#!/bin/bash
#by spiritlhl
#from https://github.com/spiritLHLS/one-click-installation-script
#version: 2022.12.17

# Try to ping Google.com
if ping -c 1 google.com; then
  echo "Ping successful"
else
  echo "Ping failed. Checking nameserver."
  
  # Check current nameserver
  nameserver=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}')
  echo "Current nameserver: $nameserver"
  
  # Try using Google's nameserver
  echo "Trying Google's nameserver: 8.8.8.8"
  sudo sed -i "s/$nameserver/8.8.8.8/g" /etc/resolv.conf
  if ping -c 1 google.com; then
    echo "Ping successful with Google's nameserver"
  else
    echo "Ping failed with Google's nameserver. Trying Cloudflare's nameserver."
    
    # Try using Cloudflare's nameserver
    echo "Trying Cloudflare's nameserver: 1.1.1.1"
    sudo sed -i "s/8.8.8.8/1.1.1.1/g" /etc/resolv.conf
    if ping -c 1 google.com; then
      echo "Ping successful with Cloudflare's nameserver"
    else
      echo "Ping failed with Cloudflare's nameserver. Checking network configuration."
      
      # Check IP type and network priority
      ip_type=$(curl -s ip.sb | grep -oP '(?<=is )(.+)(?=\.)')
      echo "IP type: $ip_type"
      if [ "$ip_type" = "IPv4" ]; then
        priority=$(cat /etc/gai.conf | grep -oP '(?<=precedence ::ffff:0:0\/96 )\d+')
      else
        priority=$(cat /etc/gai.conf | grep -oP '(?<=precedence ::/0 )\d+')
      fi
      echo "Network priority: $priority"
      
      # Modify network priority if necessary
      if [ "$ip_type" = "IPv4" ] && [ "$priority" -gt "100" ]; then
        sudo sed -i 's/precedence ::ffff:0:0\/96 100/precedence ::ffff:0:0\/96 50/' /etc/gai.conf
      elif [ "$ip_type" = "IPv6" ] && [ "$priority" -lt "100" ]; then
        sudo sed -i 's/precedence ::\/0 50/precedence ::\/0 100/' /etc/gai.conf
      else
        echo "Network configuration is correct."
      fi
      
      # Try to ping again after modifying network priority
      if ping -c 1 google.com; then
        echo "Ping successful after modifying network priority"
      else
        echo "Network problem is not related to nameserver or network priority."
      fi
    fi
  fi
fi