WP-3a: CaptureRegion geometry + Carbon HotkeyCenter per SPEC-A2a

Sources/ShotdeckCore/Capture/CaptureRegion.swift

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+import Foundation
+import AppKit  // NSScreen, NSDeviceDescriptionKey — macOS-only target, no portability concern
+
+/// A remembered rectangle, in CoreGraphics global display coordinates (origin top-left,
+/// y increasing downward — see the conversion note below).
+public struct CaptureRegion: Codable, Sendable, Equatable {
+    public let displayID: CGDirectDisplayID
+    public let rect: CGRect
+    public let capturedScale: CGFloat
+
+    public init(displayID: CGDirectDisplayID, rect: CGRect, capturedScale: CGFloat) {
+        self.displayID = displayID
+        self.rect = rect
+        self.capturedScale = capturedScale
+    }
+
+    /// Converts an AppKit rect in GLOBAL AppKit coordinates (bottom-left origin, y increasing
+    /// upward, anchored at the bottom-left of the PRIMARY screen — exactly what
+    /// `NSWindow.frame`, `NSEvent.mouseLocation` and `NSScreen.frame` already report; no
+    /// screen-local conversion is needed here) into global CoreGraphics coordinates
+    /// (top-left origin, y increasing downward, same primary-screen anchor). Both coordinate
+    /// systems share the SAME horizontal origin and the SAME anchor rectangle (the primary
+    /// screen's bounds) — only the vertical axis is mirrored around the primary's height.
+    /// That is why the flip below is correct for every attached screen, including one with a
+    /// negative AppKit x (to the left of primary) or a y that places it above the primary
+    /// (whose CG y then comes out negative): x is untouched, and the primary height is the
+    /// one fixed reference both systems agree on regardless of which physical screen the
+    /// rect is actually on.
+    public static func fromAppKit(rect: CGRect, on screen: NSScreen) -> CaptureRegion {
+        let displayID = (screen.deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")]
+            as? NSNumber)?.uint32Value ?? CGMainDisplayID()
+        let primaryHeight = NSScreen.screens.first?.frame.height ?? screen.frame.height
+        return fromAppKit(rect: rect, displayID: displayID,
+                           capturedScale: screen.backingScaleFactor, primaryHeight: primaryHeight)
+    }
+
+    /// Injectable overload for deterministic geometry tests — no dependency on real attached
+    /// displays. The public overload above is a thin adapter over this.
+    static func fromAppKit(rect: CGRect, displayID: CGDirectDisplayID,
+                            capturedScale: CGFloat, primaryHeight: CGFloat) -> CaptureRegion {
+        let cgY = primaryHeight - rect.origin.y - rect.height
+        let cgRect = CGRect(x: rect.origin.x, y: cgY, width: rect.width, height: rect.height)
+        return CaptureRegion(displayID: displayID, rect: cgRect, capturedScale: capturedScale)
+    }
+
+    /// True when `displayID` is still attached AND `rect` still lies inside its current
+    /// bounds. Uses `CGDisplayIsActive` (returns 0 safely for an unknown id, never traps) and
+    /// `CGDisplayBounds` — both real CoreGraphics calls, no injection needed since this is a
+    /// live-state check by design.
+    public var isStillValid: Bool {
+        guard CGDisplayIsActive(displayID) != 0 else { return false }
+        let bounds = CGDisplayBounds(displayID)
+        return bounds.contains(rect)
+    }
+
+    /// Persisted in UserDefaults under this key BY THE APP (WP-4a), never by this type.
+    public static let defaultsKey = "ai.flowmaster.shotdeck.region"
+}

