/*
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 bce

import (
	"io"
	"net/http"
	"os"
	"strings"

	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider/baiducloud/baiducloud-sdk-go/util"
)

var canonicalHeaders = []string{
	"host",
	"content-length",
	"content-type",
	"content-md5",
}

// Request is http request, but has some custom functions.
type Request http.Request

// NewRequest returns a request client
func NewRequest(method, url string, body io.Reader) (*Request, error) {
	method = strings.ToUpper(method)

	rawRequest, err := http.NewRequest(method, url, body)

	if file, ok := body.(*os.File); ok {
		fileInfo, err := file.Stat()

		if err != nil {
			return nil, err
		}

		rawRequest.ContentLength = fileInfo.Size()
	}

	req := (*Request)(rawRequest)
	return req, err
}

// AddHeaders Add headers to http request
func (req *Request) AddHeaders(headerMap map[string]string) {
	for key, value := range headerMap {
		req.addHeader(key, value)
	}
}

func (req *Request) addHeader(key, value string) {
	req.Header.Add(key, value)
}

// SetHeaders Set headers to http request
func (req *Request) SetHeaders(headerMap map[string]string) {
	for key, value := range headerMap {
		req.setHeader(key, value)
	}
}

func (req *Request) setHeader(key, value string) {
	req.Header.Set(key, value)
}

func (req *Request) clearHeaders() {
	for key := range req.Header {
		delete(req.Header, key)
	}
}

func (req *Request) prepareHeaders(option *SignOption) {
	req.SetHeaders(option.Headers)

	if !util.MapContains(option.Headers, generateHeaderValidCompareFunc("host")) {
		option.Headers["host"] = req.URL.Host
		req.addHeader("Host", req.URL.Host)
	}

	host := req.Header.Get("Host")
	if host != req.URL.Host {
		req.setHeader("Host", req.URL.Host)
	}
}

func (req *Request) toCanonicalHeaderString(option *SignOption) string {
	headerMap := make(map[string]string, len(req.Header))
	for key, value := range req.Header {
		if !option.headersToSignSpecified {
			if isCanonicalHeader(key) {
				headerMap[key] = value[0]
			}
		} else if util.Contains(option.HeadersToSign, key, true) {
			headerMap[key] = value[0]
		}
	}

	result := util.ToCanonicalHeaderString(headerMap)
	return result
}

func (req *Request) canonical(option *SignOption) string {
	canonicalStrings := make([]string, 0, 4)

	canonicalStrings = append(canonicalStrings, req.Method)

	canonicalURI := util.URIEncodeExceptSlash(req.URL.Path)
	canonicalStrings = append(canonicalStrings, canonicalURI)

	canonicalStrings = append(canonicalStrings, req.URL.RawQuery)

	canonicalHeader := req.toCanonicalHeaderString(option)
	canonicalStrings = append(canonicalStrings, canonicalHeader)

	return strings.Join(canonicalStrings, "\n")
}

func (req *Request) raw() *http.Request {
	return (*http.Request)(req)
}

func isCanonicalHeader(key string) bool {
	key = strings.ToLower(key)
	return util.Contains(canonicalHeaders, key, true) || strings.Index(key, "x-bce-") == 0
}