feat: add Chunk-Browser tab to RAG page

- New 'Chunk-Browser' tab for sequential chunk browsing
- Qdrant scroll API proxy (scroll + collection-count actions)
- Pagination with prev/next through all chunks in a collection
- Text search filter with highlighting
- Click to expand chunk and see all metadata
- 'In Chunks suchen' button now navigates to Chunk-Browser with correct collection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin-lehrer/app/(admin)/ai/rag/page.tsx

@@ -73,7 +73,7 @@ interface DsfaCorpusStatus {
 type RegulationCategory = 'regulations' | 'dsfa' | 'nibis' | 'templates'
 
 // Tab definitions
-type TabId = 'overview' | 'regulations' | 'map' | 'search' | 'data' | 'ingestion' | 'pipeline'
+type TabId = 'overview' | 'regulations' | 'map' | 'search' | 'chunks' | 'data' | 'ingestion' | 'pipeline'
 
 // Custom document type
 interface CustomDocument {
@@ -1850,6 +1850,18 @@ export default function RAGPage() {
   const [autoRefresh, setAutoRefresh] = useState(true)
   const [elapsedTime, setElapsedTime] = useState<string>('')
 
+  // Chunk browser state
+  const [chunkCollection, setChunkCollection] = useState('bp_compliance_gesetze')
+  const [chunkData, setChunkData] = useState<Record<string, unknown>[]>([])
+  const [chunkOffset, setChunkOffset] = useState<string | null>(null)
+  const [chunkHistory, setChunkHistory] = useState<(string | null)[]>([])
+  const [chunkLoading, setChunkLoading] = useState(false)
+  const [chunkTextSearch, setChunkTextSearch] = useState('')
+  const [chunkTotalCount, setChunkTotalCount] = useState(0)
+  const [chunkCurrentPage, setChunkCurrentPage] = useState(0)
+  const [chunkNextOffset, setChunkNextOffset] = useState<string | null>(null)
+  const [expandedChunk, setExpandedChunk] = useState<number | null>(null)
+
   // DSFA corpus state
   const [dsfaSources, setDsfaSources] = useState<DsfaSource[]>([])
   const [dsfaStatus, setDsfaStatus] = useState<DsfaCorpusStatus | null>(null)
@@ -2095,6 +2107,69 @@ export default function RAGPage() {
     return () => clearInterval(interval)
   }, [pipelineState?.started_at, pipelineState?.status])
 
+  const loadChunks = async (offset: string | null = null, newCollection?: string) => {
+    const col = newCollection || chunkCollection
+    setChunkLoading(true)
+    try {
+      const params = new URLSearchParams({
+        action: 'scroll',
+        collection: col,
+        limit: '20',
+      })
+      if (offset) params.append('offset', offset)
+      if (chunkTextSearch.trim()) params.append('text_search', chunkTextSearch.trim())
+
+      const res = await fetch(`${API_PROXY}?${params}`)
+      if (res.ok) {
+        const data = await res.json()
+        setChunkData(data.chunks || [])
+        setChunkNextOffset(data.next_offset || null)
+        setExpandedChunk(null)
+      }
+    } catch (error) {
+      console.error('Chunk scroll failed:', error)
+    } finally {
+      setChunkLoading(false)
+    }
+  }
+
+  const loadChunkCount = async (col: string) => {
+    try {
+      const res = await fetch(`${API_PROXY}?action=collection-count&collection=${encodeURIComponent(col)}`)
+      if (res.ok) {
+        const data = await res.json()
+        setChunkTotalCount(data.count || 0)
+      }
+    } catch { /* ignore */ }
+  }
+
+  const handleChunkCollectionChange = (col: string) => {
+    setChunkCollection(col)
+    setChunkOffset(null)
+    setChunkHistory([])
+    setChunkCurrentPage(0)
+    loadChunkCount(col)
+    loadChunks(null, col)
+  }
+
+  const handleChunkNext = () => {
+    if (!chunkNextOffset) return
+    setChunkHistory((prev) => [...prev, chunkOffset])
+    setChunkOffset(chunkNextOffset)
+    setChunkCurrentPage((p) => p + 1)
+    loadChunks(chunkNextOffset)
+  }
+
+  const handleChunkPrev = () => {
+    if (chunkHistory.length === 0) return
+    const prev = [...chunkHistory]
+    const prevOffset = prev.pop() ?? null
+    setChunkHistory(prev)
+    setChunkOffset(prevOffset)
+    setChunkCurrentPage((p) => Math.max(0, p - 1))
+    loadChunks(prevOffset)
+  }
+
   const handleSearch = async () => {
     if (!searchQuery.trim()) return
 
