import type { Metadata } from 'next';
import Link from 'next/link';
import { STOP_REASON_CATEGORIES, STOP_REASON_RULES, STOP_REASON_RULES_VERSION, isStopReasonCategory, type StopReasonCategory } from '@cancerindex/ranking';
import { PageHeader, Note } from '@/components/ui/section';
import { EmptyState } from '@/components/ui/empty-state';
import { Freshness } from '@/components/ui/freshness';
import { Pager } from '@/components/ui/pager';
import { Badge, ClaimBadge, StatusBadge } from '@/components/ui/badge';
import { TableProvenance } from '@/components/ui/source-badge';
import { BarChart } from '@/components/charts/bar-chart';
import { listTerminated, stoppedYears, STOPPED_STATUSES } from '@/lib/queries/trial-intelligence';
import { getCancerBySlug, getDescendantIds } from '@/lib/queries/cancers';
import { fmtDate, fmtInt, fmtPct, humanize, phaseLabel, truncate } from '@/lib/format';
import { reasonLabel } from '@/lib/trial-intel';
import { pageInfo } from '@/lib/pagination';
import { str, int, withParams, type SP } from '@/lib/search-params';

export const metadata: Metadata = { title: 'Terminated, withdrawn and suspended trials', description: 'Oncology studies that stopped early, with the reason as posted by the registrant on ClinicalTrials.gov and a keyword-rule category. Reasons are never inferred.' };
export const revalidate = 600;

const PAGE_SIZE = 50;

export default async function TerminatedTrialsPage({ searchParams }: { searchParams: Promise<SP> }) {
  const sp = await searchParams;
  const cancerSlug = str(sp, 'cancer');
  const reasonRaw = str(sp, 'reason');
  const reason: StopReasonCategory | '' = isStopReasonCategory(reasonRaw) ? reasonRaw : '';
  const status = str(sp, 'status');
  const since = int(sp, 'since', 0, 1990, 2100) || null;
  const page = int(sp, 'page', 1, 1, 100_000);
  const cancer = cancerSlug ? await getCancerBySlug(cancerSlug) : null;
  const cancerIds = cancer ? await getDescendantIds(cancer.id) : null;
  const [years, { rows, total, stopped, breakdown }] = await Promise.all([stoppedYears(), listTerminated({ cancerIds, reason, status, since, page, pageSize: PAGE_SIZE })]);
  const info = pageInfo(page, PAGE_SIZE, total);
  const current = { cancer: cancerSlug, reason, status, since: since ?? '' };
  const href = (o: Record<string, string | number | null | undefined>) => `/trials/terminated${withParams(current, o)}`;
  const chart = STOP_REASON_CATEGORIES.map((c) => ({ label: reasonLabel(c), value: breakdown[c], href: href({ reason: c, page: '' }), muted: c === 'not_stated' || c === 'other_stated' })).filter((d) => d.value > 0).sort((a, b) => b.value - a.value);
  const stated = stopped - breakdown.not_stated;

  return (
    <div>
      <PageHeader kicker="Clinical trials · failure tracking" title="Terminated, withdrawn and suspended studies" lede="Oncology studies whose overall status is TERMINATED, WITHDRAWN or SUSPENDED on ClinicalTrials.gov, with the stop reason exactly as the registrant posted it. A category is attached only when an explicit keyword rule matches the text; CancerIndex never infers why a study stopped.">
        <nav className="mt-3 flex flex-wrap gap-3 text-[12.5px]">
          <Link href="/trials/intelligence" className="ci-link">
            ← Trial intelligence
          </Link>
          <Link href="/trials" className="ci-link">
            All trials
          </Link>
        </nav>
      </PageHeader>

