MM-56083 Add PatchMultipleMembersNotifyProps plugin API (#25690)

* Add ChannelStore.UpdateMultipleMembersNotifyProps

* Make UpdateMultipleMembersNotifyProps return updated values from the DB

* Add UpdateChannelMembersNotifications plugin API

* Extract i18n

* Fix style

* Make layers

* Change to PatchMultipleMembersNotifyProps

* Add limit to PatchChannelMembersNotifyProps

* Add additional unit tests

* Address feedback

* Lowercase decodeJSON

* Have PatchMultipleMembersNotifyProps update LastUpdateAt

* Fix tests that relied on unreliable return order

* Fix i18n

server/channels/app/channel.go

@@ -24,6 +24,10 @@ import (
 	"github.com/mattermost/mattermost/server/v8/channels/store/sqlstore"
 )
 
+const (
+	UpdateMultipleMaximum = 200
+)
+
 // channelsWrapper provides an implementation of `product.ChannelService` to be used by products.
 type channelsWrapper struct {
 	app *App
@@ -1360,15 +1364,66 @@ func (a *App) UpdateChannelMemberNotifyProps(c request.CTX, data map[string]stri
 	a.invalidateCacheForChannelMembersNotifyProps(member.ChannelId)
 
 	// Notify the clients that the member notify props changed
+	err = a.sendUpdateChannelMemberNotifyPropsEvent(member)
+	if err != nil {
+		return nil, model.NewAppError("UpdateChannelMemberNotifyProps", "api.marshal_error", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	return member, nil
+}
+
+func (a *App) PatchChannelMembersNotifyProps(c request.CTX, members []*model.ChannelMemberIdentifier, notifyProps map[string]string) ([]*model.ChannelMember, *model.AppError) {
+	if len(members) > UpdateMultipleMaximum {
+		return nil, model.NewAppError("PatchChannelMembersNotifyProps", "app.channel.patch_channel_members_notify_props.too_many", map[string]any{"Max": UpdateMultipleMaximum}, "", http.StatusBadRequest)
+	}
+
+	updated, err := a.Srv().Store().Channel().PatchMultipleMembersNotifyProps(members, notifyProps)
+	if err != nil {
+		var appErr *model.AppError
+		switch {
+		case errors.As(err, &appErr):
+			return nil, appErr
+		default:
+			return nil, model.NewAppError("UpdateMultipleMembersNotifyProps", "app.channel.patch_channel_members_notify_props.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
+		}
+	}
+
+	// Invalidate caches for the users and channels that have changed
+	userIds := make(map[string]bool)
+	channelIds := make(map[string]bool)
+	for _, member := range updated {
+		userIds[member.UserId] = true
+		channelIds[member.ChannelId] = true
+	}
+
+	for userId := range userIds {
+		a.InvalidateCacheForUser(userId)
+	}
+	for channelId := range channelIds {
+		a.invalidateCacheForChannelMembersNotifyProps(channelId)
+	}
+
+	// Notify clients that their notify props have changed
+	for _, member := range updated {
+		err := a.sendUpdateChannelMemberNotifyPropsEvent(member)
+		if err != nil {
+			c.Logger().Warn("Failed to send WebSocket event for updated channel member notify props", mlog.Err(err))
+		}
+	}
+
+	return updated, nil
+}
+
+func (a *App) sendUpdateChannelMemberNotifyPropsEvent(member *model.ChannelMember) error {
 	evt := model.NewWebSocketEvent(model.WebsocketEventChannelMemberUpdated, "", "", member.UserId, nil, "")
 	memberJSON, jsonErr := json.Marshal(member)
 	if jsonErr != nil {
-		return nil, model.NewAppError("UpdateChannelMemberNotifyProps", "api.marshal_error", nil, "", http.StatusInternalServerError).Wrap(jsonErr)
+		return jsonErr
 	}
 	evt.Add("channelMember", string(memberJSON))
 	a.Publish(evt)
 
-	return member, nil
+	return nil
 }
 
 func (a *App) updateChannelMember(c request.CTX, member *model.ChannelMember) (*model.ChannelMember, *model.AppError) {