import { streamText, convertToModelMessages } from "ai";
import { openai } from "@ai-sdk/openai";
import { createSupabaseServerClient } from "@/lib/supabase-server";

export async function POST(req: Request) {
  const { messages } = await req.json();
  const supabase = await createSupabaseServerClient();
  const { data: bands } = await supabase.from("bands").select("name, genre, country, stage, time");
  const context = (bands ?? []).map((b) => `${b.name} (${b.genre}, ${b.country}) — ${b.stage} ${b.time}`).join("\n");

  const result = streamText({
    model: openai("gpt-4o-mini"),
    system: `Je bent een hulpvaardige festival-roadie voor Polderfest 2027.\nLine-up:\n${context}`,
    messages: convertToModelMessages(messages),
  });
  return result.toUIMessageStreamResponse();
}