) {
  if (!btn) return;
  if (active === undefined) {
    return btn.dataset.loading === 'true';
  }
  if (active) {
    btn.dataset.loading = 'true';
    btn.dataset.originalText = btn.textContent;
    btn.disabled = true;
    btn.textContent = btn.dataset.loadingText || 'Laddar…';
  } else {
    btn.dataset.loading = 'false';
    btn.disabled = false;
    if (btn.dataset.originalText) btn.textContent = btn.dataset.originalText;
  }
}

function escapeHtml(str) {
  return String(str)
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#39;');
}

// ─── Form helpers ─────────────────────────────────────────────────────────────

function serializeForm(form) {
  return Object.fromEntries(new FormData(form));
}

function setFormErrors(form, errors = {}) {
  form.querySelectorAll('.field-error').forEach(el => el.textContent = '');
  Object.entries(errors).forEach(([field, msg]) => {
    const el = form.querySelector(`[data-error="${field}"]`);
    if (el) el.textContent = msg;
  });
}

// ─── Render helpers ───────────────────────────────────────────────────────────

function renderTable(tableEl, rows, columns) {
  const tbody = tableEl.querySelector('tbody') || tableEl;
  tbody.innerHTML = '';

  if (!rows.length) {
    const tr = document.createElement('tr');
    tr.innerHTML = `<td colspan="${columns.length}" style="text-align:center;opacity:.6">Inga poster</td>`;
    tbody.appendChild(tr);
    return;
  }

  rows.forEach(row => {
    const tr = document.createElement('tr');
    tr.innerHTML = columns.map(col => {
      const val = typeof col.render === 'function'
        ? col.render(row[col.key], row)
        : escapeHtml(row[col.key] ?? '—');
      return `<td>${val}</td>`;
    }).join('');
    tbody.appendChild(tr);
  });
}

// ─── Init ─────────────────────────────────────────────────────────────────────

async function init() {
  if (!checkAuth()) return;

  await fetchCurrentUser();

  const usernameEl = document.getElementById('nav-username');
  if (usernameEl && state.currentUser) {
    usernameEl.textContent = state.currentUser.username || state.currentUser.name || '';
  }

  initRouter();

  document.getElementById('logout-btn')?.addEventListener('click', e => {
    e.preventDefault();
    logout();
  });
}

document.addEventListener('DOMContentLoaded', init);

// ─── Public API ───────────────────────────────────────────────────────────────

window.AAMOS = {
  // state
  state,
  getToken,
  setToken,
  setCurrentUser,

  // http
  apiFetch,

  // auth
  checkAuth,
  login,
  logout,
  fetchCurrentUser,

  // navigation
  setActivePage,
  initRouter,

  // polling
  startPolling,
  stopPolling,
  stopAllPolling,

  // ui
  showToast,
  formatDate,
  formatRelative,
  debounce,
  loadingState,
  escapeHtml,
  serializeForm,
  setFormErrors,
  renderTable,
};