refactor: improve error handling and response formatting in API

internal/gperr/hint.go

@@ -0,0 +1,43 @@
+package gperr
+
+import "github.com/yusing/go-proxy/internal/utils/strutils/ansi"
+
+type Hint struct {
+	Prefix  string
+	Message string
+	Suffix  string
+}
+
+var _ PlainError = (*Hint)(nil)
+var _ MarkdownError = (*Hint)(nil)
+
+func (h *Hint) Error() string {
+	return h.Prefix + ansi.Info(h.Message) + h.Suffix
+}
+
+func (h *Hint) Plain() []byte {
+	return []byte(h.Prefix + h.Message + h.Suffix)
+}
+
+func (h *Hint) Markdown() []byte {
+	return []byte(h.Prefix + "**" + h.Message + "**" + h.Suffix)
+}
+
+func (h *Hint) MarshalText() ([]byte, error) {
+	return h.Plain(), nil
+}
+
+func (h *Hint) String() string {
+	return h.Error()
+}
+
+func DoYouMean(s string) *Hint {
+	if s == "" {
+		return nil
+	}
+	return &Hint{
+		Prefix:  "Do you mean ",
+		Message: s,
+		Suffix:  "?",
+	}
+}