@startuml
hide empty methods

class Product {
    +char Separator [const]
    +string Invalid [const]
    +string ProductName [readonly]
    +string BarCode [readonly]
    +string BarCode [readonly]
    +{abstract} string[] CsvColumnNames
    +{abstract}string[] CsvColumnValues
    
    +Product(string, string, int)
    +string GetCsvHeader()
    +string ToCsv()
    +{static} string ToCsvLine(string[], char)
    +{static} bool IsBarcodeValid()
    +{static} T[] AppendToArray(T[], T)
}

class Food extends Product {
    -char AllergenSeparator [const]
    -SortedSet<AllergenType> Allergens [readonly]
    +AllergenType[] Allergens
    
    +Food(string, string, int, AllergenType[])
    +string[] CsvColumnNames [override]
    +string[] CsvColumnValues [override]
    +bool AddAllergen(AllergenType
    +bool RemoveAllergen(AllergenType)
    +bool ContainsAnyAllergen(AllergenType[])
}

class NonFood extends Product {
    -List<Review> Reviews [readonly]
    +Review[] Reviews
    +double? AverageRating
    +string[] CsvColumnNames [override]
    +string[] CsvColumnValues [override]
    
    +NonFood(string, string, int)
    +AddReview(Review)
}

class Review {
    -DateTime Date [readonly]
    -Rating Rating [readonly]
    -string Comment [readonly]
    +Review(DateTime, Rating, string)
}

enum Rating {
    OneStar
    TwoStars
    ThreeStars
    FourStars
    FiveStars
}

enum AllergenType {
    A
    B
    C
    D
    E
    F
    G
    H
    L
    M
    N
    O
    P
    R
}

NonFood -> Review
@enduml