// Whether the iOS/iPadOS/macOS UI should be in its controller-friendly mode (the console-style
// host launcher, gamepad settings, and the coverflow library browser instead of the touch/desktop
// layouts). A pure function, not a singleton: the reactivity comes from callers already observing
// `GamepadManager.shared` and the `DefaultsKey.gamepadUIEnabled` @AppStorage themselves (the same
// local-read pattern SettingsView already uses for GamepadManager), so this stays the single place
// the inputs combine without adding a second ObservableObject or an environment key nobody else needs.

import Foundation
import PunktfunkShared

public enum GamepadUIEnvironment {
    /// `DefaultsKey.gamepadUIMode`: take over only while a controller is attached. The default,
    /// and what the switch meant when it was a lone Bool.
    public static let modeWhenConnected = "connected"
    /// `DefaultsKey.gamepadUIMode`: take over whenever the switch is on, pad or no pad — asked
    /// for by people driving a TV-connected iPad or a couch Mac, where the console layout is the
    /// one they want and the pad is not always awake.
    public static let modeAlways = "always"

    /// `enabledSetting` is the user's Settings switch (`DefaultsKey.gamepadUIEnabled`) — off means
    /// the touch/desktop UI, full stop. `mode` is `DefaultsKey.gamepadUIMode`, and only matters
    /// once the switch is on: `modeAlways` takes over unconditionally, anything else (including a
    /// value a newer client wrote) waits for a controller.
    ///
    /// `gamepadConnected` is `GamepadManager.shared.active != nil` — active only once a usable
    /// controller is actually attached (a non-extended-profile device leaves `active` nil, which
    /// keeps the touch UI). A `Bool` rather than the `DiscoveredController` itself: this function
    /// has nothing else to inspect, and it keeps the helper testable without a real `GCController`
    /// (which XCTest can't construct).
    /// `mode` carries no default on purpose: a call site that forgot it would silently strand
    /// everyone who picked Always back on "only with a controller", which is exactly the bug
    /// this parameter exists to make impossible.
    public static func isActive(
        gamepadConnected: Bool,
        enabledSetting: Bool,
        mode: String
    ) -> Bool {
        guard enabledSetting else { return false }
        return mode == modeAlways || gamepadConnected || forced
    }

    /// Dev-only escape hatch (like ContentView's `PUNKTFUNK_AUTOCONNECT`): pretend a controller is
    /// attached so the gamepad UI can be exercised/screenshotted without physical hardware —
    /// essential on a headless CI Mac and for `swift run` UI work. Never set in production.
    private static let forced =
        ProcessInfo.processInfo.environment["PUNKTFUNK_FORCE_GAMEPAD_UI"] == "1"
}