import Link from 'next/link';
import { TOP_LEVEL_CANCERS } from '@cancerindex/ontology';
import { CommandPalette } from '@/components/layout/command-palette';
import { EmptyState } from '@/components/ui/empty-state';
import { Freshness } from '@/components/ui/freshness';
import { Section } from '@/components/ui/section';
import { Badge, ClaimBadge, ConfidenceBadge, StatusBadge } from '@/components/ui/badge';
import { getSiteCounts, getRareSpotlight } from '@/lib/queries/stats';
import { previewSnapshot } from '@/lib/queries/rankings';
import { mostActiveResearch, mostCuratedEvidence } from '@/lib/queries/trials';
import { resolveTopLevel } from '@/lib/queries/cancers';
import { listSources } from '@/lib/queries/sources';
import { fmtInt, fmtValue, fmtDate, scopeLabel, unitLabel, humanize, parseScopeKey } from '@/lib/format';
import { BurdenModule } from '@/components/home/burden-module';
import { RisingModule } from '@/components/home/rising-module';
import { GapsModule } from '@/components/home/gaps-module';

export const revalidate = 900;

export default async function HomePage() {
  const [counts, spotlight, preview, active, curated, sources] = await Promise.all([
    getSiteCounts(),
    getRareSpotlight(),
    previewSnapshot(['mortality_count', 'incidence_count', 'as_mortality_rate', 'active_trials', 'publications_5y', 'curated_evidence_items']),
    mostActiveResearch(8),
    mostCuratedEvidence(8),
    listSources(),
  ]);
  const topLevel = await resolveTopLevel(TOP_LEVEL_CANCERS.map((t) => t.ncit));
  const topMatched = TOP_LEVEL_CANCERS.filter((t) => topLevel.has(t.ncit)).length;

  const ticker: Array<{ label: string; value: number; note: string; href: string }> = [
    { label: 'Cancers indexed', value: counts.cancers, note: 'active malignant disease entities', href: '/cancers?malignant=1' },
    { label: 'Subtypes', value: counts.subtypes, note: 'histologic and molecular subtypes', href: '/cancers?entity_type=subtype' },
    { label: 'Genes', value: counts.genes, note: 'HGNC gene records', href: '/genes' },
    { label: 'Variants', value: counts.variants, note: 'distinct variant entities', href: '/genes' },
    { label: 'Clinical trials', value: counts.trials, note: 'ClinicalTrials.gov studies ingested', href: '/trials' },
    { label: 'Publications', value: counts.publications, note: 'PubMed records linked', href: '/search' },
    { label: 'Sources', value: counts.sources, note: `${counts.activeSources} active connector${counts.activeSources === 1 ? '' : 's'}`, href: '/sources' },
  ];

  return (
    <div className="pb-8">
      {/* Hero */}
      <section className="pt-10 sm:pt-16" aria-labelledby="hero-title">
        <p className="ci-kicker mb-3">Provenance-first oncology intelligence</p>
        <h1 id="hero-title" className="max-w-4xl text-4xl leading-[1.05] sm:text-6xl">
          CancerIndex — <span className="italic text-ink-2">The global index of cancer.</span>
        </h1>
        <p className="mt-4 max-w-2xl text-[16px] leading-relaxed text-ink-2">
          Every recognized malignant disease entity — taxonomy, epidemiology, genomics, variants, therapies, trials, literature and transparent rankings — with a source, a date and a formula version on every number.
        </p>
        <div className="mt-6 max-w-2xl">
          <CommandPalette variant="hero" />
          <p className="mt-2 text-[12.5px] text-ink-3">
            Try <Link className="ci-link" href="/search?q=glioma">glioma</Link>, <Link className="ci-link" href="/search?q=KRAS">KRAS</Link>, <Link className="ci-link" href="/search?q=osimertinib">osimertinib</Link> or an NCT number.
          </p>
        </div>
      </section>

      {/* Ticker */}
      <section aria-label="Index counts" className="ci-rule mt-10 pt-4">
        <ul className="grid grid-cols-2 gap-x-6 gap-y-4 sm:grid-cols-4 lg:grid-cols-7">
          {ticker.map((t) => (
            <li key={t.label}>
              <Link href={t.href} className="block no-underline">
                <span className="ci-num block font-display text-2xl text-ink sm:text-3xl">{fmtInt(t.value)}</span>
                <span className="block text-[12.5px] font-medium text-ink-2">{t.label}</span>
                <span className="block text-[11.5px] text-ink-3">{t.note}</span>
              </Link>
            </li>
          ))}
        </ul>
        <Freshness dataUpdatedAt={counts.lastIngestAt} extra="Counts are live database counts, not estimates" />
      </section>

      <div className="mt-10 grid gap-10 lg:grid-cols-[1.35fr_1fr]">
        <div className="space-y-10">
          {/* Cancer burden (US, latest year) — §105 "Cancer burden today" */}
          <BurdenModule slug="united-states" />

