make application with base logic

internal/common/errors/error.go

@@ -0,0 +1,36 @@
+package errors
+
+import (
+	"fmt"
+)
+
+const (
+	ErrNotImplemented   SimpleError = "not implemented"
+	ErrUnexpectedStatus SimpleError = "unexpected status"
+)
+
+type SimpleError string
+
+func (err SimpleError) Error() string {
+	return string(err)
+}
+
+type ValidationError struct {
+	Field  string
+	Reason string
+}
+
+func (err *ValidationError) Error() string {
+	return fmt.Sprintf("field %s is not valid for reason %s", err.Field, err.Reason)
+}
+
+func NewValidationError(field, reason string) *ValidationError {
+	if field == "" {
+		panic("field not provided")
+	}
+
+	return &ValidationError{
+		Field:  field,
+		Reason: reason,
+	}
+}