import IOKit.pwr_mgt

/// Keeps the display (and therefore the system) awake while held.
public final class SleepBlocker {
    private var assertion: IOPMAssertionID = 0

    public init?(reason: String) {
        let result = IOPMAssertionCreateWithName(
            kIOPMAssertionTypePreventUserIdleDisplaySleep as CFString,
            IOPMAssertionLevel(kIOPMAssertionLevelOn),
            reason as CFString,
            &assertion
        )
        guard result == kIOReturnSuccess else { return nil }
    }

    deinit {
        IOPMAssertionRelease(assertion)
    }
}