import type { Metadata } from 'next';
import { ScrollX } from '@/components/models/scroll-x';
import Link from 'next/link';
import { Tri } from '@/components/models/badges';
import { LICENCE_DIMENSIONS } from '@/components/models/openness-block';
import { DataTable, EmptyRow, Td, Th } from '@/components/ui/data-table';
import { Hint } from '@/components/ui/hint';
import { Container, Note, PageHeader } from '@/components/ui/section';
import { Unavailable } from '@/components/ui/unavailable';
import { apiD1, safe } from '@/lib/api';
import { cn } from '@/lib/cn';
import { fmtInt, num } from '@/lib/format';
import { SITE_NAME, SITE_URL } from '@/lib/site';

export const metadata: Metadata = {
  title: 'Model licences — commercial use, redistribution, derivatives, hosting restrictions',
  description: 'Canonical licences of AI models (Apache-2.0, MIT, Llama Community, Gemma Terms, RAIL…): category, commercial use, redistribution, derivatives, hosting restrictions, acceptable-use policy and the number of canonical models under each — permissions read from the licence text, unknown when ambiguous.',
  alternates: { canonical: '/licenses' },
  openGraph: { title: `Model licences | ${SITE_NAME}`, url: `${SITE_URL}/licenses`, type: 'website' },
};
export const revalidate = 3600;

const CATEGORY_HINT: Record<string, string> = {
  permissive: 'OSI-style licences with no field-of-use restriction (Apache, MIT, BSD).',
  copyleft: 'Derivatives must be shared under the same terms (GPL, AGPL, LGPL, MPL).',
  'creative-commons': 'Creative Commons terms; NC variants forbid commercial use, ND forbids derivatives.',
  'responsible-ai': 'RAIL / OpenRAIL licences: permissive with an attached acceptable-use policy.',
  community: 'Vendor community licences (Llama, Gemma, Qwen, NVIDIA…): downloadable weights with user caps, hosting or field-of-use clauses.',
  'research-only': 'Non-commercial / research-only terms.',
  proprietary: 'No weights redistribution; access through an API or product.',
  unknown: 'Stated licence text could not be classified.',
};

export default async function LicensesPage({ searchParams }: { searchParams: Promise<{ category?: string }> }) {
  const { category } = await searchParams;
  const res = await safe(apiD1.licenses());
  const all = (res?.items ?? []).slice().sort((a, b) => (num(b.models) ?? 0) - (num(a.models) ?? 0) || a.label.localeCompare(b.label));
  const items = category ? all.filter((l) => l.category === category) : all;
  const cats = (res?.categories ?? []).map((c) => ({ c, n: all.filter((l) => l.category === c).length, models: all.filter((l) => l.category === c).reduce((s, l) => s + (num(l.models) ?? 0), 0) })).filter((x) => x.n > 0);
  const chip = (active: boolean) => cn('inline-flex h-8 items-center gap-1.5 border px-2.5 text-xs whitespace-nowrap', active ? 'border-ink bg-ink text-canvas' : 'border-rule text-ink-2 hover:border-rule-strong hover:text-ink');
  const ld = { '@context': 'https://schema.org', '@type': 'CollectionPage', name: 'Model licences', url: `${SITE_URL}/licenses`, description: metadata.description, mainEntity: { '@type': 'ItemList', numberOfItems: all.length, itemListElement: all.slice(0, 12).map((l, i) => ({ '@type': 'ListItem', position: i + 1, name: l.label, url: `${SITE_URL}/licenses/${encodeURIComponent(l.key)}` })) } };

