package main

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"fmt"
	"math/big"
	"net"
	"net/http"
)

func main() {
	tlsVer := uint16(tls.VersionTLS13)
	clientConf := &tls.Config{
		ClientSessionCache: tls.NewLRUClientSessionCache(5),
		MinVersion:         tlsVer,
		MaxVersion:         tlsVer,
		InsecureSkipVerify: true,
	}
	tr := &http.Transport{
		TLSClientConfig: clientConf,
	}
	hc := &http.Client{Transport: tr}

	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		panic(err)
	}
	tmpl := &x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject:      pkix.Name{CommonName: "localhost"},
		DNSNames:     []string{"localhost"},
	}
	c, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, k.Public(), k)
	if err != nil {
		panic(err)
	}

	serverConf := &tls.Config{
		MinVersion: tlsVer,
		MaxVersion: tlsVer,
		VerifyConnection: func(_ tls.ConnectionState) error {
			fmt.Println("server verify connection")
			return nil
		},
		Certificates: []tls.Certificate{
			{
				Certificate: [][]byte{c},
				PrivateKey:  k,
			},
		},
	}

	l, err := net.Listen("tcp", "localhost:8181")
	if err != nil {
		panic(err)
	}
	tl := tls.NewListener(l, serverConf)
	s := http.Server{Handler: http.NotFoundHandler()}

	go func() {
		s.Serve(tl)
	}()

	fmt.Println("first")
	hc.Get("https://localhost:8181")

	fmt.Println()
	fmt.Println("second")
	resp, err := hc.Get("https://localhost:8181")
	if err != nil {
		panic(err)
	}
	fmt.Println("resumed?", resp.TLS.DidResume)
}