          {/* Rankings preview */}
          <Section
            id="rankings"
            kicker={preview && parseScopeKey(preview.snapshot.scope_key).geo !== 'WORLD' ? `Rankings · ${parseScopeKey(preview.snapshot.scope_key).geo}` : 'Global rankings'}
            title={preview ? preview.metric.name : 'Global rankings'}
            description={preview ? `${scopeLabel(preview.snapshot.scope_key)} · formula ${preview.snapshot.formula_version} · generated ${fmtDate(preview.snapshot.generated_at)} · ${fmtInt(preview.snapshot.eligible_entities)} eligible entities` : undefined}
            actions={
              <Link href="/rankings" className="ci-link">
                All rankings →
              </Link>
            }
          >
            {preview ? (
              <>
                {!preview.metric.slug.match(/incidence|mortality|survival/) ? (
                  <p className="mb-2 text-[12.5px] text-ink-3">No epidemiology-based ranking has been computed yet (awaiting licensed burden data). Showing the research-activity ranking instead — it measures registered activity, not disease burden.</p>
                ) : null}
                <div className="ci-table-wrap">
                  <table className="ci-table">
                    <thead>
                      <tr>
                        <th className="num">#</th>
                        <th>Cancer</th>
                        <th className="num">
                          {preview.metric.name} ({unitLabel(preview.metric.unit)})
                        </th>
                        <th>Confidence</th>
                      </tr>
                    </thead>
                    <tbody>
                      {preview.rows.map((r) => (
                        <tr key={r.id}>
                          <td className="num">{r.rank}</td>
                          <td>
                            <Link className="ci-link" href={`/cancer/${r.slug}`}>
                              {r.canonical_name}
                            </Link>
                          </td>
                          <td className="num">{fmtValue(r.value, r.unit)}</td>
                          <td>
                            <ConfidenceBadge level={r.confidence} />
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <div className="mt-2 flex items-center gap-2">
                  <ClaimBadge kind="computed" />
                  <Link href={`/rankings/${preview.metric.slug}?scope=${encodeURIComponent(preview.snapshot.scope_key)}`} className="ci-link text-[13px]">
                    Full table, methodology and "Why this rank?" →
                  </Link>
                </div>
                <Freshness dataUpdatedAt={preview.snapshot.generated_at} extra={`sources: ${preview.snapshot.source_ids.join(', ') || 'see methodology'}`} />
              </>
            ) : (
              <EmptyState title="Rankings not yet computed">
                Ranking snapshots are produced by the ranking engine once counters and licensed epidemiology observations are available. Nothing is shown until a snapshot exists with a scope, a formula version and an inputs hash.
                <div className="mt-1">
                  <Link href="/methodology" className="ci-link">
                    Read how rankings are computed
                  </Link>
                </div>
              </EmptyState>
            )}
          </Section>

          {/* Fastest-rising incidence (derived on the fly, §105/§328) */}
          <RisingModule slug="united-states" />

          {/* Largest trial / research gaps (§105, §265-266) */}
          <GapsModule geo="USA" />

          {/* Active research */}
          <Section id="active-research" kicker="Clinical research" title="Most active clinical research" description="Cancers with the most interventional trials in an active status (recruiting, not yet recruiting, enrolling by invitation, active not recruiting), counted over the entity and its descendants.">
            {active.length ? (
              <>
                <div className="ci-table-wrap">
                  <table className="ci-table">
                    <thead>
                      <tr>
                        <th>Cancer</th>
                        <th className="num">Active trials (count)</th>
                        <th className="num">Recruiting (count)</th>
                      </tr>
                    </thead>
                    <tbody>
                      {active.map((r) => (
                        <tr key={r.slug}>
                          <td>
                            <Link className="ci-link" href={`/cancer/${r.slug}/trials`}>
                              {r.canonical_name}
                            </Link>
                          </td>
                          <td className="num">{fmtInt(r.active_trial_count)}</td>
                          <td className="num">{fmtInt(r.recruiting_trial_count)}</td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <Freshness dataUpdatedAt={active[0]?.computed_at} extra="source: clinicaltrials · counters refreshed deterministically" />
              </>
            ) : (
              <EmptyState>
                No clinical trials have been ingested yet; trial counters are computed from ClinicalTrials.gov conditions mapped to the taxonomy.
                <div className="mt-1">
                  <Link href="/trials" className="ci-link">
                    Trials explorer
                  </Link>
                </div>
              </EmptyState>
            )}
          </Section>

