/*
Copyright 2018 The Kubernetes Authors.

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 auth

import (
	"bytes"
	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/alicloud/alibaba-cloud-sdk-go/sdk/requests"
	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/alicloud/alibaba-cloud-sdk-go/sdk/utils"
	"sort"
	"strings"
)

func signRoaRequest(request requests.AcsRequest, signer Signer, regionId string) (err error) {
	completeROASignParams(request, signer, regionId)
	stringToSign := buildRoaStringToSign(request)
	request.SetStringToSign(stringToSign)
	signature := signer.Sign(stringToSign, "")
	accessKeyId, err := signer.GetAccessKeyId()
	if err != nil {
		return nil
	}

	request.GetHeaders()["Authorization"] = "acs " + accessKeyId + ":" + signature

	return
}

func completeROASignParams(request requests.AcsRequest, signer Signer, regionId string) {
	headerParams := request.GetHeaders()

	// complete query params
	queryParams := request.GetQueryParams()
	//if _, ok := queryParams["RegionId"]; !ok {
	//	queryParams["RegionId"] = regionId
	//}
	if extraParam := signer.GetExtraParam(); extraParam != nil {
		for key, value := range extraParam {
			if key == "SecurityToken" {
				headerParams["x-acs-security-token"] = value
				continue
			}

			queryParams[key] = value
		}
	}

	// complete header params
	headerParams["Date"] = utils.GetTimeInFormatRFC2616()
	headerParams["x-acs-signature-method"] = signer.GetName()
	headerParams["x-acs-signature-version"] = signer.GetVersion()
	if request.GetFormParams() != nil && len(request.GetFormParams()) > 0 {
		formString := utils.GetUrlFormedMap(request.GetFormParams())
		request.SetContent([]byte(formString))
		headerParams["Content-Type"] = requests.Form
	}
	contentMD5 := utils.GetMD5Base64(request.GetContent())
	headerParams["Content-MD5"] = contentMD5
	if _, contains := headerParams["Content-Type"]; !contains {
		headerParams["Content-Type"] = requests.Raw
	}
	switch format := request.GetAcceptFormat(); format {
	case "JSON":
		headerParams["Accept"] = requests.Json
	case "XML":
		headerParams["Accept"] = requests.Xml
	default:
		headerParams["Accept"] = requests.Raw
	}
}

func buildRoaStringToSign(request requests.AcsRequest) (stringToSign string) {

	headers := request.GetHeaders()

	stringToSignBuilder := bytes.Buffer{}
	stringToSignBuilder.WriteString(request.GetMethod())
	stringToSignBuilder.WriteString(requests.HeaderSeparator)

	// append header keys for sign
	appendIfContain(headers, &stringToSignBuilder, "Accept", requests.HeaderSeparator)
	appendIfContain(headers, &stringToSignBuilder, "Content-MD5", requests.HeaderSeparator)
	appendIfContain(headers, &stringToSignBuilder, "Content-Type", requests.HeaderSeparator)
	appendIfContain(headers, &stringToSignBuilder, "Date", requests.HeaderSeparator)

	// sort and append headers witch starts with 'x-acs-'
	var acsHeaders []string
	for key := range headers {
		if strings.HasPrefix(key, "x-acs-") {
			acsHeaders = append(acsHeaders, key)
		}
	}
	sort.Strings(acsHeaders)
	for _, key := range acsHeaders {
		stringToSignBuilder.WriteString(key + ":" + headers[key])
		stringToSignBuilder.WriteString(requests.HeaderSeparator)
	}

	// append query params
	stringToSignBuilder.WriteString(request.BuildQueries())
	stringToSign = stringToSignBuilder.String()
	return
}

func appendIfContain(sourceMap map[string]string, target *bytes.Buffer, key, separator string) {
	if value, contain := sourceMap[key]; contain && len(value) > 0 {
		target.WriteString(sourceMap[key])
		target.WriteString(separator)
	}
}