Count func

mongox/common/count.go

@@ -0,0 +1,31 @@
+package common
+
+import (
+	"github.com/mainnika/mongox-go-driver/mongox"
+	"github.com/mainnika/mongox-go-driver/mongox/errors"
+	"github.com/mainnika/mongox-go-driver/mongox/query"
+	"github.com/mongodb/mongo-go-driver/mongo"
+	"github.com/mongodb/mongo-go-driver/mongo/options"
+)
+
+// Count function counts documents in the database by query
+// target is used only to get collection by tag so it'd be better to use nil ptr here
+func Count(db *mongox.Database, target interface{}, filters ...interface{}) (int64, error) {
+
+	collection := db.GetCollectionOf(target)
+	opts := options.Count()
+	composed := query.Compose(filters...)
+
+	opts.Limit = composed.Limiter()
+	opts.Skip = composed.Skipper()
+
+	result, err := collection.Count(db.Context(), composed.M(), opts)
+	if err == mongo.ErrNoDocuments {
+		return 0, errors.NotFoundErrorf("%s", err)
+	}
+	if err != nil {
+		return 0, errors.InternalErrorf("can't decode desult: %s", err)
+	}
+
+	return result, nil
+}