server.js

import express from 'express';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import { readFileSync, existsSync } from 'fs';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

// Load .env file if exists (simple dotenv alternative) 
const envPath = join(__dirname, '.env');
if (existsSync(envPath)) {
  const envContent = readFileSync(envPath, 'utf-8');
  for (const line of envContent.split('\n')) {
    const trimmed = line.trim();
    if (trimmed && !trimmed.startsWith('#')) {
      const [key, ...valueParts] = trimmed.split('=');
      if (key && valueParts.length > 0) {
        process.env[key.trim()] = valueParts.join('=').trim();
      }
    }
  }
}

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(express.json());
app.use(express.static(join(__dirname, 'public')));

// API endpoint to create Tavus conversation
app.post('/api/conversation', async (req, res) => {
  const apiKey = process.env.TAVUS_API_KEY;

  if (!apiKey) {
    console.error('TAVUS_API_KEY is not set in environment variables');
    return res.status(500).json({ 
      error: 'Server configuration error', 
      detail: 'API key not configured' 
    });
  }

  const { replica_id, persona_id } = req.body;

  if (!replica_id || !persona_id) {
    return res.status(400).json({ 
      error: 'Missing required fields', 
      detail: 'replica_id and persona_id are required' 
    });
  }

  try {
    const response = await fetch('https://tavusapi.com/v2/conversations', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': apiKey
      },
      body: JSON.stringify({
        replica_id,
        persona_id,
        custom_greeting: "Salut ! On pratique le français. Tu es prêt(e) ?",
        conversational_context: "You are a friendly French tutor. Speak ONLY in French. Level: A2. Correct gently. Offer 2 short suggested replies each turn.",
        properties: {
          language: "french",
          enable_closed_captions: true
        }
      })
    });

    const data = await response.json();

    if (!response.ok) {
      console.error('Tavus API error:', data);
      return res.status(response.status).json({ 
        error: 'Tavus API error', 
        detail: data.message || JSON.stringify(data) 
      });
    }

    console.log('Conversation created:', data.conversation_id);
    res.json({ conversation_url: data.conversation_url });

  } catch (error) {
    console.error('Error creating conversation:', error);
    res.status(500).json({ 
      error: 'Failed to create conversation', 
      detail: error.message 
    });
  }
});

app.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}`);
});