shannoncoat/Sources/WindowOverlay.swift

// A small floating tag pinned to a Claude window's corner, showing which
// profile it belongs to — every profile launches the same app with the
// same icon and title, so there's otherwise no way to tell two open
// Claude windows apart at a glance. Kept in sync live via AXObserver
// notifications (move/resize/miniaturize/destroy) rather than polling —
// only a persistent process can hold a watcher like this at all, which is
// exactly the gap the old one-shot CLI script couldn't close.
import AppKit
import ApplicationServices

// How the tag is drawn. A dot is for when the colour alone already
// identifies the window and the name is just clutter; it's never rotated,
// having no reading direction to preserve.
enum WindowOverlayStyle: String {
    case chip, dot
}

// The window corner a tag is anchored to. Anchoring to the *nearest*
// corner rather than always the top-right is what holds a tag still
// through a resize: one parked near the bottom-left tracks that corner,
// so dragging the top-right handle no longer drags the tag with it.
enum WindowOverlayCorner: String {
    case topLeft, topRight, bottomLeft, bottomRight

    var isTop: Bool { self == .topLeft || self == .topRight }
    var isLeft: Bool { self == .topLeft || self == .bottomLeft }

    // Quadrant test rather than four distance comparisons — same answer,
    // and it stays well-defined for a tag sitting dead centre.
    static func nearest(to point: NSPoint, in frame: NSRect) -> WindowOverlayCorner {
        switch (point.y > frame.midY, point.x < frame.midX) {
        case (true, true): return .topLeft
        case (true, false): return .topRight
        case (false, true): return .bottomLeft
        case (false, false): return .bottomRight
        }
    }
}

// Where one profile's tag sits on its window, persisted so a drag survives
// a relaunch. Stored per profile rather than once for everything: two
// windows side by side are exactly the case these tags exist for, and
// wanting each one's tag somewhere different is the normal outcome — one
// window's sidebar is not another's.
//
// Offsets are stored as the user dropped them and are never written back
// clamped. A window too small to honour the full offset shows the tag
// pushed in as far as it fits (see `WindowOverlay.frame(window:screen:)`), but the
// stored distance is left intact, so widening the window again restores
// the chosen spot instead of leaving the tag stuck where a temporary
// resize squeezed it.
struct WindowOverlayPlacement {
    // Top-right by default — top-left is where every window's close/
    // minimize/zoom controls live, which the tag must never sit over.
    var corner: WindowOverlayCorner = .topRight
    var insetX: CGFloat = 8
    var insetY: CGFloat = 6
    var isVertical: Bool = false

    private static func key(_ field: String, _ profile: String) -> String {
        "WindowOverlay\(field).\(profile)"
    }

    // From the version that kept a single shared offset. Read as a seed for
    // a profile with nothing stored yet, so an existing tag stays where it
    // already is instead of jumping on the first launch after upgrading.
    private static let legacyInsetXKey = "WindowOverlayRightInset"
    private static let legacyInsetYKey = "WindowOverlayTopInset"

    private static func number(_ defaults: UserDefaults, _ keys: String...) -> CGFloat? {
        for key in keys {
            if let value = defaults.object(forKey: key) as? Double { return CGFloat(value) }
        }
        return nil
    }

    static func load(for profile: String) -> WindowOverlayPlacement {
        let defaults = UserDefaults.standard
        var placement = WindowOverlayPlacement()
        if let raw = defaults.string(forKey: key("Corner", profile)),
           let corner = WindowOverlayCorner(rawValue: raw) {
            placement.corner = corner
        }
        if let x = number(defaults, key("InsetX", profile), legacyInsetXKey) { placement.insetX = x }
        if let y = number(defaults, key("InsetY", profile), legacyInsetYKey) { placement.insetY = y }
        placement.isVertical = defaults.bool(forKey: key("Vertical", profile))
        return placement
    }

    func save(for profile: String) {
        let defaults = UserDefaults.standard
        defaults.set(corner.rawValue, forKey: Self.key("Corner", profile))
        defaults.set(Double(insetX), forKey: Self.key("InsetX", profile))
        defaults.set(Double(insetY), forKey: Self.key("InsetY", profile))
        defaults.set(isVertical, forKey: Self.key("Vertical", profile))
    }
}

