server.js

// ============================================
// Serves the static site AND runs the /api/analyze
// relay to Claude, reading your key from .env.
//
// SETUP:
//   npm install express dotenv
//   node server.js
// Then open http://localhost:3000 in your browser.
// ============================================

require('dotenv').config();
const express = require('express');
const path = require('path');
const dns = require('dns');

// Some systems have broken/blocked IPv6 routing, which causes Node's
// native fetch to hang and time out even though the network is fine.
// Forcing IPv4 first works around this.
dns.setDefaultResultOrder('ipv4first');

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

console.log('Working directory:', process.cwd());
console.log('API key present:', !!process.env.ANTHROPIC_API_KEY);

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

app.use((req, res, next) => {
  console.log(`Incoming: ${req.method} ${req.url}`);
  next();
});

app.use(express.static(__dirname)); // serves index.html, css/, js/ as-is

app.post('/api/analyze', async (req, res) => {
  console.log('Reached /api/analyze handler');
  const { system, messages } = req.body;

  if (!system || !messages) {
    console.log('Missing system or messages in request body');
    return res.status(400).json({ error: 'Missing system prompt or messages' });
  }

  try {
    const response = await fetch('https://api.anthropic.com/v1/messages', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': process.env.ANTHROPIC_API_KEY,
        'anthropic-version': '2023-06-01'
      },
      body: JSON.stringify({
        model: 'claude-sonnet-4-6',
        max_tokens: 6000,
        system: system,
        messages: messages
      })
    });

    const data = await response.json();

    if (!response.ok) {
      console.log('Anthropic API returned an error:', JSON.stringify(data));
      return res.status(response.status).json({ error: data?.error?.message || 'API error' });
    }

    console.log('Success — analysis returned.');
    return res.status(200).json(data);

  } catch (err) {
    console.log('Caught exception in /api/analyze:', err);
    return res.status(500).json({ error: err.message || 'Server error' });
  }
});

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