'use client';

import Link from 'next/link';
import type { Route } from 'next';
import { useParams } from 'next/navigation';
import { useQuery } from '@tanstack/react-query';
import { Globe } from 'lucide-react';

import { Card, CardContent } from '@/components/ui/card';
import { Skeleton } from '@/components/ui/skeleton';
import { PageHeader } from '@/components/shared/page-header';
import { apiFetch } from '@/lib/api/client';
import { CountryFlag } from '@/components/shared/country-flag';
import { getCountryName } from '@/lib/i18n/countries';
import { cn } from '@/lib/utils';

interface ClientsByCountryRow {
  country: string;
  count: number;
}

interface ClientsByCountryResponse {
  data: ClientsByCountryRow[];
  total: number;
}

/**
 * Full per-country breakdown of the active (non-archived) client book — the
 * "Show all" destination for the dashboard `ClientsByCountryWidget`, which
 * only shows the top N. Same endpoint (it already returns every row); this
 * page just renders the complete ranked list. Each row deep-links into the
 * clients list filtered by that nationality.
 */
export function ClientsByCountryPage() {
  const params = useParams<{ portSlug: string }>();
  const portSlug = params?.portSlug ?? '';

  const { data, isLoading } = useQuery<ClientsByCountryResponse>({
    queryKey: ['dashboard', 'clients-by-country', 'all'],
    queryFn: () => apiFetch<ClientsByCountryResponse>('/api/v1/dashboard/clients-by-country'),
    staleTime: 60_000,
  });

  const rows = data?.data ?? [];
  const total = data?.total ?? rows.reduce((s, r) => s + r.count, 0);
  const maxCount = rows.reduce((m, r) => Math.max(m, r.count), 0) || 1;

  return (
    <div className="space-y-6">
      <PageHeader
        eyebrow="Clients"
        title="Clients by country"
        description="Every country represented in the active client book, ranked by client count. Select a row to view those clients."
        kpiLine={
          rows.length > 0
            ? `${total} client${total === 1 ? '' : 's'} across ${rows.length} ${
                rows.length === 1 ? 'country' : 'countries'
              }.`
            : undefined
        }
      />

      <Card>
        <CardContent className="p-4 sm:p-6">
          {isLoading ? (
            <div className="space-y-2">
              {Array.from({ length: 10 }).map((_, i) => (
                <Skeleton key={i} className="h-8 w-full" aria-hidden />
              ))}
            </div>
          ) : rows.length === 0 ? (
            <div className="flex h-40 flex-col items-center justify-center gap-2 text-center text-sm text-muted-foreground">
              <Globe className="size-6" aria-hidden />
              <p>No clients with a country recorded yet.</p>
            </div>
          ) : (
            <ol className="space-y-1">
              {rows.map((row, i) => {
                const pct = (row.count / maxCount) * 100;
                const name = getCountryName(row.country) || row.country;
                return (
                  <li key={row.country}>
                    <Link
                      href={
                        `/${portSlug}/clients?nationality=${encodeURIComponent(row.country)}` as Route
                      }
                      className="group flex items-center justify-between gap-3 rounded-md px-2 py-2 hover:bg-foreground/5"
                      title={`${row.count} client${row.count === 1 ? '' : 's'} in ${name}`}
                    >
                      <div className="flex min-w-0 flex-1 items-center gap-3">
                        <span className="w-6 shrink-0 text-end text-xs tabular-nums text-muted-foreground">
                          {i + 1}
                        </span>
                        <CountryFlag code={row.country} className="h-3.5 w-5" decorative />
                        <span className="truncate text-sm font-medium">{name}</span>
                      </div>
                      <div className="flex shrink-0 items-center gap-3">
                        <div className="h-1.5 w-32 overflow-hidden rounded-full bg-muted">
                          <div
                            className={cn('h-full rounded-full bg-brand-500')}
                            style={{ width: `${pct}%` }}
                            aria-hidden
                          />
                        </div>
                        <span className="w-10 text-end text-sm tabular-nums text-foreground">
                          {row.count}
                        </span>
                      </div>
                    </Link>
                  </li>
                );
              })}
            </ol>
          )}
        </CardContent>
      </Card>
    </div>
  );
}