IOS-175: implement the feature availability layer.

Breaks the code. Requires the next commit to work.

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/AppFeature.swift

+//
+//  AppFeature.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 24.08.2021.
+//
+
+import Foundation
+
+public enum AppFeature: String, Codable, CaseIterable {
+    case airQualityIndex
+    case attPrompt
+    case ads
+    case nwsAlertsViaMoEngage
+    case onboarding
+    case minutelyForecast
+    case shorts
+    case shortsLastNudge
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityCheckers/FeatureAvailabilityChecker.swift

+//
+//  FeatureAvailabilityChecker.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 24.08.2021.
+//
+
+import Foundation
+
+public protocol FeatureAvailabilityChecker {
+    var isAvailable: Bool { get }
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityCheckers/FeatureAvailabilityCheckerHelpers.swift

+//
+//  FeatureAvailabilityCheckerHelpers.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 25.08.2021.
+//
+
+import Foundation
+
+public extension FeatureAvailabilityChecker {
+    static prefix func ! (checker: Self) -> FeatureAvailabilityChecker {
+        return FeatureAvailabilityNot(decoratedChecker: checker)
+    }
+}
+
+public func && (first: FeatureAvailabilityChecker, second: FeatureAvailabilityChecker) -> FeatureAvailabilityChecker {
+    return FeatureAvaillabilityAnd(first: first, second: second)
+}
+
+public func || (first: FeatureAvailabilityChecker, second: FeatureAvailabilityChecker) -> FeatureAvailabilityChecker {
+    return FeatureAvaillabilityOr(first: first, second: second)
+}
+
+fileprivate struct FeatureAvailabilityNot: FeatureAvailabilityChecker {
+    private let decorated: FeatureAvailabilityChecker
+    
+    public init(decoratedChecker: FeatureAvailabilityChecker) {
+        decorated = decoratedChecker
+    }
+    
+    var isAvailable: Bool {
+        !decorated.isAvailable
+    }
+}
+
+fileprivate struct FeatureAvaillabilityAnd: FeatureAvailabilityChecker {
+    private let firstChecker: FeatureAvailabilityChecker
+    private let secondChecker: FeatureAvailabilityChecker
+    
+    public init(first: FeatureAvailabilityChecker, second: FeatureAvailabilityChecker) {
+        firstChecker = first
+        secondChecker = second
+    }
+    
+    var isAvailable: Bool {
+        firstChecker.isAvailable && secondChecker.isAvailable
+    }
+}
+
+fileprivate struct FeatureAvaillabilityOr: FeatureAvailabilityChecker {
+    private let firstChecker: FeatureAvailabilityChecker
+    private let secondChecker: FeatureAvailabilityChecker
+    
+    public init(first: FeatureAvailabilityChecker, second: FeatureAvailabilityChecker) {
+        firstChecker = first
+        secondChecker = second
+    }
+    
+    var isAvailable: Bool {
+        firstChecker.isAvailable || secondChecker.isAvailable
+    }
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityCheckers/PremiumInAppFeatureAvailabilityChecker.swift

+//
+//  PremiumInAppFeatureAvailabilityChecker.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 25.08.2021.
+//
+
+import Foundation
+
+public struct PremiumInAppFeatureAvailabilityChecker: FeatureAvailabilityChecker {
+    public init() {}
+    
+    public var isAvailable: Bool {
+        if let metricsLog = UserDefaults.standard.dictionary(forKey: kOLAppMetricsKey) {
+            return metricsLog[kEventInAppPurchasedCompleted] != nil
+        }
+        return false
+    }
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityCheckers/ProSubscriptionAvailabilityChecker.swift

+//
+//  ProSubscriptionAvailabilityChecker.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 25.08.2021.
+//
+
+import Foundation
+
+public struct ProSubscriptionAvailabilityChecker: FeatureAvailabilityChecker {
+    public init() {}
+    
+    public var isAvailable: Bool {
+        #warning("Not implemented!")
+        //TODO: Implement!
+        // IOS-155
+        
+        #if DEBUG
+        return true
+        #else
+        return false
+        #endif
+    }
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityCheckers/USOnlyFeatureAvailabilityChecker.swift

