[MM-20804] Add "Unarchive Channel" option to the channel info screen (#13349)

* add websocket hooks to restoreChannel

* add userId to call in api4

* add constant

* undo changes in en.json

* add constants to en.json

* delete  code for deleting webhooks

* Update i18n/en.json

Co-Authored-By: Ben Schumacher <ben.schumacher@mattermost.com>

* restore channel ordering

* delete Props

* Update app/channel.go

Co-Authored-By: Ben Schumacher <ben.schumacher@mattermost.com>

* Update app/channel.go

Co-Authored-By: Ben Schumacher <ben.schumacher@mattermost.com>

* change message format

* move WS message right after invalidate

* manually reorder en.json entry

* reorder en.json

* undelete to restore

* update en.json ordering

* update wording

* Update model/post.go

Co-Authored-By: Saturnino Abril <saturnino.abril@gmail.com>

* Update model/websocket_message.go

Co-Authored-By: Saturnino Abril <saturnino.abril@gmail.com>

* gofmt

* undeleted to restored

* add test to success case

* delete repeated test

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Saturnino Abril <saturnino.abril@gmail.com>
Co-authored-by: mattermod <mattermod@users.noreply.github.com>

api4/channel.go

@@ -358,7 +358,7 @@ func restoreChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	channel, err = c.App.RestoreChannel(channel)
+	channel, err = c.App.RestoreChannel(channel, c.App.Session.UserId)
 	if err != nil {
 		c.Err = err
 		return

app/channel.go

@@ -605,10 +605,40 @@ func (a *App) postChannelPrivacyMessage(user *model.User, channel *model.Channel
 	return nil
 }
 
-func (a *App) RestoreChannel(channel *model.Channel) (*model.Channel, *model.AppError) {
+func (a *App) RestoreChannel(channel *model.Channel, userId string) (*model.Channel, *model.AppError) {
+	if channel.DeleteAt == 0 {
+		return nil, model.NewAppError("restoreChannel", "api.channel.restore_channel.restored.app_error", nil, "", http.StatusBadRequest)
+	}
+
 	if err := a.Srv.Store.Channel().Restore(channel.Id, model.GetMillis()); err != nil {
 		return nil, err
 	}
+	a.InvalidateCacheForChannel(channel)
+
+	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_CHANNEL_RESTORED, channel.TeamId, "", "", nil)
+	message.Add("channel_id", channel.Id)
+	a.Publish(message)
+
+	user, err := a.Srv.Store.User().Get(userId)
+	if err != nil {
+		return nil, err
+	}
+
+	if user != nil {
+		T := utils.GetUserTranslations(user.Locale)
+
+		post := &model.Post{
+			ChannelId: channel.Id,
+			Message:   T("api.channel.restore_channel.unarchived", map[string]interface{}{"Username": user.Username}),
+			Type:      model.POST_CHANNEL_RESTORED,
+			UserId:    userId,
+		}
+
+		if _, err := a.CreatePost(post, channel, false); err != nil {
+			mlog.Error("Failed to post unarchive message", mlog.Err(err))
+		}
+	}
+
 	return channel, nil
 }
 

i18n/en.json

@@ -367,6 +367,14 @@
     "id": "api.channel.rename_channel.cant_rename_group_messages.app_error",
     "translation": "You cannot rename a group message channel"
   },
+  {
+    "id": "api.channel.restore_channel.restored.app_error",
+    "translation": "Unable to unarchive channel. The channel is not archived."
+  },
+  {
+    "id": "api.channel.restore_channel.unarchived",
+    "translation": "{{.Username}} unarchived the channel."
+  },
   {
     "id": "api.channel.update_channel.deleted.app_error",
     "translation": "The channel has been archived or deleted"

model/post.go

@@ -38,6 +38,7 @@ const (
 	POST_CONVERT_CHANNEL        = "system_convert_channel"
 	POST_PURPOSE_CHANGE         = "system_purpose_change"
 	POST_CHANNEL_DELETED        = "system_channel_deleted"
+	POST_CHANNEL_RESTORED       = "system_channel_restored"
 	POST_EPHEMERAL              = "system_ephemeral"
 	POST_CHANGE_CHANNEL_PRIVACY = "system_change_chan_privacy"
 	POST_ADD_BOT_TEAMS_CHANNELS = "add_bot_teams_channels"
@@ -264,6 +265,7 @@ func (o *Post) IsValid(maxPostSize int) *AppError {
 		POST_DISPLAYNAME_CHANGE,
 		POST_CONVERT_CHANNEL,
 		POST_CHANNEL_DELETED,
+		POST_CHANNEL_RESTORED,
 		POST_CHANGE_CHANNEL_PRIVACY,
 		POST_ME,
 		POST_ADD_BOT_TEAMS_CHANNELS:

model/websocket_message.go

@@ -18,6 +18,7 @@ const (
 	WEBSOCKET_EVENT_CHANNEL_CONVERTED       = "channel_converted"
 	WEBSOCKET_EVENT_CHANNEL_CREATED         = "channel_created"
 	WEBSOCKET_EVENT_CHANNEL_DELETED         = "channel_deleted"
+	WEBSOCKET_EVENT_CHANNEL_RESTORED        = "channel_restored"
 	WEBSOCKET_EVENT_CHANNEL_UPDATED         = "channel_updated"
 	WEBSOCKET_EVENT_CHANNEL_MEMBER_UPDATED  = "channel_member_updated"
 	WEBSOCKET_EVENT_DIRECT_ADDED            = "direct_added"