package subsonic

// Error codes from the Subsonic REST API specification, plus the
// OpenSubsonic apiKeyAuthentication extension's additions (42, 43, 44).
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
	ErrAuthMechanismUnsupported = 42 // provided authentication mechanism not supported
	ErrConflictingAuth          = 43 // multiple conflicting authentication mechanisms provided
	ErrInvalidAPIKey            = 44
	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
	HelpURL string
}

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

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

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

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)
}

const apiKeyHelpURL = "/settings#api-keys"

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")
	errConflictingAuth       = newErrorWithHelp(ErrConflictingAuth, "Provide either 'u' (with 'p' or 't'/'s') or 'apiKey', not both", apiKeyHelpURL)
	errInvalidAPIKey         = newErrorWithHelp(ErrInvalidAPIKey, "Invalid API key", apiKeyHelpURL)
)