// +build go1.7 go1.8

/*
 * MinIO Go Library for Amazon S3 Compatible Cloud Storage
 * Copyright 2017-2018 MinIO, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package minio

import (
	"crypto/tls"
	"crypto/x509"
	"net"
	"net/http"
	"time"

	"golang.org/x/net/http2"
)

// DefaultTransport - this default transport is similar to
// http.DefaultTransport but with additional param  DisableCompression
// is set to true to avoid decompressing content with 'gzip' encoding.
var DefaultTransport = func(secure bool) (http.RoundTripper, error) {
	tr := &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
		}).DialContext,
		MaxIdleConns:          1024,
		MaxIdleConnsPerHost:   1024,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
		// Set this value so that the underlying transport round-tripper
		// doesn't try to auto decode the body of objects with
		// content-encoding set to `gzip`.
		//
		// Refer:
		//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
		DisableCompression: true,
	}

	if secure {
		rootCAs, _ := x509.SystemCertPool()
		if rootCAs == nil {
			// In some systems (like Windows) system cert pool is
			// not supported or no certificates are present on the
			// system - so we create a new cert pool.
			rootCAs = x509.NewCertPool()
		}

		// Keep TLS config.
		tlsConfig := &tls.Config{
			RootCAs: rootCAs,
			// Can't use SSLv3 because of POODLE and BEAST
			// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
			// Can't use TLSv1.1 because of RC4 cipher usage
			MinVersion: tls.VersionTLS12,
		}
		tr.TLSClientConfig = tlsConfig

		// Because we create a custom TLSClientConfig, we have to opt-in to HTTP/2.
		// See https://github.com/golang/go/issues/14275
		if err := http2.ConfigureTransport(tr); err != nil {
			return nil, err
		}
	}
	return tr, nil
}