Frontend: Composables useConfirm/useChat/usePolling; Guide-Chat abbrechbar

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/composables/useChat.js

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+import { ref, nextTick } from 'vue'
+
+// Gemeinsame Chat-Mechanik: senden, abbrechen (Run-Counter), scrollen, Fokus.
+// performRequest(messages) → Promise<{ reply, … }>; send() gibt die Antwort
+// zurück, damit der Aufrufer Extras (z. B. changes) auswerten kann.
+export function useChat(performRequest) {
+  const messages = ref([])
+  const input = ref('')
+  const loading = ref(false)
+  const messagesEl = ref(null) // Template-Ref: Nachrichten-Container
+  const inputEl = ref(null)    // Template-Ref: Textarea
+  let run = 0 // laufende Anfrage identifizieren; Abbruch ignoriert ihr Ergebnis
+
+  async function scrollToBottom() {
+    await nextTick()
+    if (messagesEl.value) messagesEl.value.scrollTop = messagesEl.value.scrollHeight
+  }
+
+  function autoGrow(max = 140) {
+    const el = inputEl.value
+    if (!el) return
+    el.style.height = 'auto'
+    el.style.height = Math.min(el.scrollHeight, max) + 'px'
+  }
+
+  function cancel() {
+    run++
+    loading.value = false
+    messages.value.push({ role: 'assistant', content: 'Abgebrochen.' })
+  }
+
+  function reset() {
+    run++
+    loading.value = false
+    messages.value = []
+    input.value = ''
+  }
+
+  async function send() {
+    if (loading.value) { // zweiter Klick = abbrechen
+      cancel()
+      return null
+    }
+    const text = input.value.trim()
+    if (!text) return null
+    const current = ++run
+    messages.value.push({ role: 'user', content: text })
+    input.value = ''
+    nextTick(() => autoGrow())
+    loading.value = true
+    scrollToBottom()
+    try {
+      const res = await performRequest(messages.value)
+      if (current !== run) return null
+      messages.value.push({ role: 'assistant', content: res.reply || '…' })
+      return res
+    } catch {
+      if (current !== run) return null
+      messages.value.push({ role: 'assistant', content: 'Fehler bei der Anfrage.' })
+      return null
+    } finally {
+      if (current === run) {
+        loading.value = false
+        scrollToBottom()
+        nextTick(() => inputEl.value?.focus())
+      }
+    }
+  }
+
+  return { messages, input, loading, messagesEl, inputEl, send, cancel, reset, scrollToBottom, autoGrow }
+}