errors.go

package mysa

import (
	"errors"
	"fmt"
	"io"
	"net/http"
)

// Sentinel errors for type checking with errors.Is().
var (
	ErrNotAuthenticated = errors.New("not authenticated")
	ErrDeviceNotFound   = errors.New("device not found")
)

// UnauthenticatedError indicates authentication is required.
type UnauthenticatedError struct {
	Message string
	Cause   error
}

func (e *UnauthenticatedError) Error() string {
	if e.Cause != nil {
		return fmt.Sprintf("%s: %v", e.Message, e.Cause)
	}
	return e.Message
}

func (e *UnauthenticatedError) Unwrap() error {
	return e.Cause
}

func (e *UnauthenticatedError) Is(target error) bool {
	return target == ErrNotAuthenticated
}

// MysaApiError represents an API request failure.
type MysaApiError struct {
	StatusCode int
	Status     string
	URL        string
	Body       string
}

func (e *MysaApiError) Error() string {
	if e.Body != "" {
		return fmt.Sprintf("Mysa API error: %s returned %d (%s): %s", e.URL, e.StatusCode, e.Status, e.Body)
	}
	return fmt.Sprintf("Mysa API error: %s returned %d (%s)", e.URL, e.StatusCode, e.Status)
}

// NewMysaApiError creates an error from an HTTP response.
func NewMysaApiError(resp *http.Response) *MysaApiError {
	body, _ := io.ReadAll(resp.Body)
	return &MysaApiError{
		StatusCode: resp.StatusCode,
		Status:     resp.Status,
		URL:        resp.Request.URL.String(),
		Body:       string(body),
	}
}

// IsNotFound returns true if the error is a 404.
func (e *MysaApiError) IsNotFound() bool {
	return e.StatusCode == http.StatusNotFound
}

// IsUnauthorized returns true if the error is a 401.
func (e *MysaApiError) IsUnauthorized() bool {
	return e.StatusCode == http.StatusUnauthorized
}

// MqttPublishError represents a failed MQTT publish.
type MqttPublishError struct {
	Topic    string
	Attempts int
	Cause    error
}

func (e *MqttPublishError) Error() string {
	return fmt.Sprintf("MQTT publish to %s failed after %d attempts: %v",
		e.Topic, e.Attempts, e.Cause)
}

func (e *MqttPublishError) Unwrap() error {
	return e.Cause
}

// DeviceError represents a device-specific error.
type DeviceError struct {
	DeviceId string
	Message  string
	Cause    error
}

func (e *DeviceError) Error() string {
	if e.Cause != nil {
		return fmt.Sprintf("device %s: %s: %v", e.DeviceId, e.Message, e.Cause)
	}
	return fmt.Sprintf("device %s: %s", e.DeviceId, e.Message)
}

func (e *DeviceError) Unwrap() error {
	return e.Cause
}

func (e *DeviceError) Is(target error) bool {
	return target == ErrDeviceNotFound
}