'use client'

import React, { useEffect, useState, useCallback, use } from 'react'
import { SeverityBadge } from '../../_components/SeverityBadge'

interface Requirement {
  req_id: string
  n: number
  category: string
  title: string
  annex_anchor: string
  iso27001_ref: string[]
  description: string
  severity: string
  mapped_measures: string[]
  mapped_measure_names: { id: string; name: string }[]
  evidence_type: string
  effort_days: number
  status: string
}

interface RequirementsResponse {
  project_id: string
  classification: string | null
  total: number
  items: Requirement[]
}

export default function RequirementsPage({
  params,
}: {
  params: Promise<{ projectId: string }>
}) {
  const { projectId } = use(params)
  const [data, setData] = useState<RequirementsResponse | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [filterCategory, setFilterCategory] = useState<string>('all')
  const [filterSeverity, setFilterSeverity] = useState<string>('all')
  const [expanded, setExpanded] = useState<string | null>(null)

  const load = useCallback(async () => {
    try {
      const res = await fetch(`/api/sdk/v1/cra/projects/${projectId}/requirements`, {
        headers: { 'X-Tenant-ID': '00000000-0000-0000-0000-000000000001' },
      })
      if (!res.ok) throw new Error(await res.text())
      setData(await res.json())
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Fehler beim Laden')
    } finally {
      setLoading(false)
    }
  }, [projectId])

  useEffect(() => { load() }, [load])

  if (loading) return <div className="min-h-screen bg-gray-50 p-8"><p className="text-gray-500">Laedt...</p></div>
  if (error) return <div className="min-h-screen bg-gray-50 p-8"><p className="text-red-600">{error}</p></div>
  if (!data) return null

  const categories = Array.from(new Set(data.items.map(i => i.category)))
  const filtered = data.items.filter(r =>
    (filterCategory === 'all' || r.category === filterCategory) &&
    (filterSeverity === 'all' || r.severity === filterSeverity)
  )

  return (
    <div className="min-h-screen bg-gray-50 py-8">
      <div className="max-w-7xl mx-auto px-4">
        <div className="mb-6">
          <a href={`/sdk/cra/${projectId}`} className="text-sm text-blue-600 hover:underline">
            &larr; Zurueck zum Projekt
          </a>
          <h1 className="text-2xl font-bold text-gray-900 mt-2">CRA Annex I Requirements</h1>
          <p className="text-sm text-gray-600 mt-1">
            Alle {data.total} Essential Cybersecurity Requirements aus Annex I. Status bleibt &quot;unbewertet&quot; bis Evidence-Checks in Phase 3 verknuepft sind.
          </p>
        </div>

        <div className="flex gap-3 mb-4 flex-wrap">
          <select
            value={filterCategory}
            onChange={e => setFilterCategory(e.target.value)}
            className="px-3 py-2 border border-gray-300 rounded-lg text-sm"
          >
            <option value="all">Alle Kategorien</option>
            {categories.map(c => <option key={c} value={c}>{c}</option>)}
          </select>
          <select
            value={filterSeverity}
            onChange={e => setFilterSeverity(e.target.value)}
            className="px-3 py-2 border border-gray-300 rounded-lg text-sm"
          >
            <option value="all">Alle Severities</option>
            <option value="CRITICAL">Kritisch</option>
            <option value="HIGH">Hoch</option>
            <option value="MEDIUM">Mittel</option>
            <option value="LOW">Niedrig</option>
          </select>
          <span className="text-sm text-gray-500 self-center">
            {filtered.length} von {data.total}
          </span>
        </div>

        <div className="bg-white rounded-xl shadow-sm border border-gray-200 overflow-hidden">
          <table className="w-full">
            <thead className="bg-gray-50 border-b border-gray-200">
              <tr>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">#</th>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">Anforderung</th>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">Kategorie</th>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">Severity</th>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">Aufwand</th>
                <th className="px-3 py-2 text-left text-xs font-medium text-gray-500 uppercase">Status</th>
              </tr>
            </thead>
            <tbody className="divide-y divide-gray-100">
              {filtered.map(req => (
                <React.Fragment key={req.req_id}>
                  <tr
                    className="hover:bg-gray-50 cursor-pointer"
                    onClick={() => setExpanded(expanded === req.req_id ? null : req.req_id)}
                  >
                    <td className="px-3 py-2 text-sm text-gray-500">{req.n}</td>
                    <td className="px-3 py-2">
                      <div className="text-sm font-medium text-gray-900">{req.title}</div>
                      <div className="text-xs text-gray-500">{req.annex_anchor} · {req.req_id}</div>
                    </td>
                    <td className="px-3 py-2 text-sm text-gray-600">{req.category}</td>
                    <td className="px-3 py-2"><SeverityBadge value={req.severity} /></td>
                    <td className="px-3 py-2 text-sm text-gray-600">{req.effort_days} PT</td>
                    <td className="px-3 py-2">
                      <span className="px-2 py-0.5 text-xs rounded-full bg-gray-100 text-gray-600">{req.status}</span>
                    </td>
                  </tr>
                  {expanded === req.req_id && (
                    <tr>
                      <td colSpan={6} className="px-4 py-4 bg-blue-50">
                        <div className="space-y-3">
                          <div>
                            <p className="text-xs font-semibold text-gray-600 uppercase">Beschreibung</p>
                            <p className="text-sm text-gray-700 mt-1">{req.description}</p>
                          </div>
                          {req.iso27001_ref.length > 0 && (
                            <div>
                              <p className="text-xs font-semibold text-gray-600 uppercase">ISO 27001:2022 Mapping</p>
                              <p className="text-sm text-gray-700 mt-1">
                                {req.iso27001_ref.map(r => (
                                  <span key={r} className="inline-block mr-2 mb-1 px-2 py-0.5 bg-white rounded text-xs">{r}</span>
                                ))}
                              </p>
                            </div>
                          )}
                          {req.mapped_measure_names.length > 0 && (
                            <div>
                              <p className="text-xs font-semibold text-gray-600 uppercase">Empfohlene Massnahmen</p>
                              <ul className="text-sm text-gray-700 mt-1 space-y-0.5">
                                {req.mapped_measure_names.map(m => (
                                  <li key={m.id}>
                                    <span className="font-mono text-xs text-gray-500">{m.id}</span> — {m.name}
                                  </li>
                                ))}
                              </ul>
                            </div>
                          )}
                          <div className="text-xs text-gray-500 pt-1">
                            Evidence-Typ: <span className="font-medium">{req.evidence_type}</span>
                          </div>
                        </div>
                      </td>
                    </tr>
                  )}
                </React.Fragment>
              ))}
            </tbody>
          </table>
        </div>
      </div>
    </div>
  )
}