import Link from 'next/link';
import { Section } from '@/components/ui/section';
import { EmptyState } from '@/components/ui/empty-state';
import { Freshness } from '@/components/ui/freshness';
import { Badge, ClaimBadge } from '@/components/ui/badge';
import { SourceBadge } from '@/components/ui/source-badge';
import { getGeographyBySlug, cagrFor, CAGR_FORMULA, CAGR_FORMULA_VERSION } from '@/lib/queries/geography';
import { fmtNum, fmtValue, fmtInt, toDate } from '@/lib/format';

/**
 * Home module "Fastest-rising incidence" (§105, §328): ASIR compound annual growth rate over the last ten
 * available years, computed on the fly from observations. Shown only when ≥ 10 years exist; labelled as
 * derived, with the formula and both endpoints on every row so the number can be reproduced.
 */
export async function RisingModule({ slug = 'united-states', limit = 8 }: { slug?: string; limit?: number }) {
  const geo = await getGeographyBySlug(slug);
  const res = geo ? await cagrFor(geo.id, 'as_incidence_rate', 'all', 10) : null;
  const rows = res?.rows.slice(0, limit) ?? [];
  const first = rows[0];
  return (
    <Section
      id="rising"
      kicker="Trend"
      title={`Fastest-rising incidence${geo ? ` · ${geo.name}` : ''}`}
      description={res ? `Age-standardized incidence rate, both sexes, all ages: compound annual growth rate between ${res.startYear} and ${res.endYear} (the last 10 years published). Derived by CancerIndex from registry observations; not a source figure.` : 'Age-standardized incidence rate: compound annual growth rate over the last 10 published years.'}
      actions={
        geo ? (
          <Link href={`/country/${slug}#trend`} className="ci-link">
            Trend chart →
          </Link>
        ) : undefined
      }
    >
      {!res || rows.length === 0 ? (
        <EmptyState title="Not enough years to compute a trend">
          A 10-year growth rate is computed only when at least ten distinct years of age-standardized incidence exist for the geography{res ? ` (${res.yearsAvailable} available)` : ''}. Nothing is extrapolated from shorter series.
        </EmptyState>
      ) : (
        <>
          <div className="ci-table-wrap">
            <table className="ci-table">
              <thead>
                <tr>
                  <th>Cancer</th>
                  <th className="num">CAGR (%/yr)</th>
                  <th className="num">{res.startYear} (per 100,000)</th>
                  <th className="num">{res.endYear} (per 100,000)</th>
                  <th className="num">Years</th>
                </tr>
              </thead>
              <tbody>
                {rows.map((r) => (
                  <tr key={r.cancer_id}>
                    <td>
                      <Link className="ci-link" href={`/cancer/${r.slug}/statistics`}>
                        {r.canonical_name}
                      </Link>
                      {r.estimate_types.some((t) => t !== 'observed') ? <Badge tone="warn" className="ml-1.5">includes estimates</Badge> : null}
                    </td>
                    <td className={`num font-medium ${r.cagr > 0 ? 'text-danger' : r.cagr < 0 ? 'text-ok' : ''}`}>
                      {r.cagr > 0 ? '+' : ''}
                      {fmtNum(r.cagr * 100, 2)}
                    </td>
                    <td className="num">{fmtValue(r.start_value, r.unit)}</td>
                    <td className="num">{fmtValue(r.end_value, r.unit)}</td>
                    <td className="num text-ink-3">{fmtInt(r.n_years)}</td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
          <div className="mt-2 flex flex-wrap items-center gap-1.5 text-[12px] text-ink-3">
            <ClaimBadge kind="computed" />
            {first ? <SourceBadge p={{ sourceSlug: first.source_slug, layer: 'derived', note: 'Inputs are the two endpoint observations (start and end year) of the source series.' }} /> : null}
            <span>
              formula: <code className="ci-mono">{CAGR_FORMULA}</code>
            </span>
            <span className="ci-mono">{CAGR_FORMULA_VERSION}</span>
            {first?.standard_population ? <span>standard: {first.standard_population}</span> : null}
          </div>
          <p className="mt-1 text-[12px] text-ink-3">
            Rising incidence can reflect true risk changes, screening or diagnostic practice, coding changes or population ageing beyond what standardization removes; the rate says nothing about causes. Falling rates are listed on the <Link className="ci-link" href="/methodology#cagr">methodology page</Link> definition.
          </p>
          <Freshness dataUpdatedAt={rows.map((r) => toDate(r.updated_at)).filter((d): d is Date => !!d).sort((a, b) => b.getTime() - a.getTime())[0] ?? null} sourceVersion={`${res.startYear}–${res.endYear}`} extra={`${fmtInt(res.rows.length)} cancers with a complete 10-year series`} />
        </>
      )}
    </Section>
  );
}