import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { securityApi } from '@/api/securityApi';
import { Monitor, Smartphone, Tablet, CircleDot, XCircle, Loader2, ShieldAlert } from 'lucide-react';

export default function ActiveSessions() {
  const queryClient = useQueryClient();

  const { data: sessions, isLoading } = useQuery({
    queryKey: ['security-sessions'],
    queryFn: securityApi.getSessions,
    refetchOnWindowFocus: false,
  });

  const revokeMutation = useMutation({
    mutationFn: (sessionId: string) => securityApi.revokeSession(sessionId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['security-sessions'] });
    },
  });

  const revokeOtherMutation = useMutation({
    mutationFn: () => securityApi.revokeOtherSessions(),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['security-sessions'] });
    },
  });

  const inputClass =
    'w-full px-3 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent text-sm';

  if (isLoading) {
    return (
      <div className="bg-white rounded-xl border border-gray-200 p-6">
        <div className="flex items-center gap-3 mb-4">
          <Monitor className="h-5 w-5 text-gray-400" />
          <h3 className="text-lg font-semibold text-gray-900">Active Sessions</h3>
        </div>
        <div className="flex items-center gap-2 text-gray-400">
          <Loader2 className="h-4 w-4 animate-spin" />
          <span className="text-sm">Loading sessions...</span>
        </div>
      </div>
    );
  }

  const sessionList = sessions?.data || [];
  const otherCount = sessionList.filter((s: any) => !s.is_current).length;

  const getDeviceIcon = (ua: string) => {
    const lower = ua.toLowerCase();
    if (/mobile|android|iphone|ipad/.test(lower)) return <Smartphone className="h-4 w-4 text-gray-500" />;
    if (/tablet/.test(lower)) return <Tablet className="h-4 w-4 text-gray-500" />;
    return <Monitor className="h-4 w-4 text-gray-500" />;
  };

  const timeAgo = (iso: string) => {
    const now = new Date();
    const then = new Date(iso);
    const diff = Math.floor((now.getTime() - then.getTime()) / 1000);
    if (diff < 60) return 'just now';
    if (diff < 3600) return `${Math.floor(diff / 60)}m ago`;
    if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`;
    return `${Math.floor(diff / 86400)}d ago`;
  };

  return (
    <div className="bg-white rounded-xl border border-gray-200 p-6">
      {/* Header */}
      <div className="flex items-center justify-between mb-4">
        <div className="flex items-center gap-3">
          <Monitor className="h-5 w-5 text-gray-600" />
          <h3 className="text-lg font-semibold text-gray-900">Active Sessions</h3>
        </div>
        {otherCount > 0 && (
          <button
            onClick={() => revokeOtherMutation.mutate()}
            disabled={revokeOtherMutation.isPending}
            className="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-medium text-red-700 bg-red-50 hover:bg-red-100 rounded-lg transition-colors disabled:opacity-50"
          >
            {revokeOtherMutation.isPending ? (
              <Loader2 className="h-3.5 w-3.5 animate-spin" />
            ) : (
              <ShieldAlert className="h-3.5 w-3.5" />
            )}
            Sign out other sessions ({otherCount})
          </button>
        )}
      </div>

      <p className="text-sm text-gray-500 mb-4">
        Manage your active sessions across devices.
      </p>

      {/* Session list */}
      <div className="space-y-3">
        {sessionList.map((session: any) => (
          <div
            key={session.id}
            className={`flex items-center justify-between p-3 rounded-lg border ${
              session.is_current
                ? 'border-blue-200 bg-blue-50'
                : 'border-gray-200 bg-white'
            }`}
          >
            <div className="flex items-center gap-3 min-w-0">
              {getDeviceIcon(session.user_agent || '')}
              <div className="min-w-0">
                <div className="flex items-center gap-2">
                  <span className="text-sm font-medium text-gray-900 truncate">
                    {session.device_info || 'Unknown device'}
                  </span>
                  {session.is_current && (
                    <span className="inline-flex items-center gap-1 px-1.5 py-0.5 rounded text-xs font-medium bg-blue-100 text-blue-700 flex-shrink-0">
                      <CircleDot className="h-2.5 w-2.5" />
                      Current
                    </span>
                  )}
                </div>
                <div className="flex items-center gap-2 text-xs text-gray-500 mt-0.5">
                  <span>{session.ip_address}</span>
                  {session.last_seen && <span>· {timeAgo(session.last_seen)}</span>}
                </div>
              </div>
            </div>

            {!session.is_current && (
              <button
                onClick={() => revokeMutation.mutate(session.session_id)}
                disabled={revokeMutation.isPending}
                className="ml-2 p-1.5 text-gray-400 hover:text-red-600 hover:bg-red-50 rounded-md transition-colors flex-shrink-0"
                title="Revoke session"
              >
                {revokeMutation.isPending ? (
                  <Loader2 className="h-4 w-4 animate-spin" />
                ) : (
                  <XCircle className="h-4 w-4" />
                )}
              </button>
            )}
          </div>
        ))}

        {sessionList.length === 0 && (
          <div className="text-center py-8 text-gray-400">
            <Monitor className="h-8 w-8 mx-auto mb-2 opacity-50" />
            <p className="text-sm">No active sessions tracked yet.</p>
            <p className="text-xs mt-1">Sessions will appear here after your next login.</p>
          </div>
        )}
      </div>
    </div>
  );
}