feat: add docs chat api

app/api/docs/chat/route.ts

@@ -0,0 +1,137 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { z } from 'zod'
+
+import { getSession } from '@/lib/auth/server'
+import { detectCategories } from '@/lib/docs/category-detector'
+import { loadKnowledgeSections } from '@/lib/docs/knowledge-loader'
+import { buildSystemPrompt } from '@/lib/docs/prompt-builder'
+
+const DOCS_ASSISTANT_MODEL = process.env.DOCS_ASSISTANT_MODEL ?? 'claude-3-5-sonnet-20240620'
+const MAX_HISTORY_MESSAGES = 10
+const MAX_USER_MESSAGE_LENGTH = 2000
+
+const ChatMessageSchema = z.object({
+  role: z.enum(['user', 'assistant']),
+  content: z.string().min(1).max(4000),
+})
+
+const RequestSchema = z.object({
+  messages: z.array(ChatMessageSchema).optional(),
+  userMessage: z.string().min(1).max(MAX_USER_MESSAGE_LENGTH),
+})
+
+type ChatMessage = z.infer<typeof ChatMessageSchema>
+
+export async function POST(request: NextRequest) {
+  try {
+    const session = await getSession()
+    if (!session) {
+      return NextResponse.json({ error: 'Niet geauthenticeerd' }, { status: 401 })
+    }
+
+    const json = await request.json()
+    const parsed = RequestSchema.safeParse(json)
+
+    if (!parsed.success) {
+      return NextResponse.json(
+        {
+          error: 'Validatiefout',
+          details: parsed.error.issues.map(issue => ({
+            field: issue.path.join('.') || 'userMessage',
+            message: issue.message,
+          })),
+        },
+        { status: 400 }
+      )
+    }
+
+    const rawUserMessage = parsed.data.userMessage.trim()
+    if (!rawUserMessage) {
+      return NextResponse.json(
+        { error: 'Vraag mag niet leeg zijn' },
+        { status: 400 }
+      )
+    }
+
+    const history = (parsed.data.messages ?? [])
+      .map(normalizeMessage)
+      .filter((message): message is ChatMessage => Boolean(message))
+      .slice(-MAX_HISTORY_MESSAGES)
+
+    const conversation: ChatMessage[] = [...history, { role: 'user', content: rawUserMessage }]
+
+    const categories = detectCategories(rawUserMessage)
+    const knowledgeSections = await loadKnowledgeSections(categories)
+    const systemPrompt = buildSystemPrompt(knowledgeSections)
+
+    const apiKey = process.env.ANTHROPIC_API_KEY
+    if (!apiKey) {
+      return NextResponse.json(
+        { error: 'ANTHROPIC_API_KEY ontbreekt' },
+        { status: 500 }
+      )
+    }
+
+    const anthropicResponse = await fetch('https://api.anthropic.com/v1/messages', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'x-api-key': apiKey,
+        'anthropic-version': '2023-06-01',
+        Accept: 'text/event-stream',
+      },
+      body: JSON.stringify({
+        model: DOCS_ASSISTANT_MODEL,
+        max_tokens: 1024,
+        temperature: 0.2,
+        stream: true,
+        system: systemPrompt,
+        messages: conversation,
+      }),
+      signal: request.signal,
+    })
+
+    if (!anthropicResponse.ok || !anthropicResponse.body) {
+      const errorText = await anthropicResponse.text().catch(() => undefined)
+      return NextResponse.json(
+        {
+          error: 'Claude API error',
+          details: errorText ?? anthropicResponse.statusText,
+        },
+        { status: anthropicResponse.status || 500 }
+      )
+    }
+
+    const headers = new Headers({
+      'Content-Type': 'text/event-stream',
+      'Cache-Control': 'no-cache, no-store, no-transform',
+      Connection: 'keep-alive',
+    })
+
+    return new Response(anthropicResponse.body, {
+      status: 200,
+      headers,
+    })
+  } catch (error) {
+    if (error instanceof SyntaxError) {
+      return NextResponse.json({ error: 'Ongeldige JSON payload' }, { status: 400 })
+    }
+
+    console.error('Docs chat endpoint error:', error)
+    return NextResponse.json(
+      { error: 'Onverwachte serverfout' },
+      { status: 500 }
+    )
+  }
+}
+
+function normalizeMessage(message: ChatMessage): ChatMessage | null {
+  if (!message?.content) return null
+  const trimmed = message.content.trim()
+  if (!trimmed) return null
+
+  return {
+    role: message.role,
+    content: trimmed.slice(0, 4000),
+  }
+}