package subsonic

// Error codes from the Subsonic REST API specification.
const (
	ErrGeneric               = 0
	ErrMissingParameter      = 10
	ErrClientMustUpgrade     = 20 // client's protocol version is newer than this server supports
	ErrServerMustUpgrade     = 30 // server requires a newer client
	ErrWrongCredentials      = 40
	ErrTokenAuthNotSupported = 41 // e.g. LDAP-backed accounts with no local password
	ErrUnauthorized          = 50 // authenticated, but not permitted to perform this action
	ErrTrialExpired          = 60 // VibeSonic never returns this: no license is required
	ErrNotFound              = 70
)

// apiError is a Subsonic protocol error carrying an HTTP-agnostic code
// and message. Handlers return one instead of writing to the response
// directly, so the router can format it consistently in whatever
// wire format the caller asked for and it never leaks a raw Go error
// (which could expose internal paths/state) to the client.
type apiError struct {
	Code    int
	Message string
}

func (e *apiError) Error() string { return e.Message }

func newError(code int, message string) *apiError {
	return &apiError{Code: code, Message: message}
}

func errMissingParameter(name string) *apiError {
	return newError(ErrMissingParameter, "Required parameter '"+name+"' is missing")
}

func errNotFound(what string) *apiError {
	return newError(ErrNotFound, what+" not found")
}

func errUnauthorized(action string) *apiError {
	return newError(ErrUnauthorized, "User is not authorized for the requested "+action)
}

var (
	errWrongCredentials      = newError(ErrWrongCredentials, "Wrong username or password")
	errClientMustUpgrade     = newError(ErrClientMustUpgrade, "Incompatible Subsonic REST protocol version. Client must upgrade.")
	errTokenAuthNotSupported = newError(ErrTokenAuthNotSupported, "Token authentication is not supported for this account; use password authentication")
)