import { useState, useEffect, useRef } from 'react';
import { CheckSquare } from 'lucide-react';
import { OutlookNotificationData } from '@/components/outlook-notification';
import { format } from 'date-fns';
import { fr } from 'date-fns/locale';

interface Task {
  id: string;
  headline: string;
  dateToFinish: string | null;
  source: 'leantime' | 'twenty-crm';
  projectName: string;
  url?: string;
}

/**
 * Hook to manage task notifications and show Outlook-style notifications
 * - Leantime tasks: notification at due date time
 * - Twenty CRM tasks: notification at start date time (or due date if no start date)
 */
export function useTaskNotifications() {
  const [taskNotification, setTaskNotification] = useState<OutlookNotificationData | null>(null);
  const notifiedTaskIdsRef = useRef<Set<string>>(new Set());
  const tasksRef = useRef<Task[]>([]);
  const checkIntervalRef = useRef<NodeJS.Timeout | null>(null);

  useEffect(() => {
    console.log('[useTaskNotifications] 🎧 Hook initialized, listening for tasks-updated');
    
    // Listen for tasks updates
    const handleTasksUpdate = (event: CustomEvent) => {
      const tasks = event.detail?.tasks || [];
      
      console.log('[useTaskNotifications] 📋 Received tasks update', {
        tasksCount: tasks.length,
        tasks: tasks.map((t: any) => ({
          id: t.id,
          title: t.headline,
          dateToFinish: t.dateToFinish,
          source: t.source,
        })),
      });
      
      if (!tasks || tasks.length === 0) {
        tasksRef.current = [];
        return;
      }

      // Convert tasks to Task format
      const formattedTasks: Task[] = tasks.map((task: any) => ({
        id: task.id?.toString() || '',
        headline: task.headline || task.title || '',
        dateToFinish: task.dateToFinish || null,
        source: task.source || 'leantime',
        projectName: task.projectName || '',
        url: task.url || null,
      }));

      tasksRef.current = formattedTasks;
      console.log('[useTaskNotifications] Tasks stored', {
        count: formattedTasks.length,
        tasks: formattedTasks.map(t => ({
          id: t.id,
          title: t.headline,
          dateToFinish: t.dateToFinish,
          source: t.source,
        })),
      });
    };

    window.addEventListener('tasks-updated', handleTasksUpdate as EventListener);

    // Check for tasks that are due/starting now (every 10 seconds)
    const checkForDueTasks = () => {
      const now = new Date();
      const currentTime = now.getTime();
      
      console.log('[useTaskNotifications] 🔍 Checking for due tasks', {
        now: now.toISOString(),
        tasksCount: tasksRef.current.length,
        notifiedCount: notifiedTaskIdsRef.current.size,
      });
      
      const dueTasks = tasksRef.current.filter((task) => {
        // Skip if already notified
        if (notifiedTaskIdsRef.current.has(task.id)) {
          console.log('[useTaskNotifications] ⏭️ Task already notified', {
            id: task.id,
            title: task.headline,
          });
          return false;
        }

        // For both Leantime and Twenty CRM tasks: notification at due date time (dateToFinish)
        // Note: Leantime dates might be in MySQL format (YYYY-MM-DD HH:MM:SS) without timezone
        // We need to parse them correctly to avoid timezone issues
        let notificationDate: Date | null = null;
        
        if (task.dateToFinish) {
          const dateStr = task.dateToFinish;
          
          // Leantime dates with 'Z' are actually local time stored as UTC
          // We need to extract the time components and create a local date
          if (dateStr.endsWith('Z')) {
            // Parse as UTC first to get the components, then create local date
            // Example: "2026-01-16T01:13:00.000Z" -> treat 01:13 as local time, not UTC
            const utcDate = new Date(dateStr);
            // Extract components from UTC date and create local date
            // This assumes the UTC date actually represents local time
            notificationDate = new Date(
              utcDate.getUTCFullYear(),
              utcDate.getUTCMonth(),
              utcDate.getUTCDate(),
              utcDate.getUTCHours(),
              utcDate.getUTCMinutes(),
              utcDate.getUTCSeconds(),
              utcDate.getUTCMilliseconds()
            );
            
            console.log('[useTaskNotifications] 📅 Parsing Leantime date (Z -> local)', {
              id: task.id,
              title: task.headline,
              rawDate: dateStr,
              utcComponents: {
                year: utcDate.getUTCFullYear(),
                month: utcDate.getUTCMonth(),
                day: utcDate.getUTCDate(),
                hour: utcDate.getUTCHours(),
                minute: utcDate.getUTCMinutes(),
              },
              localDate: notificationDate.toLocaleString('fr-FR'),
              localISO: notificationDate.toISOString(),
            });
          } else if (dateStr.includes('T')) {
            // ISO format without Z - treat as local time
            notificationDate = new Date(dateStr);
          } else if (dateStr.includes(' ')) {
            // MySQL format: "YYYY-MM-DD HH:MM:SS" - parse as local time
            const isoLike = dateStr.replace(' ', 'T');
            notificationDate = new Date(isoLike);
          } else {
            // Try direct parsing
            notificationDate = new Date(dateStr);
          }
          
