refactor(sdk): simplify provider lifecycle and registration logic

sdk/access/errors.go

@@ -1,12 +1,90 @@
 package access
 
-import "errors"
-
-var (
-	// ErrNoCredentials indicates no recognizable credentials were supplied.
-	ErrNoCredentials = errors.New("access: no credentials provided")
-	// ErrInvalidCredential signals that supplied credentials were rejected by a provider.
-	ErrInvalidCredential = errors.New("access: invalid credential")
-	// ErrNotHandled tells the manager to continue trying other providers.
-	ErrNotHandled = errors.New("access: not handled")
+import (
+	"fmt"
+	"net/http"
+	"strings"
 )
+
+// AuthErrorCode classifies authentication failures.
+type AuthErrorCode string
+
+const (
+	AuthErrorCodeNoCredentials     AuthErrorCode = "no_credentials"
+	AuthErrorCodeInvalidCredential AuthErrorCode = "invalid_credential"
+	AuthErrorCodeNotHandled        AuthErrorCode = "not_handled"
+	AuthErrorCodeInternal          AuthErrorCode = "internal_error"
+)
+
+// AuthError carries authentication failure details and HTTP status.
+type AuthError struct {
+	Code       AuthErrorCode
+	Message    string
+	StatusCode int
+	Cause      error
+}
+
+func (e *AuthError) Error() string {
+	if e == nil {
+		return ""
+	}
+	message := strings.TrimSpace(e.Message)
+	if message == "" {
+		message = "authentication error"
+	}
+	if e.Cause != nil {
+		return fmt.Sprintf("%s: %v", message, e.Cause)
+	}
+	return message
+}
+
+func (e *AuthError) Unwrap() error {
+	if e == nil {
+		return nil
+	}
+	return e.Cause
+}
+
+// HTTPStatusCode returns a safe fallback for missing status codes.
+func (e *AuthError) HTTPStatusCode() int {
+	if e == nil || e.StatusCode <= 0 {
+		return http.StatusInternalServerError
+	}
+	return e.StatusCode
+}
+
+func newAuthError(code AuthErrorCode, message string, statusCode int, cause error) *AuthError {
+	return &AuthError{
+		Code:       code,
+		Message:    message,
+		StatusCode: statusCode,
+		Cause:      cause,
+	}
+}
+
+func NewNoCredentialsError() *AuthError {
+	return newAuthError(AuthErrorCodeNoCredentials, "Missing API key", http.StatusUnauthorized, nil)
+}
+
+func NewInvalidCredentialError() *AuthError {
+	return newAuthError(AuthErrorCodeInvalidCredential, "Invalid API key", http.StatusUnauthorized, nil)
+}
+
+func NewNotHandledError() *AuthError {
+	return newAuthError(AuthErrorCodeNotHandled, "authentication provider did not handle request", 0, nil)
+}
+
+func NewInternalAuthError(message string, cause error) *AuthError {
+	normalizedMessage := strings.TrimSpace(message)
+	if normalizedMessage == "" {
+		normalizedMessage = "Authentication service error"
+	}
+	return newAuthError(AuthErrorCodeInternal, normalizedMessage, http.StatusInternalServerError, cause)
+}
+
+func IsAuthErrorCode(authErr *AuthError, code AuthErrorCode) bool {
+	if authErr == nil {
+		return false
+	}
+	return authErr.Code == code
+}