dipmodel.swift

enum Empire {
    case britain
    case france
    case germany
    case russia
    case ottoman
    case austria
    case italy
}
enum CoastKind{
    case unified
    case fragmented([(String, [Territory])])
}
struct Territory {
    init(name:String, kind:Kind, occupiedBy:Unit? = nil) {
        self.name = name
        self.kind = kind
        self.occupiedBy = occupiedBy
    }
    enum Kind {case land, sea}
    let name:String
    let kind: Kind
    let occupiedBy:Unit?
    enum Change { case occupy(Unit?) }
    func execute(_ change: Change) -> Self {
        switch change {
        case .occupy(let unit): return .init(name: name, kind: kind, occupiedBy: unit)
        }
    }
}
enum Border {
    case land   (Territory, Territory)
    case coastal(Territory, Territory, CoastKind)
    case sea    (Territory, Territory)
    case channel(Territory)
}
enum Unit:Equatable {
    case army(Empire)
    case fleet(Empire)
}