Fix fan discovery, invalid readings, Settings navigation, and disk caching

Core-Monitor.xcodeproj/project.pbxproj

@@ -7,6 +7,9 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		A19400012026091900000002 /* FanReadingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = A19400012026091900000001 /* FanReadingTests.swift */; };
+		A19400022026091900000002 /* DiskStatsRefreshPolicyTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = A19400022026091900000001 /* DiskStatsRefreshPolicyTests.swift */; };
+		A19400032026091900000002 /* SettingsWindowTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = A19400032026091900000001 /* SettingsWindowTests.swift */; };
 		12AF073D73CA92C2A2FBF449 /* Cocoa.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 33D1932E6B3C54A956AF5F6C /* Cocoa.framework */; };
 		23F2064CB38FDB73EE4AB471 /* AlertEngineTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8D6F3C76B69FEDB140682676 /* AlertEngineTests.swift */; };
 		7381A6E82B87236C00C0DE01 /* CustomFanPresetTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7381A6E72B87236C00C0DE01 /* CustomFanPresetTests.swift */; };
@@ -48,6 +51,9 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		A19400012026091900000001 /* FanReadingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FanReadingTests.swift; sourceTree = "<group>"; };
+		A19400022026091900000001 /* DiskStatsRefreshPolicyTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DiskStatsRefreshPolicyTests.swift; sourceTree = "<group>"; };
+		A19400032026091900000001 /* SettingsWindowTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsWindowTests.swift; sourceTree = "<group>"; };
 		33D1932E6B3C54A956AF5F6C /* Cocoa.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Cocoa.framework; path = Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk/System/Library/Frameworks/Cocoa.framework; sourceTree = DEVELOPER_DIR; };
 		353B02D12F640A0700A65F2C /* Core-Monitor.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = "Core-Monitor.app"; sourceTree = BUILT_PRODUCTS_DIR; };
 		35F039AB2F64444D004CB9F8 /* smc-helper */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; name = "smc-helper"; path = "ventaphobia.smc-helper"; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -63,6 +69,11 @@
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedRootGroup section */
+		A19300012026091900000001 /* Shared */ = {
+			isa = PBXFileSystemSynchronizedRootGroup;
+			path = Shared;
+			sourceTree = "<group>";
+		};
 		353B02D32F640A0700A65F2C /* Core-Monitor */ = {
 			isa = PBXFileSystemSynchronizedRootGroup;
 			path = "Core-Monitor";
@@ -104,6 +115,9 @@
 		1A2F97F19E4BA4C0B1070411 /* Core-MonitorTests */ = {
 			isa = PBXGroup;
 			children = (
+				A19400012026091900000001 /* FanReadingTests.swift */,
+				A19400022026091900000001 /* DiskStatsRefreshPolicyTests.swift */,
+				A19400032026091900000001 /* SettingsWindowTests.swift */,
 				8D6F3C76B69FEDB140682676 /* AlertEngineTests.swift */,
 				7381A6E72B87236C00C0DE01 /* CustomFanPresetTests.swift */,
 				DABD10012F96000100000001 /* CoreMonitorShareKitTests.swift */,
@@ -119,6 +133,7 @@
 		353B02C82F640A0700A65F2C = {
 			isa = PBXGroup;
 			children = (
+				A19300012026091900000001 /* Shared */,
 				353B02D32F640A0700A65F2C /* Core-Monitor */,
 				35F039AC2F64444D004CB9F8 /* smc-helper */,
 				353B02D22F640A0700A65F2C /* Products */,
@@ -172,6 +187,7 @@
 			);
 			fileSystemSynchronizedGroups = (
 				353B02D32F640A0700A65F2C /* Core-Monitor */,
+				A19300012026091900000001 /* Shared */,
 			);
 			name = "Core-Monitor";
 			productName = "Core-Monitor";
@@ -192,6 +208,7 @@
 			);
 			fileSystemSynchronizedGroups = (
 				35F039AC2F64444D004CB9F8 /* smc-helper */,
+				A19300012026091900000001 /* Shared */,
 			);
 			name = "smc-helper";
 			productName = "smc-helper";
@@ -314,6 +331,9 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				A19400012026091900000002 /* FanReadingTests.swift in Sources */,
+				A19400022026091900000002 /* DiskStatsRefreshPolicyTests.swift in Sources */,
+				A19400032026091900000002 /* SettingsWindowTests.swift in Sources */,
 				23F2064CB38FDB73EE4AB471 /* AlertEngineTests.swift in Sources */,
 				7381A6E82B87236C00C0DE01 /* CustomFanPresetTests.swift in Sources */,
 				DABD10022F96000100000002 /* CoreMonitorShareKitTests.swift in Sources */,

