package nntp

import "fmt"

// An NNTPError is a coded NNTP error message.
type Error struct {
	Code int
	Msg  string
}

func (e *Error) Error() string {
	return fmt.Sprintf("%d %s", e.Code, e.Msg)
}

// ErrNoSuchGroup is returned for a request for a group that can't be found.
var ErrNoSuchGroup = &Error{411, "No such newsgroup"}

// ErrNoSuchGroup is returned for a request that requires a current
// group when none has been selected.
var ErrNoGroupSelected = &Error{412, "No newsgroup selected"}

// ErrInvalidMessageID is returned when a message is requested that can't be found.
var ErrInvalidMessageID = &Error{430, "No article with that message-id"}

// ErrInvalidArticleNumber is returned when an article is requested that can't be found.
var ErrInvalidArticleNumber = &Error{423, "No article with that number"}

// ErrNoCurrentArticle is returned when a command is executed that
// requires a current article when one has not been selected.
var ErrNoCurrentArticle = &Error{420, "Current article number is invalid"}

// ErrUnknownCommand is returned for unknown comands.
var ErrUnknownCommand = &Error{500, "Unknown command"}

// ErrSyntax is returned when a command can't be parsed.
var ErrSyntax = &Error{501, "not supported, or syntax error"}

// ErrPostingNotPermitted is returned as the response to an attempt to
// post an article where posting is not permitted.
var ErrPostingNotPermitted = &Error{440, "posting not permitted"}

// ErrPostingFailed is returned when an attempt to post an article fails.
var ErrPostingFailed = &Error{441, "posting failed"}

// ErrNotWanted is returned when an attempt to post an article is
// rejected due the server not wanting the article.
var ErrNotWanted = &Error{435, "Article not wanted"}

// ErrAuthRequired is returned to indicate authentication is required
// to proceed.
var ErrAuthRequired = &Error{450, "authorization required"}

// ErrAuthRejected is returned for invalid authentication.
var ErrAuthRejected = &Error{452, "authorization rejected"}

// ErrNotAuthenticated is returned when a command is issued that requires
// authentication, but authentication was not provided.
var ErrNotAuthenticated = &Error{480, "authentication required"}