import IGListKit

final class DiffableBox<T>: ListDiffable {
    let value: T
    let identifier: NSObjectProtocol
    let compare: (T, T) -> Bool

    init(value: T, identifier: NSObjectProtocol, compare: @escaping (T, T) -> Bool) {
        self.value = value
        self.identifier = identifier
        self.compare = compare
    }

    func diffIdentifier() -> NSObjectProtocol {
        return identifier
    }

    func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
        guard let other = object as? DiffableBox<T> else {
            return false
        }

        return compare(value, other.value)
    }
}

extension DiffableBox where T: Equatable {
    convenience init(value: T, identifier: NSObjectProtocol) {
        self.init(value: value, identifier: identifier, compare: ==)
    }
}