Core-Monitor/AlertEngine.swift

@@ -352,6 +352,7 @@ enum AlertEvaluator {
             let lowFanIndex = zip(input.snapshot.fanSpeeds, input.snapshot.fanMinSpeeds)
                 .enumerated()
                 .first { _, pair in
+                    guard pair.0 >= 0 else { return false }
                     let floor = max(pair.1 + 150, 1_200)
                     return pair.0 < floor
                 }?

Core-Monitor/DiskStatsRefreshPolicy.swift

@@ -12,3 +12,20 @@ enum DiskStatsRefreshPolicy {
         return now.timeIntervalSince(lastUpdatedAt) >= minimumInterval
     }
 }
+
+/// Owned by the sampling queue. Failed reads preserve both the last good
+/// reading and its timestamp, allowing another attempt on the next sample.
+struct DiskStatsCache {
+    private(set) var stats = DiskStats()
+    private(set) var lastUpdatedAt: Date?
+
+    mutating func read(now: Date, load: () throws -> DiskStats?) -> DiskStats {
+        guard DiskStatsRefreshPolicy.shouldRefresh(lastUpdatedAt: lastUpdatedAt, now: now),
+              let refreshed = try? load() else {
+            return stats
+        }
+        stats = refreshed
+        lastUpdatedAt = now
+        return stats
+    }
+}

Core-Monitor/FanController.swift

@@ -1013,18 +1013,9 @@ final class FanController: ObservableObject {
             return directCount
         }
 
-        for fanID in 0..<12 {
-            let actualKey = String(format: "F%dAc", fanID)
-            let minKey = String(format: "F%dMn", fanID)
-            let maxKey = String(format: "F%dMx", fanID)
-            if helperManager.readValue(key: actualKey) != nil ||
-                helperManager.readValue(key: minKey) != nil ||
-                helperManager.readValue(key: maxKey) != nil {
-                return fanID + 1
-            }
+        return SMCFanDetection.fallbackCount { key in
+            helperManager.readValue(key: key) != nil
         }
-
-        return 0
     }
 
     private func helperUnavailableMessage() -> String {

Core-Monitor/MenubarController.swift

@@ -119,7 +119,7 @@ final class MenuBarController: NSObject {
 // MARK: - SingleMenuBarItemController
 @MainActor
 final class SingleMenuBarItemController: NSObject, NSPopoverDelegate {
-    private enum StatusTone: Equatable {
+    enum StatusTone: Equatable {
         case normal
         case warning
         case critical
@@ -241,14 +241,7 @@ final class SingleMenuBarItemController: NSObject, NSPopoverDelegate {
             return ("\(pct)%", tone)
 
         case .fan:
-            let speeds = systemMonitor.fanSpeeds.filter { $0 > 0 }
-            guard let highestRPM = speeds.max() else {
-                return ("—", .secondary)
-            }
-
-            let utilization = Double(highestRPM) / Double(max(fanController.maxSpeed, 1))
-            let tone: StatusTone = utilization > 0.85 ? .critical : utilization > 0.6 ? .warning : .normal
-            return (ReadingFormat.rpmShort(highestRPM), tone)
+            return Self.fanStatusLabel(speeds: systemMonitor.fanSpeeds, maximumRPM: fanController.maxSpeed)
 
         case .memory:
             let pct = Int(systemMonitor.memoryUsagePercent.rounded())
@@ -282,6 +275,17 @@ final class SingleMenuBarItemController: NSObject, NSPopoverDelegate {
         }
     }
 
