import Link from 'next/link'
import {
  type ControlsResponse,
  type ControlItem,
  provenanceLabel,
  provenanceBadgeClass,
  severityBadgeClass,
  splitByTier,
} from '../_helpers'

const BACKEND_URL =
  process.env.COMPLIANCE_BACKEND_URL || 'http://backend-compliance:8002'

export const dynamic = 'force-dynamic'

async function getControls(useCase: string): Promise<ControlsResponse | null> {
  try {
    const res = await fetch(
      `${BACKEND_URL}/api/compliance/v1/controls/use-cases/${encodeURIComponent(
        useCase,
      )}/controls?tier=all&limit=200`,
      { cache: 'no-store' },
    )
    return res.ok ? ((await res.json()) as ControlsResponse) : null
  } catch {
    return null
  }
}

function ControlsTable({ rows }: { rows: ControlItem[] }) {
  return (
    <div className="overflow-hidden rounded-lg border border-gray-200">
      <table className="min-w-full divide-y divide-gray-200 text-sm">
        <thead className="bg-gray-50 text-left text-xs uppercase text-gray-500">
          <tr>
            <th className="px-4 py-2">Prüfaspekt</th>
            <th className="px-4 py-2">Sub-Thema</th>
            <th className="px-4 py-2">Schwere</th>
            <th className="px-4 py-2">Herkunft</th>
          </tr>
        </thead>
        <tbody className="divide-y divide-gray-100 bg-white">
          {rows.map((c) => (
            <tr key={c.id}>
              <td className="px-4 py-2 text-gray-900">{c.title}</td>
              <td className="px-4 py-2 text-xs text-gray-500">
                {c.sub_topic || '—'}
              </td>
              <td className="px-4 py-2">
                {c.severity ? (
                  <span
                    className={`rounded px-2 py-0.5 text-xs font-medium ${severityBadgeClass(
                      c.severity,
                    )}`}
                  >
                    {c.severity}
                  </span>
                ) : null}
              </td>
              <td className="px-4 py-2">
                <span
                  className={`rounded px-2 py-0.5 text-xs font-medium ${provenanceBadgeClass(
                    c.source_type,
                  )}`}
                  title={c.source_article || undefined}
                >
                  {provenanceLabel(c)}
                </span>
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  )
}

export default async function UseCaseControlsPage({
  params,
}: {
  params: Promise<{ useCase: string }>
}) {
  const { useCase } = await params
  const data = await getControls(useCase)

  if (!data) {
    return (
      <div className="mx-auto max-w-7xl space-y-4 p-6">
        <Link
          href="/sdk/coverage"
          className="text-sm text-purple-600 hover:underline"
        >
          ← Abdeckung
        </Link>
        <div className="rounded-lg border border-amber-200 bg-amber-50 p-6 text-amber-800">
          Keine atom-grain-Daten für „{useCase}" gefunden.
        </div>
      </div>
    )
  }

  const { core, review } = splitByTier(data.controls)

  return (
    <div className="mx-auto max-w-7xl space-y-8 p-6">
      <div className="flex items-center gap-2 text-sm text-gray-500">
        <Link href="/sdk/coverage" className="hover:text-purple-600">
          Abdeckung
        </Link>
        <span>/</span>
        <span className="text-gray-900">{data.label}</span>
      </div>

      <header className="space-y-1">
        <h1 className="text-2xl font-bold text-gray-900">{data.label}</h1>
        <p className="text-sm text-gray-600">
          <span className="font-semibold text-gray-900">
            {data.core_count.toLocaleString('de-DE')}
          </span>{' '}
          Kern-Pflichten ·{' '}
          <span className="font-semibold text-gray-900">
            {data.review_count.toLocaleString('de-DE')}
          </span>{' '}
          zur fachlichen Prüfung
        </p>
      </header>

      <section className="space-y-2">
        <h2 className="text-lg font-semibold text-gray-900">
          Kern-Pflichten ({core.length})
        </h2>
        {core.length ? (
          <ControlsTable rows={core} />
        ) : (
          <p className="text-sm text-gray-500">—</p>
        )}
      </section>

      <section className="space-y-2">
        <div>
          <h2 className="text-lg font-semibold text-gray-900">
            Zur fachlichen Prüfung ({review.length})
          </h2>
          <p className="text-xs text-gray-500">
            Breiter gefasste Aspekte — bewusst eher zu viel als zu wenig. Fachlich
            prüfen; nicht zutreffende lassen sich (künftig) als unanwendbar
            markieren.
          </p>
        </div>
        {review.length ? (
          <ControlsTable rows={review} />
        ) : (
          <p className="text-sm text-gray-500">—</p>
        )}
      </section>

      {data.total > data.controls.length ? (
        <p className="text-xs text-gray-400">
          Angezeigt: erste {data.controls.length.toLocaleString('de-DE')} von{' '}
          {data.total.toLocaleString('de-DE')} — Sub-Thema-Filter folgt.
        </p>
      ) : null}
    </div>
  )
}