package main

import (
	"fmt"
	"log"
	"net"
	"os"
	"strings"

	"github.com/gin-gonic/gin"
)

func main() {
	gin.SetMode(gin.ReleaseMode)
	r := gin.Default()
	r.Use(gin.Logger())
	r.Use(gin.Recovery())
	r.GET("/", func(c *gin.Context) {
		log.Printf("user-agent=%s", c.Request.UserAgent())
		hostname, _ := os.Hostname()
		resultText := fmt.Sprintf("Hostname: %s\nIP: %s\nRemoteAddr: %s\nUser-Agent: %s\nX-Forwarded-For: %s\nX-Forwarded-Port: %s\nX-Forwarded-Server: %s\nX-Real-IP: %s\n",
			hostname, strings.Join(GetIps(), ", "), c.Request.RemoteAddr, c.Request.UserAgent(), c.Request.Header.Get("X-Forwarded-For"),
			c.Request.Header.Get("X-Forwarded-Port"), c.Request.Header.Get("X-Forwarded-Server"), c.Request.Header.Get("X-Real-IP"))
		c.String(200, resultText)
	})
	port := ":80"
	log.Printf("服务器启动在 http://localhost%s", port)
	if err := r.Run(port); err != nil {
		log.Fatal("服务器启动失败:", err)
	}
}

func GetIps() []string {
	ips := []string{}
	interfaces, _ := net.Interfaces()
	for _, iface := range interfaces {
		if iface.Flags&net.FlagUp == 0 {
			continue
		}
		addrs, err := iface.Addrs()
		if err != nil {
			continue
		}
		for _, addr := range addrs {
			var ip net.IP
			switch v := addr.(type) {
			case *net.IPNet:
				ip = v.IP
			case *net.IPAddr:
				ip = v.IP
			}
			if ip == nil || ip.IsLoopback() {
				continue
			}
			ipStr := ip.String()
			if ip.To4() != nil {
				ips = append(ips, ipStr)
			}
		}
	}
	return ips
}