          {/* Curated evidence */}
          <Section id="curated" kicker="Molecular knowledge" title="Most curated molecular evidence" description="Accepted CIViC evidence items whose disease maps to the cancer or its descendants.">
            {curated.length ? (
              <>
                <div className="ci-table-wrap">
                  <table className="ci-table">
                    <thead>
                      <tr>
                        <th>Cancer</th>
                        <th className="num">Evidence items (count)</th>
                        <th className="num">Genes (count)</th>
                      </tr>
                    </thead>
                    <tbody>
                      {curated.map((r) => (
                        <tr key={r.slug}>
                          <td>
                            <Link className="ci-link" href={`/cancer/${r.slug}/evidence`}>
                              {r.canonical_name}
                            </Link>
                          </td>
                          <td className="num">{fmtInt(r.evidence_count)}</td>
                          <td className="num">{fmtInt(r.gene_count)}</td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <Freshness dataUpdatedAt={curated[0]?.computed_at} extra="source: civic" />
              </>
            ) : (
              <EmptyState>No curated evidence items have been ingested yet. CIViC evidence will appear here grouped by cancer, with native evidence levels and directions.</EmptyState>
            )}
          </Section>
        </div>

        <aside className="space-y-10">
          {/* Taxonomy at a glance */}
          <Section
            id="taxonomy"
            kicker="Taxonomy at a glance"
            title="Top-level cancers"
            description={`${topMatched} of ${TOP_LEVEL_CANCERS.length} registry site groups are currently resolved to an indexed entity through their NCIt anchor code.`}
            actions={
              <Link href="/taxonomy" className="ci-link">
                Tree browser →
              </Link>
            }
          >
            <ul className="columns-1 gap-6 text-[13.5px] sm:columns-2">
              {TOP_LEVEL_CANCERS.map((t) => {
                const m = topLevel.get(t.ncit);
                return (
                  <li key={t.key} className="flex items-baseline justify-between gap-2 border-b border-rule py-1">
                    {m ? (
                      <Link href={`/cancer/${m.slug}`} className="ci-link truncate">
                        {t.name}
                      </Link>
                    ) : (
                      <span className="truncate text-ink-3" title={`NCIt ${t.ncit} not yet indexed`}>
                        {t.name}
                      </span>
                    )}
                    <span className="ci-num shrink-0 text-[11.5px] text-ink-3">{m ? (m.descendant_count != null ? `${fmtInt(m.descendant_count)} desc.` : <span className="ci-mono">{t.ncit}</span>) : 'pending'}</span>
                  </li>
                );
              })}
            </ul>
            <p className="mt-2 text-[11.5px] text-ink-3">Site groups follow GLOBOCAN / ICD-10 ranges so burden estimates attach without double counting. "pending" = NCIt concept not yet ingested.</p>
          </Section>

          {/* Rare spotlight */}
          <Section id="spotlight" kicker="Rare cancer spotlight" title={spotlight ? spotlight.canonicalName : 'Spotlight'} description="A deterministic daily pick among indexed malignant entities, chosen to surface the long tail of the taxonomy rather than the thirty most common cancers.">
            {spotlight ? (
              <div className="text-[13.5px]">
                <div className="flex flex-wrap items-center gap-1.5">
                  <Badge>{humanize(spotlight.entityType)}</Badge>
                  {spotlight.primaryOncotreeCode ? <Badge mono>OncoTree {spotlight.primaryOncotreeCode}</Badge> : null}
                  {spotlight.rareCancer === true ? <Badge tone="accent">Rare</Badge> : null}
                </div>
                {spotlight.parentName ? (
                  <p className="mt-2 text-ink-2">
                    Classified under{' '}
                    <Link className="ci-link" href={`/cancer/${spotlight.parentSlug}`}>
                      {spotlight.parentName}
                    </Link>
                    .
                  </p>
                ) : null}
                <p className="mt-1 text-ink-3">{spotlight.rareCancer == null ? 'Rarity status unknown: no incidence observation is attached yet.' : null}</p>
                <Link href={`/cancer/${spotlight.slug}`} className="ci-link mt-2 inline-block">
                  Open entity →
                </Link>
              </div>
            ) : (
              <EmptyState compact>No malignant entity indexed yet.</EmptyState>
            )}
          </Section>

          {/* Sources */}
          <Section
            id="sources"
            kicker="Sources"
            title="Source registry"
            actions={
              <Link href="/sources" className="ci-link">
                Coverage matrix →
              </Link>
            }
          >
            {sources.length ? (
              <ul className="divide-y divide-rule text-[13.5px]">
                {sources.map((s) => (
                  <li key={s.slug} className="flex flex-wrap items-center justify-between gap-2 py-1.5">
                    <Link className="ci-link" href={`/source/${s.slug}`}>
                      {s.name}
                    </Link>
                    <span className="flex items-center gap-1.5">
                      <StatusBadge status={s.status} />
                      <Badge tone={s.license_status === 'approved' ? 'ok' : s.license_status === 'blocked' ? 'danger' : 'warn'} title="License review status">
                        license: {s.license_status}
                      </Badge>
                    </span>
                  </li>
                ))}
              </ul>
            ) : (
              <EmptyState compact>No source registered.</EmptyState>
            )}
            <Freshness dataUpdatedAt={sources.reduce<Date | null>((m, s) => (s.last_run_finished_at && (!m || s.last_run_finished_at > m) ? s.last_run_finished_at : m), null)} extra="License status is reviewed before any connector goes live" />
          </Section>
        </aside>
      </div>
    </div>
  );
}