import type { Metadata } from 'next';
import Link from 'next/link';
import { notFound } from 'next/navigation';
import { PageHeader, Section, Note } from '@/components/ui/section';
import { EmptyState } from '@/components/ui/empty-state';
import { Freshness } from '@/components/ui/freshness';
import { Badge, ClaimBadge, StatusBadge } from '@/components/ui/badge';
import { SourceBadge } from '@/components/ui/source-badge';
import { EPI_METRIC_LABEL } from '@/lib/queries/epidemiology';
import { YEAR_MIN, yearApprovalCounts, yearApprovals, yearEpidemiology, yearLiterature, yearTopSponsors, yearTrialTotals, yearTrialsByCancer, yearTrialsByPhase, yearsWithData } from '@/lib/queries/year';
import { fmtDate, fmtInt, fmtPct, humanize, phaseLabel, truncate } from '@/lib/format';

export const revalidate = 3600;

type Params = { year: string };

function parseYear(raw: string): number | null {
  if (!/^\d{4}$/.test(raw)) return null;
  const y = Number(raw);
  const max = new Date().getUTCFullYear();
  return y >= YEAR_MIN && y <= max ? y : null;
}

export async function generateMetadata({ params }: { params: Promise<Params> }): Promise<Metadata> {
  const y = parseYear((await params).year);
  return y ? { title: `${y} in cancer`, description: `Oncology approvals, registered studies, research output and registry data of ${y}, from dated records in the index.`, alternates: { canonical: `/year/${y}` } } : { title: 'Year' };
}

export default async function YearPage({ params }: { params: Promise<Params> }) {
  const year = parseYear((await params).year);
  if (year == null) notFound();
  const [years, approvalCounts, approvals, phases, totals, byCancer, sponsors, lit, epi] = await Promise.all([yearsWithData(), yearApprovalCounts(year), yearApprovals(year, 60), yearTrialsByPhase(year), yearTrialTotals(year), yearTrialsByCancer(year, 12), yearTopSponsors(year, 10), yearLiterature(year, 15), yearEpidemiology(year)]);
  const current = new Date().getUTCFullYear();
  const partial = year === current;
  const prev = years.find((y) => y < year);
  const next = [...years].reverse().find((y) => y > year);
  const totalApprovals = approvalCounts.reduce((s, r) => s + r.n, 0);

  return (
    <div className="pb-8">
      <PageHeader kicker="Year in cancer" title={`${year} in cancer`} lede={`What the index holds for ${year}: regulatory decisions dated that year, studies first posted that year, PubMed output per cancer for that year and the registry observations whose reference year it is. Every figure is a count of dated source records — nothing is estimated${partial ? '; the current year is incomplete by construction' : ''}.`}>
        <nav aria-label="Years" className="mt-3 flex flex-wrap items-center gap-2 text-[13px]">
          {prev ? (
            <Link href={`/year/${prev}`} className="ci-chip">
              ← {prev}
            </Link>
          ) : null}
          {next ? (
            <Link href={`/year/${next}`} className="ci-chip">
              {next} →
            </Link>
          ) : null}
          <span className="text-ink-3">Years with data: {years.length ? `${years[years.length - 1]}–${years[0]}` : 'none'}</span>
          <Link href="/pulse" className="ci-link">
            Last 30 days →
          </Link>
        </nav>
      </PageHeader>

      {partial ? <Note tone="warn">{year} is still in progress: counts grow with each connector run and registries have not yet published {year} observations.</Note> : null}

