// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Diagnostics.CodeAnalysis;
using System.Dynamic.Utils;
using System.Linq.Expressions;
 
namespace System.Dynamic
{
    /// <summary>
    /// Represents the invoke dynamic operation at the call site, providing the binding semantic and the details about the operation.
    /// </summary>
    [RequiresDynamicCode(Expression.CallSiteRequiresDynamicCode)]
    public abstract class InvokeBinder : DynamicMetaObjectBinder
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="InvokeBinder" />.
        /// </summary>
        /// <param name="callInfo">The signature of the arguments at the call site.</param>
        protected InvokeBinder(CallInfo callInfo)
        {
            ArgumentNullException.ThrowIfNull(callInfo);
            CallInfo = callInfo;
        }
 
        /// <summary>
        /// The result type of the operation.
        /// </summary>
        public sealed override Type ReturnType => typeof(object);
 
        /// <summary>
        /// Gets the signature of the arguments at the call site.
        /// </summary>
        public CallInfo CallInfo { get; }
 
        /// <summary>
        /// Performs the binding of the dynamic invoke operation if the target dynamic object cannot bind.
        /// </summary>
        /// <param name="target">The target of the dynamic invoke operation.</param>
        /// <param name="args">The arguments of the dynamic invoke operation.</param>
        /// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
        public DynamicMetaObject FallbackInvoke(DynamicMetaObject target, DynamicMetaObject[] args)
        {
            return FallbackInvoke(target, args, null);
        }
 
        /// <summary>
        /// Performs the binding of the dynamic invoke operation if the target dynamic object cannot bind.
        /// </summary>
        /// <param name="target">The target of the dynamic invoke operation.</param>
        /// <param name="args">The arguments of the dynamic invoke operation.</param>
        /// <param name="errorSuggestion">The binding result to use if binding fails, or null.</param>
        /// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
        public abstract DynamicMetaObject FallbackInvoke(DynamicMetaObject target, DynamicMetaObject[] args, DynamicMetaObject? errorSuggestion);
 
        /// <summary>
        /// Performs the binding of the dynamic invoke operation.
        /// </summary>
        /// <param name="target">The target of the dynamic invoke operation.</param>
        /// <param name="args">An array of arguments of the dynamic invoke operation.</param>
        /// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
        public sealed override DynamicMetaObject Bind(DynamicMetaObject target, DynamicMetaObject[] args)
        {
            ArgumentNullException.ThrowIfNull(target);
            ContractUtils.RequiresNotNullItems(args, nameof(args));
 
            return target.BindInvoke(this, args);
        }
 
        /// <summary>
        /// Always returns <c>true</c> because this is a standard <see cref="DynamicMetaObjectBinder"/>.
        /// </summary>
        internal sealed override bool IsStandardBinder => true;
    }
}