// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT license.

using System;

using System.Collections;

using System.Collections.Generic;

using System.Reflection;

using Microsoft.ClearScript.Util;

namespace Microsoft.ClearScript

{

internal partial class HostItem

{

#region initialization

private static HostItem Create(ScriptEngine engine, HostTarget target, HostItemFlags flags)

{

return TargetSupportsExpandoMembers(target, flags) ? new ExpandoHostItem(engine, target, flags) : new HostItem(engine, target, flags);

}

#endregion

#region internal members

#region member invocation

private object CreateAsyncEnumerator<T>(IEnumerable<T> enumerable)

{

return HostObject.Wrap(enumerable.GetEnumerator().ToScriptableAsyncEnumerator(Engine), typeof(IScriptableAsyncEnumerator<T>));

}

private object CreateAsyncEnumerator()

{

if ((Target is HostObject) || (Target is IHostVariable) || (Target is IByRefArg))

{

if ((Target.InvokeTarget != null) && Target.Type.IsAssignableToGenericType(typeof(IEnumerable<>), out var typeArgs))

{

var helpersHostItem = Wrap(Engine, typeof(ScriptableEnumerableHelpers<>).MakeGenericType(typeArgs).InvokeMember("HostType", BindingFlags.Public | BindingFlags.Static | BindingFlags.GetField, null, null, null), HostItemFlags.PrivateAccess);

if (MiscHelpers.Try(out var enumerator, () => ((IDynamic)helpersHostItem).InvokeMethod("GetScriptableAsyncEnumerator", this, Engine)))

{

return enumerator;

}

}

else if (BindSpecialTarget(out IEnumerable _))

{

var helpersHostItem = Wrap(Engine, ScriptableEnumerableHelpers.HostType, HostItemFlags.PrivateAccess);

if (MiscHelpers.Try(out var enumerator, () => ((IDynamic)helpersHostItem).InvokeMethod("GetScriptableAsyncEnumerator", this, Engine)))

{

return enumerator;

}

}

}

throw new NotSupportedException("The object is not async-enumerable");

}

#endregion

#endregion

}

}