package cast import "fmt" type SendRequest struct { To string `json:"to"` Message string `json:"message"` SenderID string `json:"sender_id,omitempty"` } type SendResponse struct { Success bool `json:"success"` MessageID string `json:"message_id,omitempty"` Parts int `json:"parts,omitempty"` Error string `json:"error,omitempty"` } type CastAPIError struct { StatusCode int APIError string } func (e *CastAPIError) Error() string { return fmt.Sprintf("cast api error (HTTP %d): %s", e.StatusCode, e.APIError) }