import { requireUser } from "#server/utils/context";
import { getProviderById, getModelById } from "#server/service/llm";
import { createOpenAI } from "@ai-sdk/openai";
import { streamText } from "ai";

export default defineEventHandler(async (event) => {
  const user = await requireUser(event);
  if (!user) {
    throw createError({ statusCode: 401, statusMessage: "未登录" });
  }

  const body = await readBody(event);
  const { modelId: llmModelId, messages, enableThinking } = body as {
    modelId: number;
    messages: { role: "user" | "assistant" | "system"; content: string }[];
    enableThinking?: boolean;
  };

  if (!llmModelId || !messages || !Array.isArray(messages) || messages.length === 0) {
    throw createError({ statusCode: 400, statusMessage: "参数无效" });
  }

  const model = await getModelById(llmModelId, user.id);
  if (!model) {
    throw createError({ statusCode: 404, statusMessage: "模型不存在" });
  }

  const provider = await getProviderById(model.providerId, user.id);
  if (!provider) {
    throw createError({ statusCode: 404, statusMessage: "供应商不存在" });
  }

  if (provider.status !== "active") {
    throw createError({ statusCode: 400, statusMessage: "供应商已禁用" });
  }

  if (!provider.apiKey) {
    throw createError({ statusCode: 400, statusMessage: "供应商未配置 API Key" });
  }

  const baseUrl = provider.baseUrl?.replace(/\/+$/, "") || undefined;

  const openai = createOpenAI({
    apiKey: provider.apiKey,
    baseURL: baseUrl,
  });

  const result = streamText({
    model: openai(model.modelId),
    messages,
    maxTokens: model.maxTokens || undefined,
    ...(enableThinking ? { providerOptions: { openai: { reasoningEffort: 'high' } } } : {}),
  });

  return result.toDataStreamResponse({ sendReasoning: true });
});