Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/boards/app/subscriptions.go

@@ -0,0 +1,55 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+import (
+	"github.com/mattermost/mattermost-server/v6/server/boards/model"
+	"github.com/mattermost/mattermost-server/v6/server/boards/utils"
+
+	"github.com/mattermost/mattermost-server/v6/server/platform/shared/mlog"
+)
+
+func (a *App) CreateSubscription(sub *model.Subscription) (*model.Subscription, error) {
+	sub, err := a.store.CreateSubscription(sub)
+	if err != nil {
+		return nil, err
+	}
+	a.notifySubscriptionChanged(sub)
+
+	return sub, nil
+}
+
+func (a *App) DeleteSubscription(blockID string, subscriberID string) (*model.Subscription, error) {
+	sub, err := a.store.GetSubscription(blockID, subscriberID)
+	if err != nil {
+		return nil, err
+	}
+	if err := a.store.DeleteSubscription(blockID, subscriberID); err != nil {
+		return nil, err
+	}
+	sub.DeleteAt = utils.GetMillis()
+	a.notifySubscriptionChanged(sub)
+
+	return sub, nil
+}
+
+func (a *App) GetSubscriptions(subscriberID string) ([]*model.Subscription, error) {
+	return a.store.GetSubscriptions(subscriberID)
+}
+
+func (a *App) notifySubscriptionChanged(subscription *model.Subscription) {
+	if a.notifications == nil {
+		return
+	}
+
+	board, err := a.getBoardForBlock(subscription.BlockID)
+	if err != nil {
+		a.logger.Error("Error notifying subscription change",
+			mlog.String("subscriber_id", subscription.SubscriberID),
+			mlog.String("block_id", subscription.BlockID),
+			mlog.Err(err),
+		)
+	}
+	a.wsAdapter.BroadcastSubscriptionChange(board.TeamID, subscription)
+}