Plugin API for Shared Channels: support auto invite (#25834)

* option for auto inviting plugin to all shared channels.

* auto-invite remotes to shared channels when flag set

* fix unit test

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/remote_cluster.go

@@ -22,7 +22,8 @@ const (
 	RemoteNameMinLength      = 1
 	RemoteNameMaxLength      = 64
 
-	BitflagOptionAutoShareDMs Bitmask = 1 << iota
+	BitflagOptionAutoShareDMs Bitmask = 1 << iota // Any new DM/GM is automatically shared
+	BitflagOptionAutoInvited                      // Remote is automatically invited to all shared channels
 )
 
 var (
@@ -31,6 +32,18 @@ var (
 
 type Bitmask uint32
 
+func (bm *Bitmask) IsBitSet(flag Bitmask) bool {
+	return *bm != 0
+}
+
+func (bm *Bitmask) SetBit(flag Bitmask) {
+	*bm |= flag
+}
+
+func (bm *Bitmask) UnsetBit(flag Bitmask) {
+	*bm &= ^flag
+}
+
 type RemoteCluster struct {
 	RemoteId     string  `json:"remote_id"`
 	RemoteTeamId string  `json:"remote_team_id"`
@@ -105,15 +118,15 @@ func (rc *RemoteCluster) IsValid() *AppError {
 }
 
 func (rc *RemoteCluster) IsOptionFlagSet(flag Bitmask) bool {
-	return rc.Options&flag != 0
+	return rc.Options.IsBitSet(flag)
 }
 
 func (rc *RemoteCluster) SetOptionFlag(flag Bitmask) {
-	rc.Options |= flag
+	rc.Options.SetBit(flag)
 }
 
 func (rc *RemoteCluster) UnsetOptionFlag(flag Bitmask) {
-	rc.Options &= ^flag
+	rc.Options.UnsetBit(flag)
 }
 
 func IsValidRemoteName(s string) bool {
@@ -340,4 +353,5 @@ type RemoteClusterQueryFilter struct {
 	CreatorId      string
 	OnlyConfirmed  bool
 	PluginID       string
+	RequireOptions Bitmask
 }

server/public/model/shared_channel.go

@@ -305,6 +305,7 @@ type RegisterPluginOpts struct {
 	PluginID     string // id of this plugin registering
 	CreatorID    string // id of the user/bot registering
 	AutoShareDMs bool   // when true, all DMs are automatically shared to this remote
+	AutoInvited  bool   // when true, the plugin is automatically invited and sync'd with all shared channels.
 }
 
 // GetOptionFlags returns a Bitmask of option flags as specified by the boolean options.
@@ -313,5 +314,8 @@ func (po RegisterPluginOpts) GetOptionFlags() Bitmask {
 	if po.AutoShareDMs {
 		flags |= BitflagOptionAutoShareDMs
 	}
+	if po.AutoInvited {
+		flags |= BitflagOptionAutoInvited
+	}
 	return flags
 }