@@ -2180,6 +2255,7 @@ export default function RAGPage() {
     { id: 'regulations' as TabId, name: 'Regulierungen', icon: '📜' },
     { id: 'map' as TabId, name: 'Landkarte', icon: '🗺️' },
     { id: 'search' as TabId, name: 'Suche', icon: '🔍' },
+    { id: 'chunks' as TabId, name: 'Chunk-Browser', icon: '🧩' },
     { id: 'data' as TabId, name: 'Daten', icon: '📁' },
     { id: 'ingestion' as TabId, name: 'Ingestion', icon: '⚙️' },
     { id: 'pipeline' as TabId, name: 'Pipeline', icon: '🔄' },
@@ -2535,8 +2611,11 @@ export default function RAGPage() {
                                     <button
                                       onClick={(e) => {
                                         e.stopPropagation()
-                                        setSearchQuery(reg.name)
+                                        const ragEntry = REGULATIONS_IN_RAG[reg.code as keyof typeof REGULATIONS_IN_RAG]
-                                        setActiveTab('search')
+                                        const col = ragEntry?.collection || 'bp_compliance_gesetze'
+                                        setChunkTextSearch(reg.name)
+                                        handleChunkCollectionChange(col)
+                                        setActiveTab('chunks')
                                       }}
                                       className="text-teal-600 hover:text-teal-700 font-medium"
                                     >
@@ -3183,6 +3262,175 @@ export default function RAGPage() {
           </div>
         )}
 