      <form method="get" action="/trials/terminated" className="grid gap-2 border-y border-rule py-3 text-[13.5px] sm:grid-cols-2 lg:grid-cols-[1.4fr_1.4fr_1fr_1fr_auto]" role="search" aria-label="Filter stopped studies">
        <label className="flex flex-col gap-1">
          <span className="ci-kicker">Cancer (slug, includes descendants)</span>
          <input name="cancer" defaultValue={cancerSlug} placeholder="e.g. glioblastoma" className="border border-rule-strong bg-white px-2 py-1.5 outline-none focus:border-accent" />
        </label>
        <label className="flex flex-col gap-1">
          <span className="ci-kicker">Reason category</span>
          <select name="reason" defaultValue={reason} className="border border-rule-strong bg-white px-2 py-1.5">
            <option value="">Any</option>
            {STOP_REASON_CATEGORIES.map((c) => (
              <option key={c} value={c}>
                {reasonLabel(c)} ({fmtInt(breakdown[c])})
              </option>
            ))}
          </select>
        </label>
        <label className="flex flex-col gap-1">
          <span className="ci-kicker">Status</span>
          <select name="status" defaultValue={status} className="border border-rule-strong bg-white px-2 py-1.5">
            <option value="">Any</option>
            {STOPPED_STATUSES.map((s) => (
              <option key={s} value={s}>
                {humanize(s)}
              </option>
            ))}
          </select>
        </label>
        <label className="flex flex-col gap-1">
          <span className="ci-kicker">First posted since</span>
          <select name="since" defaultValue={since ?? ''} className="border border-rule-strong bg-white px-2 py-1.5">
            <option value="">Any year</option>
            {years.map((y) => (
              <option key={y} value={y}>
                {y}
              </option>
            ))}
          </select>
        </label>
        <div className="flex items-end">
          <button type="submit" className="border border-ink bg-ink px-3 py-1.5 text-paper hover:bg-ink-2">
            Apply
          </button>
        </div>
      </form>

      <p className="mt-3 text-[13px] text-ink-2" role="status">
        <span className="ci-num font-medium text-ink">{fmtInt(stopped)}</span> stopped studies{cancer ? <> mapped to <span className="font-medium">{cancer.canonical_name}</span> and descendants</> : null}
        {since ? ` first posted since ${since}` : ''}
        {status ? ` with status ${humanize(status)}` : ''}
        {cancerSlug && !cancer ? <span className="text-warn"> — unknown cancer slug "{cancerSlug}" (ignored)</span> : null}
        {stopped > 0 ? (
          <>
            {' '}
            · <span className="ci-num">{fmtPct(stopped ? stated / stopped : null, 0)}</span> state a reason
            {reason ? (
              <>
                {' '}
                · showing <span className="ci-num">{fmtInt(total)}</span> in category <span className="font-medium">{reasonLabel(reason)}</span>
              </>
            ) : null}
          </>
        ) : null}
      </p>

      {stopped === 0 ? (
        <div className="mt-3">
          <EmptyState title="No stopped study matches these filters" knows={[{ label: 'Trial intelligence', href: '/trials/intelligence' }, { label: 'Trials explorer', href: '/trials' }]}>
            Relax a filter or clear the cancer slug.
          </EmptyState>
        </div>
      ) : (
        <>
          <section aria-labelledby="breakdown-title" className="mt-4 grid gap-4 lg:grid-cols-[minmax(0,1.4fr)_minmax(0,1fr)]">
            <div className="min-w-0">
              <h2 id="breakdown-title" className="text-lg">
                Stated reasons by category
              </h2>
              <p className="mb-2 text-[12.5px] text-ink-3">
                Over the {fmtInt(stopped)} studies matching the cancer, status and year filters (the category filter does not change this chart). Each study is counted once, in the first matching category; greyed bars are studies whose text matched no rule or was empty.
              </p>
              <BarChart data={chart} unit="count" maxBars={10} ariaLabel="Stopped studies by registrant-reported reason category" />
              <p className="mt-1 flex flex-wrap items-center gap-2 text-[11.5px] text-ink-3">
                <ClaimBadge kind="computed" />
                <span>
                  rules <span className="ci-mono">{STOP_REASON_RULES_VERSION}</span> · keyword matching only
                </span>
              </p>
            </div>
            <div className="min-w-0 text-[12.5px]">
              <h3 className="text-base">Classification rules</h3>
              <p className="mb-1.5 text-ink-3">A category is assigned when one of its keywords appears in the posted text (case-insensitive, whole words). Rules are tested in this order and the first match wins; every match is kept in the API (<code className="ci-mono">reasonMatches</code>).</p>
              <ol className="list-decimal space-y-0.5 pl-5 text-ink-2">
                {STOP_REASON_RULES.map((r) => (
                  <li key={r.category}>
                    <span className="font-medium">{reasonLabel(r.category)}</span> — <span className="ci-mono text-ink-3">{r.keywords.join(' · ')}</span>
                  </li>
                ))}
                <li>
                  <span className="font-medium">{reasonLabel('other_stated')}</span> — text present, no keyword matched
                </li>
                <li>
                  <span className="font-medium">{reasonLabel('not_stated')}</span> — no text posted
                </li>
              </ol>
            </div>
          </section>