// Chip or dot. Unlike placement this really is one setting for the whole
// app — it's a single control in Settings, not something chosen per window.
enum WindowOverlayPosition {
    private static let styleKey = "WindowOverlayStyle"

    static var style: WindowOverlayStyle {
        get {
            (UserDefaults.standard.string(forKey: styleKey)).flatMap(WindowOverlayStyle.init(rawValue:)) ?? .chip
        }
        set { UserDefaults.standard.set(newValue.rawValue, forKey: styleKey) }
    }
}

// Draws the tag itself. Custom drawing rather than a laid-out NSTextField
// because both of the things this has to get right — centring the text on
// the chip's actual midline, and rotating the whole chip when it's parked
// against a side edge — are a transform and two draw calls here, versus
// fighting a label's intrinsic baseline placement and its unrotatable
// frame.
private final class TagView: NSView {
    var text: String
    var color: NSColor
    var style: WindowOverlayStyle
    var isVertical: Bool
    // Which side edge a vertical chip is against, which decides the way it
    // reads: bottom-to-top on the left, top-to-bottom on the right, so the
    // text always leans into the window rather than away from it. Ignored
    // when horizontal.
    var isLeftSide: Bool

    static let thickness: CGFloat = 13
    static let dotDiameter: CGFloat = 11
    private static let horizontalPadding: CGFloat = 7
    private static let maxLength: CGFloat = 140
    static let font = NSFont.systemFont(ofSize: 10, weight: .semibold)

    init(text: String, color: NSColor, style: WindowOverlayStyle, isVertical: Bool, isLeftSide: Bool) {
        self.text = text
        self.color = color
        self.style = style
        self.isVertical = isVertical
        self.isLeftSide = isLeftSide
        super.init(frame: .zero)
    }

    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    // The chip's extent along its reading direction, before any rotation.
    private static func chipLength(for text: String) -> CGFloat {
        let width = (text as NSString).size(withAttributes: [.font: font]).width
        return min(maxLength, (width + horizontalPadding * 2).rounded(.up))
    }

    // Rotation is a property of the drawing, not of the panel, so the
    // panel's own width and height swap over for a vertical chip.
    static func size(text: String, style: WindowOverlayStyle, isVertical: Bool) -> NSSize {
        switch style {
        case .dot:
            return NSSize(width: dotDiameter, height: dotDiameter)
        case .chip:
            let length = chipLength(for: text)
            return isVertical
                ? NSSize(width: thickness, height: length)
                : NSSize(width: length, height: thickness)
        }
    }

    override func draw(_ dirtyRect: NSRect) {
        guard let ctx = NSGraphicsContext.current?.cgContext else { return }

        if style == .dot {
            color.setFill()
            NSBezierPath(ovalIn: bounds).fill()
            return
        }

        ctx.saveGState()
        defer { ctx.restoreGState() }

        // Lay the chip out once, horizontally, around the origin — then
        // rotate the whole coordinate space if it belongs on a side edge.
        // One layout path serves both orientations, so the vertical case
        // can't drift out of step with the horizontal one.
        ctx.translateBy(x: bounds.midX, y: bounds.midY)
        if isVertical { ctx.rotate(by: isLeftSide ? .pi / 2 : -.pi / 2) }

        let length = Self.chipLength(for: text)
        let rect = NSRect(
            x: -length / 2, y: -Self.thickness / 2, width: length, height: Self.thickness)
        color.setFill()
        NSBezierPath(roundedRect: rect, xRadius: Self.thickness / 2, yRadius: Self.thickness / 2).fill()

        let paragraph = NSMutableParagraphStyle()
        paragraph.alignment = .center
        paragraph.lineBreakMode = .byTruncatingTail
        let attributes: [NSAttributedString.Key: Any] = [
            .font: Self.font,
            .foregroundColor: ProfileColor.contrastingTextColor(on: color),
            .paragraphStyle: paragraph,
        ]
        let attributed = NSAttributedString(string: text, attributes: attributes)
        // Drawn into a rect exactly one line tall and centred on the
        // chip's midline. Handing it the chip's full height instead would
        // top-align the text inside it — the reason the old label sat
        // high rather than centred.
        let lineHeight = attributed.size().height
        attributed.draw(in: NSRect(
            x: rect.minX + Self.horizontalPadding, y: rect.midY - lineHeight / 2,
            width: rect.width - Self.horizontalPadding * 2, height: lineHeight))
    }
}