+//
+//  USOnlyFeatureAvailabilityChecker.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 25.08.2021.
+//
+
+import Foundation
+
+public struct USOnlyFeatureAvailabilityChecker: FeatureAvailabilityChecker {
+    public typealias LocationFetcher = () -> Location?
+    
+    private let locationFetcher: LocationFetcher
+    
+    public init(locationFetcher: @escaping LocationFetcher) {
+        self.locationFetcher = locationFetcher
+    }
+    
+    public var isAvailable: Bool {
+        if let location = locationFetcher() {
+            return location.countryCode == "US"
+        }
+        return false
+    }
+}

OneWeatherCore/OneWeatherCore/Managers/FeatureAvailability/FeatureAvailabilityManager.swift

+//
+//  FeatureAvailabilityManager.swift
+//  OneWeatherCore
+//
+//  Created by Demid Merzlyakov on 24.08.2021.
+//
+
+import Foundation
+
+public class FeatureAvailabilityManager {
+    public typealias ConfigFetcher = () -> AppConfig?
+    private let checkers: [AppFeature: FeatureAvailabilityChecker]
+    private let configFetcher: ConfigFetcher
+    
+    public static var shared: FeatureAvailabilityManager!
+    
+    public init(configFetcher: @escaping ConfigFetcher, checkers: [AppFeature: FeatureAvailabilityChecker]) {
+        self.configFetcher = configFetcher
+        self.checkers = checkers
+    }
+    
+    public func isAvailable(feature: AppFeature) -> Bool {
+        guard let config = configFetcher() else {
+            // TODO: log error
+            return false
+        }
+        guard config.isEnabled(feature: feature) else {
+            return false
+        }
+        if let avaiabilityChecker = checkers[feature] {
+            return avaiabilityChecker.isAvailable
+        }
+        return true
+    }
+}
+
+// TODO: make FeatureAvailabilityCheckers observe the values and notify the FeatureAvailabilityManager that the value has been changed. Move from observing different things across the app (ConfigManager, LocationManager, etc.) to observing just the FeatureAvailabilityManager
+//public protocol FeatureAvailabilityObserver {
+//    func manager(_ manager: FeatureAvailabilityManager, updatedAvailability isAvailable: Bool, for feature: AppFeature)
+//}

OneWeatherCore/OneWeatherCore/ModelObjects/Config/AppConfig.swift

@@ -11,31 +11,29 @@ public struct AppConfig: Codable {
     public let popularCities: [GeoNamesPlace]?
     public let adConfig: AdConfig
     public let ccpaUpdateInterval: TimeInterval?
-    public let nwsAlertsViaMoEngageEnabled: Bool
-    public let showAttPrompt: Bool
     public let shortsLeftBelowCount: Int
-    public let shortsLastNudgeEnabled: Bool
     public let shortsSwipeUpNudgeCount: Int
-    public let showOnboarding: Bool
+    private let explicitFeatureAvailability: [AppFeature: Bool]
     
     public init(popularCities: [GeoNamesPlace]?,
                 adConfig: AdConfig,
                 ccpaUpdateInterval: TimeInterval?,
-                nwsAlertsViaMoEngageEnabled: Bool,
-                showAttPrompt: Bool,
                 shortsLeftBelowCountKey: Int,
-                shortsLastNudgeEnabledKey: Bool,
                 shortsSwipeUpNudgeCountKey: Int,
-                showOnboarding: Bool
+                explicitFeatureAvailability: [AppFeature: Bool]
     ) {
         self.popularCities = popularCities
         self.adConfig = adConfig
         self.ccpaUpdateInterval = ccpaUpdateInterval
-        self.nwsAlertsViaMoEngageEnabled = nwsAlertsViaMoEngageEnabled
-        self.showAttPrompt = showAttPrompt
         self.shortsLeftBelowCount = shortsLeftBelowCountKey
-        self.shortsLastNudgeEnabled = shortsLastNudgeEnabledKey
         self.shortsSwipeUpNudgeCount = shortsSwipeUpNudgeCountKey
-        self.showOnboarding = showOnboarding
+        self.explicitFeatureAvailability = explicitFeatureAvailability
+    }
+    
+    public func isEnabled(feature: AppFeature) -> Bool {
+        if feature == .ads {
+            return adConfig.adsEnabled
+        }
+        return explicitFeatureAvailability[feature] ?? true
     }
 }