import Foundation
import ServiceManagement

/// The viewer's own preferences. The connections themselves are in
/// ConnectionStore.
final class ViewerSettings: ObservableObject {

    static let shared = ViewerSettings()
    private let defaults = UserDefaults.standard

    /// Keep the display on while a dashboard is on screen — a booth display
    /// that dims halfway through a service is the failure this is here for.
    @Published var keepDisplayAwake: Bool {
        didSet { defaults.set(keepDisplayAwake, forKey: "keepDisplayAwake") }
    }

    private init() {
        defaults.register(defaults: ["keepDisplayAwake": true])
        keepDisplayAwake = defaults.bool(forKey: "keepDisplayAwake")
    }

    /// The window was in full screen when the viewer last quit, so it opens in
    /// full screen again — a booth Mac that restarts comes back as it was left.
    var reopenInFullScreen: Bool {
        get { defaults.bool(forKey: "reopenInFullScreen") }
        set { defaults.set(newValue, forKey: "reopenInFullScreen") }
    }

    /// The tab that was showing, so the viewer reopens on it.
    var selectedConnection: UUID? {
        get { defaults.string(forKey: "selectedConnection").flatMap(UUID.init(uuidString:)) }
        set { defaults.set(newValue?.uuidString, forKey: "selectedConnection") }
    }
}

/// "Open at login", through the macOS 13 login-item API. The operator may
/// still have to approve it in System Settings — hence `needsApproval`, which
/// Settings shows rather than failing silently.
enum LoginItem {

    static var isEnabled: Bool { SMAppService.mainApp.status == .enabled }
    static var needsApproval: Bool { SMAppService.mainApp.status == .requiresApproval }

    /// Nil when it worked; otherwise what went wrong, for Settings to show.
    static func set(_ enabled: Bool) -> String? {
        do {
            if enabled {
                if SMAppService.mainApp.status != .enabled { try SMAppService.mainApp.register() }
            } else {
                if SMAppService.mainApp.status != .notRegistered { try SMAppService.mainApp.unregister() }
            }
            return nil
        } catch {
            return error.localizedDescription
        }
    }

    static func openSystemSettings() {
        SMAppService.openSystemSettingsLoginItems()
    }
}