bundesmessenger-ios/bwi/ServerMaintenance/ValidAppVersionsDefaultService.swift

//
/*
 * Copyright (c) 2022 BWI GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import Foundation

@objcMembers class ValidAppVersionsDefaultService : NSObject {

    var currentAppVersion: String? {
        return Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String
    }

    var updateBeforeVersion: String? {
        guard let data = UserDefaults.standard.data(forKey: "BWI_ValidAppVersions") else {
            return nil
        }
        guard let validAppVersions = try? JSONDecoder().decode(ValidAppVersions.self, from: data) else {
            return nil
        }
        return validAppVersions.updateBefore
    }

    var warnBeforeVersion: String? {
        guard let data = UserDefaults.standard.data(forKey: "BWI_ValidAppVersions") else {
            return nil
        }
        guard let validAppVersions = try? JSONDecoder().decode(ValidAppVersions.self, from: data) else {
            return nil
        }
        return validAppVersions.warnBefore
    }

    enum AppVersionState {
        case valid
        case outdated
        case deprecated
        case unknown
    }

    func versionCompare(version1: String, version2: String) -> ComparisonResult {
        var components1 = version1.components(separatedBy: ".")
        var components2 = version2.components(separatedBy: ".")

        if components1.count == components2.count {
            return version1.compare(version2, options: .numeric)
        } else {
            let zeros = Array(repeating: "0", count: abs(components1.count - components2.count))
            if components1.count > components2.count {
                components2.append(contentsOf: zeros)
            } else {
                components1.append(contentsOf: zeros)
            }
            
            let normalizedVersion1 = components1.joined(separator: ".")
            let normalizedVersion2 = components2.joined(separator: ".")
            return normalizedVersion1.compare(normalizedVersion2, options: .numeric)
        }
    }
    
    func currentAppVersionState() -> AppVersionState {
        guard let currentAppVersion = currentAppVersion else {
            return .unknown
        }
        guard let updateBeforeVersion = updateBeforeVersion, let warnBeforeVersion = warnBeforeVersion else {
            return .valid
        }

        if versionCompare(version1: currentAppVersion, version2: updateBeforeVersion) == .orderedAscending {
            return .deprecated
        }
        else if versionCompare(version1: currentAppVersion, version2: warnBeforeVersion) == .orderedAscending {
            return .outdated
        } else {
            return .valid
        }
    }

}

extension  ValidAppVersionsDefaultService : ValidAppVersionsService {

    @objc func isCurrentAppVersionOutdated() -> Bool {
        return currentAppVersionState() == .outdated || currentAppVersionState() == .deprecated
    }
    
    @objc func isCurrentAppVersionDeprecated() -> Bool {
        return currentAppVersionState() == .deprecated
    }
    
    @objc func wasOutdatedAlertShown() -> Bool {
        return UserDefaults.standard.bool(forKey: "BWIOutdatedAlertShown")
    }

    @objc func setOutdatedAlertShown(_ shown: Bool) {
        UserDefaults.standard.set(shown, forKey: "BWIOutdatedAlertShown")
        UserDefaults.standard.synchronize()
    }
}