messaging

var (
	// ErrMissingScope reports a token without the scope a read needs; a
	// MissingScopeError carrying the scope's name wraps it.
	ErrMissingScope = errors.New("the Slack token lacks a scope")
	// ErrNoUserGroups reports a workspace or token that has no user groups to
	// read: a free workspace, or a token Slack will not answer them for.
	ErrNoUserGroups = errors.New("this Slack workspace has no user groups")
	// ErrLookupRefused reports a directory read Slack would not answer, for a
	// reason that is neither the token nor its scopes.
	ErrLookupRefused = errors.New("the lookup was refused")
	// ErrChannelNotFound reports a channel name none of the user's channels has.
	ErrChannelNotFound = errors.New("no channel of yours has that name")
	// ErrDirectoryTooLarge reports a read still paging after its page cap:
	// MaxPages, or UserListPages for Users.
	ErrDirectoryTooLarge = errors.New("the Slack directory is too large to read")
	// ErrNotTaggable reports a user who is not a person to tag: deactivated,
	// a bot, or Slackbot.
	ErrNotTaggable = errors.New("not a Slack user who can be tagged")
	// ErrInvalidSlackID reports a value that is not a Slack user or group ID.
	ErrInvalidSlackID = errors.New("not a Slack ID")
)

var (
	// ErrNoCredential reports that messaging has no credential to post with:
	// neither transport is set, or the user token has no source to give one.
	ErrNoCredential = errors.New("messaging has no credential")
	// ErrWebhookUncheckable reports that a webhook cannot be verified.
	ErrWebhookUncheckable = errors.New("an incoming webhook cannot be checked without posting with it")
	// ErrRejected reports a credential the service would not accept: Slack's no
	// to a token, or a webhook a service answered a post to with a 401, a 403,
	// a 404, or one of Slack's codes for a webhook that no longer works.
	ErrRejected = errors.New("the credential was not accepted")
	// ErrTokenExpired reports a user token Slack called expired after the
	// source was asked for a newer one, which it answers as ErrRejected too.
	ErrTokenExpired = errors.New("the Slack user token has expired")
	// ErrPostRefused reports a message the service would not deliver, for a
	// reason that is not about the credential: Slack's for its channel, or any
	// other 4xx a webhook answers a post with, such as a message too long. Its
	// words name no verb, because an announcement and the Summary both post
	// through here.
	ErrPostRefused = errors.New("the message was refused")
	// ErrUnexpectedStatus reports a response status the API does not document.
	ErrUnexpectedStatus = errors.New("unexpected response status")
	// ErrUnreachable reports a request that never got an answer.
	ErrUnreachable = errors.New("could not reach the messaging service")
	// ErrNoWorkspace reports an auth.test answer naming no Slack workspace, or
	// one not shaped like a workspace's ID.
	ErrNoWorkspace = errors.New("auth.test named no Slack workspace for the token")
)

var ErrInsecureWebhook = errors.New("messaging.webhook_url is not an https URL")

var ErrTooLong = errors.New("too long")