using System.Numerics;
using CoreAgent.Domain.Interfaces;

namespace CoreAgent.Infrastructure.Network;

/// <summary>
/// 提供IP地址相关的工具方法
/// </summary>
public static class IPAddressUtils
{
    /// <summary>
    /// 检查两个IPv4地址是否在同一个子网内
    /// </summary>
    /// <param name="ip1">第一个IP地址</param>
    /// <param name="ip2">第二个IP地址</param>
    /// <param name="subnetMask">子网掩码</param>
    /// <returns>如果两个IP地址在同一个子网内返回true，否则返回false</returns>
    /// <exception cref="ArgumentException">当IP地址或子网掩码不是IPv4格式时抛出</exception>
    public static bool IsSameIPv4Subnet(System.Net.IPAddress ip1, System.Net.IPAddress ip2, System.Net.IPAddress subnetMask)
    {
        if (ip1.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork ||
            ip2.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork ||
            subnetMask.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
        {
            throw new ArgumentException("IP addresses and subnet mask must be IPv4.");
        }

        byte[] ip1Bytes = ip1.GetAddressBytes();
        byte[] ip2Bytes = ip2.GetAddressBytes();
        byte[] subnetBytes = subnetMask.GetAddressBytes();

        byte[] network1 = new byte[4];
        byte[] network2 = new byte[4];

        for (int i = 0; i < 4; i++)
        {
            network1[i] = (byte)(ip1Bytes[i] & subnetBytes[i]);
            network2[i] = (byte)(ip2Bytes[i] & subnetBytes[i]);
        }

        return new System.Net.IPAddress(network1).Equals(new System.Net.IPAddress(network2));
    }

    /// <summary>
    /// 检查两个IPv6地址是否在同一个子网内
    /// </summary>
    /// <param name="ip1">第一个IP地址</param>
    /// <param name="ip2">第二个IP地址</param>
    /// <param name="prefixLength">前缀长度</param>
    /// <returns>如果两个IP地址在同一个子网内返回true，否则返回false</returns>
    /// <exception cref="ArgumentException">当IP地址不是IPv6格式时抛出</exception>
    public static bool IsSameIPv6Subnet(System.Net.IPAddress ip1, System.Net.IPAddress ip2, int prefixLength)
    {
        if (ip1.AddressFamily != System.Net.Sockets.AddressFamily.InterNetworkV6 ||
            ip2.AddressFamily != System.Net.Sockets.AddressFamily.InterNetworkV6)
        {
            throw new ArgumentException("IP addresses must be IPv6.");
        }

        BigInteger ip1Value = new BigInteger(ip1.GetAddressBytes());
        BigInteger ip2Value = new BigInteger(ip2.GetAddressBytes());

        BigInteger mask = BigInteger.One << (128 - prefixLength);
        mask -= BigInteger.One;
        mask = ~mask;

        return (ip1Value & mask) == (ip2Value & mask);
    }

    /// <summary>
    /// 获取系统的IPv4地址列表
    /// </summary>
    /// <param name="commandStrategyFactory">命令策略工厂</param>
    /// <param name="source">取消令牌源</param>
    /// <param name="logger">日志记录器</param>
    /// <returns>IPv4地址列表</returns>
    public static async Task<IEnumerable<string>> CheckAddressIPv4(ICommandStrategyFactory commandStrategyFactory, CancellationTokenSource source)
    {
        List<string> addrs = new List<string>();
        var inet4result = await commandStrategyFactory.CreateStrategy().ExecuteBufferedAsync("ifconfig | grep 'inet ' | awk '{print $2}'", source);
        if (!string.IsNullOrWhiteSpace(inet4result))
            addrs.AddRange(RemoveNewLines(inet4result));
        return addrs;
    }

