import express from 'express';
import fetch from 'node-fetch';
import cors from 'cors';
import rateLimit from 'express-rate-limit';
import dotenv from 'dotenv';

dotenv.config();

const app = express();
app.use(cors());
app.use(express.json({ limit: '1mb' }));

const limiter = rateLimit({ windowMs: 60*1000, max: 60 });
app.use(limiter);

const OPENAI_KEY = process.env.OPENAI_API_KEY;
if(!OPENAI_KEY) console.warn('OPENAI_API_KEY not set in environment.');

app.post('/api/ask', async (req, res) => {
  try {
    const { prompt, system, model } = req.body;
    if(!prompt) return res.status(400).json({ ok:false, error: 'missing prompt' });
    const messages = [
      { role: 'system', content: system || 'You are a senior marketing expert with 20 years experience. Provide concise, tactical advice.' },
      { role: 'user', content: prompt }
    ];
    const payload = { model: model || 'gpt-4o-mini', messages, max_tokens: 900, temperature: 0.2 };
    const r = await fetch('https://api.openai.com/v1/chat/completions', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer ' + OPENAI_KEY },
      body: JSON.stringify(payload)
    });
    if(!r.ok) {
      const text = await r.text();
      return res.status(502).json({ ok:false, error: 'OpenAI error', detail: text });
    }
    const data = await r.json();
    const answer = data.choices && data.choices[0] && data.choices[0].message ? data.choices[0].message.content : JSON.stringify(data);
    res.json({ ok:true, answer });
  } catch(err) {
    console.error(err);
    res.status(500).json({ ok:false, error: String(err) });
  }
});

app.get('/', (req, res) => res.send('AI proxy running'));

const PORT = process.env.PORT || 5174;
app.listen(PORT, () => console.log('Server listening on', PORT));