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/channels/app/teams/service.go

@@ -0,0 +1,68 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package teams
+
+import (
+	"errors"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+	"github.com/mattermost/mattermost-server/v6/server/channels/store"
+)
+
+type TeamService struct {
+	store        store.TeamStore
+	groupStore   store.GroupStore
+	channelStore store.ChannelStore // TODO: replace this with ChannelService in the future
+	users        Users
+	wh           WebHub
+	config       func() *model.Config
+	license      func() *model.License
+}
+
+// ServiceConfig is used to initialize the TeamService.
+type ServiceConfig struct {
+	// Mandatory fields
+	TeamStore    store.TeamStore
+	GroupStore   store.GroupStore
+	ChannelStore store.ChannelStore
+	Users        Users
+	WebHub       WebHub
+	ConfigFn     func() *model.Config
+	LicenseFn    func() *model.License
+}
+
+// Users is a subset of UserService interface
+type Users interface {
+	GetUser(userID string) (*model.User, error)
+}
+
+// WebHub is used to publish events, the name should be given appropriately
+// while developing the websocket or clustering service
+type WebHub interface {
+	Publish(message *model.WebSocketEvent)
+}
+
+func New(c ServiceConfig) (*TeamService, error) {
+	if err := c.validate(); err != nil {
+		return nil, err
+	}
+
+	return &TeamService{
+		store:        c.TeamStore,
+		groupStore:   c.GroupStore,
+		channelStore: c.ChannelStore,
+		users:        c.Users,
+		config:       c.ConfigFn,
+		license:      c.LicenseFn,
+		wh:           c.WebHub,
+	}, nil
+}
+
+func (c *ServiceConfig) validate() error {
+	if c.ConfigFn == nil || c.TeamStore == nil || c.LicenseFn == nil || c.Users == nil || c.ChannelStore == nil || c.GroupStore == nil || c.WebHub == nil {
+		return errors.New("required parameters are not provided")
+	}
+
+	return nil
+}