restrict import/export to minimal store interface

app/migrator/disqus.go

@@ -10,12 +10,11 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/umputun/remark/app/store"
-	"github.com/umputun/remark/app/store/service"
 )
 
 // Disqus implements Importer from disqus xml
 type Disqus struct {
-	DataStore *service.DataStore
+	DataStore Store
 }
 
 type disqusThread struct {

app/migrator/migrator.go

@@ -9,8 +9,7 @@ import (
 	"os"
 
 	"github.com/pkg/errors"
-
-	"github.com/umputun/remark/app/store/service"
+	"github.com/umputun/remark/app/store"
 )
 
 // Importer defines interface to convert posts from external sources
@@ -23,9 +22,17 @@ type Exporter interface {
 	Export(w io.Writer, siteID string) (int, error)
 }
 
+// Store defines minimal interface needed to export and import comments
+type Store interface {
+	Create(comment store.Comment) (commentID string, err error)
+	Find(locator store.Locator, sort string) ([]store.Comment, error)
+	List(siteID string, limit int, skip int) ([]store.PostInfo, error)
+	DeleteAll(siteID string) error
+}
+
 // ImportParams defines everything needed to run import
 type ImportParams struct {
-	DataStore *service.DataStore
+	DataStore Store
 	InputFile string
 	Provider  string
 	SiteID    string

app/migrator/remark.go

@@ -8,14 +8,12 @@ import (
 	"log"
 
 	"github.com/pkg/errors"
-	"github.com/umputun/remark/app/store/service"
-
 	"github.com/umputun/remark/app/store"
 )
 
 // Remark implements exporter and importer for internal store format
 type Remark struct {
-	DataStore *service.DataStore
+	DataStore Store
 }
 
 // Export all comments to writer as json strings. Each comment is one string, separated by "\n"