package main

import (
	"fmt"
	"log"
	"net/http"
	"slices"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		log.Print(r)
		fmt.Fprintf(w, "Method: %v\n", r.Method)
		fmt.Fprintf(w, "URL: %v\n", r.URL)
		fmt.Fprintf(w, "Proto: %v\n", r.Proto)
		fmt.Fprintf(w, "Header:\n")

		for _, key := range headerSortedKeys(r.Header) {
			value := r.Header[key]
			fmt.Fprintf(w, "\t%v: ", key)
			for _, v := range value {
				fmt.Fprintf(w, "'%v' ", v)
			}
			fmt.Fprintf(w, "\n")
		}
		fmt.Fprintf(w, "RemoteAddr: %v\n", r.RemoteAddr)
	})
	if err := http.ListenAndServe(":8000", nil); err != nil {
		log.Fatalf("failed to listen and serve: %v", err)
	}
}

func headerSortedKeys(header http.Header) []string {
	keys := []string{}
	for key := range header {
		keys = append(keys, key)
	}
	slices.Sort(keys)
	return keys
}