/* ============================================
   Grubflip Admin — Core Application Module
   Sidebar, API client, toast, auth helpers
   ============================================ */

const AdminApp = (() => {
  'use strict';

  const API_BASE = '/api';

  // --- Auth ---
  function getToken() {
    return localStorage.getItem('gf_token');
  }

  function getUser() {
    try {
      return JSON.parse(localStorage.getItem('gf_user') || '{}');
    } catch {
      return {};
    }
  }

  function requireAuth() {
    if (!getToken()) {
      window.location.href = 'index.html';
      return false;
    }
    return true;
  }

  function logout() {
    localStorage.removeItem('gf_token');
    localStorage.removeItem('gf_user');
    window.location.href = 'index.html';
  }

  // --- API Client ---
  async function api(endpoint, options = {}) {
    const url = `${API_BASE}${endpoint}`;
    const headers = {
      'Accept': 'application/json',
      ...options.headers,
    };

    const token = getToken();
    if (token) {
      headers['Authorization'] = `Bearer ${token}`;
    }

    if (options.body && !(options.body instanceof FormData)) {
      headers['Content-Type'] = 'application/json';
      if (typeof options.body === 'object') {
        options.body = JSON.stringify(options.body);
      }
    }

    const resp = await fetch(url, { ...options, headers });

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

    if (!resp.ok) {
      const data = await resp.json().catch(() => ({}));
      throw new Error(data.message || `Request failed (${resp.status})`);
    }

    if (resp.status === 204) return null;
    return resp.json();
  }

  // --- Sidebar ---
  function initSidebar() {
    const sidebar = document.getElementById('sidebar');
    const overlay = document.getElementById('sidebarOverlay');
    const toggle = document.getElementById('menuToggle');

    if (!sidebar || !toggle) return;

    toggle.addEventListener('click', () => {
      sidebar.classList.toggle('open');
      if (overlay) overlay.classList.toggle('visible');
    });

    if (overlay) {
      overlay.addEventListener('click', () => {
        sidebar.classList.remove('open');
        overlay.classList.remove('visible');
      });
    }

    // Close on Escape
    document.addEventListener('keydown', (e) => {
      if (e.key === 'Escape' && sidebar.classList.contains('open')) {
        sidebar.classList.remove('open');
        if (overlay) overlay.classList.remove('visible');
      }
    });
  }

  // --- Toast System ---
  function toast(message, type = 'info', duration = 4000) {
    const container = document.getElementById('toastContainer');
    if (!container) return;

    const icons = {
      success: '✅',
      error: '❌',
      warning: '⚠️',
      info: 'ℹ️'
    };

    const el = document.createElement('div');
    el.className = `toast toast-${type}`;
    el.innerHTML = `<span>${icons[type] || ''}</span> <span>${escapeHtml(message)}</span>`;
    container.appendChild(el);

    setTimeout(() => {
      el.classList.add('removing');
      el.addEventListener('animationend', () => el.remove());
    }, duration);
  }

  // --- Utilities ---
  function escapeHtml(str) {
    const div = document.createElement('div');
    div.textContent = str;
    return div.innerHTML;
  }

  function formatDate(dateStr) {
    if (!dateStr) return '--';
    const d = new Date(dateStr);
    return d.toLocaleDateString('en-US', { month: 'short', day: 'numeric', year: 'numeric' });
  }

  function formatTime(dateStr) {
    if (!dateStr) return '--';
    const d = new Date(dateStr);
    return d.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit' });
  }

  function timeAgo(dateStr) {
    if (!dateStr) return '--';
    const now = Date.now();
    const then = new Date(dateStr).getTime();
    const diff = Math.floor((now - then) / 1000);

    if (diff < 60) return 'just now';
    if (diff < 3600) return `${Math.floor(diff / 60)} min ago`;
    if (diff < 86400) return `${Math.floor(diff / 3600)} hr ago`;
    if (diff < 604800) return `${Math.floor(diff / 86400)}d ago`;
    return formatDate(dateStr);
  }

  // --- Confirm Dialog ---
  function confirm(message) {
    return new Promise((resolve) => {
      // Use native confirm for now — can replace with modal later
      resolve(window.confirm(message));
    });
  }

  return {
    api,
    getToken,
    getUser,
    requireAuth,
    logout,
    initSidebar,
    toast,
    escapeHtml,
    formatDate,
    formatTime,
    timeAgo,
    confirm,
  };
})();