  return (
    <Container wide>
      <script type="application/ld+json" dangerouslySetInnerHTML={{ __html: JSON.stringify(ld) }} />
      <PageHeader eyebrow="Licences" title="Model licences" lede="The canonical licence ontology behind the openness classification. Permissions are read from each licence text; a dash means the text is ambiguous — never assumed." aside={res ? <p className="tnum text-sm text-ink-3">{fmtInt(items.length)}{category ? ` of ${fmtInt(all.length)}` : ''} licences</p> : undefined}>
        {cats.length > 0 && (
          <nav aria-label="Category" className="no-scrollbar -mx-4 mt-6 flex gap-1.5 overflow-x-auto px-4 md:mx-0 md:flex-wrap md:px-0">
            <Link href="/licenses" className={chip(!category)} aria-current={!category ? 'true' : undefined}>
              All <span className="tnum opacity-70">{fmtInt(all.length)}</span>
            </Link>
            {cats.map(({ c, n, models }) => (
              <Link key={c} href={`/licenses?category=${encodeURIComponent(c)}`} className={chip(category === c)} aria-current={category === c ? 'true' : undefined} title={`${CATEGORY_HINT[c] ?? c} · ${fmtInt(models)} models`}>
                {c} <span className="tnum opacity-70">{fmtInt(n)}</span>
              </Link>
            ))}
          </nav>
        )}
      </PageHeader>
      <div className="pb-16">
        {!res ? (
          <Unavailable what="Licences" />
        ) : (
          <>
            {category && CATEGORY_HINT[category] && <p className="mb-3 text-sm text-ink-2">{CATEGORY_HINT[category]}</p>}
            <ScrollX><DataTable caption="Licences" compact>
              <thead>
                <tr>
                  <Th>Licence</Th>
                  <Th>Category</Th>
                  {LICENCE_DIMENSIONS.slice(0, 5).map((d) => (
                    <Th key={d.key} title={d.hint} className="cursor-help underline decoration-dotted decoration-rule-strong underline-offset-2">
                      {d.label}
                    </Th>
                  ))}
                  <Th num>Models</Th>
                </tr>
              </thead>
              <tbody>
                {items.length === 0 && <EmptyRow cols={8}>No licence in this category.</EmptyRow>}
                {items.map((l) => (
                  <tr key={l.key}>
                    <Td primary>
                      <Link href={`/licenses/${encodeURIComponent(l.key)}`} className="text-ink hover:text-accent hover:underline">
                        {l.label}
                      </Link>
                      <span className="mono block text-[11px] text-ink-3">
                        {l.key}
                        {l.spdx && l.spdx !== l.key ? ` · SPDX ${l.spdx}` : ''}
                        {l.osi_approved ? ' · OSI' : ''}
                      </span>
                    </Td>
                    <Td label="Category" className="text-ink-2">
                      <Link href={`/licenses?category=${encodeURIComponent(l.category)}`} className="hover:text-accent">
                        {l.category}
                      </Link>
                    </Td>
                    {LICENCE_DIMENSIONS.slice(0, 5).map((d) => (
                      <Td key={d.key} label={d.label}>
                        <Tri v={l[d.key] as boolean | null} yes={d.invert ? 'Yes — restricted' : 'Yes'} no={d.invert ? 'None' : 'No'} />
                      </Td>
                    ))}
                    <Td num label="Models" className="tnum">
                      {num(l.models) ? (
                        <Link href={`/models?license=${encodeURIComponent(l.key)}`} className="hover:text-accent">
                          {fmtInt(l.models)}
                        </Link>
                      ) : (
                        <span className="text-ink-3">0</span>
                      )}
                    </Td>
                  </tr>
                ))}
              </tbody>
            </DataTable></ScrollX>
            {res.unclassified?.length > 0 && (
              <section className="mt-8">
                <p className="eyebrow mb-2">
                  Unclassified licence labels <span className="tnum text-ink-3">{fmtInt(res.unclassified.length)}</span>
                </p>
                <ul className="flex flex-wrap gap-1.5 text-xs">
                  {res.unclassified.map((u) => (
                    <li key={u.raw} className="border border-dashed border-rule-strong px-2 py-1 text-ink-2">
                      “{u.raw}” <span className="tnum text-ink-3">{fmtInt(u.models)}</span>
                    </li>
                  ))}
                </ul>
              </section>
            )}
            <Note className="mt-3">{res.note ?? 'Permissions are read from the licence text (null = the text is ambiguous). Counts cover canonical models only.'} Hosting restrictions / acceptable-use: “Yes — restricted” means the clause exists.</Note>
            <dl className="mt-3 grid gap-x-6 gap-y-1 text-[11px] text-ink-3 sm:grid-cols-2 lg:grid-cols-3" data-licence-definitions>
              {LICENCE_DIMENSIONS.map((d) => (
                <div key={d.key} className="flex gap-1.5">
                  <dt className="shrink-0 font-medium text-ink-2">{d.label}</dt>
                  <dd className="flex items-center gap-1">
                    {d.hint}
                    <Hint text={d.hint} align="right" className="hidden" />
                  </dd>
                </div>
              ))}
            </dl>
          </>
        )}
      </div>
    </Container>
  );
}