'use client'

import { useEffect, useState } from 'react'

// Stufe 1 of the Attribution Renderer (Task #23): the global
// "Quellen & Lizenzen" overview. Aggregates all 314k canonical_controls
// by their license_rule and shows the source regulations behind each
// bucket. Drives the footer link and gives auditors a one-page view of
// what licence classes the platform is operating under.

type SourceCount = {
  regulation_id: string
  regulation_name_de: string | null
  license_rule: number
  license_type: string | null
  attribution: string | null
  jurisdiction: string | null
  source_type: string | null
  n_controls: number
}

type RuleBucket = {
  rule: number
  label_de: string
  label_en: string
  attribution_required: boolean
  render_full_text: boolean
  total_controls: number
  distinct_sources: number
  sources: SourceCount[]
}

type Overview = {
  total_controls: number
  buckets: RuleBucket[]
}

const RULE_COLOR: Record<number, string> = {
  1: 'border-emerald-200 bg-emerald-50',
  2: 'border-amber-200 bg-amber-50',
  3: 'border-slate-200 bg-slate-50',
}

const RULE_BADGE: Record<number, string> = {
  1: 'bg-emerald-600 text-white',
  2: 'bg-amber-600 text-white',
  3: 'bg-slate-600 text-white',
}

export default function LicensesPage() {
  const [data, setData] = useState<Overview | null>(null)
  const [error, setError] = useState<string | null>(null)

  useEffect(() => {
    fetch('/api/sdk/v1/compliance/licenses/overview')
      .then((r) => (r.ok ? r.json() : Promise.reject(`HTTP ${r.status}`)))
      .then(setData)
      .catch((e) => setError(String(e)))
  }, [])

  if (error) {
    return (
      <div className="p-6">
        <h1 className="text-xl font-semibold mb-2">Quellen &amp; Lizenzen</h1>
        <p className="text-red-600">Fehler beim Laden: {error}</p>
      </div>
    )
  }
  if (!data) {
    return (
      <div className="p-6">
        <h1 className="text-xl font-semibold">Quellen &amp; Lizenzen</h1>
        <p className="text-slate-500 mt-2">Lade …</p>
      </div>
    )
  }

  return (
    <div className="p-6 max-w-7xl">
      <header className="mb-6">
        <h1 className="text-2xl font-semibold">Quellen &amp; Lizenzen</h1>
        <p className="text-sm text-slate-600 mt-1">
          Diese Plattform stützt sich auf {data.total_controls.toLocaleString('de-DE')}{' '}
          klassifizierte Compliance-Controls aus den unten genannten Quellen.
          Jeder Control trägt eine deterministische Lizenzregel (R1–R3), die das
          Render-Verhalten in Berichten und im Frontend steuert.
        </p>
      </header>

      <section className="mb-8">
        <h2 className="text-lg font-medium mb-3">Klassifizierungs-Schema</h2>
        <div className="grid grid-cols-1 md:grid-cols-3 gap-3 text-sm">
          {data.buckets.map((b) => (
            <div key={b.rule} className={`rounded border ${RULE_COLOR[b.rule] ?? 'border-slate-200'} p-3`}>
              <div className="flex items-center gap-2 mb-2">
                <span className={`inline-flex items-center justify-center w-7 h-7 rounded-full text-xs font-bold ${RULE_BADGE[b.rule] ?? 'bg-slate-600 text-white'}`}>
                  R{b.rule}
                </span>
                <span className="font-medium">{b.label_de}</span>
              </div>
              <ul className="text-xs text-slate-700 space-y-1">
                <li>{b.total_controls.toLocaleString('de-DE')} Controls</li>
                <li>{b.distinct_sources} Quellen</li>
                <li>{b.render_full_text ? 'Volltext-Anzeige erlaubt' : 'Nur Identifier-Verweis'}</li>
                <li>{b.attribution_required ? 'Attribution-Pflicht in Output' : 'keine Attribution-Pflicht'}</li>
              </ul>
            </div>
          ))}
        </div>
      </section>

      {data.buckets.map((b) => (
        <section key={b.rule} className="mb-8">
          <h2 className="text-lg font-medium mb-3 flex items-center gap-2">
            <span className={`inline-flex items-center justify-center w-7 h-7 rounded-full text-xs font-bold ${RULE_BADGE[b.rule] ?? 'bg-slate-600 text-white'}`}>
              R{b.rule}
            </span>
            {b.label_de}{' '}
            <span className="text-sm text-slate-500 font-normal">
              ({b.total_controls.toLocaleString('de-DE')} Controls aus {b.distinct_sources} Quellen)
            </span>
          </h2>

          <div className="overflow-x-auto border rounded">
            <table className="w-full text-sm">
              <thead className="bg-slate-100 text-slate-700">
                <tr>
                  <th className="text-left p-2">Quelle</th>
                  <th className="text-left p-2">Lizenztyp</th>
                  <th className="text-left p-2">Rechtsraum</th>
                  <th className="text-left p-2">Attribution</th>
                  <th className="text-right p-2">Controls</th>
                </tr>
              </thead>
              <tbody>
                {b.sources.map((s) => (
                  <tr key={`${b.rule}-${s.regulation_id}`} className="border-t">
                    <td className="p-2">{s.regulation_name_de ?? s.regulation_id}</td>
                    <td className="p-2 text-slate-600">{s.license_type ?? '—'}</td>
                    <td className="p-2 text-slate-600">{s.jurisdiction ?? '—'}</td>
                    <td className="p-2 text-slate-600">{s.attribution ?? '—'}</td>
                    <td className="p-2 text-right tabular-nums">{s.n_controls.toLocaleString('de-DE')}</td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        </section>
      ))}

      <footer className="text-xs text-slate-500 border-t pt-4 mt-8">
        Klassifizierung: deterministisch über parent_control_uuid-Vererbung,
        control_parent_links → regulation_registry, source_citation,
        canonical_processed_chunks (Pipeline-Ground-Truth) und LLM-Aggregat-
        Identifikation für eigene Werke. Audit-Skripte unter
        breakpilot-core/control-pipeline/scripts/.
      </footer>
    </div>
  )
}