/**
 * Graph Viewer API for HuggingClaw
 * Simple D3-based graph visualization
 */

const express = require('express');
const neo4j = require('neo4j-driver');

const app = express();
const PORT = process.env.GRAPH_VIEWER_PORT || 7861;

// Connect to Memgraph using Bolt protocol
const driver = neo4j.driver(
  'bolt://localhost:7687',
  neo4j.auth.basic('', '')
);

// Security & Robustness Configuration (Bugs #19 & #20)
const cors = require('cors');
const rateLimit = require('express-rate-limit');

// CORS Configuration for Obsidian integration
app.use(cors({
  origin: ['obsidian://*', 'https://*.hf.space']
}));

// API Rate Limiting to prevent exhaustion
app.use(rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100 // limit each IP to 100 requests per windowMs
}));

// Serve static files
app.use(express.static('public'));

// API: Get full graph
app.get('/api/graph', async (req, res) => {
  const session = driver.session();
  try {
    const result = await session.run('MATCH (n) RETURN n');
    const edgesResult = await session.run('MATCH ()-[r]->() RETURN r');
    
    res.json({
      nodes: result.records.map(record => record.get('n').properties),
      edges: edgesResult.records.map(record => ({
        ...record.get('r').properties,
        type: record.get('r').type
      }))
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  } finally {
    await session.close();
  }
});

// API: Get graph by project
app.get('/api/graph/:project', async (req, res) => {
  const session = driver.session();
  try {
    const { project } = req.params;
    
    const result = await session.run(
      'MATCH (n {project: $project}) RETURN n',
      { project }
    );
    
    const edgesResult = await session.run(
      'MATCH (n {project: $project})-[r]->(m {project: $project}) RETURN r',
      { project }
    );
    
    res.json({
      nodes: result.records.map(record => record.get('n').properties),
      edges: edgesResult.records.map(record => ({
        ...record.get('r').properties,
        type: record.get('r').type
      }))
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  } finally {
    await session.close();
  }
});

// API: Health check
app.get('/health', async (req, res) => {
  let memgraphReady = false;
  const session = driver.session();
  try {
    const result = await session.run('RETURN 1');
    memgraphReady = result.records.length > 0;
  } catch (e) {
    memgraphReady = false;
  } finally {
    await session.close();
  }

  res.json({
    status: memgraphReady ? 'healthy' : 'degraded',
    version: '1.2.0',
    build_date: new Date().toISOString().split('T')[0],
    services: {
      memgraph: memgraphReady,
      graph_viewer: true,
      omniroute: 'check-port-20128' // Placeholder for port-based check
    },
    timestamp: new Date().toISOString()
  });
});

// Start server
app.listen(PORT, '0.0.0.0', () => {
  console.log(`📊 Graph Viewer running on port ${PORT}`);
  console.log(`   http://localhost:${PORT}`);
  console.log(`   API: http://localhost:${PORT}/api/graph`);
});

// Graceful driver shutdown
process.on('SIGTERM', () => {
  driver.close();
});

module.exports = app;