Sources/ShotdeckCore/Capture/HotkeyCenter.swift

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+import Carbon.HIToolbox
+import Foundation
+
+/// Carbon's C event handler cannot capture Swift closures, so live handlers are kept in one
+/// process-wide table keyed by the numeric EventHotKeyID Carbon hands back on fire. Safe
+/// because InstallEventHandler on GetApplicationEventTarget() always delivers on the main
+/// thread, and every access here happens either from a @MainActor HotkeyCenter method or from
+/// the C callback below, which this process only ever invokes on the main run loop.
+private final class HotkeyDispatchTable: @unchecked Sendable {
+    static let shared = HotkeyDispatchTable()
+    private var handlers: [UInt32: @MainActor () -> Void] = [:]
+    private init() {}
+    func set(_ numericID: UInt32, _ handler: @escaping @MainActor () -> Void) {
+        handlers[numericID] = handler
+    }
+    func remove(_ numericID: UInt32) { handlers.removeValue(forKey: numericID) }
+    func fire(_ numericID: UInt32) { MainActor.assumeIsolated { handlers[numericID]?() } }
+}
+
+private func shotdeckCarbonHotkeyHandler(
+    _ nextHandler: EventHandlerCallRef?, _ event: EventRef?, _ userData: UnsafeMutableRawPointer?
+) -> OSStatus {
+    guard let event else { return OSStatus(eventNotHandledErr) }
+    var hotKeyID = EventHotKeyID()
+    let status = GetEventParameter(event, EventParamName(kEventParamDirectObject),
+        EventParamType(typeEventHotKeyID), nil, MemoryLayout<EventHotKeyID>.size, nil, &hotKeyID)
+    guard status == noErr else { return status }
+    HotkeyDispatchTable.shared.fire(hotKeyID.id)
+    return noErr
+}
+
+/// Four-character creator code used for every `EventHotKeyID` this process registers.
+private let shotdeckHotKeySignature: OSType = 0x53484F54 // "SHOT"
+
+@MainActor
+public final class HotkeyCenter {
+    private var bindings: [String: (ref: EventHotKeyRef, numericID: UInt32)] = [:]
+    private var nextNumericID: UInt32 = 1
+
+    private static var didInstallGlobalCarbonHandler = false
+    private static var carbonHandlerRef: EventHandlerRef?
+
+    public init() { HotkeyCenter.installGlobalCarbonHandlerIfNeeded() }
+
+    /// Registers a hotkey. `id` is a caller-chosen stable identifier. Re-registering the same
+    /// `id` first unregisters its previous binding, then attempts the new one (idempotent).
+    /// Returns false when Carbon's `RegisterEventHotKey` reports a non-`noErr` status — the
+    /// most common cause is the same keyCode+modifiers combination already being claimed
+    /// system-wide by this or another process.
+    @discardableResult
+    public func register(
+        id: String,
+        keyCode: UInt32,
+        modifiers: UInt32,
+        handler: @escaping @MainActor () -> Void
+    ) -> Bool {
+        unregister(id: id)
+
+        let hotKeyID = EventHotKeyID(signature: shotdeckHotKeySignature, id: nextNumericID)
+        var ref: EventHotKeyRef?
+        let status = RegisterEventHotKey(
+            keyCode,
+            modifiers,
+            hotKeyID,
+            GetApplicationEventTarget(),
+            0,
+            &ref
+        )
+        guard status == noErr, let ref else {
+            return false
+        }
+        bindings[id] = (ref: ref, numericID: nextNumericID)
+        HotkeyDispatchTable.shared.set(nextNumericID, handler)
+        nextNumericID += 1
+        return true
+    }
+
+    public func unregister(id: String) {
+        guard let binding = bindings.removeValue(forKey: id) else { return }
+        _ = UnregisterEventHotKey(binding.ref)
+        HotkeyDispatchTable.shared.remove(binding.numericID)
+    }
+
+    public func unregisterAll() {
+        let ids = Array(bindings.keys)
+        for id in ids {
+            unregister(id: id)
+        }
+    }
+
+    /// Installs the process-wide Carbon hot-key pressed handler exactly once.
+    private static func installGlobalCarbonHandlerIfNeeded() {
+        guard !didInstallGlobalCarbonHandler else { return }
+        didInstallGlobalCarbonHandler = true
+
+        var handlerRef: EventHandlerRef?
+        var eventTypes = [
+            EventTypeSpec(
+                eventClass: OSType(kEventClassKeyboard),
+                eventKind: OSType(kEventHotKeyPressed)
+            )
+        ]
+        let status = InstallEventHandler(
+            GetApplicationEventTarget(),
+            shotdeckCarbonHotkeyHandler,
+            1,
+            &eventTypes,
+            nil,
+            &handlerRef
+        )
+        if status == noErr {
+            carbonHandlerRef = handlerRef
+        }
+    }
+}