final class WindowOverlay: NSObject, NSWindowDelegate {
    let pid: pid_t
    private let axWindow: AXUIElement
    private var observer: AXObserver?
    private let panel: NSPanel
    private let tagView: TagView
    private let profileName: String
    private var placement: WindowOverlayPlacement
    // True only while `reposition` is moving the panel itself — see
    // `windowDidMove`, which must ignore those moves.
    private var isRepositioning = false
    private var dragSettle: DispatchWorkItem?
    private var isMinimized = false

    init?(profileName: String, color: NSColor, pid: pid_t) {
        let axApp = AXUIElementCreateApplication(pid)
        guard let window = Self.firstWindow(of: axApp) else { return nil }
        self.pid = pid
        self.axWindow = window
        self.profileName = profileName
        let placement = WindowOverlayPlacement.load(for: profileName)
        self.placement = placement

        let style = WindowOverlayPosition.style
        let tagView = TagView(
            text: profileName, color: color, style: style,
            isVertical: style == .chip && placement.isVertical,
            isLeftSide: placement.corner.isLeft)
        tagView.autoresizingMask = [.width, .height]
        self.tagView = tagView

        let panel = NSPanel(
            contentRect: NSRect(origin: .zero, size: NSSize(width: 1, height: 1)),
            styleMask: [.borderless, .nonactivatingPanel],
            backing: .buffered, defer: false)
        panel.isOpaque = false
        panel.backgroundColor = .clear
        panel.hasShadow = true
        panel.level = .floating
        // Draggable (so it can be moved off whatever it's obstructing),
        // but .nonactivatingPanel keeps a click/drag from stealing focus
        // away from the Claude window underneath.
        panel.isMovableByWindowBackground = true
        panel.collectionBehavior = [.stationary, .ignoresCycle]
        panel.contentView = tagView

        self.panel = panel
        super.init()
        panel.delegate = self

        guard reposition() else { return nil }
        startObserving()
    }

    // A cold Electron launch can take a second or more between the
    // process starting (which is what triggers `updateWindowOverlays`,
    // via NSWorkspace's launch notification) and its first window
    // actually existing — the same race ClaudeControl.focus's
    // waitForWindow already handles for the same reason. `init?` can't
    // retry on its own (once it returns nil, that attempt is done), so
    // this polls it every quarter second for up to ~3s before giving up.
    static func attach(
        profileName: String, color: NSColor, pid: pid_t, attemptsRemaining: Int = 12,
        completion: @escaping (WindowOverlay?) -> Void
    ) {
        if let overlay = WindowOverlay(profileName: profileName, color: color, pid: pid) {
            completion(overlay)
        } else if attemptsRemaining > 0 {
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) {
                attach(
                    profileName: profileName, color: color, pid: pid, attemptsRemaining: attemptsRemaining - 1,
                    completion: completion)
            }
        } else {
            completion(nil)
        }
    }

    deinit {
        dragSettle?.cancel()
        stopObserving()
        panel.orderOut(nil)
    }

    private static func firstWindow(of axApp: AXUIElement) -> AXUIElement? {
        var value: CFTypeRef?
        guard AXUIElementCopyAttributeValue(axApp, kAXWindowsAttribute as CFString, &value) == .success,
              let windows = value as? [AXUIElement], let first = windows.first
        else { return nil }
        return first
    }

    private static func frame(of window: AXUIElement) -> CGRect? {
        var posValue: CFTypeRef?
        var sizeValue: CFTypeRef?
        guard AXUIElementCopyAttributeValue(window, kAXPositionAttribute as CFString, &posValue) == .success,
              AXUIElementCopyAttributeValue(window, kAXSizeAttribute as CFString, &sizeValue) == .success,
              CFGetTypeID(posValue) == AXValueGetTypeID(), CFGetTypeID(sizeValue) == AXValueGetTypeID()
        else { return nil }
        var point = CGPoint.zero
        var size = CGSize.zero
        guard AXValueGetValue(posValue as! AXValue, .cgPoint, &point),
              AXValueGetValue(sizeValue as! AXValue, .cgSize, &size)
        else { return nil }
        return CGRect(origin: point, size: size)
    }

    private static func screen(containing axFrame: CGRect) -> NSScreen? {
        NSScreen.screens.first { $0.frame.minX <= axFrame.midX && axFrame.midX <= $0.frame.maxX } ?? NSScreen.main
    }

