import { useCallback, useRef } from 'react';
import { useSession } from 'next-auth/react';
import { logger } from '@/lib/logger';

export interface NotificationItem {
  id: string;
  title: string;
  message: string;
  link?: string;
  timestamp: Date;
  metadata?: Record<string, any>;
}

export interface WidgetNotificationData {
  source: 'email' | 'rocketchat' | 'leantime' | 'calendar';
  count: number;
  items?: NotificationItem[];
}

/**
 * Hook to trigger notifications from widgets
 * Use this when widgets detect new items (emails, messages, tasks, events)
 */
export function useWidgetNotification() {
  const { data: session } = useSession();
  const lastUpdateRef = useRef<Record<string, number>>({});
  const DEBOUNCE_MS = 1000; // 1 second debounce per source

  const triggerNotification = useCallback(async (data: WidgetNotificationData) => {
    if (!session?.user?.id) {
      logger.debug('[useWidgetNotification] No session, skipping notification');
      return;
    }

    const { source, count, items } = data;
    const now = Date.now();
    const lastUpdate = lastUpdateRef.current[source] || 0;

    // Debounce per source to avoid excessive API calls
    if (now - lastUpdate < DEBOUNCE_MS) {
      logger.debug('[useWidgetNotification] Debouncing notification', { source, count });
      return;
    }
    lastUpdateRef.current[source] = now;

    try {
      logger.debug('[useWidgetNotification] Triggering notification update', {
        source,
        count,
        itemsCount: items?.length || 0,
      });

      // Send notification data to the registry
      const response = await fetch('/api/notifications/update', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({
          source,
          count,
          items: items?.map(item => ({
            ...item,
            timestamp: item.timestamp.toISOString(),
          })) || [],
        }),
      });

      if (!response.ok) {
        const errorText = await response.text();
        logger.error('[useWidgetNotification] Failed to update notification', {
          source,
          status: response.status,
          error: errorText,
        });
        return;
      }

      // Dispatch event for immediate UI update
      window.dispatchEvent(new CustomEvent('notification-updated', {
        detail: { source, count }
      }));

      logger.debug('[useWidgetNotification] Notification updated successfully', {
        source,
        count,
      });
    } catch (error) {
      logger.error('[useWidgetNotification] Error updating notification', {
        source,
        error: error instanceof Error ? error.message : String(error),
      });
    }
  }, [session?.user?.id]);

  return { triggerNotification };
}