#!/usr/bin/env bash
set -e

# Rocketry Service Installer
# Installs the React SPA as a systemd service on the system

# Preflight checks
command -v node  >/dev/null || { echo "Error: node not found"; exit 1; }
command -v npm   >/dev/null || { echo "Error: npm not found"; exit 1; }
command -v sudo  >/dev/null || { echo "Error: sudo not found"; exit 1; }

echo "Rocketry Service Installer"
echo "=========================="
echo ""

# Port prompt
read -p "Port to run on [default: 8080]: " PORT
PORT=${PORT:-8080}

# Validate port
if ! [[ "$PORT" =~ ^[0-9]+$ ]] || [ "$PORT" -lt 1 ] || [ "$PORT" -gt 65535 ]; then
  echo "Error: Invalid port number. Must be between 1 and 65535."
  exit 1
fi

echo ""
echo "Building application..."
npm run build

# Install directory
INSTALL_DIR="/opt/rocketry"
echo "Installing to $INSTALL_DIR..."
sudo mkdir -p "$INSTALL_DIR"
sudo cp -r dist "$INSTALL_DIR/"

# Write server.js to /opt/rocketry/server.js
echo "Writing server.js..."
sudo tee "$INSTALL_DIR/server.js" > /dev/null <<'SERVEREOF'
#!/usr/bin/env node
const http = require('http');
const fs = require('fs');
const path = require('path');

const PORT = process.env.PORT || 8080;
const DIST_DIR = path.join(__dirname, 'dist');

const MIME_TYPES = {
  '.html': 'text/html; charset=utf-8',
  '.js': 'text/javascript; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.svg': 'image/svg+xml',
  '.png': 'image/png',
  '.ico': 'image/x-icon',
  '.woff2': 'font/woff2',
  '.json': 'application/json',
};

const server = http.createServer((req, res) => {
  // Normalize URL
  let urlPath = decodeURIComponent(req.url);
  if (urlPath === '/') {
    urlPath = '/index.html';
  }

  // Resolve file path
  const filePath = path.join(DIST_DIR, urlPath);

  // Security check: ensure we're within DIST_DIR
  if (!filePath.startsWith(DIST_DIR)) {
    res.writeHead(403, { 'Content-Type': 'text/plain' });
    res.end('Forbidden');
    return;
  }

  fs.stat(filePath, (err, stats) => {
    if (err) {
      // File not found; serve index.html for SPA routing (unless it's a file with extension)
      const ext = path.extname(urlPath);
      if (ext && ext !== '.html') {
        // Likely a missing asset file
        res.writeHead(404, { 'Content-Type': 'text/plain' });
        res.end('Not Found');
        return;
      }

      // SPA fallback: serve index.html
      const indexPath = path.join(DIST_DIR, 'index.html');
      fs.readFile(indexPath, 'utf-8', (readErr, data) => {
        if (readErr) {
          res.writeHead(500, { 'Content-Type': 'text/plain' });
          res.end('Internal Server Error');
          return;
        }
        res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });
        res.end(data);
      });
      return;
    }

    if (stats.isDirectory()) {
      // Try to serve index.html from the directory
      const indexPath = path.join(filePath, 'index.html');
      fs.readFile(indexPath, 'utf-8', (readErr, data) => {
        if (readErr) {
          // Directory exists but no index.html; fall back to SPA index
          const mainIndexPath = path.join(DIST_DIR, 'index.html');
          fs.readFile(mainIndexPath, 'utf-8', (mainErr, mainData) => {
            if (mainErr) {
              res.writeHead(404, { 'Content-Type': 'text/plain' });
              res.end('Not Found');
              return;
            }
            res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });
            res.end(mainData);
          });
          return;
        }
        res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });
        res.end(data);
      });
      return;
    }

    // Serve file with appropriate MIME type
    const ext = path.extname(filePath).toLowerCase();
    const contentType = MIME_TYPES[ext] || 'application/octet-stream';

    fs.readFile(filePath, (readErr, data) => {
      if (readErr) {
        res.writeHead(500, { 'Content-Type': 'text/plain' });
        res.end('Internal Server Error');
        return;
      }
      res.writeHead(200, { 'Content-Type': contentType });
      res.end(data);
    });
  });
});

server.listen(PORT, () => {
  console.log(`Rocketry server listening on http://localhost:${PORT}`);
});

server.on('error', (err) => {
  if (err.code === 'EACCES') {
    console.error(`Error: Permission denied. Port ${PORT} may require elevated privileges.`);
  } else if (err.code === 'EADDRINUSE') {
    console.error(`Error: Port ${PORT} is already in use.`);
  } else {
    console.error('Server error:', err.message);
  }
  process.exit(1);
});
SERVEREOF

# Make server.js executable
sudo chmod +x "$INSTALL_DIR/server.js"

# Write systemd unit file
echo "Writing systemd service file..."
sudo bash -c "cat > /etc/systemd/system/rocketry.service" <<UNITEOF
[Unit]
Description=Rocketry Equation Solver
After=network.target

[Service]
Type=simple
User=nobody
WorkingDirectory=/opt/rocketry
ExecStart=/usr/bin/node /opt/rocketry/server.js
Environment="PORT=$PORT"
Restart=on-failure
RestartSec=5
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target
UNITEOF

# Enable and start service
echo "Configuring systemd service..."
sudo systemctl daemon-reload
sudo systemctl enable rocketry
sudo systemctl restart rocketry

echo ""
echo "✓ Rocketry service installed successfully!"
echo ""
echo "  Location:  $INSTALL_DIR"
echo "  Port:      $PORT"
echo "  URL:       http://localhost:$PORT"
echo ""
echo "Service status:"
sudo systemctl status rocketry --no-pager | sed 's/^/  /'
echo ""
echo "Useful commands:"
echo "  Check status:    sudo systemctl status rocketry"
echo "  View logs:       sudo journalctl -u rocketry -f"
echo "  Restart:         sudo systemctl restart rocketry"
echo "  Stop:            sudo systemctl stop rocketry"
echo "  Uninstall:       sudo systemctl disable rocketry && sudo rm -rf $INSTALL_DIR /etc/systemd/system/rocketry.service && sudo systemctl daemon-reload"