    // AX coordinates are top-left-origin (screen top = y 0); AppKit screen
    // coordinates are bottom-left-origin. Returns the window's frame
    // translated into AppKit's space.
    private static func appKitFrame(of axFrame: CGRect, on screen: NSScreen) -> NSRect {
        NSRect(x: axFrame.origin.x, y: screen.frame.maxY - axFrame.origin.y - axFrame.height,
               width: axFrame.width, height: axFrame.height)
    }

    private var currentGeometry: (window: NSRect, screen: NSScreen)? {
        guard let axFrame = Self.frame(of: axWindow), let screen = Self.screen(containing: axFrame)
        else { return nil }
        return (Self.appKitFrame(of: axFrame, on: screen), screen)
    }

    // The tag's frame for a given window frame: measured inward from its
    // anchored corner, with the offsets clamped so it always stays over
    // the window no matter how small that window gets. Only the *drawn*
    // position is clamped — see WindowOverlayPlacement.
    //
    // Then clamped again, into whatever part of the window is actually on
    // screen. A window dragged half off the edge takes its anchored corner
    // with it, and a tag that follows it out of view identifies nothing —
    // the whole point is telling, at a glance, which profile the window you
    // can still see belongs to. Clamped to the window's *visible* portion
    // rather than to the screen at large so the tag stays on the thing it
    // labels instead of drifting off onto its own. `visibleFrame` keeps it
    // clear of the menu bar and Dock, which would hide it just as
    // effectively as the screen edge.
    //
    // Both clamps are presentational only — neither is written back to
    // `placement`, which changes solely when the user drags the tag. So the
    // anchor is remembered throughout, and the tag returns to it the moment
    // the window is fully back on screen.
    private func frame(window: NSRect, screen: NSScreen) -> NSRect {
        let style = WindowOverlayPosition.style
        let size = TagView.size(
            text: profileName, style: style,
            isVertical: style == .chip && placement.isVertical)
        let corner = placement.corner
        let insetX = placement.insetX
            .clamped(to: 0...max(0, window.width - size.width))
        let insetY = placement.insetY
            .clamped(to: 0...max(0, window.height - size.height))
        var origin = NSPoint(
            x: corner.isLeft ? window.minX + insetX : window.maxX - insetX - size.width,
            y: corner.isTop ? window.maxY - insetY - size.height : window.minY + insetY)

        // A window entirely off screen leaves nothing to clamp into; fall
        // back to the screen so the tag stays reachable rather than being
        // pinned to an empty rect.
        let onScreen = window.intersection(screen.visibleFrame)
        let bounds = onScreen.isEmpty ? screen.visibleFrame : onScreen
        origin.x = origin.x.clamped(to: bounds.minX...max(bounds.minX, bounds.maxX - size.width))
        origin.y = origin.y.clamped(to: bounds.minY...max(bounds.minY, bounds.maxY - size.height))
        return NSRect(origin: origin, size: size)
    }

    // Puts the tag where the current placement says it belongs. Returns
    // false (and hides the tag) if the window has no readable frame right
    // now — minimized, or Accessibility not granted.
    @discardableResult
    private func reposition() -> Bool {
        guard let (windowFrame, screen) = currentGeometry else {
            panel.orderOut(nil)
            return false
        }
        let style = WindowOverlayPosition.style
        tagView.style = style
        tagView.isVertical = style == .chip && placement.isVertical
        tagView.isLeftSide = placement.corner.isLeft
        tagView.needsDisplay = true

        isRepositioning = true
        defer { isRepositioning = false }
        let tagFrame = frame(window: windowFrame, screen: screen)
        panel.setFrame(tagFrame, display: true)
        // The shadow is derived from the content's alpha, so a shape or
        // size change leaves a stale one behind without this.
        panel.invalidateShadow()
        // Positioned either way — only the showing is conditional, so a
        // hidden tag still knows where it belongs and can be revealed later
        // without recomputing anything.
        if isMinimized || !isTargetVisible(tagFrame: tagFrame) {
            panel.orderOut(nil)
        } else if !panel.isVisible {
            panel.orderFrontRegardless()
        }
        return true
    }

