import OpenAI from 'openai';

const client = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });

export interface ChatCompletionChunk {
  text: string;
  done?: boolean;
}

export async function *streamChat(model: string, messages: { role: 'user'|'assistant'|'system'; content: string }[]) {
  // 使用新的 responses API (若版本支持)；否则回退到 chat.completions
  const stream = await client.chat.completions.create({
    model,
    messages,
    stream: true,
    temperature: 0.7,
  });
  for await (const part of stream) {
    const delta = part.choices?.[0]?.delta?.content;
    if (delta) {
      yield { text: delta } as ChatCompletionChunk;
    }
  }
  yield { text: '', done: true };
}

export async function oneShot(model: string, messages: { role: 'user'|'assistant'|'system'; content: string }[]) {
  const completion = await client.chat.completions.create({ model, messages });
  return completion.choices[0]?.message?.content || '';
}