import Foundation

/// What the widget shows (#428): the unread count and the episode you were last on. Written by
/// the app into the App Group the two share, since the widget has no sign-in and no player of its
/// own; it shows what the app last knew.
struct Snapshot: Codable, Equatable {
    var unread: Int?
    var title: String?
    var feedTitle: String?
    var position: Double?
    var duration: Double?
    var playing = false

    static let group = "group.net.sdf1.ipx"
    private static let key = "ipx.snapshot"

    static func load(from defaults: UserDefaults? = UserDefaults(suiteName: group)) -> Snapshot {
        defaults?.data(forKey: key).flatMap { try? JSONDecoder().decode(Snapshot.self, from: $0) } ?? Snapshot()
    }

    func save(to defaults: UserDefaults? = UserDefaults(suiteName: group)) {
        if let data = try? JSONEncoder().encode(self) { defaults?.set(data, forKey: Self.key) }
    }

    /// How far through, 0 to 1, when both are known.
    var progress: Double? {
        guard let position, let duration, duration > 0 else { return nil }
        return min(1, max(0, position / duration))
    }
}