import { z } from "zod";
import { apiError, apiJson } from "@/lib/api-handler";
import { resolveApiAuth } from "@/lib/api-auth";
import { isLlmConfigured } from "@/lib/llm";
import { runAgentChat } from "@/modules/agent/server/run";

const chatInput = z.object({
  messages: z
    .array(
      z.object({
        role: z.enum(["user", "assistant"]),
        content: z.string().trim().min(1).max(8000),
      }),
    )
    .min(1)
    .max(40),
});

export async function POST(request: Request) {
  const auth = await resolveApiAuth(request);
  if (!auth) {
    return apiError("Unauthorized", 401);
  }

  let body: unknown;
  try {
    body = await request.json();
  } catch {
    return apiError("Invalid JSON body", 400);
  }

  const parsed = chatInput.safeParse(body);
  if (!parsed.success) {
    return apiError(parsed.error.issues[0]?.message ?? "Validation error", 400);
  }

  try {
    const result = await runAgentChat({
      messages: parsed.data.messages,
      request,
    });

    return apiJson({
      ...result,
      configured: isLlmConfigured(),
      provider: isLlmConfigured() ? "openai" : "mock",
    });
  } catch (err) {
    const message = err instanceof Error ? err.message : "Agent request failed";
    return apiError(message, 502);
  }
}