import {
  Users,
  UserCheck,
  UserX,
  Activity,
  Smartphone,
  LogIn,
  ShieldAlert,
} from 'lucide-react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Skeleton } from '@/components/ui/skeleton';
import { useAdminDashboard, useAuditLog } from '@/hooks/useAdmin';
import { getRelativeTime } from '@/lib/date-utils';
import { cn } from '@/lib/utils';

interface StatCardProps {
  icon: React.ReactNode;
  label: string;
  value: string | number;
  iconBg?: string;
}

function StatCard({ icon, label, value, iconBg = 'bg-accent/10' }: StatCardProps) {
  return (
    <Card className="bg-gradient-to-br from-accent/[0.03] to-transparent">
      <CardContent className="p-5">
        <div className="flex items-center gap-3">
          <div className={cn('p-1.5 rounded-md', iconBg)}>{icon}</div>
          <div>
            <p className="text-[10px] tracking-wider uppercase text-muted-foreground">{label}</p>
            <p className="font-heading text-xl font-bold tabular-nums">{value}</p>
          </div>
        </div>
      </CardContent>
    </Card>
  );
}

function actionColor(action: string): string {
  if (action.includes('failed') || action.includes('locked') || action.includes('disabled')) {
    return 'bg-red-500/15 text-red-400';
  }
  if (action.includes('login') || action.includes('create') || action.includes('enabled')) {
    return 'bg-green-500/15 text-green-400';
  }
  if (action.includes('config') || action.includes('role') || action.includes('password')) {
    return 'bg-orange-500/15 text-orange-400';
  }
  return 'bg-blue-500/15 text-blue-400';
}

export default function AdminDashboardPage() {
  const { data: dashboard, isLoading } = useAdminDashboard();
  const { data: auditData } = useAuditLog(1, 10);

  const mfaPct = dashboard ? Math.round(dashboard.mfa_adoption_rate * 100) : null;
  const disabledUsers =
    dashboard ? dashboard.total_users - dashboard.active_users : null;

  return (
    <div className="px-6 py-6 space-y-6 animate-fade-in">
      {/* Stats grid */}
      <div className="grid gap-2.5 grid-cols-2 lg:grid-cols-5">
        {isLoading ? (
          Array.from({ length: 5 }).map((_, i) => (
            <Card key={i}>
              <CardContent className="p-5">
                <Skeleton className="h-12 w-full" />
              </CardContent>
            </Card>
          ))
        ) : (
          <>
            <StatCard
              icon={<Users className="h-5 w-5 text-accent" />}
              label="Total Users"
              value={dashboard?.total_users ?? '—'}
            />
            <StatCard
              icon={<UserCheck className="h-5 w-5 text-green-400" />}
              label="Active Users"
              value={dashboard?.active_users ?? '—'}
              iconBg="bg-green-500/10"
            />
            <StatCard
              icon={<UserX className="h-5 w-5 text-red-400" />}
              label="Disabled Users"
              value={disabledUsers ?? '—'}
              iconBg="bg-red-500/10"
            />
            <StatCard
              icon={<Activity className="h-5 w-5 text-blue-400" />}
              label="Active Sessions"
              value={dashboard?.active_sessions ?? '—'}
              iconBg="bg-blue-500/10"
            />
            <StatCard
              icon={<Smartphone className="h-5 w-5 text-purple-400" />}
              label="MFA Adoption"
              value={mfaPct !== null ? `${mfaPct}%` : '—'}
              iconBg="bg-purple-500/10"
            />
          </>
        )}
      </div>

      <div className="grid gap-5 lg:grid-cols-2">
        {/* Recent logins */}
        <Card>
          <CardHeader>
            <div className="flex items-center gap-2">
              <div className="p-1.5 rounded-md bg-green-500/10">
                <LogIn className="h-4 w-4 text-green-400" />
              </div>
              <CardTitle>Recent Logins</CardTitle>
            </div>
          </CardHeader>
          <CardContent className="p-0">
            {isLoading ? (
              <div className="px-5 pb-5 space-y-2">
                {Array.from({ length: 5 }).map((_, i) => (
                  <Skeleton key={i} className="h-8 w-full" />
                ))}
              </div>
            ) : !dashboard?.recent_logins?.length ? (
              <p className="px-5 pb-5 text-sm text-muted-foreground">No recent logins.</p>
            ) : (
              <div className="overflow-x-auto">
                <table className="w-full text-sm">
                  <thead>
                    <tr className="border-b border-border bg-card-elevated/50">
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        Username
                      </th>
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        When
                      </th>
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        IP
                      </th>
                    </tr>
                  </thead>
                  <tbody>
                    {dashboard.recent_logins.map((entry, idx) => (
                      <tr
                        key={idx}
                        className={cn(
                          'border-b border-border hover:bg-card-elevated/50 transition-colors',
                          idx % 2 === 0 ? '' : 'bg-card-elevated/25'
                        )}
                      >
                        <td className="px-5 py-2.5 font-medium">{entry.username}</td>
                        <td className="px-5 py-2.5 text-xs text-muted-foreground">
                          {getRelativeTime(entry.last_login_at)}
                        </td>
                        <td className="px-5 py-2.5 text-xs text-muted-foreground font-mono">
                          {entry.ip_address ?? '—'}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
          </CardContent>
        </Card>

        {/* Recent admin actions */}
        <Card>
          <CardHeader>
            <div className="flex items-center gap-2">
              <div className="p-1.5 rounded-md bg-orange-500/10">
                <ShieldAlert className="h-4 w-4 text-orange-400" />
              </div>
              <CardTitle>Recent Admin Actions</CardTitle>
            </div>
          </CardHeader>
          <CardContent className="p-0">
            {!auditData?.entries?.length ? (
              <p className="px-5 pb-5 text-sm text-muted-foreground">No recent actions.</p>
            ) : (
              <div className="overflow-x-auto">
                <table className="w-full text-sm">
                  <thead>
                    <tr className="border-b border-border bg-card-elevated/50">
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        Action
                      </th>
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        Actor
                      </th>
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        Target
                      </th>
                      <th className="px-5 py-2.5 text-left text-[11px] uppercase tracking-wider text-muted-foreground font-medium">
                        When
                      </th>
                    </tr>
                  </thead>
                  <tbody>
                    {auditData.entries.slice(0, 10).map((entry, idx) => (
                      <tr
                        key={entry.id}
                        className={cn(
                          'border-b border-border hover:bg-card-elevated/50 transition-colors',
                          idx % 2 === 0 ? '' : 'bg-card-elevated/25'
                        )}
                      >
                        <td className="px-5 py-2.5">
                          <span
                            className={cn(
                              'text-[9px] px-1.5 py-0.5 rounded font-medium uppercase tracking-wide whitespace-nowrap',
                              actionColor(entry.action)
                            )}
                          >
                            {entry.action}
                          </span>
                        </td>
                        <td className="px-5 py-2.5 text-xs font-medium">
                          {entry.actor_username ?? (
                            <span className="text-muted-foreground italic">system</span>
                          )}
                        </td>
                        <td className="px-5 py-2.5 text-xs text-muted-foreground">
                          {entry.target_username ?? '—'}
                        </td>
                        <td className="px-5 py-2.5 text-xs text-muted-foreground whitespace-nowrap">
                          {getRelativeTime(entry.created_at)}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
          </CardContent>
        </Card>
      </div>
    </div>
  );
}