// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using ICSharpCode.Decompiler.Semantics;
using ICSharpCode.Decompiler.TypeSystem;

namespace ICSharpCode.Decompiler.CSharp.Resolver
{
	/// <summary>
	/// Represents the result of an await expression.
	/// </summary>
	public class AwaitResolveResult : ResolveResult
	{
		/// <summary>
		/// The method representing the GetAwaiter() call. Can be an <see cref="InvocationResolveResult"/> or a <see cref="DynamicInvocationResolveResult"/>.
		/// </summary>
		public readonly ResolveResult GetAwaiterInvocation;

		/// <summary>
		/// Awaiter type. Will not be null (but can be UnknownType).
		/// </summary>
		public readonly IType AwaiterType;

		/// <summary>
		/// Property representing the IsCompleted property on the awaiter type. Can be null if the awaiter type or the property was not found, or when awaiting a dynamic expression.
		/// </summary>
		public readonly IProperty IsCompletedProperty;

		/// <summary>
		/// Method representing the OnCompleted method on the awaiter type. Can be null if the awaiter type or the method was not found, or when awaiting a dynamic expression.
		/// This can also refer to an UnsafeOnCompleted method, if the awaiter type implements <c>System.Runtime.CompilerServices.ICriticalNotifyCompletion</c>.
		/// </summary>
		public readonly IMethod OnCompletedMethod;

		/// <summary>
		/// Method representing the GetResult method on the awaiter type. Can be null if the awaiter type or the method was not found, or when awaiting a dynamic expression.
		/// </summary>
		public readonly IMethod GetResultMethod;

		public AwaitResolveResult(IType resultType, ResolveResult getAwaiterInvocation, IType awaiterType, IProperty isCompletedProperty, IMethod onCompletedMethod, IMethod getResultMethod)
			: base(resultType)
		{
			if (awaiterType == null)
				throw new ArgumentNullException(nameof(awaiterType));
			if (getAwaiterInvocation == null)
				throw new ArgumentNullException(nameof(getAwaiterInvocation));
			this.GetAwaiterInvocation = getAwaiterInvocation;
			this.AwaiterType = awaiterType;
			this.IsCompletedProperty = isCompletedProperty;
			this.OnCompletedMethod = onCompletedMethod;
			this.GetResultMethod = getResultMethod;
		}

		public override bool IsError {
			get { return this.GetAwaiterInvocation.IsError || (AwaiterType.Kind != TypeKind.Dynamic && (this.IsCompletedProperty == null || this.OnCompletedMethod == null || this.GetResultMethod == null)); }
		}

		public override IEnumerable<ResolveResult> GetChildResults()
		{
			return new[] { GetAwaiterInvocation };
		}
	}
}
