// UnmarshalMeta unmarshals the REST metadata of a response in a REST service
func UnmarshalMeta(r *request.Request) {
	r.RequestID = r.HTTPResponse.Header.Get("X-Amzn-Requestid")
	if r.DataFilled() {
		v := reflect.Indirect(reflect.ValueOf(r.Data))
		unmarshalLocationElements(r, v)
	}
}

// Build builds the REST component of a service request.
func Build(r *request.Request) {
	if r.ParamsFilled() {
		v := reflect.ValueOf(r.Params).Elem()
		buildLocationElements(r, v)
		buildBody(r, v)
	}
}

func unmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()

	if r.HTTPResponse.StatusCode == http.StatusMovedPermanently {
		r.Error = awserr.New("BucketRegionError",
			fmt.Sprintf("incorrect region, the bucket is not in '%s' region", aws.StringValue(r.Service.Config.Region)), nil)
		return
	}

	if r.HTTPResponse.ContentLength == int64(0) {
		// No body, use status code to generate an awserr.Error
		r.Error = awserr.NewRequestFailure(
			awserr.New(strings.Replace(r.HTTPResponse.Status, " ", "", -1), r.HTTPResponse.Status, nil),
			r.HTTPResponse.StatusCode,
			"",
		)
		return
	}

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = awserr.New("SerializationError", "failed to decode S3 XML error response", nil)
	} else {
		r.Error = awserr.NewRequestFailure(
			awserr.New(resp.Code, resp.Message, nil),
			r.HTTPResponse.StatusCode,
			"",
		)
	}
}

// Unmarshal unmarshals a response for an AWS Query service.
func Unmarshal(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	if r.DataFilled() {
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, r.Operation.Name+"Result")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed decoding Query response", err)
			return
		}
	}
}

func populateLocationConstraint(r *request.Request) {
	if r.ParamsFilled() && aws.StringValue(r.Service.Config.Region) != "us-east-1" {
		in := r.Params.(*CreateBucketInput)
		if in.CreateBucketConfiguration == nil {
			r.Params = awsutil.CopyOf(r.Params)
			in = r.Params.(*CreateBucketInput)
			in.CreateBucketConfiguration = &CreateBucketConfiguration{
				LocationConstraint: r.Service.Config.Region,
			}
		}
	}
}

// Build builds a request payload for the REST XML protocol.
func Build(r *request.Request) {
	rest.Build(r)

	if t := rest.PayloadType(r.Params); t == "structure" || t == "" {
		var buf bytes.Buffer
		err := xmlutil.BuildXML(r.Params, xml.NewEncoder(&buf))
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed to encode rest XML request", err)
			return
		}
		r.SetBufferBody(buf.Bytes())
	}
}

// UnmarshalError unmarshals an error response for an AWS Query service.
func UnmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = awserr.New("SerializationError", "failed to decode query XML error response", err)
	} else {
		r.Error = awserr.NewRequestFailure(
			awserr.New(resp.Code, resp.Message, nil),
			r.HTTPResponse.StatusCode,
			resp.RequestID,
		)
	}
}

// Sign requests with signature version 4.
//
// Will sign the requests with the service config's Credentials object
// Signing is skipped if the credentials is the credentials.AnonymousCredentials
// object.
func Sign(req *request.Request) {
	// If the request does not need to be signed ignore the signing of the
	// request if the AnonymousCredentials object is used.
	if req.Service.Config.Credentials == credentials.AnonymousCredentials {
		return
	}

	region := req.Service.SigningRegion
	if region == "" {
		region = aws.StringValue(req.Service.Config.Region)
	}

	name := req.Service.SigningName
	if name == "" {
		name = req.Service.ServiceName
	}

	s := signer{
		Request:     req.HTTPRequest,
		Time:        req.Time,
		ExpireTime:  req.ExpireTime,
		Query:       req.HTTPRequest.URL.Query(),
		Body:        req.Body,
		ServiceName: name,
		Region:      region,
		Credentials: req.Service.Config.Credentials,
		Debug:       req.Service.Config.LogLevel.Value(),
		Logger:      req.Service.Config.Logger,
	}

	req.Error = s.sign()
}

func buildGetBucketLocation(r *request.Request) {
	if r.DataFilled() {
		out := r.Data.(*GetBucketLocationOutput)
		b, err := ioutil.ReadAll(r.HTTPResponse.Body)
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed reading response body", err)
			return
		}

		match := reBucketLocation.FindSubmatch(b)
		if len(match) > 1 {
			loc := string(match[1])
			out.LocationConstraint = &loc
		}
	}
}

func buildHeader(r *request.Request, v reflect.Value, name string) {
	str, err := convertType(v)
	if err != nil {
		r.Error = awserr.New("SerializationError", "failed to encode REST request", err)
	} else if str != nil {
		r.HTTPRequest.Header.Add(name, *str)
	}
}

func buildQueryString(r *request.Request, v reflect.Value, name string, query url.Values) {
	str, err := convertType(v)
	if err != nil {
		r.Error = awserr.New("SerializationError", "failed to encode REST request", err)
	} else if str != nil {
		query.Set(name, *str)
	}
}

func unmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	_, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "unable to unmarshal EC2 metadata error respose", err)
	}

