import express from 'express';
import cors from 'cors';
import { GoogleGenAI } from '@google/genai';
import path from 'path';
import { fileURLToPath } from 'url';

// Fix __dirname in ES module
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
app.use(cors());
app.use(express.json());

// Serve Vite frontend build
app.use(express.static(path.join(__dirname, '../dist')));

app.post('/api/translate', async (req, res) => {
  const { inputCode, outputLanguage } = req.body;
  if (!inputCode || !outputLanguage) return res.status(400).json({ error: 'Missing input' });

  try {
    const ai = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY });
    const prompt = `Translate code to ${outputLanguage} only, no markdown:\n${inputCode}`;

    const stream = await ai.models.generateContentStream({
      model: 'gemini-3-flash-preview',
      contents: prompt,
      config: { systemInstruction: "Only output raw code, no explanations." }
    });

    let full = '';
    for await (const chunk of stream) full += chunk.text || '';
    const displayCode = full.replace(/^```\w*\n?/, '').replace(/```$/, '');
    res.json({ code: displayCode });
  } catch (e) {
    console.error(e);
    res.status(500).json({ error: 'Generation failed' });
  }
});

// Serve index.html for all other routes
app.get('*', (req, res) => {
  res.sendFile(path.join(__dirname, '../dist/index.html'));
});

const PORT = process.env.PORT || 7860;
app.listen(PORT, () => console.log(`Server running on port ${PORT}`));