Moving slash-commands out of app package (#14979)

* Moving slash-commands out of app package

* Fixing golint checks

* Fixing golangci-lint

* Fixing golangci-lint errors

app/slashcommands/command_dnd.go

@@ -0,0 +1,50 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package slashcommands
+
+import (
+	goi18n "github.com/mattermost/go-i18n/i18n"
+	"github.com/mattermost/mattermost-server/v5/app"
+	"github.com/mattermost/mattermost-server/v5/model"
+)
+
+type DndProvider struct {
+}
+
+const (
+	CMD_DND = "dnd"
+)
+
+func init() {
+	app.RegisterCommandProvider(&DndProvider{})
+}
+
+func (me *DndProvider) GetTrigger() string {
+	return CMD_DND
+}
+
+func (me *DndProvider) GetCommand(a *app.App, T goi18n.TranslateFunc) *model.Command {
+	return &model.Command{
+		Trigger:          CMD_DND,
+		AutoComplete:     true,
+		AutoCompleteDesc: T("api.command_dnd.desc"),
+		DisplayName:      T("api.command_dnd.name"),
+	}
+}
+
+func (me *DndProvider) DoCommand(a *app.App, args *model.CommandArgs, message string) *model.CommandResponse {
+	status, err := a.GetStatus(args.UserId)
+	if err != nil {
+		return &model.CommandResponse{ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL, Text: args.T("api.command_dnd.error")}
+	} else {
+		if status.Status == "dnd" {
+			a.SetStatusOnline(args.UserId, true)
+			return &model.CommandResponse{ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL, Text: args.T("api.command_dnd.disabled")}
+		}
+	}
+
+	a.SetStatusDoNotDisturb(args.UserId)
+
+	return &model.CommandResponse{ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL, Text: args.T("api.command_dnd.success")}
+}