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

func generateSignedS3URL(region AWSRegion, bucket string, key string, expiry uint, endpoint string) (string, error) {
	s3ForcePathStyle := false
	if endpoint != "" {
		s3ForcePathStyle = true
	}

	// We want to use the default credentials chain so that it will attempt Env & Instance role creds
	svc := s3.New(&aws.Config{
		Region:           string(region),
		Endpoint:         endpoint,
		S3ForcePathStyle: s3ForcePathStyle,
	})

	var req *aws.Request
	req, _ = svc.GetObjectRequest(&s3.GetObjectInput{
		Bucket: &bucket,
		Key:    &key,
	})

	url, err := req.Presign(time.Duration(expiry) * time.Second)
	if err != nil {
		return "", err
	}
	return url, nil
}

// Unmarshal unmarshals the REST component of a response in a REST service.
func Unmarshal(r *aws.Request) {
	if r.DataFilled() {
		v := reflect.Indirect(reflect.ValueOf(r.Data))
		unmarshalBody(r, v)
		unmarshalLocationElements(r, v)
	}
}

// Build builds a JSON payload for a JSON RPC request.
func Build(req *aws.Request) {
	var buf []byte
	var err error
	if req.ParamsFilled() {
		buf, err = jsonutil.BuildJSON(req.Params)
		if err != nil {
			req.Error = apierr.New("Marshal", "failed encoding JSON RPC request", err)
			return
		}
	} else {
		buf = emptyJSON
	}

	if req.Service.TargetPrefix != "" || string(buf) != "{}" {
		req.SetBufferBody(buf)
	}

	if req.Service.TargetPrefix != "" {
		target := req.Service.TargetPrefix + "." + req.Operation.Name
		req.HTTPRequest.Header.Add("X-Amz-Target", target)
	}
	if req.Service.JSONVersion != "" {
		jsonVersion := req.Service.JSONVersion
		req.HTTPRequest.Header.Add("Content-Type", "application/x-amz-json-"+jsonVersion)
	}
}

// UnmarshalError unmarshals a response error for the REST JSON protocol.
func UnmarshalError(r *aws.Request) {
	code := r.HTTPResponse.Header.Get("X-Amzn-Errortype")
	bodyBytes, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "failed reading REST JSON error response", err)
		return
	}
	if len(bodyBytes) == 0 {
		r.Error = awserr.NewRequestFailure(
			awserr.New("SerializationError", r.HTTPResponse.Status, nil),
			r.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		r.Error = awserr.New("SerializationError", "failed decoding REST JSON error response", err)
		return
	}

	if code == "" {
		code = jsonErr.Code
	}

	codes := strings.SplitN(code, ":", 2)
	r.Error = awserr.NewRequestFailure(
		awserr.New(codes[0], jsonErr.Message, nil),
		r.HTTPResponse.StatusCode,
		"",
	)
}

// UnmarshalError unmarshals an error response for a JSON RPC service.
func UnmarshalError(req *aws.Request) {
	defer req.HTTPResponse.Body.Close()
	bodyBytes, err := ioutil.ReadAll(req.HTTPResponse.Body)
	if err != nil {
		req.Error = apierr.New("Unmarshal", "failed reading JSON RPC error response", err)
		return
	}
	if len(bodyBytes) == 0 {
		req.Error = apierr.NewRequestError(
			apierr.New("Unmarshal", req.HTTPResponse.Status, nil),
			req.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		req.Error = apierr.New("Unmarshal", "failed decoding JSON RPC error response", err)
		return
	}

	codes := strings.SplitN(jsonErr.Code, "#", 2)
	req.Error = apierr.NewRequestError(
		apierr.New(codes[len(codes)-1], jsonErr.Message, nil),
		req.HTTPResponse.StatusCode,
		"",
	)
}

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

	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,
			"",
		)
	}
}

func assertMD5(t *testing.T, req *aws.Request) {
	err := req.Build()
	assert.NoError(t, err)

	b, _ := ioutil.ReadAll(req.HTTPRequest.Body)
	out := md5.Sum(b)
	assert.NotEmpty(t, b)
	assert.Equal(t, base64.StdEncoding.EncodeToString(out[:]), req.HTTPRequest.Header.Get("Content-MD5"))
}

// Unmarshal unmarshals a response for a JSON RPC service.
func Unmarshal(req *aws.Request) {
	defer req.HTTPResponse.Body.Close()
	if req.DataFilled() {
		err := jsonutil.UnmarshalJSON(req.Data, req.HTTPResponse.Body)
		if err != nil {
			req.Error = apierr.New("Unmarshal", "failed decoding JSON RPC response", err)
		}
	}
	return
}

func addAccountID(r *aws.Request) {
	if !r.ParamsFilled() {
		return
	}

	v := reflect.Indirect(reflect.ValueOf(r.Params))
	if f := v.FieldByName("AccountID"); f.IsNil() {
		f.Set(reflect.ValueOf(&defaultAccountID))
	}
}

func verifySendMessage(r *aws.Request) {
	if r.DataFilled() && r.ParamsFilled() {
		in := r.Params.(*SendMessageInput)
		out := r.Data.(*SendMessageOutput)
		err := checksumsMatch(in.MessageBody, out.MD5OfMessageBody)
		if err != nil {
			setChecksumError(r, err.Error())
		}
	}
}

// Unmarshal unmarshals a response for an AWS Query service.
func Unmarshal(r *aws.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 = apierr.New("Unmarshal", "failed decoding Query response", err)
			return
		}
	}
}

// Unmarshal unmarshals a response body for the EC2 protocol.
func Unmarshal(r *aws.Request) {
	defer r.HTTPResponse.Body.Close()
	if r.DataFilled() {
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, "")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed decoding EC2 Query response", err)
			return
		}
	}
}

func populateLocationConstraint(r *aws.Request) {
	if r.ParamsFilled() && r.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.Config.Region,
			}
		}
	}
}

// Build builds a request payload for the REST XML protocol.
func Build(r *aws.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 = apierr.New("Marshal", "failed to enode rest XML request", err)
			return
		}
		r.SetBufferBody(buf.Bytes())
	}
}

// updatePredictEndpoint rewrites the request endpoint to use the
// "PredictEndpoint" parameter of the Predict operation.
func updatePredictEndpoint(r *aws.Request) {
	if !r.ParamsFilled() {
		return
	}

	r.Endpoint = *r.Params.(*PredictInput).PredictEndpoint

	uri, err := url.Parse(r.Endpoint)
	if err != nil {
		r.Error = err
		return
	}
	r.HTTPRequest.URL = uri
}

// UnmarshalError unmarshals an error response for an AWS Query service.
func UnmarshalError(r *aws.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,
		)
	}
}

func verifyReceiveMessage(r *aws.Request) {
	if r.DataFilled() && r.ParamsFilled() {
		ids := []string{}
		out := r.Data.(*ReceiveMessageOutput)
		for _, msg := range out.Messages {
			err := checksumsMatch(msg.Body, msg.MD5OfBody)
			if err != nil {
				ids = append(ids, *msg.MessageID)
			}
		}
		if len(ids) > 0 {
			setChecksumError(r, "invalid messages: %s", strings.Join(ids, ", "))
		}
	}
}

// UnmarshalError unmarshals a response error for the EC2 protocol.
func UnmarshalError(r *aws.Request) {
	defer r.HTTPResponse.Body.Close()

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = apierr.New("Unmarshal", "failed decoding EC2 Query error response", err)
	} else {
		r.Error = apierr.NewRequestError(
			apierr.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 *aws.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()
}