server.js

import express from 'express';
import cors from 'cors';
import 'dotenv/config';

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

const GROQ_API_KEY = process.env.GROQ_API_KEY;
const GROQ_API_URL = 'https://api.groq.com/openai/v1/chat/completions';

app.get('/health', (req, res) => {
  res.json({ status: 'ok', timestamp: new Date().toISOString() });
});

const SYSTEM_PROMPT = `You are an expert database architect. When the user describes an application or system, generate a complete database schema.

Respond ONLY with valid JSON in this exact format:
{
  "tables": [
    {
      "name": "table_name",
      "columns": [
        {
          "name": "column_name",
          "dataType": "INT|VARCHAR|TEXT|BOOLEAN|DATE|TIMESTAMP|DECIMAL|FLOAT|DOUBLE|UUID|BIGINT|JSON",
          "length": 255,
          "isPrimaryKey": true,
          "isForeignKey": false,
          "autoIncrement": true,
          "unique": false,
          "notNull": true,
          "defaultValue": null
        }
      ],
      "description": "What this table stores"
    }
  ],
  "relationships": [
    {
      "sourceTable": "table_with_foreign_key",
      "targetTable": "referenced_table",
      "sourceColumn": "fk_column",
      "targetColumn": "pk_column",
      "type": "ONE_TO_ONE|ONE_TO_MANY|MANY_TO_MANY"
    }
  ]
}

Rules:
- Always include id (INT, PK, autoIncrement) in every table
- Use appropriate data types for each column
- Add created_at (TIMESTAMP) to all tables
- Create junction tables for MANY_TO_MANY relationships
- Add meaningful indexes
- Keep response concise, only JSON no extra text
- Do not wrap in markdown code blocks, return raw JSON only`;

app.post('/api/schema', async (req, res) => {
  try {
    const { prompt, history } = req.body;
    const messages = [
      ...(history || []).slice(-10).map((m) => ({ role: m.role, content: m.content })),
      { role: 'user', content: prompt },
    ];

    const response = await fetch(GROQ_API_URL, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${GROQ_API_KEY}`,
      },
      body: JSON.stringify({
        model: 'llama-3.3-70b-versatile',
        messages: [{ role: 'system', content: SYSTEM_PROMPT }, ...messages],
        temperature: 0.3,
        max_tokens: 4096,
      }),
    });

    if (!response.ok) {
      const error = await response.json().catch(() => ({}));
      return res.status(response.status).json({ error: error.error?.message || 'Groq API error' });
    }

    const data = await response.json();
    res.json({ content: data.choices[0]?.message?.content || '' });
  } catch (err) {
    res.status(500).json({ error: 'Server error: ' + err.message });
  }
});

app.post('/api/chat', async (req, res) => {
  try {
    const { messages } = req.body;

    const response = await fetch(GROQ_API_URL, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${GROQ_API_KEY}`,
      },
      body: JSON.stringify({
        model: 'llama-3.3-70b-versatile',
        messages: [{ role: 'system', content: 'You are a helpful database design assistant. Answer questions about database design, suggest improvements, and help with schema planning. Be concise and technical.' }, ...messages],
        temperature: 0.5,
        max_tokens: 2048,
      }),
    });

    if (!response.ok) {
      const error = await response.json().catch(() => ({}));
      return res.status(response.status).json({ error: error.error?.message || 'Groq API error' });
    }

    const data = await response.json();
    res.json({ content: data.choices[0]?.message?.content || '' });
  } catch (err) {
    res.status(500).json({ error: 'Server error: ' + err.message });
  }
});

const PORT = 3001;
app.listen(PORT, () => {
  console.log(`AI Proxy server running on http://127.0.0.1:${PORT}`);
});