import { openai } from "@ai-sdk/openai";
import { streamText, Output, stepCountIs, convertToModelMessages } from "ai";
import { devTools } from "../tools";
import { z } from "zod";

// Allow streaming responses up to 60 seconds for more complex generations
export const maxDuration = 60;

export function errorHandler(error: unknown) {
  if (error == null) {
    return "unknown error";
  }
  if (typeof error === "string") {
    return error;
  }
  if (error instanceof Error) {
    return error.message;
  }
  return JSON.stringify(error);
}

// Structured output schema for website code
const WebsiteSchema = z.object({
  html: z.string().describe("Whole HTML code"),
});

export async function POST(req: Request) {
  try {
    const { messages } = await req.json();

    // Validate messages
    if (!Array.isArray(messages)) {
      return new Response("Invalid messages format", { status: 400 });
    }

    const result = streamText({
      model: openai.responses(process.env.OPENAI_MODEL || "gpt-4o"),
      system: "...",
      messages: convertToModelMessages(messages),
      stopWhen: stepCountIs(100),
      tools: devTools,
      abortSignal: req.signal, // Add abort signal for proper cancellation
      experimental_output: Output.object({
        schema: WebsiteSchema,
      }),
    });

    return result.toUIMessageStreamResponse({
      onError: errorHandler,
    });
  } catch (error) {
    console.error("Dev API error:", error);
    return new Response(errorHandler(error), { status: 500 });
  }
}