refactor auth pkg into libraries

auth/pwdless/errors.go

@@ -0,0 +1,50 @@
+package pwdless
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/go-chi/render"
+)
+
+// The list of error types presented to the end user as error message.
+var (
+	ErrInvalidLogin  = errors.New("invalid email address")
+	ErrUnknownLogin  = errors.New("email not registered")
+	ErrLoginDisabled = errors.New("login for account disabled")
+	ErrLoginToken    = errors.New("invalid or expired login token")
+)
+
+// ErrResponse renderer type for handling all sorts of errors.
+type ErrResponse struct {
+	Err            error `json:"-"` // low-level runtime error
+	HTTPStatusCode int   `json:"-"` // http response status code
+
+	StatusText string `json:"status"`          // user-level status message
+	AppCode    int64  `json:"code,omitempty"`  // application-specific error code
+	ErrorText  string `json:"error,omitempty"` // application-level error message, for debugging
+}
+
+// Render sets the application-specific error code in AppCode.
+func (e *ErrResponse) Render(w http.ResponseWriter, r *http.Request) error {
+	render.Status(r, e.HTTPStatusCode)
+	return nil
+}
+
+// ErrUnauthorized renders status 401 Unauthorized with custom error message.
+func ErrUnauthorized(err error) render.Renderer {
+	return &ErrResponse{
+		Err:            err,
+		HTTPStatusCode: http.StatusUnauthorized,
+		StatusText:     http.StatusText(http.StatusUnauthorized),
+		ErrorText:      err.Error(),
+	}
+}
+
+// The list of default error types without specific error message.
+var (
+	ErrInternalServerError = &ErrResponse{
+		HTTPStatusCode: http.StatusInternalServerError,
+		StatusText:     http.StatusText(http.StatusInternalServerError),
+	}
+)