// Copyright 2020 The Go 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 main

import (
	"net/http"
	"strings"

	"golang.org/x/website/internal/env"
)

// googleCN reports whether request r is considered
// to be served from golang.google.cn.
// TODO: This is duplicated within internal/proxy. Move to a common location.
func googleCN(r *http.Request) bool {
	if r.FormValue("googlecn") != "" {
		return true
	}
	if strings.HasSuffix(r.Host, ".cn") {
		return true
	}
	if !env.CheckCountry() {
		return false
	}
	switch r.Header.Get("X-Appengine-Country") {
	case "", "ZZ", "CN":
		return true
	}
	return false
}