Deterministic pagination in random albums sort (#1841)

* Deterministic pagination in random albums sort

* Reseed on first random page

* Add unit tests

* Use rand in Subsonic API

* Use different seeds per user on SEEDEDRAND() SQLite3 function

* Small refactor

* Fix id mismatch

* Add seeded random to media_file (subsonic endpoint `getRandomSongs`)

* Refactor

* Remove unneeded import

---------

Co-authored-by: Deluan <deluan@navidrome.org>

persistence/sql_base_repository.go

@@ -14,6 +14,7 @@ import (
 	"github.com/navidrome/navidrome/log"
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/model/request"
+	"github.com/navidrome/navidrome/utils/hasher"
 	"github.com/pocketbase/dbx"
 )
 
@@ -137,6 +138,18 @@ func (r sqlRepository) applyFilters(sq SelectBuilder, options ...model.QueryOpti
 	return sq
 }
 
+func (r sqlRepository) seededRandomSort() string {
+	u, _ := request.UserFrom(r.ctx)
+	return fmt.Sprintf("SEEDEDRAND('%s', id)", r.tableName+u.ID)
+}
+
+func (r sqlRepository) resetSeededRandom(options []model.QueryOptions) {
+	if len(options) > 0 && options[0].Offset == 0 && options[0].Sort == "random" {
+		u, _ := request.UserFrom(r.ctx)
+		hasher.Reseed(r.tableName + u.ID)
+	}
+}
+
 func (r sqlRepository) executeSQL(sq Sqlizer) (int64, error) {
 	query, args, err := r.toSQL(sq)
 	if err != nil {