	// TODO extract the error...
}

func buildHeaderMap(r *request.Request, v reflect.Value, prefix string) {
	for _, key := range v.MapKeys() {
		str, err := convertType(v.MapIndex(key))
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed to encode REST request", err)
		} else if str != nil {
			r.HTTPRequest.Header.Add(prefix+key.String(), *str)
		}
	}
}

func unmarshalHandler(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	b, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "unable to unmarshal EC2 metadata respose", err)
	}

	data := r.Data.(*metadataOutput)
	data.Content = string(b)
}

func buildURI(r *request.Request, v reflect.Value, name string) {
	value, err := convertType(v)
	if err != nil {
		r.Error = awserr.New("SerializationError", "failed to encode REST request", err)
	} else if value != nil {
		uri := r.HTTPRequest.URL.Path
		uri = strings.Replace(uri, "{"+name+"}", EscapePath(*value, true), -1)
		uri = strings.Replace(uri, "{"+name+"+}", EscapePath(*value, false), -1)
		r.HTTPRequest.URL.Path = uri
	}
}

func unmarshalBody(r *request.Request, v reflect.Value) {
	if field, ok := v.Type().FieldByName("SDKShapeTraits"); ok {
		if payloadName := field.Tag.Get("payload"); payloadName != "" {
			pfield, _ := v.Type().FieldByName(payloadName)
			if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
				payload := v.FieldByName(payloadName)
				if payload.IsValid() {
					switch payload.Interface().(type) {
					case []byte:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
						} else {
							payload.Set(reflect.ValueOf(b))
						}
					case *string:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
						} else {
							str := string(b)
							payload.Set(reflect.ValueOf(&str))
						}
					default:
						switch payload.Type().String() {
						case "io.ReadSeeker":
							payload.Set(reflect.ValueOf(aws.ReadSeekCloser(r.HTTPResponse.Body)))
						case "aws.ReadSeekCloser", "io.ReadCloser":
							payload.Set(reflect.ValueOf(r.HTTPResponse.Body))
						default:
							r.Error = awserr.New("SerializationError",
								"failed to decode REST response",
								fmt.Errorf("unknown payload type %s", payload.Type()))
						}
					}
				}
			}
		}
	}
}

// Unmarshal unmarshals a payload response for the REST XML protocol.
func Unmarshal(r *request.Request) {
	if t := rest.PayloadType(r.Data); t == "structure" || t == "" {
		defer r.HTTPResponse.Body.Close()
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, "")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed to decode REST XML response", err)
			return
		}
	} else {
		rest.Unmarshal(r)
	}
}

// contentMD5 computes and sets the HTTP Content-MD5 header for requests that
// require it.
func contentMD5(r *request.Request) {
	h := md5.New()

	// hash the body.  seek back to the first position after reading to reset
	// the body for transmission.  copy errors may be assumed to be from the
	// body.
	_, err := io.Copy(h, r.Body)
	if err != nil {
		r.Error = awserr.New("ContentMD5", "failed to read body", err)
		return
	}
	_, err = r.Body.Seek(0, 0)
	if err != nil {
		r.Error = awserr.New("ContentMD5", "failed to seek body", err)
		return
	}

	// encode the md5 checksum in base64 and set the request header.
	sum := h.Sum(nil)
	sum64 := make([]byte, base64.StdEncoding.EncodedLen(len(sum)))
	base64.StdEncoding.Encode(sum64, sum)
	r.HTTPRequest.Header.Set("Content-MD5", string(sum64))
}

func unmarshalLocationElements(r *request.Request, v reflect.Value) {
	for i := 0; i < v.NumField(); i++ {
		m, field := v.Field(i), v.Type().Field(i)
		if n := field.Name; n[0:1] == strings.ToLower(n[0:1]) {
			continue
		}

		if m.IsValid() {
			name := field.Tag.Get("locationName")
			if name == "" {
				name = field.Name
			}

			switch field.Tag.Get("location") {
			case "statusCode":
				unmarshalStatusCode(m, r.HTTPResponse.StatusCode)
			case "header":
				err := unmarshalHeader(m, r.HTTPResponse.Header.Get(name))
				if err != nil {
					r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
					break
				}
			case "headers":
				prefix := field.Tag.Get("locationName")
				err := unmarshalHeaderMap(m, r.HTTPResponse.Header, prefix)
				if err != nil {
					r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
					break
				}
			}
		}
		if r.Error != nil {
			return
		}
	}
}

func copyMultipartStatusOKUnmarhsalError(r *request.Request) {
	b, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "unable to read response body", err)
		return
	}
	body := bytes.NewReader(b)
	r.HTTPResponse.Body = aws.ReadSeekCloser(body)
	defer r.HTTPResponse.Body.(aws.ReaderSeekerCloser).Seek(0, 0)

	if body.Len() == 0 {
		// If there is no body don't attempt to parse the body.
		return
	}

	unmarshalError(r)
	if err, ok := r.Error.(awserr.Error); ok && err != nil {
		if err.Code() == "SerializationError" {
			r.Error = nil
			return
		}
		r.HTTPResponse.StatusCode = http.StatusServiceUnavailable
	}
}