'use client';

import { useQuery } from '@tanstack/react-query';
import { Activity, Wifi, AlertTriangle, CheckCircle2 } from 'lucide-react';

import { apiFetch } from '@/lib/api/client';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { ServiceHealthCard } from './service-health-card';
import { QueueOverview } from './queue-overview';
import { PageHeader } from '@/components/shared/page-header';
import type {
  HealthStatus,
  QueueStatus,
  ConnectionStatus,
  RecentError,
} from '@/lib/services/system-monitoring.service';

export function SystemMonitoringDashboard() {
  const { data: healthData } = useQuery({
    queryKey: ['system', 'health'],
    queryFn: () => apiFetch<{ data: HealthStatus }>('/api/v1/admin/health').then((r) => r.data),
    staleTime: 30_000,
    refetchInterval: 30_000,
  });

  const { data: queuesData } = useQuery({
    queryKey: ['system', 'queues'],
    queryFn: () => apiFetch<{ data: QueueStatus[] }>('/api/v1/admin/queues').then((r) => r.data),
    staleTime: 10_000,
    refetchInterval: 10_000,
  });

  const { data: connectionsData } = useQuery({
    queryKey: ['system', 'connections'],
    queryFn: () =>
      apiFetch<{ data: ConnectionStatus }>('/api/v1/admin/connections').then((r) => r.data),
    staleTime: 30_000,
    refetchInterval: 30_000,
  });

  const queues: QueueStatus[] = queuesData ?? [];
  const health: HealthStatus | undefined = healthData;
  const connections = connectionsData?.totalConnections ?? 0;

  const totalFailed = queues.reduce((sum, q) => sum + q.failed, 0);

  return (
    <div className="space-y-8">
      <PageHeader
        title="System Monitoring"
        description="Real-time health, queue status and connection tracking"
      />

      {/* Service health */}
      <section className="space-y-3">
        <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
          Service Health
        </h2>
        {health ? (
          <>
            <div className="flex items-center gap-2 mb-3">
              {health.overall === 'healthy' ? (
                <CheckCircle2 className="h-4 w-4 text-green-500" aria-hidden />
              ) : (
                <AlertTriangle className="h-4 w-4 text-yellow-500" aria-hidden />
              )}
              <span className="text-sm text-muted-foreground">
                All services checked at {new Date(health.checkedAt).toLocaleTimeString()}
              </span>
            </div>
            <div className="flex flex-wrap gap-3">
              {health.services.map((service) => (
                <ServiceHealthCard key={service.name} service={service} />
              ))}
            </div>
          </>
        ) : (
          <div className="flex gap-3">
            {[1, 2, 3, 4].map((i) => (
              <div key={i} className="h-[88px] w-[160px] rounded-xl border bg-card animate-pulse" />
            ))}
          </div>
        )}
      </section>

      {/* Stats row */}
      <section className="grid grid-cols-2 sm:grid-cols-3 gap-4">
        <Card>
          <CardHeader className="pb-2">
            <CardTitle className="text-xs text-muted-foreground font-medium uppercase tracking-wide flex items-center gap-1.5">
              <Wifi className="h-3.5 w-3.5" aria-hidden />
              Active Connections
            </CardTitle>
          </CardHeader>
          <CardContent>
            <p className="text-3xl font-bold">{connections}</p>
          </CardContent>
        </Card>

        <Card>
          <CardHeader className="pb-2">
            <CardTitle className="text-xs text-muted-foreground font-medium uppercase tracking-wide flex items-center gap-1.5">
              <AlertTriangle className="h-3.5 w-3.5" aria-hidden />
              Total Failed Jobs
            </CardTitle>
          </CardHeader>
          <CardContent>
            <p className={`text-3xl font-bold ${totalFailed > 0 ? 'text-destructive' : ''}`}>
              {totalFailed}
            </p>
          </CardContent>
        </Card>

        <Card>
          <CardHeader className="pb-2">
            <CardTitle className="text-xs text-muted-foreground font-medium uppercase tracking-wide flex items-center gap-1.5">
              <Activity className="h-3.5 w-3.5" aria-hidden />
              Active Jobs
            </CardTitle>
          </CardHeader>
          <CardContent>
            <p className="text-3xl font-bold">{queues.reduce((sum, q) => sum + q.active, 0)}</p>
          </CardContent>
        </Card>
      </section>

      {/* Queue overview */}
      <section className="space-y-3">
        <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
          Queue Overview
        </h2>
        {queues.length > 0 ? (
          <QueueOverview queues={queues} />
        ) : (
          <div className="grid grid-cols-5 gap-3">
            {[1, 2, 3, 4, 5].map((i) => (
              <div key={i} className="h-[110px] rounded-xl border bg-card animate-pulse" />
            ))}
          </div>
        )}
      </section>

      {/* Recent errors */}
      <RecentErrorsPanel />
    </div>
  );
}

function RecentErrorsPanel() {
  const { data: errorsData } = useQuery({
    queryKey: ['system', 'errors'],
    queryFn: () => apiFetch<{ data: RecentError[] }>('/api/v1/admin/errors').then((r) => r.data),
    staleTime: 30_000,
    refetchInterval: 30_000,
  });

  const errors: RecentError[] = errorsData ?? [];

  return (
    <section className="space-y-3">
      <h2 className="text-sm font-semibold text-muted-foreground uppercase tracking-wide">
        Recent Errors
      </h2>
      {errors.length === 0 ? (
        <p className="text-sm text-muted-foreground">No recent errors.</p>
      ) : (
        <div className="space-y-2">
          {errors.map((error) => (
            <div
              key={error.id}
              className="flex items-start justify-between gap-4 rounded-lg border px-4 py-3 text-sm"
            >
              <div className="space-y-0.5 min-w-0">
                <p className="font-medium truncate">{error.message}</p>
                <p className="text-xs text-muted-foreground">
                  {error.source === 'queue' ? 'Queue' : 'Audit'} -{' '}
                  {new Date(error.timestamp).toLocaleString()}
                </p>
              </div>
            </div>
          ))}
        </div>
      )}
    </section>
  );
}
