import { useState, useEffect } from 'react';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { Alert, AlertDescription } from '@/components/ui/alert';
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table';
import { AlertTriangle, CheckCircle, RefreshCw, Loader2 } from 'lucide-react';
import { supabase } from '@/integrations/supabase/client';
import { format } from 'date-fns';

interface DuplicateStats {
  date: string | null;
  total_attempts: number | null;
  duplicates_prevented: number | null;
  prevention_rate: number | null;
  health_status: 'healthy' | 'warning' | 'critical';
}

interface RecentDuplicate {
  id: string;
  user_id: string;
  channel: string;
  idempotency_key: string | null;
  created_at: string;
  profiles?: {
    username: string;
    display_name: string | null;
  };
}

export function NotificationDebugPanel() {
  const [stats, setStats] = useState<DuplicateStats[]>([]);
  const [recentDuplicates, setRecentDuplicates] = useState<RecentDuplicate[]>([]);
  const [isLoading, setIsLoading] = useState(true);

  useEffect(() => {
    loadData();
  }, []);

  const loadData = async () => {
    setIsLoading(true);
    try {
      // Load health dashboard
      const { data: healthData, error: healthError } = await supabase
        .from('notification_health_dashboard')
        .select('*')
        .limit(7);

      if (healthError) throw healthError;
      if (healthData) {
        setStats(healthData.map(stat => ({
          ...stat,
          health_status: stat.health_status as 'healthy' | 'warning' | 'critical'
        })));
      }

      // Load recent prevented duplicates
      const { data: duplicates, error: duplicatesError } = await supabase
        .from('notification_logs')
        .select(`
          id,
          user_id,
          channel,
          idempotency_key,
          created_at
        `)
        .eq('is_duplicate', true)
        .order('created_at', { ascending: false })
        .limit(10);

      if (duplicatesError) throw duplicatesError;
      
      if (duplicates) {
        // Fetch profiles separately
        const userIds = [...new Set(duplicates.map(d => d.user_id))];
        const { data: profiles } = await supabase
          .from('profiles')
          .select('user_id, username, display_name')
          .in('user_id', userIds);

        const profileMap = new Map(profiles?.map(p => [p.user_id, p]) || []);
        
        setRecentDuplicates(duplicates.map(dup => ({
          ...dup,
          profiles: profileMap.get(dup.user_id)
        })));
      }
    } catch (error) {
      console.error('Failed to load notification debug data:', error);
    } finally {
      setIsLoading(false);
    }
  };

  const getHealthBadge = (status: string) => {
    switch (status) {
      case 'healthy':
        return (
          <Badge variant="default" className="bg-green-500">
            <CheckCircle className="h-3 w-3 mr-1" />
            Healthy
          </Badge>
        );
      case 'warning':
        return (
          <Badge variant="secondary">
            <AlertTriangle className="h-3 w-3 mr-1" />
            Warning
          </Badge>
        );
      case 'critical':
        return (
          <Badge variant="destructive">
            <AlertTriangle className="h-3 w-3 mr-1" />
            Critical
          </Badge>
        );
      default:
        return <Badge>Unknown</Badge>;
    }
  };

  if (isLoading) {
    return (
      <Card>
        <CardContent className="pt-6">
          <div className="flex items-center justify-center">
            <Loader2 className="h-6 w-6 animate-spin text-muted-foreground" />
          </div>
        </CardContent>
      </Card>
    );
  }

  return (
    <div className="space-y-4">
      <Card>
        <CardHeader>
          <div className="flex items-center justify-between">
            <div>
              <CardTitle>Notification Health Dashboard</CardTitle>
              <CardDescription>Monitor duplicate prevention and notification system health</CardDescription>
            </div>
            <Button variant="outline" size="sm" onClick={loadData} disabled={isLoading}>
              <RefreshCw className={`h-4 w-4 mr-2 ${isLoading ? 'animate-spin' : ''}`} />
              Refresh
            </Button>
          </div>
        </CardHeader>
        <CardContent>
          {stats.length === 0 ? (
            <Alert>
              <AlertDescription>No notification statistics available yet</AlertDescription>
            </Alert>
          ) : (
            <Table>
              <TableHeader>
                <TableRow>
                  <TableHead>Date</TableHead>
                  <TableHead className="text-right">Total Attempts</TableHead>
                  <TableHead className="text-right">Duplicates Prevented</TableHead>
                  <TableHead className="text-right">Prevention Rate</TableHead>
                  <TableHead>Status</TableHead>
                </TableRow>
              </TableHeader>
              <TableBody>
                {stats.map((stat) => (
                  <TableRow key={stat.date || 'unknown'}>
                    <TableCell>{stat.date ? format(new Date(stat.date), 'MMM d, yyyy') : 'N/A'}</TableCell>
                    <TableCell className="text-right">{stat.total_attempts ?? 0}</TableCell>
                    <TableCell className="text-right">{stat.duplicates_prevented ?? 0}</TableCell>
                    <TableCell className="text-right">{stat.prevention_rate !== null ? stat.prevention_rate.toFixed(1) : 'N/A'}%</TableCell>
                    <TableCell>{getHealthBadge(stat.health_status)}</TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          )}
        </CardContent>
      </Card>

      <Card>
        <CardHeader>
          <CardTitle>Recent Prevented Duplicates</CardTitle>
          <CardDescription>Notifications that were blocked due to duplication</CardDescription>
        </CardHeader>
        <CardContent>
          {recentDuplicates.length === 0 ? (
            <Alert>
              <CheckCircle className="h-4 w-4" />
              <AlertDescription>No recent duplicates detected</AlertDescription>
            </Alert>
          ) : (
            <div className="space-y-2">
              {recentDuplicates.map((dup) => (
                <div key={dup.id} className="flex items-center justify-between p-3 border rounded-lg">
                  <div>
                    <div className="font-medium">
                      {dup.profiles?.display_name || dup.profiles?.username || 'Unknown User'}
                    </div>
                    <div className="text-xs text-muted-foreground">
                      Channel: {dup.channel} • Key: {dup.idempotency_key?.substring(0, 12)}...
                    </div>
                  </div>
                  <div className="text-xs text-muted-foreground">
                    {format(new Date(dup.created_at), 'PPp')}
                  </div>
                </div>
              ))}
            </div>
          )}
        </CardContent>
      </Card>
    </div>
  );
}