      <div className="mt-6 grid gap-10 lg:grid-cols-[1.35fr_1fr]">
        <div className="space-y-10">
          <Section id="approvals" kicker="Regulatory" title={`Approval records dated ${year} (${fmtInt(totalApprovals)})`} description="Approved, accelerated or conditional records by authority; original applications and records naming one cancer are listed first. One record is one decision for one application or product identifier.">
            {approvalCounts.length ? (
              <>
                <p className="mb-2 flex flex-wrap gap-1.5 text-[12px]">
                  {approvalCounts.map((r) => (
                    <Badge key={`${r.authority}-${r.jurisdiction}`} tone="outline" title={`${r.drugs} distinct drugs · ${r.with_cancer} records naming one cancer`}>
                      {r.authority} · {r.jurisdiction}: {fmtInt(r.n)} records / {fmtInt(r.drugs)} drugs
                    </Badge>
                  ))}
                </p>
                <ul className="divide-y divide-rule text-[13.5px]">
                  {approvals.map((a) => (
                    <li key={a.id} className="grid gap-x-3 py-2 sm:grid-cols-[92px_1fr]">
                      <span className="ci-mono text-[12px] text-ink-3">{fmtDate(a.approval_date)}</span>
                      <span className="min-w-0">
                        <Link href={`/drug/${a.drug_slug}`} className="ci-link font-medium">
                          {a.drug_name}
                        </Link>{' '}
                        <Badge tone="outline">
                          {a.authority} · {a.jurisdiction}
                        </Badge>{' '}
                        {a.approval_type ? <Badge tone={a.approval_type === 'ORIG' ? 'accent' : 'neutral'}>{a.approval_type === 'ORIG' ? 'original application' : a.approval_type === 'SUPPL' ? 'supplement' : a.approval_type}</Badge> : null}{' '}
                        {a.accelerated ? <Badge tone="warn">accelerated</Badge> : null}{' '}
                        <StatusBadge status={a.status} />{' '}
                        {a.cancer_slug ? (
                          <Link href={`/cancer/${a.cancer_slug}`} className="ci-link">
                            {a.cancer_name}
                          </Link>
                        ) : a.tumor_agnostic ? (
                          <Badge tone="accent">tumor-agnostic</Badge>
                        ) : (
                          <span className="text-ink-3">cancer not stated in this record</span>
                        )}
                        <span className="mt-0.5 block text-[12.5px] text-ink-2" title={a.indication}>
                          {truncate(a.indication, 160)}
                        </span>
                        <SourceBadge p={{ sourceSlug: a.source_slug }} compact />
                      </span>
                    </li>
                  ))}
                </ul>
                <p className="mt-2 flex items-center gap-2 text-[12px]">
                  <ClaimBadge kind="regulatory" />
                  <Link href={`/approvals?from=${year}&to=${year}`} className="ci-link">
                    All {year} records with filters →
                  </Link>
                </p>
              </>
            ) : (
              <EmptyState compact title={`No approval record dated ${year}`}>Approval records exist from the authorities ingested (FDA via openFDA, Health Canada, EMA); older decisions may be undated in the source.</EmptyState>
            )}
          </Section>

          <Section id="trials" kicker="Clinical research" title={`Studies first posted in ${year}`} description="ClinicalTrials.gov oncology studies whose first-posted date falls in the year (all study types unless stated). Cancer attribution uses reconciled conditions over descendants; one study can count for several top-level cancers.">
            {totals ? (
              <>
                <dl className="mb-3 grid grid-cols-2 gap-x-6 gap-y-2 text-[13.5px] sm:grid-cols-3 lg:grid-cols-6">
                  {[
                    ['Studies', totals.total],
                    ['Interventional', totals.interventional],
                    ['Phase III', totals.phase3],
                    ['Industry-led', totals.industry],
                    ['With posted results', totals.with_results],
                    ['Countries with sites', totals.countries],
                  ].map(([k, v]) => (
                    <div key={String(k)}>
                      <dt className="ci-kicker">{k}</dt>
                      <dd className="ci-num text-left font-display text-2xl">{fmtInt(v as number)}</dd>
                    </div>
                  ))}
                </dl>
                <div className="grid gap-6 lg:grid-cols-2">
                  <div className="ci-table-wrap">
                    <table className="ci-table">
                      <caption className="pb-1 text-[12.5px] text-ink-3">By phase (a study with two phases counts in both)</caption>
                      <thead>
                        <tr>
                          <th>Phase</th>
                          <th className="num">Studies</th>
                          <th className="num">Interventional</th>
                          <th className="num">Industry share</th>
                        </tr>
                      </thead>
                      <tbody>
                        {phases.map((p) => (
                          <tr key={p.phase}>
                            <td>{p.phase === 'NA' ? 'Not applicable / not stated' : phaseLabel(p.phase)}</td>
                            <td className="num">{fmtInt(p.n)}</td>
                            <td className="num">{fmtInt(p.interventional)}</td>
                            <td className="num text-ink-3">{fmtPct(p.n ? p.industry / p.n : 0, 0)}</td>
                          </tr>
                        ))}
                      </tbody>
                    </table>
                  </div>
                  <div className="ci-table-wrap">
                    <table className="ci-table">
                      <caption className="pb-1 text-[12.5px] text-ink-3">Top-level cancers by studies (descendants included)</caption>
                      <thead>
                        <tr>
                          <th>Cancer</th>
                          <th className="num">Studies</th>
                          <th className="num">Phase III</th>
                        </tr>
                      </thead>
                      <tbody>
                        {byCancer.map((c) => (
                          <tr key={c.id}>
                            <td>
                              <Link href={`/cancer/${c.slug}/trials`} className="ci-link">
                                {c.canonical_name}
                              </Link>
                            </td>
                            <td className="num">{fmtInt(c.trials)}</td>
                            <td className="num">{fmtInt(c.phase3)}</td>
                          </tr>
                        ))}
                      </tbody>
                    </table>
                  </div>
                </div>
                <div className="mt-4 ci-table-wrap">
                  <table className="ci-table">
                    <caption className="pb-1 text-[12.5px] text-ink-3">Lead sponsors of interventional studies first posted in {year}</caption>
                    <thead>
                      <tr>
                        <th>Lead sponsor</th>
                        <th>Class</th>
                        <th className="num">Studies</th>
                        <th className="num">Phase III</th>
                      </tr>
                    </thead>
                    <tbody>
                      {sponsors.map((s) => (
                        <tr key={s.lead_sponsor}>
                          <td>
                            <Link href={`/trials?q=${encodeURIComponent(s.lead_sponsor)}`} className="ci-link">
                              {s.lead_sponsor}
                            </Link>
                          </td>
                          <td className="text-[12.5px] text-ink-3">{s.lead_sponsor_class ? humanize(s.lead_sponsor_class) : '—'}</td>
                          <td className="num">{fmtInt(s.n)}</td>
                          <td className="num">{fmtInt(s.phase3)}</td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <p className="mt-2 flex items-center gap-2 text-[12px]">
                  <ClaimBadge kind="published" /> <span className="text-ink-3">source: clinicaltrials · first_posted_date as posted</span>
                </p>
              </>
            ) : (
              <EmptyState compact title={`No study first posted in ${year} in the index`}>The ClinicalTrials.gov connector ingests oncology studies of every year; first-posted dates start in 1999 for most registrations.</EmptyState>
            )}
          </Section>
        </div>