    /// <summary>
    /// 获取系统的IPv6地址列表
    /// </summary>
    /// <param name="commandStrategyFactory">命令策略工厂</param>
    /// <param name="source">取消令牌源</param>
    /// <param name="logger">日志记录器</param>
    /// <returns>IPv6地址列表</returns>
    public static async Task<IEnumerable<string>> CheckAddressIPv6(ICommandStrategyFactory commandStrategyFactory, CancellationTokenSource source)
    {
        List<string> addrs = new List<string>();
        var inet6result = await commandStrategyFactory.CreateStrategy().ExecuteBufferedAsync("ifconfig | grep 'inet6 ' | awk '{print $2}'", source);
        if (!string.IsNullOrWhiteSpace(inet6result))
            addrs.AddRange(RemoveNewLines(inet6result));
        return addrs;
    }

    /// <summary>
    /// 获取系统的IPv4地址和子网掩码列表
    /// </summary>
    /// <param name="commandStrategyFactory">命令策略工厂</param>
    /// <param name="source">取消令牌源</param>
    /// <param name="logger">日志记录器</param>
    /// <returns>IPv4地址和子网掩码的元组列表</returns>
    public static async Task<List<(string ipv4, string mask)>> CheckAddressIPv4Mask(ICommandStrategyFactory commandStrategyFactory, CancellationTokenSource source)
    {
        List<(string ipv4, string mask)> addrs = new List<(string ipv4, string mask)>();
        var inet4result = await commandStrategyFactory.CreateStrategy().ExecuteBufferedAsync("ifconfig | grep 'inet ' | awk '{print $2\\\"|\\\"$4}'", source);
        if (!string.IsNullOrWhiteSpace(inet4result))
            addrs.AddRange(RemoveNewLines(inet4result).Select(s => (s.Split("|")[0], s.Split("|")[1])));
        return addrs;
    }

    /// <summary>
    /// 获取系统的IPv6地址和前缀长度列表
    /// </summary>
    /// <param name="commandStrategyFactory">命令策略工厂</param>
    /// <param name="source">取消令牌源</param>
    /// <param name="logger">日志记录器</param>
    /// <returns>IPv6地址和前缀长度的元组列表</returns>
    public static async Task<List<(string ipv6, string Prefix)>> CheckAddressIPv6Prefix(ICommandStrategyFactory commandStrategyFactory, CancellationTokenSource source)
    {
        List<(string ipv6, string Prefix)> addrs = new List<(string ipv6, string Prefix)>();
        var inet6result = await commandStrategyFactory.CreateStrategy().ExecuteBufferedAsync("ifconfig | grep 'inet6 ' | awk '{print $2\\\"|\\\"$4}'", source);
        if (!string.IsNullOrWhiteSpace(inet6result))
            addrs.AddRange(RemoveNewLines(inet6result).Select(s => (s.Split("|")[0], s.Split("|")[1])));
        return addrs;
    }

    /// <summary>
    /// 计算两个IP地址的匹配位数
    /// </summary>
    /// <param name="ip1">第一个IP地址</param>
    /// <param name="ip2">第二个IP地址</param>
    /// <returns>匹配的位数</returns>
    public static int GetMatchingBits(string ip1, string ip2)
    {
        byte[] bytes1 = System.Net.IPAddress.Parse(ip1).GetAddressBytes();
        byte[] bytes2 = System.Net.IPAddress.Parse(ip2).GetAddressBytes();
        int matchingBits = 0;
        for (int i = 0; i < bytes1.Length; i++)
        {
            int diff = bytes1[i] ^ bytes2[i]; // 异或计算不同位
            for (int bit = 7; bit >= 0; bit--)
            {
                if ((diff & (1 << bit)) == 0)
                    matchingBits++;
                else
                    return matchingBits;
            }
        }
        return matchingBits;
    }

    /// <summary>
    /// 移除字符串中的换行符并分割成数组
    /// </summary>
    /// <param name="input">输入字符串</param>
    /// <returns>分割后的字符串数组</returns>
    private static string[] RemoveNewLines(string input)
    {
        return input.Split("\n", StringSplitOptions.RemoveEmptyEntries);
    }
}