+    static func fanStatusLabel(speeds: [Int], maximumRPM: Int) -> (text: String, tone: StatusTone) {
+        // Zero is a valid reading. Only negative values mean the read failed.
+        guard let highestRPM = speeds.filter({ $0 >= 0 }).max() else {
+            return ("—", .secondary)
+        }
+
+        let utilization = Double(highestRPM) / Double(max(maximumRPM, 1))
+        let tone: StatusTone = utilization > 0.85 ? .critical : utilization > 0.6 ? .warning : .normal
+        return (ReadingFormat.rpmShort(highestRPM), tone)
+    }
+
     private func statusBarIcon() -> NSImage? {
         let configuration = NSImage.SymbolConfiguration(pointSize: 13, weight: .regular)
         let image = NSImage(systemSymbolName: kind.systemImageName, accessibilityDescription: kind.title)?

Core-Monitor/SettingsWindow.swift

@@ -1,4 +1,5 @@
 import AppKit
+import Combine
 import SwiftUI
 
 // MARK: - Window manager
@@ -8,11 +9,17 @@ import SwiftUI
 final class SettingsWindowManager: NSObject, NSWindowDelegate {
     static let shared = SettingsWindowManager()
 
-    private var window: NSWindow?
+    private(set) var window: NSWindow?
+    private let selection = SettingsSelection()
     private var systemMonitor: SystemMonitor?
     private var fanController: FanController?
     private var startupManager: StartupManager?
 
+    init(startupManager: StartupManager? = nil) {
+        self.startupManager = startupManager
+        super.init()
+    }
+
     /// Called once at launch so any surface (toolbar, popovers, app menu)
     /// can open Settings without threading dependencies around.
     func configure(
@@ -27,6 +34,7 @@ final class SettingsWindowManager: NSObject, NSWindowDelegate {
 
     func show(tab: SettingsTab = .general) {
         guard let startupManager else { return }
+        selection.tab = tab
 
         if let window {
             window.makeKeyAndOrderFront(nil)
@@ -36,7 +44,7 @@ final class SettingsWindowManager: NSObject, NSWindowDelegate {
 
         let rootView = SettingsView(
             startupManager: startupManager,
-            initialTab: tab
+            selection: selection
         )
         let hostingController = NSHostingController(rootView: rootView)
         let newWindow = NSWindow(contentViewController: hostingController)
@@ -85,20 +93,17 @@ enum SettingsTab: String, CaseIterable, Identifiable {
 
 // MARK: - Root
 
+@MainActor
+final class SettingsSelection: ObservableObject {
+    @Published var tab: SettingsTab = .general
+}
+
 struct SettingsView: View {
     @ObservedObject var startupManager: StartupManager
-    @State private var tab: SettingsTab
-
-    init(
-        startupManager: StartupManager,
-        initialTab: SettingsTab = .general
-    ) {
-        self.startupManager = startupManager
-        _tab = State(initialValue: initialTab)
-    }
+    @ObservedObject var selection: SettingsSelection
 
     var body: some View {
-        TabView(selection: $tab) {
+        TabView(selection: $selection.tab) {
             GeneralSettingsTab(startupManager: startupManager)
                 .tabItem { Label(SettingsTab.general.title, systemImage: SettingsTab.general.symbolName) }
                 .tag(SettingsTab.general)

Core-Monitor/SystemMonitor.swift

@@ -186,8 +186,7 @@ final class SystemMonitor: ObservableObject {
     var networkStats: NetworkStats { snapshot.networkStats }
     private var previousNetworkBytes: (sent: UInt64, received: UInt64) = (0, 0)
     private var previousNetworkTime: Date = Date()
-    private var cachedDiskStats = DiskStats()
-    private var lastDiskStatsRefreshAt: Date?
+    private var diskStatsCache = DiskStatsCache()
 