        <aside className="space-y-10">
          <Section id="literature" kicker="Research output" title={`PubMed records, ${year}`} description="Records matching each top-level cancer's stored PubMed query with a publication year equal to this year, with the previous year for comparison. A count of indexed records, not of scientific impact.">
            {lit.length ? (
              <>
                <div className="ci-table-wrap">
                  <table className="ci-table">
                    <thead>
                      <tr>
                        <th>Cancer</th>
                        <th className="num">{year}</th>
                        <th className="num">{year - 1}</th>
                        <th className="num">Change</th>
                      </tr>
                    </thead>
                    <tbody>
                      {lit.map((l) => {
                        const d = l.prev_count ? ((l.count - l.prev_count) / l.prev_count) * 100 : null;
                        return (
                          <tr key={l.id}>
                            <td>
                              <Link href={`/cancer/${l.slug}/research`} className="ci-link" title={l.query}>
                                {l.canonical_name}
                              </Link>
                            </td>
                            <td className="num">{fmtInt(l.count)}</td>
                            <td className="num text-ink-3">{l.prev_count == null ? '—' : fmtInt(l.prev_count)}</td>
                            <td className={`num ${d == null ? 'text-ink-4' : d > 0 ? 'text-ok' : d < 0 ? 'text-danger' : 'text-ink-3'}`}>{d == null ? '—' : `${d > 0 ? '+' : ''}${d.toFixed(0)} %`}</td>
                          </tr>
                        );
                      })}
                    </tbody>
                  </table>
                </div>
                <p className="mt-2 flex items-center gap-2 text-[12px]">
                  <ClaimBadge kind="computed" /> <span className="text-ink-3">literature_counts · window y{year} · query stored per row (hover a cancer)</span>
                </p>
                <Freshness dataUpdatedAt={lit[0]?.computed_at ?? null} extra="source: pubmed" />
              </>
            ) : (
              <EmptyState compact title={`No literature window for ${year}`}>Yearly PubMed windows are computed from 2016 onwards for entities with a stored query.</EmptyState>
            )}
          </Section>

          <Section id="epidemiology" kicker="Registries" title={`Observations with reference year ${year}`} description="What registries have published for this year: observations by source, metric and geography. Registries publish with a lag of one to three years.">
            {epi.length ? (
              <div className="ci-table-wrap">
                <table className="ci-table">
                  <thead>
                    <tr>
                      <th>Geography</th>
                      <th>Metric</th>
                      <th>Source</th>
                      <th className="num">Observations</th>
                      <th className="num">Cancers</th>
                    </tr>
                  </thead>
                  <tbody>
                    {epi.map((e) => (
                      <tr key={`${e.geography_slug}-${e.metric}-${e.source_slug}`}>
                        <td>
                          <Link href={`/country/${e.geography_slug}?year=${year}`} className="ci-link">
                            {e.geography_name}
                          </Link>
                        </td>
                        <td className="text-[12.5px]">{EPI_METRIC_LABEL[e.metric] ?? humanize(e.metric)}</td>
                        <td>
                          <SourceBadge p={{ sourceSlug: e.source_slug, sourceName: e.source_name }} compact />
                        </td>
                        <td className="num">{fmtInt(e.n)}</td>
                        <td className="num">{fmtInt(e.cancers)}</td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            ) : (
              <EmptyState compact title={`No registry observation for ${year} yet`}>Registries publish with a lag; explore available years in the Data explorer.</EmptyState>
            )}
            <p className="mt-2 text-[12px]">
              <Link href={`/explore?from=${year}&to=${year}`} className="ci-link">
                Open {year} in the Data explorer →
              </Link>
            </p>
          </Section>
        </aside>
      </div>
    </div>
  );
}