    // Re-evaluate whether the tag should currently be on screen. Called
    // when some app activates, which is the usual way a window ends up
    // buried or uncovered without moving at all.
    func refreshVisibility() {
        reposition()
    }

    // A tag is a floating panel, which puts it above every ordinary window
    // on the system rather than merely above the window it belongs to. Left
    // alone it hovers over the browser, the editor, everything — even when
    // its own window is buried or on another Space.
    //
    // There is no cross-process way to attach one window above another:
    // `addChildWindow` is same-process only, and the private ordering call
    // window managers use is a one-shot operation that goes stale the
    // moment anything else reorders, so it wouldn't avoid this work either.
    // So the tag is shown only when the window it labels is genuinely
    // visible underneath it.
    //
    // The window server returns its list strictly front-to-back, which
    // answers both halves in one pass: walk forward, and anything
    // overlapping the tag before we reach our own window is covering it.
    // Reaching our window with nothing in the way means the tag is showing
    // real estate that actually belongs to that window; never reaching it
    // means the window isn't on screen at all — minimized, hidden, or on
    // another Space — and the tag has nothing to label.
    private func isTargetVisible(tagFrame: NSRect) -> Bool {
        guard let listing = CGWindowListCopyWindowInfo(
            [.optionOnScreenOnly, .excludeDesktopElements], kCGNullWindowID) as? [[String: Any]]
        else { return true }  // can't tell — better a stray tag than a missing one

        let tag = Self.cgRect(of: tagFrame)
        let ownPid = getpid()
        for entry in listing {
            guard let owner = entry[kCGWindowOwnerPID as String] as? pid_t,
                  let boundsDict = entry[kCGWindowBounds as String],
                  let bounds = CGRect(dictionaryRepresentation: boundsDict as! CFDictionary)
            else { continue }
            // Identified by owner alone, deliberately. Matching the exact
            // rect meant comparing a freshly-read AX frame against the
            // window server's snapshot, and mid-move the two disagree —
            // AX already reports the new position while the listing still
            // has the old one. The match then failed, the walk continued
            // past our own window, and the first unrelated window that
            // happened to overlap the tag "occluded" it. Whether that
            // occurred came down to what was nearby, which is why it
            // looked as though only certain drag directions broke it.
            //
            // A dialog of the same app landing here counts as reaching our
            // window, which is right: Claude covering its own window is
            // not a reason to disown the tag.
            if owner == pid, bounds.intersects(tag) { return true }
            // Our own tags are in this list too, and one tag sitting over
            // another's window must not hide it.
            if owner == ownPid { continue }
            // Only ordinary windows can bury another ordinary window.
            // Everything above that band — the menu bar, the Dock,
            // notification banners, and the invisible one-pixel markers
            // some utilities park in a screen corner — is permanently in
            // front of everything and would veto the tag forever. One such
            // marker at the bottom-left corner is what made a tag vanish
            // there, and only there: it takes a move off two edges at once
            // for the tag to clamp into that exact pixel.
            guard (entry[kCGWindowLayer as String] as? Int) == 0 else { continue }
            if bounds.intersects(tag) { return false }
        }
        return false
    }

    // AppKit is bottom-left-origin per screen; the window server is
    // top-left-origin from the primary screen (screens[0], the one with the
    // menu bar).
    private static func cgRect(of rect: NSRect) -> CGRect {
        let primaryMaxY = NSScreen.screens.first?.frame.maxY ?? rect.maxY
        return CGRect(x: rect.minX, y: primaryMaxY - rect.maxY, width: rect.width, height: rect.height)
    }

    // MARK: - User placement

    // Fires for every panel move — ours (from `reposition`, when the
    // tracked window itself moves/resizes) and the user's (dragging the
    // tag). Only the latter should redefine the placement, which is what
    // the `isRepositioning` guard filters for.
    //
    // Re-deriving the offset from our own moves too looks like it should
    // be a harmless no-op — recomputing the very offset we just positioned
    // against — but it isn't, because the two halves read the window at
    // different instants. AppKit posts this notification synchronously
    // from inside `setFrame`, and during a live window drag the AX frame
    // read here is already newer than the one `reposition` derived the
    // origin from, so each move event bakes in the few points the window
    // travelled in between. Those errors accumulate across the hundreds
    // of events one drag produces, until the offset saturates and the tag
    // has walked clear across its window — off-screen entirely, if that
    // edge of the window is.
    func windowDidMove(_ notification: Notification) {
        guard !isRepositioning else { return }
        scheduleDragSettle()
    }

