Chatbot IA com OpenAI

import OpenAI from "openai";
import { z } from "zod";
import { SYSTEM_PROMPT } from "@/lib/chat/system-prompt";
 
const bodySchema = z.object({
  messages: z.array(z.union([
    z.object({ role: z.literal("user"), content: z.string().max(500) }),
    z.object({ role: z.literal("assistant"), content: z.string().max(2000) }),
  ])),
});
 
export async function POST(request: Request) {
  const body = await request.json();
  const parsed = bodySchema.safeParse(body);
  if (!parsed.success) return Response.json({ error: "Invalid" }, { status: 400 });
 
  const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
 
  const stream = await openai.chat.completions.create({
    model: "gpt-4.1-nano",
    max_tokens: 300,
    stream: true,
    messages: [
      { role: "system", content: SYSTEM_PROMPT },
      ...parsed.data.messages.slice(-6),
    ],
  });
 
  const readable = new ReadableStream({
    async start(controller) {
      for await (const chunk of stream) {
        const text = chunk.choices[0]?.delta?.content;
        if (text) controller.enqueue(new TextEncoder().encode(text));
      }
      controller.close();
    },
  });
 
  return new Response(readable, {
    headers: { "Content-Type": "text/plain; charset=utf-8" },
  });
}