/*
Command http2client tests HTTP2 client request muliplexing of concurrent requests to the same service.

*/
package main

import (
	"crypto/tls"
	"log"
	"net/http"
	"net/http/httptrace"
	"net/url"
	"os"
)

var (

	//Mutual Auth HTTP Client
	client http.Client

	//Trace Context
	clientTrace = httptrace.ClientTrace{GetConn: getConn, GotConn: gotConn, PutIdleConn: putIdleConn, GotFirstResponseByte: gotFirstResponseByte, Got100Continue: got100Continue, DNSStart: dnsStart, DNSDone: dnsDone, ConnectStart: connectStart, ConnectDone: connectDone, TLSHandshakeStart: tlsHandshakeStart, TLSHandshakeDone: tlsHandshakeDone, WroteHeaders: wroteHeaders, Wait100Continue: wait100Continue, WroteRequest: wroteRequest}
)

//HTTP Trace hooks
func getConn(s string) {
	log.Printf("GetCon                  %s\n", s)
}

func gotConn(p httptrace.GotConnInfo) {
	log.Printf("gotConn                 %+v\n", p)
}

func putIdleConn(err error) {
	log.Printf("putIdleConn\n")
}

func gotFirstResponseByte() {
	log.Printf("gotFirstResponseByte\n")
}

func got100Continue() {
	log.Printf("got100Continue\n")
}

func dnsStart(p httptrace.DNSStartInfo) {
	log.Printf("dnsStart                %+v\n", p)
}

func dnsDone(p httptrace.DNSDoneInfo) {
	log.Printf("dnsDone                 %+v\n", p)
}

func connectStart(network, addr string) {
	log.Printf("connectStart            %s: %s\n", network, addr)
}

func connectDone(network, addr string, err error) {
	log.Printf("connectDone             %s: %s\n", network, addr)
}

func tlsHandshakeStart() {
	log.Printf("tlsHandshakeStart\n")
}

func tlsHandshakeDone(conState tls.ConnectionState, err error) {
	log.Printf("tlsHandshakeDone        %+v\n", conState)
}

func wroteHeaders() {
	log.Printf("wroteHeaders\n")
}

func wait100Continue() {
	log.Printf("wait100Continue\n")
}

func wroteRequest(wri httptrace.WroteRequestInfo) {
	log.Printf("wroteRequest\n")
}

func request(ch chan int) {
	var (
		req http.Request
		rsp *http.Response
		err error
	)

	req.Method = http.MethodGet
	req.URL, _ = url.ParseRequestURI("https://http2.golang.org/file/gopher.png")
	tracedReq := req.WithContext(httptrace.WithClientTrace(req.Context(), &clientTrace))
	rsp, err = client.Do(tracedReq)
	if err != nil {
		log.Printf("Ping error: %s\n", err)
		os.Exit(1)
	}
	if rsp.StatusCode != http.StatusOK {
		log.Printf("Ping status: %s\n", rsp.Status)
		os.Exit(1)
	}

	//Signal request has completed
	ch <- 1
} //request

func main() {
	var (
		requestCh      chan int
		requestDoneCnt int
	)

	//Execute three concurrent requests to verify request multiplexing on the cached controller conection
	requestCh = make(chan int, 100)
	go request(requestCh)
	go request(requestCh)
	go request(requestCh)

gatherPings:
	for {
		select {
		case <-requestCh:
			requestDoneCnt += 1
			if requestDoneCnt >= 3 {
				break gatherPings
			}
		}
	}

}