automatically remove mailboxes in empty rooms, fixes #3

bot/bot.go

@@ -19,14 +19,14 @@ import (
 
 // Bot represents matrix bot
 type Bot struct {
-	noowner           bool
-	federation        bool
-	prefix            string
-	domain            string
-	rooms             sync.Map
-	log               *logger.Logger
-	lp                *linkpearl.Linkpearl
-	handledJoinEvents sync.Map
+	noowner                 bool
+	federation              bool
+	prefix                  string
+	domain                  string
+	rooms                   sync.Map
+	log                     *logger.Logger
+	lp                      *linkpearl.Linkpearl
+	handledMembershipEvents sync.Map
 }
 
 // New creates a new matrix bot

bot/command.go

@@ -112,7 +112,7 @@ func (b *Bot) handleCommand(ctx context.Context, evt *event.Event, command []str
 	case "help":
 		b.sendHelp(ctx, evt.RoomID)
 	case "stop":
-		b.runStop(ctx)
+		b.runStop(ctx, true)
 	default:
 		b.handleOption(ctx, command)
 	}
@@ -159,7 +159,7 @@ func (b *Bot) sendHelp(ctx context.Context, roomID id.RoomID) {
 	b.Notice(ctx, roomID, msg.String())
 }
 
-func (b *Bot) runStop(ctx context.Context) {
+func (b *Bot) runStop(ctx context.Context, checkAllowed bool) {
 	evt := eventFromContext(ctx)
 	cfg, err := b.getSettings(evt.RoomID)
 	if err != nil {
@@ -167,7 +167,7 @@ func (b *Bot) runStop(ctx context.Context) {
 		return
 	}
 
-	if !cfg.Allowed(b.noowner, evt.Sender) {
+	if checkAllowed && !cfg.Allowed(b.noowner, evt.Sender) {
 		b.Notice(ctx, evt.RoomID, "you don't have permission to do that")
 		return
 	}

bot/sync.go

@@ -29,11 +29,16 @@ func (b *Bot) initSync() {
 func (b *Bot) onMembership(evt *event.Event) {
 	ctx := newContext(evt)
 
-	if evt.Content.AsMember().Membership == event.MembershipJoin && evt.Sender == b.lp.GetClient().UserID {
+	evtType := evt.Content.AsMember().Membership
+	if evtType == event.MembershipJoin && evt.Sender == b.lp.GetClient().UserID {
 		b.onBotJoin(ctx)
 		return
 	}
 
+	if evtType == event.MembershipBan || evtType == event.MembershipLeave && evt.Sender != b.lp.GetClient().UserID {
+		b.onLeave(ctx)
+	}
+
 	// Potentially handle other membership events in the future
 }
 
@@ -68,7 +73,7 @@ func (b *Bot) onBotJoin(ctx context.Context) {
 	evt := eventFromContext(ctx)
 	// Workaround for membership=join events which are delivered to us twice,
 	// as described in this bug report: https://github.com/matrix-org/synapse/issues/9768
-	_, ok := b.handledJoinEvents.LoadOrStore(evt.ID, true)
+	_, ok := b.handledMembershipEvents.LoadOrStore(evt.ID, true)
 	if ok {
 		b.log.Info("Suppressing already handled event %s", evt.ID)
 		return
@@ -77,3 +82,22 @@ func (b *Bot) onBotJoin(ctx context.Context) {
 	b.sendIntroduction(ctx, evt.RoomID)
 	b.sendHelp(ctx, evt.RoomID)
 }
+
+func (b *Bot) onLeave(ctx context.Context) {
+	evt := eventFromContext(ctx)
+	_, ok := b.handledMembershipEvents.LoadOrStore(evt.ID, true)
+	if ok {
+		b.log.Info("Suppressing already handled event %s", evt.ID)
+		return
+	}
+	members := b.lp.GetStore().GetRoomMembers(evt.RoomID)
+	count := len(members)
+	if count == 1 && members[0] == b.lp.GetClient().UserID {
+		b.log.Info("no more users left in the %s room", evt.RoomID)
+		b.runStop(ctx, false)
+		_, err := b.lp.GetClient().LeaveRoom(evt.RoomID)
+		if err != nil {
+			b.Error(ctx, evt.RoomID, "cannot leave empty room: %v", err)
+		}
+	}
+}