CS Rotator

CallbackMessage (chat_callback.go:89)
    └─ chat_callback.go:305
       └─ h.svc.GetRotator(ctx, device.StoreId, instance) → returnid_cs
          └─ internal/service/chat_service.go:36

chatListRepo    := repository.NewChatListRepository(db)
userRepo        := repository.NewUserRepository(db)
chatListService := service.NewChatListService(chatListRepo, userRepo)
chatListHandler := handlers.NewChatListHandler(chatListService)

type ChatService interface {
    GetRotator(ctx context.Context, storeID string, instanceID string) (string, error)
}

1. fetchRotatorSettings(ctx, storeID)        — chat_service.go:40
   └─ read settings collection, decode SettingsStruct
   └─ error: ErrSettingsNotFound jika tidak ada

2. validateRotatorSettings(settings)         — chat_service.go:46
   └─ error: ErrEmptyTeam jika Team kosong (chat_service.go:160-165)

3. fetchActiveCountPerCS(ctx, storeID, team, instance)  — chat_service.go:51
   └─ aggregate chat_histories:
      $match store_id, team_id $in team, chat_status $ne "close", instance
      $group by team_id, count
   └─ return map[csID]int (init semua team ke 0)

4. switch settings.TypeDistribution:
   ├─ "percentage" → selectByPercentage(settings, activeCounts)
   └─ default      → selectBySame(settings.Team, activeCounts)

func selectBySame(team []string, activeCounts map[string]int) (string, error) {
    if len(team) == 0 {
        return "", ErrEmptyTeam
    }
    selected := team[0]
    min := activeCounts[selected]
    for _, csID := range team[1:] {
        if activeCounts[csID] < min {
            selected = csID
            min = activeCounts[csID]
        }
    }
    return selected, nil
}

1. Sum dist.Total across settings.Distribution → totalBobot
   └─ jika 0: fall back ke selectBySame (TIDAK return ErrInvalidBobot)

2. Build distByID map: Distribution.ID → Distribution

3. For each CS in team:
   ├─ skip jika tidak ada distribution atau dist.Total == 0
   ├─ normalizedWeight = dist.Total / totalBobot
   ├─ score = activeCounts[csID] / normalizedWeight
   │          (rasio beban saat ini vs alokasi)
   └─ pilih score terendah
   └─ tie-break: prefer normalizedWeight lebih tinggi

4. Jika semua skip → fall back ke selectBySame

type GlobalAssignationStruct struct {
    Role             string
    Team             []string       // daftar CS ID
    Distribution     []Distribution // bobot per CS (untuk percentage)
    TypeDistribution string         // "percentage" atau lainnya → selectBySame
}

type SettingsStruct struct {
    // ...
    GlobalAssignation GlobalAssignationStruct `bson:"globalAssignation"`
}

type Distribution struct {
    Name  string
    ID    string
    Total int    // bobot
}