// 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(req *request.Request) {
	bodyBytes, err := ioutil.ReadAll(req.HTTPResponse.Body)
	if err != nil {
		req.Error = awserr.New("UnmarshaleError", req.HTTPResponse.Status, err)
		return
	}
	if len(bodyBytes) == 0 {
		req.Error = awserr.NewRequestFailure(
			awserr.New("UnmarshaleError", req.HTTPResponse.Status, fmt.Errorf("empty body")),
			req.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		req.Error = awserr.New("UnmarshaleError", "JSON unmarshal", err)
		return
	}
	req.Error = awserr.NewRequestFailure(
		awserr.New(jsonErr.Code, jsonErr.Message, nil),
		req.HTTPResponse.StatusCode,
		"",
	)
}

// Unmarshal unmarshals a response body for the EC2 protocol.
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, "")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed decoding EC2 Query response", err)
			return
		}
	}
}

// UnmarshalError unmarshals a response error for the EC2 protocol.
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 decoding EC2 Query 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.Config.Credentials == credentials.AnonymousCredentials {
		return
	}

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

	name := req.ClientInfo.SigningName
	if name == "" {
		name = req.ClientInfo.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.Config.Credentials,
		Debug:       req.Config.LogLevel.Value(),
		Logger:      req.Config.Logger,
	}

	req.Error = s.sign()
}

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 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 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 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 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 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 fillPresignedURL(r *request.Request) {
	if !r.ParamsFilled() {
		return
	}

	params := r.Params.(*CopySnapshotInput)

	// Stop if PresignedURL/DestinationRegion is set
	if params.PresignedUrl != nil || params.DestinationRegion != nil {
		return
	}

	// First generate a copy of parameters
	r.Params = awsutil.CopyOf(r.Params)
	params = r.Params.(*CopySnapshotInput)

	// Set destination region. Avoids infinite handler loop.
	// Also needed to sign sub-request.
	params.DestinationRegion = r.Service.Config.Region

	// Create a new client pointing at source region.
	// We will use this to presign the CopySnapshot request against
	// the source region
	config := r.Service.Config.Copy().
		WithEndpoint("").
		WithRegion(*params.SourceRegion)

	client := New(config)

	// Presign a CopySnapshot request with modified params
	req, _ := client.CopySnapshotRequest(params)
	url, err := req.Presign(300 * time.Second) // 5 minutes should be enough.

	if err != nil { // bubble error back up to original request
		r.Error = err
	}

	// We have our URL, set it on params
	params.PresignedUrl = &url
}

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()))
						}
					}
				}
			}
		}
	}
}

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 buildLocationElements(r *request.Request, v reflect.Value) {
	query := r.HTTPRequest.URL.Query()

	for i := 0; i < v.NumField(); i++ {
		m := v.Field(i)
		if n := v.Type().Field(i).Name; n[0:1] == strings.ToLower(n[0:1]) {
			continue
		}

		if m.IsValid() {
			field := v.Type().Field(i)
			name := field.Tag.Get("locationName")
			if name == "" {
				name = field.Name
			}
			if m.Kind() == reflect.Ptr {
				m = m.Elem()
			}
			if !m.IsValid() {
				continue
			}

			var err error
			switch field.Tag.Get("location") {
			case "headers": // header maps
				err = buildHeaderMap(&r.HTTPRequest.Header, m, field.Tag.Get("locationName"))
			case "header":
				err = buildHeader(&r.HTTPRequest.Header, m, name)
			case "uri":
				err = buildURI(r.HTTPRequest.URL, m, name)
			case "querystring":
				err = buildQueryString(query, m, name)
			}
			r.Error = err
		}
		if r.Error != nil {
			return
		}
	}

	r.HTTPRequest.URL.RawQuery = query.Encode()
	updatePath(r.HTTPRequest.URL, r.HTTPRequest.URL.Path)
}

func buildBody(r *request.Request, v reflect.Value) {
	if field, ok := v.Type().FieldByName("_"); ok {
		if payloadName := field.Tag.Get("payload"); payloadName != "" {
			pfield, _ := v.Type().FieldByName(payloadName)
			if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
				payload := reflect.Indirect(v.FieldByName(payloadName))
				if payload.IsValid() && payload.Interface() != nil {
					switch reader := payload.Interface().(type) {
					case io.ReadSeeker:
						r.SetReaderBody(reader)
					case []byte:
						r.SetBufferBody(reader)
					case string:
						r.SetStringBody(reader)
					default:
						r.Error = awserr.New("SerializationError",
							"failed to encode REST request",
							fmt.Errorf("unknown payload type %s", payload.Type()))
					}
				}
			}
		}
	}
}

func validateEndpointHandler(r *request.Request) {
	if r.ClientInfo.Endpoint == "" {
		r.Error = aws.ErrMissingEndpoint
	}
}

// ShouldRetry returns if the request should be retried.
func (d DefaultRetryer) ShouldRetry(r *request.Request) bool {
	if r.HTTPResponse.StatusCode >= 500 {
		return true
	}
	return r.IsErrorRetryable()
}

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