// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.

// Licensed to the .NET Foundation under one or more agreements.

// The .NET Foundation licenses this file to you under the MIT license.

// See the LICENSE file in the project root for full license information.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Diagnostics.CodeAnalysis;

using System.Diagnostics.Contracts;

using System.Linq;

using System.Reactive;

using System.Reactive.Concurrency;

using System.Reactive.Disposables;

using System.Reactive.Linq;

using System.Reactive.Subjects;

using System.Reflection;

using System.Runtime.CompilerServices;

using System.Runtime.Serialization;

using System.Text;

using System.Threading;

using Android.App;

using Android.Content;

using Android.OS;

using Android.Runtime;

using Android.Util;

using Android.Views;

using Android.Widget;

using Splat;

namespace ReactiveUI.AndroidSupport

{

/// <summary>

/// This is a Fragment that is both an Activity and has ReactiveObject powers

/// (i.e. you can call RaiseAndSetIfChanged).

/// </summary>

/// <typeparam name="TViewModel">The view model type.</typeparam>

[SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:FileMayOnlyContainASingleType", Justification = "Classes with the same class names within.")]

public class ReactiveFragment<TViewModel> : ReactiveFragment, IViewFor<TViewModel>, ICanActivate

where TViewModel : class

{

private TViewModel _viewModel;

/// <summary>

/// Initializes a new instance of the <see cref="ReactiveFragment{TViewModel}"/> class.

/// </summary>

protected ReactiveFragment()

{

}

/// <inheritdoc/>

public TViewModel ViewModel

{

get => _viewModel;

set => this.RaiseAndSetIfChanged(ref _viewModel, value);

}

/// <inheritdoc/>

object IViewFor.ViewModel

{

get => _viewModel;

set => _viewModel = (TViewModel)value;

}

}

/// <summary>

/// This is a Fragment that is both an Activity and has ReactiveObject powers

/// (i.e. you can call RaiseAndSetIfChanged).

/// </summary>

[SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:FileMayOnlyContainASingleType", Justification = "Classes with the same class names within.")]

public class ReactiveFragment : Android.Support.V4.App.Fragment, IReactiveNotifyPropertyChanged<ReactiveFragment>, IReactiveObject, IHandleObservableErrors

{

private readonly Subject<Unit> _activated = new Subject<Unit>();

private readonly Subject<Unit> _deactivated = new Subject<Unit>();

/// <summary>

/// Initializes a new instance of the <see cref="ReactiveFragment"/> class.

/// </summary>

protected ReactiveFragment()

{

}

/// <inheritdoc/>

public event PropertyChangingEventHandler PropertyChanging

{

add => PropertyChangingEventManager.AddHandler(this, value);

remove => PropertyChangingEventManager.RemoveHandler(this, value);

}

/// <inheritdoc/>

public event PropertyChangedEventHandler PropertyChanged

{

add => PropertyChangedEventManager.AddHandler(this, value);

remove => PropertyChangedEventManager.RemoveHandler(this, value);

}

/// <inheritdoc/>

public IObservable<Exception> ThrownExceptions => this.GetThrownExceptionsObservable();

/// <summary>

/// Gets a signal when the fragment is activated.

/// </summary>

public IObservable<Unit> Activated => _activated.AsObservable();

/// <summary>

/// Gets a signal when the fragment is deactivated.

/// </summary>

public IObservable<Unit> Deactivated => _deactivated.AsObservable();

/// <inheritdoc />

public IObservable<IReactivePropertyChangedEventArgs<ReactiveFragment>> Changing => this.GetChangingObservable();

/// <inheritdoc />

public IObservable<IReactivePropertyChangedEventArgs<ReactiveFragment>> Changed => this.GetChangedObservable();

/// <inheritdoc/>

void IReactiveObject.RaisePropertyChanging(PropertyChangingEventArgs args)

{

PropertyChangingEventManager.DeliverEvent(this, args);

}

/// <inheritdoc/>

void IReactiveObject.RaisePropertyChanged(PropertyChangedEventArgs args)

{

PropertyChangedEventManager.DeliverEvent(this, args);

}

/// <inheritdoc />

public IDisposable SuppressChangeNotifications()

{

return IReactiveObjectExtensions.SuppressChangeNotifications(this);

}

/// <inheritdoc/>

public override void OnPause()

{

base.OnPause();

_deactivated.OnNext(Unit.Default);

}

/// <inheritdoc/>

public override void OnResume()

{

base.OnResume();

_activated.OnNext(Unit.Default);

}

}

}