// UnmarshalError unmarshals a response error for the REST JSON protocol.
func UnmarshalError(r *request.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
	}

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

// loadProfiles loads from the file pointed to by shared credentials filename for profile.
// The credentials retrieved from the profile will be returned or error. Error will be
// returned if it fails to read from the file, or the data is invalid.
func loadProfile(filename, profile string) (Value, error) {
	config, err := ini.Load(filename)
	if err != nil {
		return Value{}, awserr.New("SharedCredsLoad", "failed to load shared credentials file", err)
	}
	iniProfile, err := config.GetSection(profile)
	if err != nil {
		return Value{}, awserr.New("SharedCredsLoad", "failed to get profile", err)
	}

	id, err := iniProfile.GetKey("aws_access_key_id")
	if err != nil {
		return Value{}, awserr.New("SharedCredsAccessKey",
			fmt.Sprintf("shared credentials %s in %s did not contain aws_access_key_id", profile, filename),
			err)
	}

	secret, err := iniProfile.GetKey("aws_secret_access_key")
	if err != nil {
		return Value{}, awserr.New("SharedCredsSecret",
			fmt.Sprintf("shared credentials %s in %s did not contain aws_secret_access_key", profile, filename),
			nil)
	}

	// Default to empty string if not found
	token := iniProfile.Key("aws_session_token")

	return Value{
		AccessKeyID:     id.String(),
		SecretAccessKey: secret.String(),
		SessionToken:    token.String(),
	}, nil
}

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

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

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

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

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

func buildQueryString(query url.Values, v reflect.Value, name string) error {
	switch value := v.Interface().(type) {
	case []*string:
		for _, item := range value {
			query.Add(name, *item)
		}
	case map[string]*string:
		for key, item := range value {
			query.Add(key, *item)
		}
	case map[string][]*string:
		for key, items := range value {
			for _, item := range items {
				query.Add(key, *item)
			}
		}
	default:
		str, err := convertType(v)
		if err == errValueNotSet {
			return nil
		} else if err != nil {
			return awserr.New("SerializationError", "failed to encode REST request", err)
		}
		query.Set(name, str)
	}

	return nil
}

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...
}

// requestCredList requests a list of credentials from the EC2 service.
// If there are no credentials, or there is an error making or receiving the request
func requestCredList(client *ec2metadata.EC2Metadata) ([]string, error) {
	resp, err := client.GetMetadata(iamSecurityCredsPath)
	if err != nil {
		return nil, awserr.New("EC2RoleRequestError", "failed to list EC2 Roles", err)
	}

	credsList := []string{}
	s := bufio.NewScanner(strings.NewReader(resp))
	for s.Scan() {
		credsList = append(credsList, s.Text())
	}

	if err := s.Err(); err != nil {
		return nil, awserr.New("SerializationError", "failed to read list of EC2 Roles", err)
	}

	return credsList, nil
}

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

// 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 {
		reqID := resp.RequestID
		if reqID == "" {
			reqID = r.RequestID
		}
		r.Error = awserr.NewRequestFailure(
			awserr.New(resp.Code, resp.Message, nil),
			r.HTTPResponse.StatusCode,
			reqID,
		)
	}
}

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)
}

// 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 buildHeader(header *http.Header, v reflect.Value, name string) error {
	str, err := convertType(v)
	if err == errValueNotSet {
		return nil
	} else if err != nil {
		return awserr.New("SerializationError", "failed to encode REST request", err)
	}

	header.Add(name, str)

	return nil
}

func unmarshalBody(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 := 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 buildHeaderMap(header *http.Header, v reflect.Value, prefix string) error {
	for _, key := range v.MapKeys() {
		str, err := convertType(v.MapIndex(key))
		if err == errValueNotSet {
			continue
		} else if err != nil {
			return awserr.New("SerializationError", "failed to encode REST request", err)

		}

		header.Add(prefix+key.String(), str)
	}
	return nil
}

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
		}
	}
}

// requestCred requests the credentials for a specific credentials from the EC2 service.
//
// If the credentials cannot be found, or there is an error reading the response
// and error will be returned.
func requestCred(client *ec2metadata.EC2Metadata, credsName string) (ec2RoleCredRespBody, error) {
	resp, err := client.GetMetadata(path.Join(iamSecurityCredsPath, credsName))
	if err != nil {
		return ec2RoleCredRespBody{},
			awserr.New("EC2RoleRequestError",
				fmt.Sprintf("failed to get %s EC2 Role credentials", credsName),
				err)
	}

	respCreds := ec2RoleCredRespBody{}
	if err := json.NewDecoder(strings.NewReader(resp)).Decode(&respCreds); err != nil {
		return ec2RoleCredRespBody{},
			awserr.New("SerializationError",
				fmt.Sprintf("failed to decode %s EC2 Role credentials", credsName),
				err)
	}

	if respCreds.Code != "Success" {
		// If an error code was returned something failed requesting the role.
		return ec2RoleCredRespBody{}, awserr.New(respCreds.Code, respCreds.Message, nil)
	}

	return respCreds, nil
}

func buildURI(u *url.URL, v reflect.Value, name string) error {
	value, err := convertType(v)
	if err == errValueNotSet {
		return nil
	} else if err != nil {
		return awserr.New("SerializationError", "failed to encode REST request", err)
	}

	uri := u.Path
	uri = strings.Replace(uri, "{"+name+"}", EscapePath(value, true), -1)
	uri = strings.Replace(uri, "{"+name+"+}", EscapePath(value, false), -1)
	u.Path = uri

	return nil
}

// Build builds a request for an AWS Query service.
func Build(r *request.Request) {
	body := url.Values{
		"Action":  {r.Operation.Name},
		"Version": {r.ClientInfo.APIVersion},
	}
	if err := queryutil.Parse(body, r.Params, false); err != nil {
		r.Error = awserr.New("SerializationError", "failed encoding Query request", err)
		return
	}

	if r.ExpireTime == 0 {
		r.HTTPRequest.Method = "POST"
		r.HTTPRequest.Header.Set("Content-Type", "application/x-www-form-urlencoded; charset=utf-8")
		r.SetBufferBody([]byte(body.Encode()))
	} else { // This is a pre-signed request
		r.HTTPRequest.Method = "GET"
		r.HTTPRequest.URL.RawQuery = body.Encode()
	}
}

// Retrieve retrieves credentials from the EC2 service.
// Error will be returned if the request fails, or unable to extract
// the desired credentials.
func (m *EC2RoleProvider) Retrieve() (credentials.Value, error) {
	credsList, err := requestCredList(m.Client)
	if err != nil {
		return credentials.Value{}, err
	}

	if len(credsList) == 0 {
		return credentials.Value{}, awserr.New("EmptyEC2RoleList", "empty EC2 Role list", nil)
	}
	credsName := credsList[0]

	roleCreds, err := requestCred(m.Client, credsName)
	if err != nil {
		return credentials.Value{}, err
	}

	m.SetExpiration(roleCreds.Expiration, m.ExpiryWindow)

	return credentials.Value{
		AccessKeyID:     roleCreds.AccessKeyID,
		SecretAccessKey: roleCreds.SecretAccessKey,
		SessionToken:    roleCreds.Token,
	}, nil
}

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()))
					}
				}
			}
		}
	}
}