    // A tag drag emits a continuous stream of moves, and re-anchoring on
    // each one would snap the tag out from under the cursor mid-gesture
    // (and flip its orientation repeatedly on the way past an edge). So
    // the placement is only committed once the moves stop, which is as
    // close to a "drag ended" signal as a background-movable window gets
    // — NSWindow has no such delegate callback, unlike live resize.
    private func scheduleDragSettle() {
        dragSettle?.cancel()
        let work = DispatchWorkItem { [weak self] in self?.commitUserPlacement() }
        dragSettle = work
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2, execute: work)
    }

    private func commitUserPlacement() {
        guard let windowFrame = currentGeometry?.window else { return }
        let tagFrame = panel.frame
        let centre = NSPoint(x: tagFrame.midX, y: tagFrame.midY)
        let corner = WindowOverlayCorner.nearest(to: centre, in: windowFrame)

        // Orientation follows whichever edge the tag ended up nearest: a
        // chip against a side reads vertically, so it can sit close in
        // without covering the window's own controls. Dots have no
        // reading direction, so they're never rotated.
        let toSide = min(centre.x - windowFrame.minX, windowFrame.maxX - centre.x)
        let toTopOrBottom = min(windowFrame.maxY - centre.y, centre.y - windowFrame.minY)
        let isVertical = WindowOverlayPosition.style == .chip && toSide < toTopOrBottom

        // Offsets run inward from the anchored corner. Stored unclamped at
        // the top end (a drag outside the window is clamped to zero, but a
        // long reach into a wide window is kept in full) so a later resize
        // can restore it.
        let insetX = corner.isLeft
            ? tagFrame.minX - windowFrame.minX : windowFrame.maxX - tagFrame.maxX
        let insetY = corner.isTop
            ? windowFrame.maxY - tagFrame.maxY : tagFrame.minY - windowFrame.minY

        placement = WindowOverlayPlacement(
            corner: corner, insetX: max(0, insetX), insetY: max(0, insetY), isVertical: isVertical)
        placement.save(for: profileName)

        // Snap into the committed placement — this is what applies a
        // rotation the drag just earned, and squares the tag up against
        // its corner.
        reposition()
    }

    // MARK: - Live tracking

    private func startObserving() {
        var newObserver: AXObserver?
        guard AXObserverCreate(pid, WindowOverlay.axCallback, &newObserver) == .success, let newObserver
        else { return }
        observer = newObserver

        let refcon = Unmanaged.passUnretained(self).toOpaque()
        for name in [
            kAXMovedNotification, kAXResizedNotification, kAXUIElementDestroyedNotification,
            kAXWindowMiniaturizedNotification, kAXWindowDeminiaturizedNotification,
        ] {
            AXObserverAddNotification(newObserver, axWindow, name as CFString, refcon)
        }
        CFRunLoopAddSource(CFRunLoopGetCurrent(), AXObserverGetRunLoopSource(newObserver), .defaultMode)
    }

    private func stopObserving() {
        guard let observer else { return }
        CFRunLoopRemoveSource(CFRunLoopGetCurrent(), AXObserverGetRunLoopSource(observer), .defaultMode)
        self.observer = nil
    }

    private static let axCallback: AXObserverCallback = { _, _, notification, refcon in
        guard let refcon else { return }
        let overlay = Unmanaged<WindowOverlay>.fromOpaque(refcon).takeUnretainedValue()
        switch notification as String {
        case kAXUIElementDestroyedNotification:
            overlay.panel.orderOut(nil)
        case kAXWindowMiniaturizedNotification:
            overlay.isMinimized = true
            overlay.reposition()
        case kAXWindowDeminiaturizedNotification:
            overlay.isMinimized = false
            overlay.reposition()
        default:
            overlay.reposition()
        }
    }
}

extension Comparable {
    func clamped(to range: ClosedRange<Self>) -> Self {
        min(max(self, range.lowerBound), range.upperBound)
    }
}