package client

import (
	"net/http"
)

const (
	connectionHeaderKey          = "Connection"
	connectionUserAgentHeaderKey = "User-Agent"
	connectionCloseHeader        = "close"
	connectionKeepAliveHeader    = "keep-alive"
)

var (
	connectionCloseHeaderValue     = []string{connectionCloseHeader}
	connectionKeepAliveHeaderValue = []string{connectionKeepAliveHeader}
)

type predefinedHeaderTransport struct {
	useragentName []string
	http.Transport
}

func (pht *predefinedHeaderTransport) RoundTrip(req *http.Request) (res *http.Response, err error) {
	var connectionValue []string
	if pht.DisableKeepAlives {
		connectionValue = connectionCloseHeaderValue
	} else {
		connectionValue = connectionKeepAliveHeaderValue
	}
	req.Header[connectionHeaderKey] = connectionValue
	req.Header[connectionUserAgentHeaderKey] = pht.useragentName
	res, err = pht.Transport.RoundTrip(req)
	return
}