          if (!notificationDate || isNaN(notificationDate.getTime())) {
            console.error('[useTaskNotifications] ❌ Invalid date', {
              id: task.id,
              rawDate: dateStr,
            });
            return false;
          }
        }

        if (!notificationDate || isNaN(notificationDate.getTime())) {
          return false;
        }

        const notificationTime = notificationDate.getTime();
        const timeUntilNotification = notificationTime - currentTime;
        const timeUntilNotificationMinutes = Math.round(timeUntilNotification / 1000 / 60);
        const timeUntilNotificationSeconds = Math.round(timeUntilNotification / 1000);
        
        // Notification window: within 2 minutes of the notification time (1 minute before to 1 minute after)
        // This allows catching tasks that are due now or just became due
        const notificationWindow = 60 * 1000; // 1 minute
        const inNotificationWindow = 
          timeUntilNotification >= -notificationWindow && 
          timeUntilNotification <= notificationWindow;
        
        console.log('[useTaskNotifications] ⏰ Checking task', {
          id: task.id,
          title: task.headline,
          source: task.source,
          rawDate: task.dateToFinish,
          notificationDateLocal: notificationDate.toLocaleString('fr-FR'),
          notificationDateISO: notificationDate.toISOString(),
          nowLocal: now.toLocaleString('fr-FR'),
          nowISO: now.toISOString(),
          timeUntilNotificationMinutes,
          timeUntilNotificationSeconds,
          inWindow: inNotificationWindow,
        });
        
        return inNotificationWindow;
      });

      if (dueTasks.length > 0) {
        // Sort by notification time (earliest first)
        dueTasks.sort((a, b) => {
          const dateA = a.dateToFinish ? new Date(a.dateToFinish).getTime() : Infinity;
          const dateB = b.dateToFinish ? new Date(b.dateToFinish).getTime() : Infinity;
          return dateA - dateB;
        });
        
        // Show notification for the first task
        const task = dueTasks[0];
        
        const notificationDate = task.dateToFinish 
          ? new Date(task.dateToFinish) 
          : new Date();
        
        const timeStr = format(notificationDate, 'HH:mm', { locale: fr });
        const sourceLabel = task.source === 'twenty-crm' ? 'Médiation' : 'Agilité';
        
        console.log('[useTaskNotifications] ✅ Task due detected!', {
          id: task.id,
          title: task.headline,
          source: task.source,
          notificationDate: notificationDate.toISOString(),
          now: now.toISOString(),
        });

        const notification: OutlookNotificationData = {
          id: `task-${task.id}-${Date.now()}`,
          source: 'leantime',
          title: 'Devoirs',
          subtitle: task.source === 'twenty-crm' ? 'Tâche Médiation' : 'Tâche Agilité',
          message: `${task.headline} - Échéance à ${timeStr} (${sourceLabel})`,
          icon: CheckSquare,
          iconColor: 'text-blue-600',
          iconBgColor: 'bg-blue-100',
          borderColor: 'border-blue-500',
          link: task.url || '/agilite',
          timestamp: notificationDate,
          autoDismiss: 30000, // 30 seconds
          actions: [
            {
              label: 'Ouvrir',
              onClick: () => {
                if (task.url) {
                  window.open(task.url, '_blank');
                } else {
                  window.location.href = '/agilite';
                }
              },
              variant: 'default',
              className: 'bg-blue-600 hover:bg-blue-700 text-white',
            },
          ],
        };

        setTaskNotification(notification);
        notifiedTaskIdsRef.current.add(task.id);

        // Clean up old notified tasks (older than 1 hour) to allow re-notification if needed
        setTimeout(() => {
          notifiedTaskIdsRef.current.delete(task.id);
        }, 60 * 60 * 1000); // 1 hour
      }
    };

    // Check immediately and then every 10 seconds for more responsive notifications
    checkForDueTasks();
    checkIntervalRef.current = setInterval(checkForDueTasks, 10000); // Every 10 seconds

    return () => {
      window.removeEventListener('tasks-updated', handleTasksUpdate as EventListener);
      if (checkIntervalRef.current) {
        clearInterval(checkIntervalRef.current);
      }
    };
  }, []);

  const handleDismiss = () => {
    setTaskNotification(null);
  };

  return {
    taskNotification,
    setTaskNotification: handleDismiss,
  };
}