#@ template debug="false" hostspecific="false" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ output extension=".cs" #>
// 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 more information. 
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace System.Linq
{
    public static partial class AsyncEnumerable
    {
<#
var os = new[]
{
    new { type = "int", zero = "0", @checked = true },
    new { type = "long", zero = "0L", @checked = true },
    new { type = "float", zero = "0.0f", @checked = false },
    new { type = "double", zero = "0.0", @checked = false },
    new { type = "decimal", zero = "0m", @checked = false },
    new { type = "int?", zero = "0", @checked = true },
    new { type = "long?", zero = "0L", @checked = true },
    new { type = "float?", zero = "0.0f", @checked = false },
    new { type = "double?", zero = "0.0", @checked = false },
    new { type = "decimal?", zero = "0m", @checked = false },
};
foreach (var o in os)
{
    var n = o.type.EndsWith("?") ? ".GetValueOrDefault()" : "";
    var typeStr = o.type;
    if (o.type.EndsWith("?")) {
        typeStr = "Nullable{" + o.type.Substring(0, 1).ToUpper() + o.type.Substring(1, o.type.Length - 2) + "}";
    }
#>
        /// 
        /// Computes the sum of a sequence of  values.
        /// 
        /// A sequence of  values to calculate the sum of.
        /// The optional cancellation token to be used for cancelling the sequence at any time.
        /// An async-enumerable sequence containing a single element with the sum of the values in the source sequence.
        ///  is null.
        /// The return type of this operator differs from the corresponding operator on IEnumerable in order to retain asynchronous behavior.
        public static ValueTask<<#=o.type#>> SumAsync(this IAsyncEnumerable<<#=o.type#>> source, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            return Core(source, cancellationToken);
            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable<<#=o.type#>> source, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;
                await foreach (<#=o.type#> value in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }
                return sum;
            }
        }
        /// 
        /// Computes the sum of a sequence of  values that are obtained by invoking a transform function on each element of the input sequence.
        /// 
        /// The type of the elements in the source sequence.
        /// A sequence of values that are used to calculate a sum.
        /// A transform function to apply to each element.
        /// The optional cancellation token to be used for cancelling the sequence at any time.
        /// An async-enumerable sequence containing a single element with the sum of the values in the source sequence.
        ///  or  is null.
        /// The return type of this operator differs from the corresponding operator on IEnumerable in order to retain asynchronous behavior.
        public static ValueTask<<#=o.type#>> SumAsync(this IAsyncEnumerable source, Func> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));
            return Core(source, selector, cancellationToken);
            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable source, Func> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;
                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = selector(item);
<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }
                return sum;
            }
        }
        internal static ValueTask<<#=o.type#>> SumAwaitAsyncCore(this IAsyncEnumerable source, Func>> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));
            return Core(source, selector, cancellationToken);
            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable source, Func>> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;
                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = await selector(item).ConfigureAwait(false);
<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }
                return sum;
            }
        }
#if !NO_DEEP_CANCELLATION
        internal static ValueTask<<#=o.type#>> SumAwaitWithCancellationAsyncCore(this IAsyncEnumerable source, Func>> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));
            return Core(source, selector, cancellationToken);
            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable source, Func>> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;
                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = await selector(item, cancellationToken).ConfigureAwait(false);
<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }
                return sum;
            }
        }
#endif
<#
}
#>
    }
}