+        {activeTab === 'chunks' && (
+          <div className="space-y-6">
+            {/* Collection Selector + Controls */}
+            <div className="bg-white rounded-xl border border-slate-200 p-6">
+              <h3 className="font-semibold text-slate-900 mb-4">Chunk-Browser</h3>
+              <div className="flex flex-wrap gap-4 items-end">
+                <div>
+                  <label className="block text-sm font-medium text-slate-700 mb-1">Collection</label>
+                  <select
+                    value={chunkCollection}
+                    onChange={(e) => handleChunkCollectionChange(e.target.value)}
+                    className="px-3 py-2 border rounded-lg text-sm focus:ring-2 focus:ring-teal-500"
+                  >
+                    <option value="bp_compliance_gesetze">bp_compliance_gesetze</option>
+                    <option value="bp_compliance_ce">bp_compliance_ce</option>
+                    <option value="bp_compliance_datenschutz">bp_compliance_datenschutz</option>
+                    <option value="bp_dsfa_corpus">bp_dsfa_corpus</option>
+                    <option value="bp_compliance_recht">bp_compliance_recht</option>
+                    <option value="bp_legal_templates">bp_legal_templates</option>
+                    <option value="bp_compliance_gdpr">bp_compliance_gdpr</option>
+                    <option value="bp_compliance_schulrecht">bp_compliance_schulrecht</option>
+                    <option value="bp_dsfa_templates">bp_dsfa_templates</option>
+                    <option value="bp_dsfa_risks">bp_dsfa_risks</option>
+                  </select>
+                </div>
+                <div className="flex-1 min-w-[200px]">
+                  <label className="block text-sm font-medium text-slate-700 mb-1">Textsuche (filtert geladene Seite)</label>
+                  <div className="flex gap-2">
+                    <input
+                      type="text"
+                      value={chunkTextSearch}
+                      onChange={(e) => setChunkTextSearch(e.target.value)}
+                      onKeyDown={(e) => { if (e.key === 'Enter') loadChunks(null) }}
+                      placeholder="z.B. DSGVO, IFRS, Maschinenverordnung..."
+                      className="flex-1 px-3 py-2 border rounded-lg text-sm focus:ring-2 focus:ring-teal-500"
+                    />
+                    <button
+                      onClick={() => { setChunkOffset(null); setChunkHistory([]); setChunkCurrentPage(0); loadChunks(null) }}
+                      className="px-4 py-2 bg-teal-600 text-white text-sm rounded-lg hover:bg-teal-700"
+                    >
+                      Laden
+                    </button>
+                  </div>
+                </div>
+                <div className="text-sm text-slate-500">
+                  {chunkTotalCount > 0 && <span>{chunkTotalCount.toLocaleString()} Chunks total</span>}
+                </div>
+              </div>
+            </div>
+
+            {/* Pagination */}
+            {chunkData.length > 0 && (
+              <div className="flex items-center justify-between">
+                <button
+                  onClick={handleChunkPrev}
+                  disabled={chunkCurrentPage === 0}
+                  className="px-4 py-2 text-sm border rounded-lg bg-white hover:bg-slate-50 disabled:opacity-30"
+                >
+                  Zurueck
+                </button>
+                <span className="text-sm text-slate-600">
+                  Seite {chunkCurrentPage + 1} — {chunkData.length} Chunks angezeigt
+                </span>
+                <button
+                  onClick={handleChunkNext}
+                  disabled={!chunkNextOffset}
+                  className="px-4 py-2 text-sm border rounded-lg bg-white hover:bg-slate-50 disabled:opacity-30"
+                >
+                  Weiter
+                </button>
+              </div>
+            )}
+
+            {/* Chunk List */}
+            {chunkLoading ? (
+              <div className="text-center py-12 text-slate-500">Chunks werden geladen...</div>
+            ) : chunkData.length === 0 ? (
+              <div className="text-center py-12 text-slate-400">
+                Collection waehlen und &quot;Laden&quot; klicken um Chunks anzuzeigen.
+              </div>
+            ) : (
+              <div className="space-y-2">
+                {chunkData.map((chunk, i) => {
+                  const text = String(chunk.text || chunk.content || chunk.chunk_text || '')
+                  const source = String(chunk.source_name || chunk.regulation_code || chunk.guideline_name || chunk.regulation_short || '')
+                  const isExpanded = expandedChunk === i
+                  const highlightTerm = chunkTextSearch.trim().toLowerCase()
+
+                  const renderHighlighted = (str: string) => {
+                    if (!highlightTerm) return str
+                    const idx = str.toLowerCase().indexOf(highlightTerm)
+                    if (idx === -1) return str
+                    return (
+                      <>
+                        {str.slice(0, idx)}
+                        <mark className="bg-yellow-200 px-0.5 rounded">{str.slice(idx, idx + highlightTerm.length)}</mark>
+                        {str.slice(idx + highlightTerm.length)}
+                      </>
+                    )
+                  }
+
+                  return (
+                    <div
+                      key={String(chunk.id || i)}
+                      className={`bg-white rounded-lg border transition-all cursor-pointer ${
+                        isExpanded ? 'border-teal-300 shadow-md' : 'border-slate-200 hover:border-slate-300'
+                      }`}
+                      onClick={() => setExpandedChunk(isExpanded ? null : i)}
+                    >
+                      <div className="px-4 py-3">
+                        <div className="flex items-center gap-2 mb-1">
+                          <span className="text-xs font-mono text-slate-400">#{chunkCurrentPage * 20 + i + 1}</span>
+                          {source && (
+                            <span className="px-2 py-0.5 text-xs rounded bg-slate-100 text-slate-600">{source}</span>
+                          )}
+                          {chunk.article && (
+                            <span className="text-xs text-slate-500">Art. {String(chunk.article)}</span>
+                          )}
+                          {chunk.language && (
+                            <span className="text-xs text-slate-400 ml-auto">{String(chunk.language).toUpperCase()}</span>
+                          )}
+                        </div>
+                        <p className={`text-sm text-slate-700 ${isExpanded ? '' : 'line-clamp-3'}`}>
+                          {renderHighlighted(text)}
+                        </p>
+                      </div>
+                      {isExpanded && (
+                        <div className="px-4 py-3 border-t border-slate-100 bg-slate-50 text-xs text-slate-500 space-y-1">
+                          <div className="grid grid-cols-2 md:grid-cols-4 gap-2">
+                            {Object.entries(chunk).filter(([k]) => !['text', 'content', 'chunk_text', 'id'].includes(k)).map(([k, v]) => (
+                              <div key={k}>
+                                <span className="font-medium text-slate-600">{k}:</span>{' '}
+                                <span>{String(v)}</span>
+                              </div>
+                            ))}
+                          </div>
+                        </div>
+                      )}
+                    </div>
+                  )
+                })}
+              </div>
+            )}
+
+            {/* Bottom Pagination */}
+            {chunkData.length > 0 && (
+              <div className="flex items-center justify-between">
+                <button
+                  onClick={handleChunkPrev}
+                  disabled={chunkCurrentPage === 0}
+                  className="px-4 py-2 text-sm border rounded-lg bg-white hover:bg-slate-50 disabled:opacity-30"
+                >
+                  Zurueck
+                </button>
+                <span className="text-sm text-slate-600">
+                  Seite {chunkCurrentPage + 1}
+                </span>
+                <button
+                  onClick={handleChunkNext}
+                  disabled={!chunkNextOffset}
+                  className="px-4 py-2 text-sm border rounded-lg bg-white hover:bg-slate-50 disabled:opacity-30"
+                >
+                  Weiter
+                </button>
+              </div>
+            )}
+          </div>
+        )}
+
         {activeTab === 'data' && (
           <div className="space-y-6">
             {/* Upload Document */}

