import AppKit

/// Headless verification for `swift run SimpleTopBar --self-test`.
/// Exercises the background-app overflow helpers and reports the live split
/// between regular and background applications, then exits 0/1.
func runSelfTest() {
    var failures = 0

    func check(_ condition: Bool, _ label: String) {
        print((condition ? "PASS" : "FAIL") + ": " + label)
        if !condition { failures += 1 }
    }

    // clampedVisibleCount never exceeds the total and never goes negative.
    check(AppListModel.clampedVisibleCount(current: 10, total: 3) == 3, "clamp caps at total")
    check(AppListModel.clampedVisibleCount(current: -2, total: 5) == 0, "clamp floors at zero")
    check(AppListModel.clampedVisibleCount(current: 2, total: 5) == 2, "clamp keeps valid value")

    // nextVisibleCount pages by backgroundPageSize and stops at the total.
    let page = AppListModel.backgroundPageSize
    check(AppListModel.nextVisibleCount(current: page, total: 100) == page * 2, "show more pages forward")
    check(AppListModel.nextVisibleCount(current: 4, total: 5) == 5, "show more stops at total")
    check(AppListModel.nextVisibleCount(current: 5, total: 5) == 5, "show more is a no-op at the end")

    // The section reveals exactly `min(visibleCount, total)` entries.
    let apps = (0..<12).map { index in
        RunningApp(
            id: pid_t(index + 1),
            name: "App \(index)",
            bundleID: nil,
            icon: NSImage(),
            isHidden: false,
            isActive: false
        )
    }
    let hidden = max(0, apps.count - 3)
    check(hidden == 9, "overflow count hides the tail")

    // Live snapshot: the split must cover every running app exactly once.
    let running = NSWorkspace.shared.runningApplications.filter {
        $0.bundleIdentifier != Bundle.main.bundleIdentifier
    }
    let regular = running.filter { $0.activationPolicy == .regular }.count
    let background = running.filter { $0.activationPolicy != .regular }.count
    print("running=\(running.count) regular=\(regular) background=\(background)")
    check(regular + background == running.count, "every running app is classified")

    print(failures == 0 ? "ALL PASS" : "\(failures) FAILURE(S)")
    exit(failures == 0 ? 0 : 1)
}