// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

package websocket

import (

	"bufio"

	"encoding/base64"

	"errors"

	"net"

	"net/http"

	"net/url"

	"strings"

)

type netDialerFunc func(network, addr string) (net.Conn, error)

func (fn netDialerFunc) Dial(network, addr string) (net.Conn, error) {

	return fn(network, addr)

}

func init() {

	proxy_RegisterDialerType("http", func(proxyURL *url.URL, forwardDialer proxy_Dialer) (proxy_Dialer, error) {

		return &httpProxyDialer{proxyURL: proxyURL, forwardDial: forwardDialer.Dial}, nil

	})

}

type httpProxyDialer struct {

	proxyURL    *url.URL

	forwardDial func(network, addr string) (net.Conn, error)

}

func (hpd *httpProxyDialer) Dial(network string, addr string) (net.Conn, error) {

	hostPort, _ := hostPortNoPort(hpd.proxyURL)

	conn, err := hpd.forwardDial(network, hostPort)

	if err != nil {

		return nil, err

	}

	connectHeader := make(http.Header)

	if user := hpd.proxyURL.User; user != nil {

		proxyUser := user.Username()

		if proxyPassword, passwordSet := user.Password(); passwordSet {

			credential := base64.StdEncoding.EncodeToString([]byte(proxyUser + ":" + proxyPassword))

			connectHeader.Set("Proxy-Authorization", "Basic "+credential)

		}

	}

	connectReq := &http.Request{

		URL:    &url.URL{Opaque: addr},

		Host:   addr,

		Header: connectHeader,

	}

	if err := connectReq.Write(conn); err != nil {

		conn.Close()

		return nil, err

	}

	// Read response. It's OK to use and discard buffered reader here becaue

	// the remote server does not speak until spoken to.

	br := bufio.NewReader(conn)

	resp, err := http.ReadResponse(br, connectReq)

	if err != nil {

		conn.Close()

		return nil, err

	}

	if resp.StatusCode != 200 {

		conn.Close()

		f := strings.SplitN(resp.Status, " ", 2)

		return nil, errors.New(f[1])

	}

	return conn, nil

}