admin-lehrer/app/api/legal-corpus/route.ts

@@ -66,6 +66,72 @@ export async function GET(request: NextRequest) {
         url += `/traceability?chunk_id=${encodeURIComponent(chunkId || '')}&regulation=${encodeURIComponent(regulation || '')}`
         break
       }
+      case 'scroll': {
+        const collection = searchParams.get('collection') || 'bp_compliance_gesetze'
+        const limit = parseInt(searchParams.get('limit') || '20', 10)
+        const offsetParam = searchParams.get('offset')
+        const filterKey = searchParams.get('filter_key')
+        const filterValue = searchParams.get('filter_value')
+        const textSearch = searchParams.get('text_search')
+
+        const scrollBody: Record<string, unknown> = {
+          limit: Math.min(limit, 100),
+          with_payload: true,
+          with_vector: false,
+        }
+        if (offsetParam) {
+          scrollBody.offset = offsetParam
+        }
+        if (filterKey && filterValue) {
+          scrollBody.filter = {
+            must: [{ key: filterKey, match: { value: filterValue } }],
+          }
+        }
+
+        const scrollRes = await fetch(`${QDRANT_URL}/collections/${encodeURIComponent(collection)}/points/scroll`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify(scrollBody),
+          cache: 'no-store',
+        })
+        if (!scrollRes.ok) {
+          return NextResponse.json({ error: 'Qdrant scroll failed' }, { status: scrollRes.status })
+        }
+        const scrollData = await scrollRes.json()
+        const points = (scrollData.result?.points || []).map((p: { id: string; payload?: Record<string, unknown> }) => ({
+          id: p.id,
+          ...p.payload,
+        }))
+
+        // Client-side text search filter
+        let filtered = points
+        if (textSearch && textSearch.trim()) {
+          const term = textSearch.toLowerCase()
+          filtered = points.filter((p: Record<string, unknown>) => {
+            const text = String(p.text || p.content || p.chunk_text || '')
+            return text.toLowerCase().includes(term)
+          })
+        }
+
+        return NextResponse.json({
+          chunks: filtered,
+          next_offset: scrollData.result?.next_page_offset || null,
+          total_in_page: points.length,
+        })
+      }
+      case 'collection-count': {
+        const col = searchParams.get('collection') || 'bp_compliance_gesetze'
+        const countRes = await fetch(`${QDRANT_URL}/collections/${encodeURIComponent(col)}`, {
+          cache: 'no-store',
+        })
+        if (!countRes.ok) {
+          return NextResponse.json({ count: 0 })
+        }
+        const countData = await countRes.json()
+        return NextResponse.json({
+          count: countData.result?.points_count || 0,
+        })
+      }
       default:
         return NextResponse.json({ error: 'Unknown action' }, { status: 400 })
     }