Tests/ShotdeckCoreTests/CaptureRegionTests.swift

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+import Carbon.HIToolbox
+import Foundation
+import Testing
+@testable import ShotdeckCore
+
+@Test("GEO-1 primary-only 1080-tall screen, AppKit rect (100,100,400,300)")
+func geo1_primaryOnlyAppKitRectConvertsToExpectedCGRect() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 100, y: 100, width: 400, height: 300),
+        displayID: 1,
+        capturedScale: 2,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: 100, y: 680, width: 400, height: 300))
+}
+
+@Test("GEO-2 rect flush to AppKit bottom (y=0), h=300, primaryHeight=1080")
+func geo2_flushToAppKitBottomYieldsCGY780() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 50, y: 0, width: 200, height: 300),
+        displayID: 1,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect.origin.y == 780)
+}
+
+@Test("GEO-3 rect flush to AppKit top (y+h=primaryHeight), primaryHeight=1080, h=300")
+func geo3_flushToAppKitTopYieldsCGY0() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 50, y: 780, width: 200, height: 300),
+        displayID: 1,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect.origin.y == 0)
+}
+
+@Test("GEO-4 round-trip AppKit→CG via injectable overload, then invert recovers original")
+func geo4_invertRecoverOriginalAppKitRect() {
+    let original = CGRect(x: 100, y: 100, width: 400, height: 300)
+    let primaryHeight: CGFloat = 1080
+    let region = CaptureRegion.fromAppKit(
+        rect: original,
+        displayID: 1,
+        capturedScale: 2,
+        primaryHeight: primaryHeight
+    )
+    let appKitY = primaryHeight - region.rect.origin.y - region.rect.height
+    let recovered = CGRect(
+        x: region.rect.origin.x,
+        y: appKitY,
+        width: region.rect.width,
+        height: region.rect.height
+    )
+    #expect(recovered == original)
+}
+
+@Test("GEO-5 isStillValid for displayID 999_999 is false and does not trap")
+func geo5_unknownDisplayIsNotStillValid() {
+    let region = CaptureRegion(
+        displayID: 999_999,
+        rect: CGRect(x: 0, y: 0, width: 100, height: 100),
+        capturedScale: 1
+    )
+    #expect(region.isStillValid == false)
+}
+
+@Test("GEO-6 CaptureRegion JSONEncoder→JSONDecoder round-trip equals original")
+func geo6_codableRoundTripEqualsOriginal() throws {
+    let original = CaptureRegion(
+        displayID: 42,
+        rect: CGRect(x: 10, y: 20, width: 300, height: 400),
+        capturedScale: 2
+    )
+    let data = try JSONEncoder().encode(original)
+    let decoded = try JSONDecoder().decode(CaptureRegion.self, from: data)
+    #expect(decoded == original)
+}
+
+@Test("GEO-7 secondary screen negative x: AppKit (−1800,200,500,400) → CG (−1800,480,500,400)")
+func geo7_secondaryNegativeXLeavesXUnchanged() {
+    // Secondary AppKit frame (−1920, 0, 1920, 1080); primaryHeight=1080.
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: -1800, y: 200, width: 500, height: 400),
+        displayID: 2,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: -1800, y: 480, width: 500, height: 400))
+}
+
+@Test("GEO-8 secondary screen stacked above primary: AppKit (300,1300,600,350) → CG (300,−570,600,350)")
+func geo8_secondaryPositiveYProducesNegativeCGY() {
+    // Secondary AppKit frame (0, 1080, 1920, 1080); primaryHeight=1080.
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 300, y: 1300, width: 600, height: 350),
+        displayID: 2,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: 300, y: -570, width: 600, height: 350))
+}
+
+/// Carbon registrations are process-wide, so these cases must not run in parallel.
+@Suite(.serialized)
+@MainActor
+struct HotkeyCenterCarbonTests {
+    /// kVK_ANSI_2. The app registers this combo once (WP-4a); tests only exercise the registrar.
+    private let captureKeyCode: UInt32 = 19
+    private let captureModifiers = UInt32(optionKey) | UInt32(shiftKey)
+
+    @Test("HK-1 register id a with Option-Shift-2 returns true")
+    func hk1_registerReturnsTrue() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let ok = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !ok {
+            Issue.record("HK-1: RegisterEventHotKey returned non-noErr inside swift test (no NSApplication). Carbon registration did not function headlessly.")
+            return
+        }
+        #expect(ok)
+    }
+
+    @Test("HK-2 register same combo under a different id returns false")
+    func hk2_duplicateComboRejected() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !first {
+            Issue.record("HK-2: first RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate duplicate-combo rejection.")
+            return
+        }
+        let second = center.register(id: "b", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(second == false)
+    }
+
+    @Test("HK-3 unregister frees the combination so a later register succeeds")
+    func hk3_unregisterFreesCombination() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !first {
+            Issue.record("HK-3: first RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate unregister.")
+            return
+        }
+        center.unregister(id: "a")
+        let again = center.register(id: "c", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(again)
+    }
+
+    @Test("HK-4 unregisterAll frees combinations so a later register succeeds")
+    func hk4_unregisterAllFreesCombinations() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        let other = center.register(
+            id: "other",
+            keyCode: UInt32(kVK_ANSI_3),
+            modifiers: captureModifiers
+        ) {}
+        if !first {
+            Issue.record("HK-4: RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate unregisterAll.")
+            return
+        }
+        _ = other
+        center.unregisterAll()
+        let again = center.register(id: "c", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(again)
+    }
+}