feat: add combine location manager extension

Sources/ExtensionKit/CoreLocation/CLLocationManager.swift

@@ -0,0 +1,104 @@
+import Combine
+import CoreLocation
+
+public extension CLLocationManager {
+
+    static func requestLocationAuthorization(
+        with manager: CLLocationManager = .init(),
+        type: AuthorizationType
+    ) -> AnyPublisher<CLAuthorizationStatus, Never> {
+        AuthorizationPublisher(manager: manager, authorizationType: type)
+            .eraseToAnyPublisher()
+    }
+
+    enum AuthorizationType: String {
+        case always, whenInUse
+    }
+
+}
+
+protocol PublisherAuthorizationDelegate: class {
+    func send(status: CLAuthorizationStatus)
+}
+
+protocol SubscriptionAuthorizationDelegate: class {
+    func requestAuthorization(type: CLLocationManager.AuthorizationType)
+}
+
+final class AuthorizationSubscription <S: Subscriber>: NSObject,
+    PublisherAuthorizationDelegate,
+    Subscription where S.Input == CLAuthorizationStatus,
+    S.Failure == Never {
+
+    typealias Output = CLAuthorizationStatus
+    typealias Failure = Never
+
+    var subscriber: S?
+    private weak var delegate: SubscriptionAuthorizationDelegate?
+    private let authorizationType: CLLocationManager.AuthorizationType
+
+    init(
+        subscriber: S,
+        authorizationType: CLLocationManager.AuthorizationType,
+        delegate: SubscriptionAuthorizationDelegate
+    ) {
+        self.subscriber = subscriber
+        self.delegate = delegate
+        self.authorizationType = authorizationType
+    }
+
+    func request(_ demand: Subscribers.Demand) {
+        delegate?.requestAuthorization(type: authorizationType)
+    }
+
+    func cancel() {
+        subscriber = nil
+        delegate = nil
+    }
+
+    func send(status: CLAuthorizationStatus) {
+        _ = subscriber?.receive(status)
+    }
+}
+
+
+final class AuthorizationPublisher: NSObject, Publisher, CLLocationManagerDelegate, SubscriptionAuthorizationDelegate {
+
+    typealias Output = CLAuthorizationStatus
+    typealias Failure = Never
+
+    private let manager: CLLocationManager
+    private let authorizationType: CLLocationManager.AuthorizationType
+    private weak var publisherAuthorizationDelegate: PublisherAuthorizationDelegate?
+
+    init(manager: CLLocationManager, authorizationType: CLLocationManager.AuthorizationType) {
+        self.manager = manager
+        self.authorizationType = authorizationType
+    }
+
+    func receive<S>(subscriber: S) where S: Subscriber, AuthorizationPublisher.Failure == S.Failure, AuthorizationPublisher.Output == S.Input {
+        let subscription = AuthorizationSubscription(
+            subscriber: subscriber,
+            authorizationType: authorizationType,
+            delegate: self
+        )
+        publisherAuthorizationDelegate = subscription
+    }
+
+    // MARK: - CLLocationManagerDelegate
+
+    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
+        publisherAuthorizationDelegate?.send(status: status)
+    }
+
+    // MARK: - AuthorizationSubscriptionDelegate
+
+    func requestAuthorization(type: CLLocationManager.AuthorizationType) {
+        switch type {
+        case .whenInUse:
+            manager.requestWhenInUseAuthorization()
+        case .always:
+            manager.requestAlwaysAuthorization()
+        }
+    }
+}