import type { Metadata } from 'next';
import Link from 'next/link';
import { ActionButton, AdminFilters, AdminTitle, Mono, Notice } from '@/components/admin/ui';
import { EntityBadge } from '@/components/ui/badges';
import { DataTable, EmptyRow, Td, Th } from '@/components/ui/data-table';
import { Unavailable } from '@/components/ui/unavailable';
import { mergeAction } from '@/lib/admin/actions';
import { adminApi, load, requireAdmin } from '@/lib/admin/admin-api';
import type { DuplicateSide } from '@/lib/admin/types';
import { fmtDate, fmtInt, fmtPct, num } from '@/lib/format';
import { routes } from '@/lib/site';

export const metadata: Metadata = { title: 'Duplicates', robots: { index: false, follow: false } };
export const dynamic = 'force-dynamic';

const TYPES = ['model', 'company', 'organization', 'lab', 'paper', 'provider', 'benchmark', 'hardware', 'framework', 'library', 'dataset', 'tool', 'repository', 'researcher'];

function Side({ s, type }: { s: DuplicateSide; type: string }) {
  return (
    <div className="min-w-0">
      <Link href={routes.entity({ entity_type: type, slug: s.slug })} className="block truncate text-sm font-medium text-ink hover:text-accent" title={s.name}>
        {s.name}
      </Link>
      <p className="truncate text-[11px] text-ink-3">
        <Mono>{s.slug}</Mono>
        {s.organization && <span> · {s.organization}</span>}
      </p>
      <p className="tnum text-[11px] text-ink-3">
        {fmtInt(s.claims)} claims · first seen {fmtDate(s.first_seen_at)}
      </p>
    </div>
  );
}

export default async function AdminDuplicatesPage({ searchParams }: { searchParams: Promise<Record<string, string | undefined>> }) {
  await requireAdmin();
  const sp = await searchParams;
  const type = sp.type ?? 'model';
  const ret = `/admin/entities/duplicates?type=${encodeURIComponent(type)}`;
  const res = await load(adminApi.duplicates({ type, limit: 200 }));
  return (
    <>
      <AdminTitle title="Duplicate candidates" count={res.ok ? fmtInt(res.data.items.length) : undefined} lede={res.ok ? `pg_trgm similarity ≥ ${fmtPct((num(res.data.threshold) ?? 0) * 100, 0)} on normalized names, within one type. Merging moves aliases, identifiers, claims, relations and events into the target and marks the source merged_into.` : undefined} />
      <Notice notice={sp.notice} level={sp.level} />
      <AdminFilters action="/admin/entities/duplicates" className="mb-4" fields={[{ kind: 'select', name: 'type', label: 'Type', value: type, any: 'model', options: TYPES.map((t) => ({ value: t, label: t })) }]} />
      {!res.ok ? (
        <Unavailable what="Duplicates" reason={res.error} />
      ) : (
        <DataTable compact caption="Duplicate candidates">
          <thead>
            <tr>
              <Th>A</Th>
              <Th>B</Th>
              <Th num>Similarity</Th>
              <Th>Merge</Th>
            </tr>
          </thead>
          <tbody>
            {res.data.items.length === 0 && <EmptyRow cols={4}>No candidate pairs for this type.</EmptyRow>}
            {res.data.items.map((d) => {
              const aClaims = num(d.a.claims) ?? 0;
              const bClaims = num(d.b.claims) ?? 0;
              // Default suggestion: the record with fewer claims (or the newer one) is the source, the richer one the target.
              const preferAB = aClaims < bClaims || (aClaims === bClaims && (d.a.first_seen_at ?? '') > (d.b.first_seen_at ?? ''));
              return (
                <tr key={`${d.a.id}-${d.b.id}`}>
                  <Td label="A" primary>
                    <div className="flex items-start gap-2">
                      <EntityBadge type={d.entity_type} small className="mt-0.5" />
                      <Side s={d.a} type={d.entity_type} />
                    </div>
                  </Td>
                  <Td label="B" primary>
                    <div className="flex items-start gap-2">
                      <EntityBadge type={d.entity_type} small className="mt-0.5" />
                      <Side s={d.b} type={d.entity_type} />
                    </div>
                  </Td>
                  <Td num label="Similarity" className="tnum text-xs">{fmtPct((num(d.similarity) ?? 0) * 100, 0)}</Td>
                  <Td label="Merge" wide>
                    <div className="flex flex-wrap items-center gap-1.5">
                      <form action={mergeAction}>
                        <input type="hidden" name="source_id" value={d.a.id} />
                        <input type="hidden" name="target_id" value={d.b.id} />
                        <input type="hidden" name="return" value={ret} />
                        <ActionButton tone={preferAB ? 'accent' : 'neutral'} title={`Merge ${d.a.slug} into ${d.b.slug} (A disappears, B keeps everything)`}>
                          Merge A → B{preferAB ? ' · suggested' : ''}
                        </ActionButton>
                      </form>
                      <form action={mergeAction}>
                        <input type="hidden" name="source_id" value={d.b.id} />
                        <input type="hidden" name="target_id" value={d.a.id} />
                        <input type="hidden" name="return" value={ret} />
                        <ActionButton tone={preferAB ? 'neutral' : 'accent'} title={`Merge ${d.b.slug} into ${d.a.slug} (B disappears, A keeps everything)`}>
                          Merge B → A{preferAB ? '' : ' · suggested'}
                        </ActionButton>
                      </form>
                    </div>
                  </Td>
                </tr>
              );
            })}
          </tbody>
        </DataTable>
      )}
    </>
  );
}