♻️ Separate some of the PHP config logic from the app

phpmon-common/PhpSwitcher.swift

@@ -0,0 +1,60 @@
+//
+//  PhpSwitcher.swift
+//  PHP Monitor
+//
+//  Created by Nico Verbruggen on 21/12/2021.
+//  Copyright © 2021 Nico Verbruggen. All rights reserved.
+//
+
+import Foundation
+
+protocol PhpSwitcherDelegate: AnyObject {
+    func switcherDidStartSwitching()
+    func switcherDidCompleteSwitch()
+}
+
+class PhpSwitcher {
+    
+    init() {
+        self.currentInstall = ActivePhpInstallation()
+    }
+    
+    /** The delegate that is informed of updates. */
+    weak var delegate: PhpSwitcherDelegate?
+
+    /** The static app instance. Accessible at any time. */
+    static let shared = PhpSwitcher()
+    
+    /** Whether the switcher is busy performing any actions. */
+    var isBusy: Bool = false
+    
+    /** All available versions of PHP. */
+    var availablePhpVersions: [String] = []
+    
+    /** Cached information about the PHP installations. */
+    var cachedPhpInstallations: [String: PhpInstallation] = [:]
+    
+    /** Static accessor for `PhpSwitcher.shared.currentInstall`. */
+    static var phpInstall: ActivePhpInstallation {
+        return Self.shared.currentInstall
+    }
+    
+    /** Information about the currently linked PHP installation. */
+    var currentInstall: ActivePhpInstallation
+    
+    /**
+     The version that the `php` formula via Brew is aliased to on the current system.
+     
+     If you're up to date, `php` will be aliased to the latest version,
+     but that might not be the case.
+     */
+    var brewPhpVersion: String {
+        return homebrewPackage.version
+    }
+    
+    /**
+     Information we were able to discern from the Homebrew info command.
+     */
+    var homebrewPackage: HomebrewPackage! = nil
+    
+}