using System;

using System.Collections.Generic;

using System.Linq;

using System.Reactive.Disposables;

using System.Text;

using System.Threading;

using Android.Support.V4.View;

using Android.Views;

using Splat;

using Object = Java.Lang.Object;

namespace ReactiveUI

{

/// <summary>

/// ReactivePagerAdapter is a PagerAdapter that will interface with a

/// ReactiveList, in a similar fashion to ReactiveTableViewSource.

/// </summary>

public class ReactivePagerAdapter<TViewModel> : PagerAdapter, IEnableLogger

where TViewModel : class

{

readonly IReadOnlyReactiveList<TViewModel> list;

readonly Func<TViewModel, ViewGroup, View> viewCreator;

readonly Action<TViewModel, View> viewInitializer;

IDisposable inner;

public ReactivePagerAdapter(IReadOnlyReactiveList<TViewModel> backingList,

Func<TViewModel, ViewGroup, View> viewCreator,

Action<TViewModel, View> viewInitializer = null)

{

this.list = backingList;

this.viewCreator = viewCreator;

this.viewInitializer = viewInitializer;

inner = this.list.Changed.Subscribe(_ => NotifyDataSetChanged());

}

public override bool IsViewFromObject(View view, Object @object)

{

return ((View)@object) == view;

}

public override Object InstantiateItem(ViewGroup container, int position)

{

var data = list[position];

// NB: PagerAdapter does not recycle itself.

var theView = viewCreator(data, container);

var ivf = theView.GetViewHost() as IViewFor<TViewModel>;

if (ivf != null) {

ivf.ViewModel = data;

}

if (viewInitializer != null) {

viewInitializer(data, theView);

}

container.AddView(theView, 0);

return theView;

}

public override void DestroyItem(ViewGroup container, int position, Object @object)

{

var view = (View)@object;

container.RemoveView(view);

}

public override int Count {

get { return list.Count; }

}

protected override void Dispose(bool disposing)

{

base.Dispose(disposing);

Interlocked.Exchange(ref inner, Disposable.Empty).Dispose();

}

}

}