/**
 * OTRS Turbo — Core Application
 * SPA router, API client, lookup cache, and utility functions.
 */
const App = {
  lookups: {
    queues: [],
    states: [],
    priorities: [],
    users: [],
    types: [],
  },
  lookupsLoaded: false,

  /** Initialize the application */
  init() {
    Toast.init();

    // Hash-based SPA router
    window.addEventListener('hashchange', () => this.route());

    // Global search
    const searchInput = document.getElementById('global-search');
    if (searchInput) {
      let timeout;
      searchInput.addEventListener('input', () => {
        clearTimeout(timeout);
        timeout = setTimeout(() => {
          const hash = window.location.hash;
          if (hash.startsWith('#/tickets') && !hash.includes('/new') && !hash.match(/#\/tickets\/\d+/)) {
            TicketListView.currentPage = 1;
            TicketListView.render();
          } else {
            // Navigate to ticket list with search
            window.location.hash = '#/tickets';
          }
        }, 350);
      });

      searchInput.addEventListener('keydown', (e) => {
        if (e.key === 'Enter') {
          e.preventDefault();
          const hash = window.location.hash;
          if (!hash.startsWith('#/tickets') || hash.includes('/new') || hash.match(/#\/tickets\/\d+/)) {
            window.location.hash = '#/tickets';
          } else {
            TicketListView.currentPage = 1;
            TicketListView.render();
          }
        }
      });
    }

    // Check DB connection
    this.checkConnection();

    // Init active agent selector
    this.initAgentSelector();

    // Initial route
    if (!window.location.hash || window.location.hash === '#/') {
      window.location.hash = '#/dashboard';
    } else {
      this.route();
    }
  },

  /** Route based on current hash */
  route() {
    const hash = window.location.hash || '#/dashboard';
    const titleEl = document.getElementById('page-title');

    // Update active nav link
    document.querySelectorAll('.nav-link').forEach(link => {
      link.classList.remove('active');
    });

    if (hash === '#/dashboard') {
      document.getElementById('nav-dashboard')?.classList.add('active');
      titleEl.textContent = 'Dashboard';
      DashboardView.render();

    } else if (hash === '#/tickets') {
      document.getElementById('nav-tickets')?.classList.add('active');
      titleEl.textContent = 'Ticket';
      TicketListView.render();

    } else if (hash === '#/tickets/new') {
      document.getElementById('nav-new-ticket')?.classList.add('active');
      titleEl.textContent = 'Nuovo Ticket';
      TicketCreateView.render();

    } else if (hash.match(/^#\/tickets\/(\d+)$/)) {
      const id = hash.match(/^#\/tickets\/(\d+)$/)[1];
      document.getElementById('nav-tickets')?.classList.add('active');
      titleEl.textContent = `Ticket #${id}`;
      TicketDetailView.render(id);

    } else {
      // Fallback to dashboard
      window.location.hash = '#/dashboard';
    }
  },

  /** API fetch wrapper */
  async api(url, options = {}) {
    const activeAgentId = localStorage.getItem('activeAgentId') || '1';
    const defaultOptions = {
      headers: {
        'Content-Type': 'application/json',
        'X-Agent-ID': activeAgentId,
      },
    };

    const headers = { ...defaultOptions.headers, ...(options.headers || {}) };
    const response = await fetch(url, { ...defaultOptions, ...options, headers });

    if (!response.ok) {
      const errData = await response.json().catch(() => ({}));
      throw new Error(errData.error || errData.message || `HTTP ${response.status}`);
    }

    return response.json();
  },

  /** Ensure lookup data is loaded (cached) */
  async ensureLookups() {
    if (this.lookupsLoaded) return;

    try {
      const [queues, states, priorities, users, types] = await Promise.all([
        this.api('/api/queues'),
        this.api('/api/states'),
        this.api('/api/priorities'),
        this.api('/api/users'),
        this.api('/api/types'),
      ]);

      this.lookups = { queues, states, priorities, users, types };
      this.lookupsLoaded = true;
    } catch (err) {
      console.error('Failed to load lookups:', err);
      throw err;
    }
  },

  /** Check database connection */
  async checkConnection() {
    const dot = document.getElementById('connection-status');
    const text = document.getElementById('connection-text');

    try {
      await this.api('/api/queues');
      dot.classList.add('connected');
      dot.classList.remove('error');
      text.textContent = 'DB connesso';
    } catch (err) {
      dot.classList.add('error');
      dot.classList.remove('connected');
      text.textContent = 'DB non raggiungibile';
      Toast.error('Impossibile connettersi al database OTRS');
    }
  },

  /** Escape HTML to prevent XSS */
  escapeHtml(str) {
    const div = document.createElement('div');
    div.textContent = str || '';
    return div.innerHTML;
  },

  /** Format date for display */
  formatDate(dateStr) {
    if (!dateStr) return '—';
    try {
      const d = new Date(dateStr);
      return d.toLocaleDateString('it-IT', { day: '2-digit', month: '2-digit', year: 'numeric' });
    } catch {
      return dateStr;
    }
  },

  /** Format date+time for display */
  formatDateTime(dateStr) {
    if (!dateStr) return '—';
    try {
      const d = new Date(dateStr);
      return d.toLocaleDateString('it-IT', {
        day: '2-digit', month: '2-digit', year: 'numeric',
        hour: '2-digit', minute: '2-digit',
      });
    } catch {
      return dateStr;
    }
  },

  /** Initialize active agent dropdown */
  async initAgentSelector() {
    const select = document.getElementById('active-agent-select');
    if (!select) return;

    try {
      // Ensure lookups are loaded
      await this.ensureLookups();

      // Populate select dropdown
      select.innerHTML = (this.lookups.users || []).map(u => 
        `<option value="${u.id}">${u.first_name} ${u.last_name} (${u.login})</option>`
      ).join('');

      // Load saved agent ID or default to the first available
      const savedAgentId = localStorage.getItem('activeAgentId');
      if (savedAgentId && (this.lookups.users || []).some(u => String(u.id) === String(savedAgentId))) {
        select.value = savedAgentId;
      } else if ((this.lookups.users || []).length > 0) {
        select.value = this.lookups.users[0].id;
        localStorage.setItem('activeAgentId', select.value);
      }

      // Handle dropdown change event
      select.addEventListener('change', () => {
        localStorage.setItem('activeAgentId', select.value);
        Toast.success(`Agente attivo cambiato: ${select.options[select.selectedIndex].text}`);
      });
    } catch (err) {
      console.error('Failed to init agent selector:', err);
    }
  },

  /** Map priority name to a 1-5 index for styling */
  priorityIndex(name) {
    if (!name) return 3;
    const lower = name.toLowerCase();
    if (lower.includes('very low') || lower.includes('1')) return 1;
    if (lower.includes('low') || lower.includes('2')) return 2;
    if (lower.includes('normal') || lower.includes('3')) return 3;
    if (lower.includes('high') && !lower.includes('very') || lower.includes('4')) return 4;
    if (lower.includes('very high') || lower.includes('5')) return 5;
    return 3;
  },
};

// Start the app when DOM is ready
document.addEventListener('DOMContentLoaded', () => App.init());