     // MARK: - History buffers (60 samples, used by menu bar popovers)
     private(set) var cpuHistory:     [Double] = Array(repeating: 0, count: 60)
@@ -697,17 +696,12 @@ final class SystemMonitor: ObservableObject {
     }
     // MARK: - Disk stats (via FileManager)
     private func readDiskStats(now: Date = Date()) -> DiskStats {
-        guard DiskStatsRefreshPolicy.shouldRefresh(lastUpdatedAt: lastDiskStatsRefreshAt, now: now) else {
-            return cachedDiskStats
-        }
-
-        var stats = DiskStats()
-        do {
+        diskStatsCache.read(now: now) {
             let attrs = try FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory())
             guard
                 let totalRaw = attrs[.systemSize] as? Int64,
                 let freeRaw  = attrs[.systemFreeSize] as? Int64
-            else { return stats }
+            else { return nil }
 
             let totalBytes = Double(totalRaw)
             let freeBytes  = Double(freeRaw)
@@ -722,15 +716,14 @@ final class SystemMonitor: ObservableObject {
 
             let usedBytes = max(0, totalBytes - freeBytes - purgeableBytes)
 
+            var stats = DiskStats()
             stats.totalGB       = totalBytes       / 1_073_741_824
             stats.usedGB        = usedBytes        / 1_073_741_824
             stats.freeGB        = freeBytes        / 1_073_741_824
             stats.purgeableGB   = purgeableBytes   / 1_073_741_824
             stats.usagePercent  = totalBytes > 0 ? usedBytes / totalBytes * 100 : 0
-        } catch {}
-        cachedDiskStats = stats
-        lastDiskStatsRefreshAt = now
-        return cachedDiskStats
+            return stats
+        }
     }
 
     private func readFanReadings() -> (speeds: [Int], mins: [Int], maxs: [Int]) {

Core-MonitorTests/AlertEngineTests.swift

@@ -394,6 +394,57 @@ final class AlertEngineTests: XCTestCase {
         )
     }
 
+    func testMissingFanReadingsDoNotTriggerLowSpeedAlerts() {
+        for speeds in [[-1], [-1, -1], [-1, 3_000], [3_000, -1]] {
+            let outcome = evaluateHotFans(speeds: speeds, temperature: 95)
+
+            XCTAssertNil(outcome.activeState, "Speeds: \(speeds)")
+            XCTAssertNil(outcome.event)
+            XCTAssertFalse(outcome.shouldNotify)
+        }
+    }
+
+    func testMissingFirstFanDoesNotHideSlowSecondFan() {
+        let outcome = evaluateHotFans(speeds: [-1, 1_000], temperature: 85)
+
+        XCTAssertEqual(outcome.activeState?.severity, .warning)
+        XCTAssertNotNil(outcome.event)
+    }
+
+    func testZeroRPMStillTriggersCriticalStallAlertUnderHeat() {
+        let outcome = evaluateHotFans(speeds: [-1, 0], temperature: 85)
+
+        XCTAssertEqual(outcome.activeState?.severity, .critical)
+        XCTAssertTrue(outcome.shouldNotify)
+    }
+
+    func testSlowFanStillEscalatesAtCriticalTemperature() {
+        let outcome = evaluateHotFans(speeds: [1_000, -1], temperature: 95)
+
+        XCTAssertEqual(outcome.activeState?.severity, .critical)
+    }
+
+    private func evaluateHotFans(speeds: [Int], temperature: Double) -> AlertEvaluationOutcome {
+        let config = AlertRuleConfig(
+            kind: .fanTooLowUnderHeat,
+            isEnabled: true,
+            threshold: .init(warning: 80, critical: 90, hysteresis: 3),
+            cooldownMinutes: 10,
+            debounceSamples: 1,
+            desktopNotificationsEnabled: true
+        )
+        return AlertEvaluator.evaluate(
+            config: config,
+            runtime: .initial(for: .fanTooLowUnderHeat),
+            input: makeInput { snapshot in
+                snapshot.cpuTemperature = temperature
+                snapshot.numberOfFans = speeds.count
+                snapshot.fanSpeeds = speeds
+                snapshot.fanMinSpeeds = Array(repeating: 1_500, count: speeds.count)
+            }
+        )
+    }
+
     private func makeInput(
         fanMode: FanControlMode = .automatic,
         helperInstalled: Bool = true,