refactor: update interface contract and applies some fixes

internal/repository/scanner_helper.go

@@ -0,0 +1,55 @@
+package repository
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+)
+
+func scanRow(row *sql.Row, dest any) error {
+	destValue := reflect.ValueOf(dest).Elem()
+	fields := make([]any, destValue.NumField())
+
+	for i := 0; i < destValue.NumField(); i++ {
+		fields[i] = destValue.Field(i).Addr().Interface()
+	}
+
+	return row.Scan(fields...)
+}
+
+func ScanRows(rows *sql.Rows, destSlice any) error {
+	sliceValue := reflect.ValueOf(destSlice)
+	if sliceValue.Kind() != reflect.Pointer || sliceValue.Elem().Kind() != reflect.Slice {
+		return fmt.Errorf("destSlice must be a pointer to a slice")
+	}
+
+	sliceElem := sliceValue.Elem()
+	structType := sliceElem.Type().Elem()
+
+	for rows.Next() {
+		newStruct := reflect.New(structType).Elem()
+
+		fields := make([]any, newStruct.NumField())
+		for i := 0; i < newStruct.NumField(); i++ {
+			fields[i] = newStruct.Field(i).Addr().Interface()
+		}
+
+		if err := rows.Scan(fields...); err != nil {
+			return err
+		}
+
+		sliceElem.Set(reflect.Append(sliceElem, newStruct))
+	}
+
+	return rows.Err()
+}
+
+func GetStructFieldsPtr(object any) []any {
+	destValue := reflect.ValueOf(object).Elem()
+	fields := make([]any, destValue.NumField())
+
+	for i := 0; i < destValue.NumField(); i++ {
+		fields[i] = destValue.Field(i).Addr().Interface()
+	}
+	return fields
+}