Self-maintained passcode lock

- No cancel button anywhere in the passcode lock yet
- Poor UI

passKit/Models/PasscodeLock.swift

@@ -0,0 +1,35 @@
+//
+//  PasscodeLock.swift
+//  PassKit
+//
+//  Created by Yishi Lin on 28/1/2018.
+//  Copyright © 2017 Yishi Lin. All rights reserved.
+//
+
+import Foundation
+import LocalAuthentication
+
+open class PasscodeLock {
+    public static let shared = PasscodeLock()
+    
+    fileprivate let passcodeKey = "passcode.lock.passcode"
+    fileprivate var passcode: String? {
+        return SharedDefaults[.passcodeKey]
+    }
+    
+    public var hasPasscode: Bool {
+        return passcode != nil
+    }
+    
+    public func save(passcode: String) {
+        SharedDefaults[.passcodeKey] = passcode
+    }
+    
+    public func check(passcode: String) -> Bool {
+        return self.passcode == passcode
+    }
+    
+    public func delete() {
+        SharedDefaults[.passcodeKey] = nil
+    }
+}