Initial release

Sources/KnotchyCore/Setup/HostChecks.swift

@@ -0,0 +1,44 @@
+import Foundation
+import Virtualization
+
+/// Knotchy is built for Apple silicon only; macOS itself refuses to open it on an Intel Mac.
+public enum Unsupported: Equatable, Sendable {
+    case noVirtualization
+}
+
+public struct HostFacts: Equatable, Sendable {
+    public var unsupported: Unsupported?
+    public var osVersion: String
+    public var bytesFree: Int64?
+
+    public init(unsupported: Unsupported?, osVersion: String, bytesFree: Int64?) {
+        self.unsupported = unsupported
+        self.osVersion = osVersion
+        self.bytesFree = bytesFree
+    }
+}
+
+public protocol HostChecking: Sendable {
+    func facts() async -> HostFacts
+}
+
+public struct SystemHost: HostChecking {
+    public init() {}
+
+    /// Synchronous, so the app can decide on minimal mode before it registers anything.
+    @MainActor
+    public static func unsupported() -> Unsupported? {
+        VZVirtualMachine.isSupported ? nil : .noVirtualization
+    }
+
+    public func facts() async -> HostFacts {
+        let unsupported = await Self.unsupported()
+        let version = ProcessInfo.processInfo.operatingSystemVersion
+        var os = "macOS \(version.majorVersion).\(version.minorVersion)"
+        if version.patchVersion > 0 { os += ".\(version.patchVersion)" }
+        // The runtime keeps its data under the home folder.
+        let values = try? URL(fileURLWithPath: NSHomeDirectory())
+            .resourceValues(forKeys: [.volumeAvailableCapacityForImportantUsageKey])
+        return HostFacts(unsupported: unsupported, osVersion: os, bytesFree: values?.volumeAvailableCapacityForImportantUsage)
+    }
+}