From 3a9cece9299190bc43a71d283803b19e807f95be Mon Sep 17 00:00:00 2001
From: duffyduck <info@hacker-net.de>
Date: Sat, 30 May 2026 14:33:11 +0200
Subject: [PATCH] Vertragshistorie: Vertragsnummern als Link in neuem Tab
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Erwähnte Vertragsnummern (Pattern PREFIX-RANDOM) in Title und
Description werden gegen previousContract + followUpContract des
aktuellen Vertrags aufgelöst und als Link mit target="_blank"
gerendert. Nicht aufgelöste Nummern bleiben als Text.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../contracts/ContractHistorySection.tsx      | 53 +++++++++++++++++--
 .../src/pages/contracts/ContractDetail.tsx    |  8 +++
 2 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/frontend/src/components/contracts/ContractHistorySection.tsx b/frontend/src/components/contracts/ContractHistorySection.tsx
index a944b7af..6df7ff87 100644
--- a/frontend/src/components/contracts/ContractHistorySection.tsx
+++ b/frontend/src/components/contracts/ContractHistorySection.tsx
@@ -1,4 +1,5 @@
 import { useState } from 'react';
+import { Link } from 'react-router-dom';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { Plus, Edit, Trash2, ChevronDown, ChevronUp, History, Clock, Bot, User } from 'lucide-react';
 import Modal from '../ui/Modal';
@@ -11,11 +12,57 @@ import type { ContractHistoryEntry } from '../../types';
 interface ContractHistorySectionProps {
   contractId: number;
   canEdit: boolean;
+  // Map: contractNumber → contractId. Wird genutzt um in title/description
+  // erwähnte Vertragsnummern als Link auf den jeweiligen Vertrag zu rendern.
+  // Aufgebaut aus previousContract + followUpContract des aktuellen Vertrags.
+  knownContracts?: Record<string, number>;
+}
+
+// Vertragsnummer-Pattern: 3 Großbuchstaben + Bindestrich + Alphanumerisch
+// (siehe backend/src/utils/helpers.ts generateContractNumber).
+const CONTRACT_NUMBER_REGEX = /\b([A-Z]{3}-[A-Z0-9]{6,})\b/g;
+
+// Rendert einen Text und ersetzt enthaltene Vertragsnummern durch Links,
+// falls sie in der knownContracts-Map auflösbar sind. Nicht aufgelöste Nummern
+// bleiben als normaler Text.
+function renderTextWithContractLinks(
+  text: string,
+  knownContracts?: Record<string, number>,
+): React.ReactNode {
+  if (!knownContracts || Object.keys(knownContracts).length === 0) return text;
+  const parts: React.ReactNode[] = [];
+  let lastIndex = 0;
+  let match: RegExpExecArray | null;
+  CONTRACT_NUMBER_REGEX.lastIndex = 0;
+  while ((match = CONTRACT_NUMBER_REGEX.exec(text)) !== null) {
+    const num = match[1];
+    const id = knownContracts[num];
+    if (match.index > lastIndex) parts.push(text.slice(lastIndex, match.index));
+    if (id) {
+      parts.push(
+        <Link
+          key={`${match.index}-${num}`}
+          to={`/contracts/${id}`}
+          target="_blank"
+          rel="noopener noreferrer"
+          className="text-blue-600 hover:text-blue-800 hover:underline font-mono"
+        >
+          {num}
+        </Link>,
+      );
+    } else {
+      parts.push(num);
+    }
+    lastIndex = match.index + num.length;
+  }
+  if (lastIndex < text.length) parts.push(text.slice(lastIndex));
+  return parts.length > 0 ? <>{parts}</> : text;
 }
 
 export default function ContractHistorySection({
   contractId,
   canEdit,
+  knownContracts,
 }: ContractHistorySectionProps) {
   const [isExpanded, setIsExpanded] = useState(false);
   const [showAddModal, setShowAddModal] = useState(false);
@@ -84,7 +131,7 @@ export default function ContractHistorySection({
             })}
           </span>
           {' - '}
-          {sortedEntries[0].title}
+          {renderTextWithContractLinks(sortedEntries[0].title, knownContracts)}
         </div>
       )}
 
@@ -99,7 +146,7 @@ export default function ContractHistorySection({
               <div className="flex-1">
                 <div className="flex items-center gap-2 mb-1">
                   <span className="text-sm font-medium text-gray-800">
-                    {entry.title}
+                    {renderTextWithContractLinks(entry.title, knownContracts)}
                   </span>
                   {entry.isAutomatic ? (
                     <span className="flex items-center gap-1 px-1.5 py-0.5 text-xs rounded bg-blue-100 text-blue-700" title="Automatisch erstellt">
@@ -115,7 +162,7 @@ export default function ContractHistorySection({
                 </div>
                 {entry.description && (
                   <p className="text-sm text-gray-600 whitespace-pre-wrap mb-1">
-                    {entry.description}
+                    {renderTextWithContractLinks(entry.description, knownContracts)}
                   </p>
                 )}
                 <div className="flex items-center gap-3 text-xs text-gray-400">
diff --git a/frontend/src/pages/contracts/ContractDetail.tsx b/frontend/src/pages/contracts/ContractDetail.tsx
index 71524935..10fa9995 100644
--- a/frontend/src/pages/contracts/ContractDetail.tsx
+++ b/frontend/src/pages/contracts/ContractDetail.tsx
@@ -3224,6 +3224,14 @@ export default function ContractDetail() {
         <ContractHistorySection
           contractId={contractId}
           canEdit={hasPermission('contracts:update')}
+          knownContracts={{
+            ...(c.previousContract?.contractNumber
+              ? { [c.previousContract.contractNumber]: c.previousContract.id }
+              : {}),
+            ...(c.followUpContract?.contractNumber
+              ? { [c.followUpContract.contractNumber]: c.followUpContract.id }
+              : {}),
+          }}
         />
       )}