feat(server): persist story quest difficulty and configurable starting chapter

go/internal/server/world/start_pack.go

@@ -0,0 +1,52 @@
+package world
+
+import (
+	"fmt"
+
+	"bd2server/internal/server/progress"
+)
+
+func (s *Service) startingPack() int {
+	if s.startingPackID != 0 {
+		return s.startingPackID
+	}
+	if id := s.state.StartPackID(); id != 0 {
+		return id
+	}
+	return s.seed.PackID
+}
+
+// ConfigureStartPack keeps server policy separate from the versioned tutorial
+// seed. The entry chapter is committed once when an account is initialized.
+func (s *Service) ConfigureStartPack(packID int, initialize bool) error {
+	if initialize {
+		pack, ok := s.storyCatalog.Packs[packID]
+		if !ok || len(pack.MainQuestIDs) == 0 {
+			return fmt.Errorf("world: starting chapter %d has no main quest", packID)
+		}
+		if err := s.state.SetStartPack(packID); err != nil {
+			return err
+		}
+		if err := s.state.SetActivePackID(packID); err != nil {
+			return err
+		}
+		if err := s.state.SelectQuest(packID, progress.QuestSelection{QuestID: pack.MainQuestIDs[0]}); err != nil {
+			return err
+		}
+	}
+	entry := s.state.StartPackID()
+	if _, ok := s.storyCatalog.Packs[entry]; !ok {
+		return fmt.Errorf("world: invalid persisted starting chapter %d", entry)
+	}
+	s.startingPackID = entry
+	active := s.state.ActivePackID()
+	if active == 0 {
+		return fmt.Errorf("world: account has no active chapter")
+	}
+	s.setCurrentPack(active)
+	return nil
+}
+
+func (s *Service) tutorialRosterRestricted() bool {
+	return s.startingPack() == s.seed.PackID && !s.state.QuestCleared(s.seed.BattleUnlockQuestID, s.seed.PackID)
+}