using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WIDESEA_Core.Helper
{
    public static class HttpContextHelper
    {
        /// <summary>
        /// 获取客户端真实IP地址
        /// </summary>
        /// <param name="context">Http上下文对象</param>
        /// <returns>客户端IP地址字符串</returns>
        /// <remarks>
        /// 优先从X-Real-IP和X-Forwarded-For请求头中获取IP地址，
        /// 如果不存在则返回连接远程IP地址
        /// </remarks>
        public static string GetUserIp(this HttpContext context)
        {
            string realIP = null;
            string forwarded = null;
            string remoteIpAddress = context.Connection.RemoteIpAddress.ToString();
            if (context.Request.Headers.ContainsKey("X-Real-IP"))
            {
                realIP = context.Request.Headers["X-Real-IP"].ToString();
                if (realIP != remoteIpAddress)
                {
                    remoteIpAddress = realIP;
                }
            }
            if (context.Request.Headers.ContainsKey("X-Forwarded-For"))
            {
                forwarded = context.Request.Headers["X-Forwarded-For"].ToString();
                if (forwarded != remoteIpAddress)
                {
                    remoteIpAddress = forwarded;
                }
            }
            return remoteIpAddress;
        }
    }
}