///*
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//See LICENSE folder for this sample’s licensing information.
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//Abstract:
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//A data manager that manages data conforming to `Codable` and stores it in `UserDefaults`.
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//*/
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//using System;
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//using Foundation;
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//using CoreFoundation;
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//namespace SiriKit
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//{
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// public struct UserDefaultsStorageDescriptor
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// {
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// public string Key { get; set; }
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// public UserDefaultsStorageDescriptor(string key)
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// {
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// Key = key;
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// }
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// }
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// public static class NotificationKeys
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// {
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// // Clients of `DataManager` that want to know when the data changes can
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// // listen for this notification.
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// public const string DataChanged = "DataChangedNotification";
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// }
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// public class DataManager<ManagedDataType> : NSObject
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// where ManagedDataType : NSObject, INSCoding
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// {
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// // This sample uses App Groups to share a suite of data between the
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// // main app and the different extensions.
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// protected NSUserDefaults UserDefaults = NSUserDefaultsHelper.DataSuite;
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// // To prevent data races, all access to `UserDefaults` uses this queue.
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// protected DispatchQueue UserDefaultsAccessQueue = new DispatchQueue("User Defaults Access Queue");
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// // Storage and observation information.
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// protected UserDefaultsStorageDescriptor StorageDescriptor;
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// // A flag to avoid receiving notifications about data this instance just
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// // wrote to `UserDefaults`.
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// protected bool IgnoreLocalUserDefaultsChanges = false;
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// // The observer object handed back after registering to observe a
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// // property.
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// IDisposable UserDefaultsObserver;
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// // The data managed by this `DataManager`.
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// //此“DataManager”管理的数据。
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// protected ManagedDataType ManagedDataBackingInstance;
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// // Access to `managedDataBackingInstance` needs to occur on a dedicated
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// // queue to avoid data races.
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// protected DispatchQueue DataAccessQueue = new DispatchQueue("Data Access Queue");
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// // Public access to the managed data for clients of `DataManager`
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// public ManagedDataType ManagedData
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// {
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// get
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// {
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// ManagedDataType data = null;
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// DataAccessQueue.DispatchSync(() => data = ManagedDataBackingInstance);
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// return data;
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// }
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// }
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// // See note below about createInitialData and initialData
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// public DataManager(UserDefaultsStorageDescriptor storageDescriptor, ManagedDataType initialData)
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// {
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// StorageDescriptor = storageDescriptor;
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// LoadData();
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// if (ManagedDataBackingInstance is null)
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// {
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// ManagedDataBackingInstance = initialData;
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// WriteData();
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// }
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// ObserveChangesInUserDefaults();
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// }
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// // createInitialData
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// //
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// // The Swift version of this app has a createInitialData method.
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// // Each child class of the DataManager class overrides this method, and
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// // then the DataManager base class calls the derived versions to get
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// // the initial data. C# gives a compiler warning for this ("Virtual
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// // member call in constructor"). Since in C# the base class constructor
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// // is run before the child class constructor, having the base clas
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// // constructor call out to a method on the derived class is calling
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// // a method on an object that has not yet been fully constructed.
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// // The C# version of this sample works around this problem by passing
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// // in the initial data to the constructor.
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// void ObserveChangesInUserDefaults()
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// {
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// var weakThis = new WeakReference<DataManager<ManagedDataType>>(this);
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// Action<NSObservedChange> changeHandler = (change) =>
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// {
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// if (weakThis.TryGetTarget(out var dataManager))
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// {
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// // Ignore any change notifications coming from data this
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// // instance just saved to `NSUserDefaults`.
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// if (dataManager is null || dataManager.IgnoreLocalUserDefaultsChanges)
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// {
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// return;
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// }
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// // The underlying data changed in `NSUserDefaults`, so
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// // update this instance with the change and notify clients
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// // of the change.
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// dataManager.LoadData();
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// dataManager.NotifyClientsDataChanged();
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// }
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// };
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// UserDefaultsObserver = UserDefaults.AddObserver(
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// StorageDescriptor.Key,
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// NSKeyValueObservingOptions.Initial | NSKeyValueObservingOptions.New,
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// changeHandler
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// );
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// }
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// // Notifies clients the data changed by posting an `NSNotification` with
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// // the key `NotificationKeys.DataChanged`
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// void NotifyClientsDataChanged()
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// {
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// var notification = NSNotification.FromName(NotificationKeys.DataChanged, this);
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// NSNotificationCenter.DefaultCenter.PostNotification(notification);
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// }
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// protected virtual void FinishUnarchiving(NSObject unarchivedData)
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// {
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// throw new NotImplementedException();
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// }
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// // Loads the data from `NSUserDefaults`.
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// void LoadData()
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// {
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// UserDefaultsAccessQueue.DispatchSync(() =>
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// {
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// NSData archivedData = UserDefaults.DataForKey(StorageDescriptor.Key);
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// try
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// {
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// // Let the derived classes handle the specifics of
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// // putting the unarchived data in the correct format.
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// // This is necessary because the derived classes
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// // (SoupMenuManager, SoupOrderMenuManager) are using
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// // generic data formats (NSMutableSet<T> or NSMutableArray<T>)
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// // and these types cannot be casted directly from the
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// // deserialized data.
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// NSObject unarchivedData = NSKeyedUnarchiver.UnarchiveObject(archivedData);
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// FinishUnarchiving(unarchivedData);
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// }
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// catch (Exception e)
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// {
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// if (!(e is null))
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// {
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// Console.WriteLine($"Error: {e.Message}");
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// }
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// }
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// });
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// }
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// // Writes the data to `NSUserDefaults`
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// protected void WriteData()
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// {
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// UserDefaultsAccessQueue.DispatchAsync(() =>
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// {
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// try
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// {
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// NSData encodedData = NSKeyedArchiver.ArchivedDataWithRootObject(ManagedDataBackingInstance);
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// IgnoreLocalUserDefaultsChanges = true;
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// UserDefaults.SetValueForKey(encodedData, (NSString)StorageDescriptor.Key);
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// IgnoreLocalUserDefaultsChanges = false;
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// NotifyClientsDataChanged();
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// }
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// catch (Exception e)
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// {
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// throw new Exception($"Could not save data. Reason: {e.Message}");
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// }
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// });
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// }
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// }
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//}
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