          <div className="mt-5">
            <TableProvenance p={{ sourceSlug: 'clinicaltrials', sourceName: 'ClinicalTrials.gov', layer: 'normalized', note: 'Status, dates, sponsor and "why stopped" are shown as posted by the registrant. Only the category column is computed.' }} claim={<ClaimBadge kind="observed" />}>
              Showing {fmtInt(info.from)}–{fmtInt(info.to)} of {fmtInt(total)} studies, most recently updated first
            </TableProvenance>
            {rows.length === 0 ? (
              <EmptyState compact title="No study in this category for these filters" />
            ) : (
              <div className="ci-table-wrap">
                <table className="ci-table">
                  <thead>
                    <tr>
                      <th>NCT</th>
                      <th>Title</th>
                      <th>Phase</th>
                      <th>Status</th>
                      <th>First posted</th>
                      <th>Lead sponsor</th>
                      <th>Why stopped (as posted)</th>
                      <th>Category</th>
                    </tr>
                  </thead>
                  <tbody>
                    {rows.map((t) => (
                      <tr key={t.id}>
                        <td className="ci-mono whitespace-nowrap">
                          <Link className="ci-link" href={`/trial/${t.nct_id}`}>
                            {t.nct_id}
                          </Link>
                        </td>
                        <td className="max-w-[26rem]" title={t.brief_title}>
                          {truncate(t.brief_title, 90)}
                          {t.acronym ? <span className="ml-1 text-ink-3">({t.acronym})</span> : null}
                        </td>
                        <td className="whitespace-nowrap">{t.phases.length ? t.phases.map(phaseLabel).join(' / ') : '—'}</td>
                        <td>
                          <StatusBadge status={t.overall_status} />
                        </td>
                        <td className="whitespace-nowrap">{fmtDate(t.first_posted_date)}</td>
                        <td className="max-w-[14rem] truncate" title={`${t.lead_sponsor ?? ''}${t.lead_sponsor_class ? ` (${humanize(t.lead_sponsor_class)})` : ''}`}>
                          {t.lead_sponsor ?? '—'}
                        </td>
                        <td className="max-w-[22rem]" title={t.why_stopped ?? 'No reason posted'}>
                          {t.why_stopped ? truncate(t.why_stopped, 100) : <span className="text-ink-4">not stated</span>}
                        </td>
                        <td>
                          <Badge tone={t.reason_category === 'not_stated' ? 'outline' : t.reason_category === 'other_stated' ? 'neutral' : 'accent'} title={t.reason_matches.length > 1 ? `also matched: ${t.reason_matches.slice(1).map(reasonLabel).join(', ')}` : t.reason_category === 'not_stated' ? 'No text posted by the registrant' : t.reason_category === 'other_stated' ? 'Text posted, no keyword rule matched' : `Keyword rule: ${reasonLabel(t.reason_category)}`}>
                            {reasonLabel(t.reason_category)}
                          </Badge>
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
            <Pager page={info.page} pageSize={PAGE_SIZE} total={total} hrefFor={(p) => href({ page: p === 1 ? '' : p })} label="Stopped study pages" noun="studies" />
            <Note>
              Stop reasons are registrant-reported free text and are displayed verbatim (truncated; hover for the full text). Categories come from explicit keyword rules and are never inferred from the study design, sponsor or outcome; a study that stopped for several reasons is filed under the first rule that matched. A TERMINATED status does not imply a negative result.
            </Note>
            <Freshness dataUpdatedAt={rows.reduce<Date | string | null>((m, t) => (m == null || String(t.updated_at) > String(m) ? t.updated_at : m), null)} sourceUpdatedAt={rows[0]?.last_update_posted_date ?? null} extra="source: clinicaltrials" />
          </div>
        </>
      )}
    </div>
  );
}