// 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. 

<#@ 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" #>
<#
var types = new[]
{
    new { source = typeof(int),     target = typeof(double)  },
    new { source = typeof(long),    target = typeof(double)  },
    new { source = typeof(float),   target = typeof(float)   },
    new { source = typeof(double),  target = typeof(double)  },
    new { source = typeof(decimal), target = typeof(decimal) },
};
var name = "Average";
#>
using System.Threading.Tasks;

namespace System.Reactive.Linq
{
    partial class AsyncObservable
    {
<#
foreach (var t in types)
{
    var sourceType = t.source;
    var targetType = t.target;

    foreach (var n in new[] { false, true })
    {
        var sourceTypeName = n ? sourceType.Name + "?" : sourceType.Name;
        var targetTypeName = n ? targetType.Name + "?" : targetType.Name;
        var methodName = n ? "Nullable" + sourceType.Name : sourceType.Name;

#>
        public static IAsyncObservable<<#=targetTypeName#>> <#=name#>(this IAsyncObservable<<#=sourceTypeName#>> source)
        {
            if (source == null)
                throw new ArgumentNullException(nameof(source));

            return Create<<#=targetTypeName#>>(observer => source.SubscribeSafeAsync(AsyncObserver.<#=name#><#=methodName#>(observer)));
        }

        public static IAsyncObservable<<#=targetTypeName#>> <#=name#><TSource>(this IAsyncObservable<TSource> source, Func<TSource, <#=sourceTypeName#>> selector)
        {
            if (source == null)
                throw new ArgumentNullException(nameof(source));
            if (selector == null)
                throw new ArgumentNullException(nameof(selector));

            return Create<<#=targetTypeName#>>(observer => source.SubscribeSafeAsync(AsyncObserver.<#=name#><#=methodName#>(observer, selector)));
        }

        public static IAsyncObservable<<#=targetTypeName#>> <#=name#><TSource>(this IAsyncObservable<TSource> source, Func<TSource, Task<<#=sourceTypeName#>>> selector)
        {
            if (source == null)
                throw new ArgumentNullException(nameof(source));
            if (selector == null)
                throw new ArgumentNullException(nameof(selector));

            return Create<<#=targetTypeName#>>(observer => source.SubscribeSafeAsync(AsyncObserver.<#=name#><#=methodName#>(observer, selector)));
        }

<#
    }
}
#>
    }

    partial class AsyncObserver
    {
<#
foreach (var t in types)
{
    var sourceType = t.source;
    var targetType = t.target;

    foreach (var n in new[] { false, true })
    {
        var sourceTypeName = n ? sourceType.Name + "?" : sourceType.Name;
        var targetTypeName = n ? targetType.Name + "?" : targetType.Name;
        var methodName = n ? "Nullable" + sourceType.Name : sourceType.Name;

#>
        public static IAsyncObserver<TSource> <#=name#><#=methodName#><TSource>(IAsyncObserver<<#=targetTypeName#>> observer, Func<TSource, <#=sourceTypeName#>> selector)
        {
            if (observer == null)
                throw new ArgumentNullException(nameof(observer));
            if (selector == null)
                throw new ArgumentNullException(nameof(selector));

            return Select(<#=name#><#=methodName#>(observer), selector);
        }

        public static IAsyncObserver<TSource> <#=name#><#=methodName#><TSource>(IAsyncObserver<<#=targetTypeName#>> observer, Func<TSource, Task<<#=sourceTypeName#>>> selector)
        {
            if (observer == null)
                throw new ArgumentNullException(nameof(observer));
            if (selector == null)
                throw new ArgumentNullException(nameof(selector));

            return Select(<#=name#><#=methodName#>(observer), selector);
        }

<#
    }
}
#>
    }
}