import AppKit

extension NSScreen {

    // MARK: - Stable display identifier

    /// Returns a stable UUID string for this screen by querying CoreGraphics.
    /// Falls back to the localized name if the CG UUID is unavailable.
    var displayUUID: String {
        guard let screenNumber = deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")] as? CGDirectDisplayID else {
            return localizedName
        }
        guard let uuid = CGDisplayCreateUUIDFromDisplayID(screenNumber) else {
            return localizedName
        }
        return CFUUIDCreateString(nil, uuid.takeUnretainedValue()) as String
    }

    // MARK: - Notch detection

    /// `true` when this screen has a physical camera notch (safe area inset at top > 0).
    var hasNotch: Bool {
        safeAreaInsets.top > 0
    }

    // MARK: - Closed notch sizing

    /// Computes the closed-state notch size for this screen,
    /// respecting the user's height mode and custom height preferences.
    func closedNotchSize(using settings: AppSettings.DisplaySettings) -> CGSize {
        let height = closedNotchHeight(using: settings)
        let width  = closedNotchWidth()
        return CGSize(width: width, height: height)
    }

    /// Height of the closed notch bar, determined by the user's chosen mode.
    private func closedNotchHeight(using settings: AppSettings.DisplaySettings) -> CGFloat {
        if hasNotch {
            let mode = NotchHeightMode(rawValue: settings.notchHeightMode)
                ?? .matchRealNotchSize
            switch mode {
            case .matchRealNotchSize:
                return safeAreaInsets.top
            case .matchMenuBar:
                return menuBarHeight()
            case .custom:
                return settings.notchHeight
            }
        } else {
            let mode = NonNotchHeightMode(rawValue: settings.nonNotchHeightMode)
                ?? .matchMenuBar
            switch mode {
            case .matchMenuBar:
                return menuBarHeight()
            case .custom:
                return settings.nonNotchHeight
            }
        }
    }

    /// Width of the closed notch.
    /// On notch screens, spans from one auxiliary top area to the other.
    /// On non-notch screens, uses a reasonable fixed width.
    private func closedNotchWidth() -> CGFloat {
        if hasNotch {
            if let topLeft = auxiliaryTopLeftArea,
               let topRight = auxiliaryTopRightArea {
                // The notch occupies the space between the two menu bar segments
                return frame.width - topLeft.width - topRight.width + 4
            }
            // Fallback for older API — approximate from safe area
            return 220
        } else {
            // Non-notch screens: a compact simulated notch
            return 220
        }
    }

    /// The effective menu bar height for this screen.
    private func menuBarHeight() -> CGFloat {
        return frame.maxY - visibleFrame.maxY
    }
}