#!/bin/bash
# Network troubleshooting script for LXC containers

# Exit on any error
set -e

echo "Starting network troubleshooting..."

# Check if we can ping IP addresses
echo "Testing basic connectivity..."
if ping -c 2 8.8.8.8 >/dev/null 2>&1; then
  echo "✅ Basic network connectivity works (can ping 8.8.8.8)"
else
  echo "❌ Cannot ping 8.8.8.8 - basic network connectivity issue"
  echo "Checking network interfaces..."
  ip a
fi

# Check and fix DNS
echo "Checking DNS configuration..."
if ! grep -q "nameserver" /etc/resolv.conf || ! host archive.ubuntu.com >/dev/null 2>&1; then
  echo "❌ DNS resolution not working, fixing..."
  
  # Add Google DNS servers
  echo "nameserver 8.8.8.8
nameserver 8.8.4.4" > /etc/resolv.conf
  
  echo "✅ Added Google DNS servers to /etc/resolv.conf"
  
  # Make DNS changes persistent
  echo "Making DNS changes persistent..."
  mkdir -p /etc/systemd/resolved.conf.d/
  cat > /etc/systemd/resolved.conf.d/dns_servers.conf << EOF
[Resolve]
DNS=8.8.8.8 8.8.4.4
FallbackDNS=1.1.1.1
EOF
  
  # Try to restart systemd-resolved if it exists
  if systemctl status systemd-resolved >/dev/null 2>&1; then
    systemctl restart systemd-resolved
    echo "✅ Restarted systemd-resolved"
  fi
  
  # Try to restart systemd-networkd if it exists
  if systemctl status systemd-networkd >/dev/null 2>&1; then
    systemctl restart systemd-networkd
    echo "✅ Restarted systemd-networkd"
  fi
else
  echo "✅ DNS configuration looks good"
fi

# Add hosts entries as a fallback
echo "Adding fallback entries to /etc/hosts..."
if ! grep -q "archive.ubuntu.com" /etc/hosts; then
  cat >> /etc/hosts << EOF
185.125.190.36 archive.ubuntu.com
185.125.190.36 security.ubuntu.com
EOF
  echo "✅ Added Ubuntu repositories to /etc/hosts"
fi

# Test DNS resolution
echo "Testing DNS resolution..."
if host archive.ubuntu.com >/dev/null 2>&1; then
  echo "✅ DNS resolution working for archive.ubuntu.com"
else
  echo "❌ DNS resolution still not working for archive.ubuntu.com"
  echo "Trying ping with hosts file..."
  if ping -c 2 archive.ubuntu.com >/dev/null 2>&1; then
    echo "✅ Can ping archive.ubuntu.com using hosts file entry"
  else
    echo "❌ Still cannot reach archive.ubuntu.com"
    echo "This may be a more serious network issue with your LXC container"
  fi
fi

echo "Network troubleshooting completed"
echo "Try running 'apt update' now to see if it works"